The founders of epidural anesthesia are considered to be J. Sicard and F. Cathelin, who independently published the results of administering a cocaine solution through hiatus sacralis (caudal anesthesia) in 1901. That same year, Tuffier attempted a lumbar epidural but failed. In 1906, G. Forestier successfully solved this problem by using the “loss of resistance” technique he proposed (see below). However, only thanks to the numerous works of the Italian surgeon Dogliotti in the 30s of the twentieth century, epidural anesthesia gained well-deserved popularity. The next significant events in the development of the method were the proposal by E.B.Yuohy in 1944 of a special needle for catheterization and J.A.Lee (1960) - a marked needle that allows you to clearly determine the depth of its insertion.

In the USSR, the first epidural anesthesia was performed by B.N. Kholtsov (1933). Subsequently, in our country, this method of pain relief developed poorly due to the lack of special instruments and the shortage of amide anesthetics. The authors can testify that even in the 70-80s, our surgeons who were interested in this method were forced to use homemade Tuohy needles and use insulation from telephone wires as catheters. Of no small importance was the directive to perform all operations only under local infiltration anesthesia according to the method of A.V. Vishnevsky, which prevailed in our country until the mid-70s of the twentieth century and the authority of S.S. Yudin, who was a passionate promoter of spinal anesthesia.

Essence of the method consists of introducing a local anesthetic into the epidural (peridural) fiber space located between the posterior wall of the spinal canal and the dura mater. The epidural space contains the dorsal roots of the spinal cord, which extend beyond the dura mater. By contacting them, the anesthetic turns off pain sensitivity while maintaining motor functions provided by the anterior roots. With spinal anesthesia, unlike epidural, both the anterior and posterior roots of the spinal cord are blocked, resulting in anesthesia and myoplegia.

The depth of the epidural space in adults in the lumbar region is 3-5 mm. Since the distribution of anesthetic in the cellular space is worse than in the subarachnoid space during spinal anesthesia, large quantities of anesthetic have to be administered (20-30 ml per injection), sometimes into several intervertebral spaces.

Indications and contraindications for epidural anesthesia

Indications:

Operations on the chest organs, abdominal cavity, urological, gynecological interventions, operations on the lower extremities

Operations in patients with high anesthetic risk (obesity, diseases of the cardiovascular, respiratory systems, liver and kidney diseases, elderly and senile age, “full stomach”).

A component of combined anesthesia that provides blockade of pain impulses

Postoperative pain relief

Pain relief for severe combined injuries with fractures of the ribs, pelvis, and bones of the lower extremities

Treatment of intestinal paresis with peritonitis, acute pancreatitis

Combating chronic pain syndrome in cancer patients

Treatment component for status asthmaticus

Absolute contraindications for epidural anesthesia:

Purulent-inflammatory diseases in the area of ​​the proposed puncture

Uncorrected hypovolemia and shock

• Blood clotting disorders (risk of epidural hematoma)

  Increased intracranial pressure

  Intolerance to local anesthetics

  Reluctance of the patient to undergo this type of anesthesia

Relative contraindications for epidural anesthesia:

Spinal deformity making puncture difficult

Nervous system diseases

Hypovolemia

Arterial hypotension

Epidural administration of narcotic analgesics increases the risk of anastomotic leakage in patients at high risk of this complication (oncology)

Epidural and spinal anesthesia

Compiled by Virus

Chapter I. CONCEPT OF NEUROPHISIOLOGICAL MECHANISMS OF PAIN

There are two points of view regarding the general physiological mechanisms of pain.
The theory of specific pain receptors (M. Frey, 1894) - there are specific pain receptors, represented by free, non-encapsulated nerve endings, which have many terminal branches with small axonoplasmic processes. Distinctive feature These endings are characterized by their high chemosensitivity. Any tissue damage is accompanied by the release of allogeneic chemicals, which are divided into three types - tissue (serotonin, histamine, acetylcholine, etc.), plasma (bradykinin, kallidin) and released from nerve endings (substance P). In addition, the activation of free nerve endings is caused by tissue destruction products formed during inflammation, injury, and hypoxia.
The intensity theory of A. Goldscheider (1894) - pain occurs due to excessive activation of all types of receptors (the main factor is the intensity of the effect).
The main conductors of cutaneous and visceral pain sensitivity are myelinated A-5 and non-myelinated C-fibers. (Table 1)
Table 1 Types and functions of nerve fibers
A- ?
Diameter (µm) 12-20
Pulse speed (m/s) 70-120
Fiber function Innervation of skeletal muscles. Proprioception
A- ?
Diameter (µm) 5-15
Pulse speed (m/s) 30-70
Fiber Function Touch Pressure
A - ?
Diameter (µm) 3-6
Pulse speed (m/s) 15-30
Fiber function Maintaining skeletal muscle tone
A- ?
Diameter (µm) 2-5
Pulse speed (m/s) 12-30
Fiber function Conducting rapid pain Touch Temperature sensitivity
B
Diameter (µm) 3
Pulse speed (m/s) 3-15
Fiber function Preganglionic fibers of the autonomic nervous system
WITH
Diameter (µm) 0.4-1.2
Pulse speed (m/s) 0.5-2.0
Fiber function Conduction of slow pain Touch Temperature sensitivity Postganglion sympathetic fibers

Short-term activation of C-fibers causes a sensation of moderate and poorly localized pain. With prolonged nociceptive exposure, the phenomenon of fatigue with a simultaneous decrease in pain is observed in C afferents, but after a short time sensitization occurs, manifested sharp decline threshold of irritation of C-fibers and an increase in the intensity of pain.
With impulse activity in A-? - fibers are associated with the sensation of acute stabbing pain that a person experiences immediately after severe thermal damage to the skin (local burn, touching a hot object).
It should be emphasized that A-? and C-fibers are not exclusively conductors of pain signals. These fibers are activated by damaging thermal (cold and heat) and mechanical (touch, slight compression) influences.
After entering the spinal cord, A-c and C-fibers as part of the Lissauer fact go in the caudal and rostral directions and end in the dorsal part of the dorsal horn, where there are three groups of neurons. The first group (I layer of gray matter spinal cord) is activated exclusively by nociceptive stimuli or irritations A-? and C-fibers. The second group (IV, V and, partially, VI layers) respond to nociceptive and non-nociceptive influences. The third group, represented by neurons of the gelatinous substance, forms a system for controlling afferent input into the spinal cord and forming an ascending nociceptive flow of impulses. The axons of gelatinous neurons terminate in layers I, II, IV and V of the gray matter of the spinal cord.
The substantia gelatinosa functions not only as a relay instance, but also modulates the effectiveness of the synaptic effects of afferent inputs on neurons in the dorsal horn of the spinal cord. It plays a key role in the “entry gate” theory of R. Melzack and P. Wall (1965), which explains the formation of the nociceptive flow at the segmental level based on the central interaction of the fast-conducting myelin (non-nociceptive) and slow-conducting non-myelin systems on the first relay neurons of the spinal cord .
A large number of opiate receptors were found in the gelatinous substance, which are located on both the outer and inner surfaces of the cell membrane. The types of opiate receptors and their characteristics are presented in Table 2.
Table 2 Characteristics of opiate receptors
? (mu) Supraspinal analgesia, respiratory depression, miosis. hypothermia, orodycardia. euphoria, catalepsy, decreased activity of aortic arch baroreceptors, intestinal paresis, constipation
? (delta) Tachycardia, tachypnea, dysphoria, hallucinations, mydriasis, nausea, no analgesia
To (kappa) Spinal analgesia, dystrophy, sedation, miosis. decreased appetite. The receptors are activated during hemorrhagic shock.
? (sigma) Spinal analgesia. stress-induced analgesia, respiratory depression, hyperthermia, hypotension. Receptors are activated during septic and hemorrhagic shock
In the areas of the dorsal horns of the spinal cord (mainly in the gelatinous substance), through which nociceptive signals are transmitted, the presence of a significant number of adrenergic receptors was revealed, and what? 2-adrenergic receptors predominate in superficial areas. Experimentally, using intrathecal microinjections of adrenolytics having different affinities for? 1- and? 2-adrenergic receptors, it has been established that pain reactions at the segmental level are controlled by the adrenergic system through? 2-adrenergic receptors.
Assessing the effect of adrenopositive compounds (primarily the “reference” drug - clonidine) on segmental neurons and nociceptive reflexes, it was established that the analgesic effect of clonidine is not blocked by naloxone and is eliminated by adrenoblockers? 2-receptors. Clonidine did not cause significant changes in motor functions and non-nociceptive reflexes. All this made it possible to test the administration of clonidine in an oncology clinic, where a good analgesic effect was obtained, and against the background of tolerance to morphine (D. Coombs et al., 1986).
The discovery of the analgesic effect of adrenopositive compounds marked new stage in the development of non-opiate drug anesthesia. At the moment, there is every reason to believe that the adrenergic system is an independent pain regulation system, independent of opioidergic and other neurotransmitter mechanisms (Yu.D. Ignatov et al., 1994).
The study of the effects of combined use of adrenopositive compounds with narcotic analgesics indicates a fairly pronounced synergism of adreno- and opiate receptor agonists. The interaction of the adrenergic and opioidergic analgesic mechanisms does not have a metabolic basis, but occurs either on a common receptor substrate or through different receptors, but with the subsequent launch of a common analgesic mechanism. (A.A. Zaitsev, Yu.D. Ignatov, 1990, Yu.D. Ignatov et al., 1994).
It should be noted that there are no specialized pathways for pain sensitivity in the central nervous system. Integration of pain occurs at various levels of the central nervous system based on complex interactions of lemniscal and extralemniscal projections.
The path of so-called primary pain (fast, well localized) is presented as follows. Pain activates fast-conducting myelinated fibers. Nociceptive information is transmitted along the neospinothalamic tract and, partially, through the system of dorsolateral and dorsal lemniscal projections, through the ventrolateral part of the thalamus reaches the somatosensory cortex. The rapid transmission of information through this system ensures precise localization of pain, assessment of its duration and intensity.
Secondary pain is caused by the conduction of nociceptive information along slow unmyelinated C-fibers, which is then transmitted along the spinoreticulothalamic, spinomesencephalothalamic tract, and the proprioceptive system. As nociceptive signals pass, the reticular formation, hypothalamus, limbic and striopalidal systems are activated. Through the medial, intralaminar and posterior nuclei of the thalamus, the nociceptive flow reaches various areas of the cerebral cortex. This entire system of ascending projections and brain structures causes pain that is difficult to differentiate in quality and localization and its visceromotor and emotional-affective manifestations.

Chapter II. CLINICAL PHARMACOLOGY OF DRUGS USED FOR REGIONAL ANESTHESIA AND ANALGESIA

Brief characteristics of local anesthetics

Most local anesthetics consist of an aromatic ring linked by a carbon bridge to an amino group. Depending on the type of carbon group, local anesthetics are divided into ether (novocaine, chloroprocaine, etc.) and amide (lidocaine, mepivacaine, marcaine, etc.) types. Ether anesthetics are relatively unstable in solution and are quickly hydrolyzed in the body by blood pseudocholinesterase. One of their breakdown products is para-aminobenzoate, which is associated with allergic reactions. Amide anesthetics are relatively stable in solution; their biotransformation occurs in the liver by diethylation followed by cleavage of the amide group. When re-introducing amides, the maximum permissible dose should be strictly observed.
In body tissues, local anesthetics acquire either an ionized or non-ionized form, and the ratio of forms will depend on the pH of the solution and the pK of the particular drug. The non-ionized base then diffuses through the perineural tissues, nerve sheath and neuronal membrane, reaching the axoplasm, where it is partially ionized again. In ionized form, local anesthetics pass (from within the nerve fiber) through sodium channels formed by protein macromolecules embedded in the liquid phase of the membrane and either block them or bind to receptors located at the inner mouth of the sodium channel.
Considering that in order to connect with the receptor, the local anesthetic needs to penetrate the lipid phase of the membrane, the most effective will be the anesthetic that is better soluble in the membrane lipids. With the same solubility in lipids, the strength and duration of action of the anesthetic will depend on the affinity of the anesthetic for the receptor (B.I. Khodorov, 1976). Anesthetics reduce the rate and degree of depolarization of the synaptic membrane to such a level that the threshold potential of nerve transmission is not reached and excitation does not spread along the nerve fiber.
Local anesthetics are bases that are almost insoluble in water. Their solubility is increased by combining with hydrochloric acid and forming hydrochlorides. Solutions of local anesthetics are acidic (pH 4.0-5.5) and contain stabilizers (sodium metabisulfite, sodium pyrosulfite, etc.) and a fungicide.
Because anesthetics cause vasodilation and are rapidly absorbed, vasoconstrictors are often added to increase the potency and duration of action. The latter reduce systemic toxicity and increase safety by reducing the rate of absorption, which depends on local blood flow in the tissues.
One of the most commonly used vasoconstrictors is epinephrine, used at a concentration of 1:200,000 (5 μg/ml). To achieve the required concentration, 0.1 ml (0.1 mg) of adrenaline is added to 20 ml of local anesthetic solution or one drop from a needle for subcutaneous administration per 5 ml of local anesthetic solution.
Accurate adherence to the dosage of adrenaline must be mandatory, since with an increase in its concentration, hypertensive reactions (up to hypertensive crises), disorders heart rate, as well as neurological consequences associated with local ischemia of nerve tissue (A.Yu. Pashchuk, 1987, M.I. Kuzin, S.Sh. Kharnas, 1993).
Adrenaline increases the duration of action of epidural anesthesia when added to mepivacaine, lidocaine, trimecaine, but practically does not change the duration of action of prilocaine, bupivacaine and etidocaine.
The prolongation of the analytical effect of local anesthetics during epidural anesthesia with the sympathomimetic adrenaline occurs not only due to a decrease in resorption from the epidural space through local vasospasm, but is realized through activation? 2-adrenergic receptors of the spinal cord.
The use of mesatone or ephedrine as a vasoconstrictor is much less effective, and norepinephrine causes too intense and generalized vasoconstriction (J. Adriani, 1978).
Another vasoconstrictor, felypressin (octapressin), is added to local anesthetics (in particular, prilocaine) at a concentration of 0.003 U/ml. It is chemically similar to the posterior pituitary hormone, but is not a catecholamine. Solutions of local anesthetics with felypressin are produced officially.
The duration of the analgesic effect of trimecaine during epidural anesthesia can be increased by using trimecaine-albumin complex, which consists of an equal amount of 5% trimecaine solution and 10% donor albumin solution. The duration of action of 8-10 ml of this mixture ranges from 4 to 13.5 hours (V.A. Koryachkin, 1994).
The use of sealed autoblood solutions of local anesthetics, previously widely used in practice, is now considered inappropriate due to the possibility of developing adhesive processes in the epidural space (P.G. Tarkkila et al., 1988).
The current state of the pharmacology of local anesthetics opens up wide opportunities for a differentiated approach to achieving anesthesia and analgesia. At minimal concentrations of local anesthetics, a blockade of sympathetic fibers develops; an increase in the concentration of the drug leads to the development of a sensory block, and then to a blockade of motor and proprioceptive innervation (Table 3).
Table 3 Pharmacological basis and drugs of choice for differentiated conduction block (V. A. Svetlov, S. P. Kozlov, 1996)
Lidocaine
sympathetic +++
sensory +++
motor +++
Trimekain
sympathetic +++
sensory +++
motor +
Bupivacaine
sympathetic +++
sensory +++
motor +
Etidocaine
sympathetic ++
touch ++
motor +++
Ultracaine
sympathetic +++
sensory +++
motor +++
To obtain a sympathetic blockade for therapeutic and diagnostic purposes, a lidocaine solution is used in a concentration of less than 0.75%; to achieve analgesia for acute and chronic pain, a 1.0-0.75% lidocaine solution is used; for anesthesia during surgery, lidocaine solutions are used in concentrations 2-4%.

Local anesthetics of ether type.

Nezacaine (chloroprocaine).
A. Very fast onset of action, short analgesic effect, low toxicity.
b. Rapid hydrolysis by cholinesterase determines the short duration of action of the drug and its low toxicity.
V. It is used for infiltration anesthesia, blockade of nerve trunks and epidural anesthesia.
d. Subarachnoid administration of the drug is not indicated, because Nezacaine has a low pH solution, and sodium metabisulfite is used as a stabilizer.
e. Nezacaine is the drug of choice when regional anesthesia is indicated in a patient with a tendency to malignant hyperthermia.
Tetracaine (dicaine, pontocaine).
A. Long lasting effect, high potency and toxicity.
b. Used primarily for spinal anesthesia.
V. The motor block exceeds the sensory block in duration and depth.

Amide-type local anesthetics.

Lidocaine (lignocaine, xylocaine).
A. Rapid onset and relatively short-lasting analgesic effect, moderate potency and toxicity.
b. Used for all types of local anesthesia.
Mepivacaine (carbocaine, scandicaine).
A. Moderate potency and toxicity, the analgesic effect is longer than that of lidocaine.
b. It is used for infiltration anesthesia, blockade of nerve trunks, and epidural anesthesia.
Bupivacaine (marcaine, carbostezin, anecaine).
A. Slow onset and long-lasting analgesic effect, high potency and toxicity.
b. Used for all types of local and regional anesthesia.
V. Sensory blockade is more intense and lasting than motor blockade.
d. Accidental intravenous administration of the drug may cause treatment-resistant cardiac arrest. Pregnant women are especially sensitive to the drug.
Etidocaine (Duranest).
A. Rapid onset and long-lasting analgesic effect, high potency and toxicity.
b. Nerve blockade and epidural anesthesia are used.
V. Motor blockade is more intense than sensory blockade.
Due to too fast metabolism With chloroprocapne, it is not possible to determine the degree of its binding to proteins.
Ropivacaine (naropin).
A. Slow onset and long lasting analgesic effect. The potency is high. Cardiotoxicity is less pronounced than that of bupivacaine.
b. Used for epidural and spinal anesthesia, for conduction blockades.
V. Sensory blockade is less intense and lasting than motor blockade.

Narcotic analgesics

The first report of epidural administration of morphine for pain relief belongs to M. Behar et al. (1979).
Narcotic analgesics administered epidurally are quickly absorbed by the venous plexuses, the remaining part (2.0-3.6% of the administered dose) penetrates rather slowly into the cerebrospinal fluid through the dura mater. The peak concentration of morphine in the cerebrospinal fluid is reached after 20-120 minutes, and its concentration in the cerebrospinal fluid is 25 times higher than the concentration in plasma. 4 hours after administration, 80% of the administered dose is present in the cerebrospinal fluid, after 12 hours - about 50%.
Narcotic analgesics penetrate through diffusion into the gelatinous substance of the dorsal horns of the spinal cord, where they bind to opiate receptors and cause a blockade of pain sensitivity. The time of onset and duration of analgesia depend on the affinity of the narcotic analgesic for the opiate receptors of the spinal cord and the dose of the drug used.
For epidural pain relief, any narcotic analgesics can be used except piritramide (dipidolor), if it accidentally enters the cerebrospinal fluid due to the low pH of the drug (piritramide pH is 3.96), protein precipitation occurs. Other opiates have a pH greater than 4-6.
The delivery of a narcotic analgesic to the affected segment of the spinal cord is important for achieving effective postoperative analgesia. The effectiveness of this type of pain relief is 85-97%. However, in patients operated on the chest and upper abdominal organs, it is possible to administer an analgesic at the lumbar level without taking into account segmentation. In this case, the dose of the analgesic should be increased (maximum dose of morphine 8 - 10 mg).
The pharmacological basis of this method is the possibility of prolonged circulation of opiates (in the form of morphine glucoronide) in the subarachnoid space and their binding to opiate receptors at the level of the thoracic spinal cord. The main advantage of this method is that puncture and catheterization of the epidural space at the lumbar level is technically simpler than at the thoracic level.
The first report of spinal administration of narcotic analgesics was made by J. Wang in 1977.*
Intrathecal use of opiates has a number of advantages: simplicity, reliability, low doses, and the possibility of administration through a catheter. Dose-dependent side effects of narcotic analgesics when administered intrathecally are reduced to a minimum, because analgesia is achieved using doses 10-16 times lower than with epidural anesthesia (with epidural administration, the amount of the drug reaching the spinal cord receptors through the dura mater is affected by systemic absorption and sequestration of opiates in the adipose tissue of the epidural space).
It should be noted that the combination of local anesthetics and narcotic analgesics (lidocaine + morphine, lidocaine + fentanyl) for epidural and spinal anesthesia significantly improves the quality of anesthesia during surgery and the effectiveness of analgesia in postoperative period.

Adrenergic agents

Works by Yu.D. Ignatov and A.A. Zaitsev (1984-1996) convincingly showed that the adrenergic system is an independent pain regulation system. The analgesic effect of central adrenopositive drugs has been fully confirmed in the clinic in the treatment of pain syndrome of various etiologies (V.I. Strashnoye and his colleagues, 1987-1999, V.A. Mikhailovich and his employees, 1991-1996).
Among various chemical compounds, which have a central adrenopositive effect, clonidine (clonidine, catapressan, hemitone) is most widely used. Epidural administration of clonidine causes sufficiently high-quality and long-lasting analgesia, normalizes blood circulation and respiration in pain. The advantages and benefits of clonidine anesthesia are clearly emphasized by its comparison with the analgesic effect of epidurally administered morphine (Table 5).
Table 5 Comparative characteristics of epidural analgesia with morphine and clonidine
Morphine
Optimal analgesic dose 5 mg
Latent period of analgesia 30 - 60 minutes
Maximum intensity 60 - 90 minutes
Maximum analgesia, reduction in pain by 70%
Duration of analgesia 13.5 hours
There are no hemodynamic changes
Bradypnea without gas exchange disturbance
There are no changes in “stress” hormones in the blood
Side effects: retention, urination, nausea, vomiting, itching
Tolerance develops quickly
Clonidine
Optimal analgesic dose 100 mg
Latent period of analgesia 15 minutes
Maximum intensity 30 minutes
Maximum analgesia, reduction in pain by 90%
Duration of analgesia 5 hours
Individual variability is pronounced
Normalization of hyperdynamic shifts
No changes in breathing
There is no decrease in “stress” hormones in the blood
Side effects dry mouth
Tolerance is absent or develops slowly
Two important circumstances should be emphasized. First, fears of the development of hypotension during clonidine analgesia are unfounded, because clonidine has not so much a hypotensive, but an antihypertensive effect. Fears of decline blood pressure may occur when clonidine analgesia is used only in patients with a predisposition to this (hypovolemia, cachexia). And second, clonidine has no narcotic potential.

The use of clonidine for spinal anesthesia can significantly improve the quality of pain relief. Thus, spinal anesthesia using a combination of 75 mcg of clonidine, 100 mg of lidocaine and 50 mcg of fentanyl allows surgical interventions lasting up to 2.5-3.0 hours with postoperative pain relief maintained for 5.0-6.5 hours.

Chapter III. SPINAL ANESTHESIA

Indications for spinal anesthesia include surgical interventions on organs located below the diaphragm, especially in situations where, for one reason or another, other methods of anesthesia are undesirable.
Relative contraindications may be heart failure, hypovolmia, septic conditions, cachexia, increased excitability of the nervous system, a history of frequent headaches, and coronary heart disease.
Absolute contraindications to spinal anesthesia are: inflammatory processes V lumbar region, pustular diseases back skin, uncorrected hypovolemia, severe anemia, mental illness, curvature of the spine (severe scoliosis, kyphosis, etc.), allergies to local anesthetics, increased intracranial pressure, patient reluctance to undergo this method of pain relief.
Patients who are offered spinal anesthesia must have sufficient compensatory capabilities of the cardiovascular system, because hemodynamic effects are integral components of the course of this type of anesthesia and the depth of their manifestations is directly dependent on the adaptive capabilities of the body. Severe atherosclerosis, diabetes mellitus, hypertension, chronic ischemic heart disease, heart failure, and advanced age are considered unfavorable factors when performing spinal anesthesia.
Premedication before spinal anesthesia should provide an optimal emotional background without grossly affecting the body's adaptive capabilities. Psychogenic preparation of patients, prescription of narcotic and sedatives on the eve of surgery and intramuscular injection 30-40 minutes before surgery standard doses of narcotic and antihistamines. The issue of including atropine in premedication is decided individually.
30 minutes before the spinal puncture, 2 ml of a 20% caffeine solution is injected subcutaneously. The preventive administration of dihydroergotamine in two doses of 0.25 mg (0.5 ml of 0.05% solution) is quite effective, which increases tone venous vessels and increases venous return.
The usual measure to prevent arterial hypotension is the infusion of 800-1200 ml of colloid and crystalloid solutions in a 1:1 ratio, carried out immediately before spinal anesthesia.

Spinal anesthesia technique

Puncture of the spinal space is performed with the patient sitting or lying on his side with a well-bent spine, hips pressed to the stomach and head bent to the chest. The assistant needs to hold the patient in this position. The skin of the back is treated with an antiseptic or alcohol twice. Iodine solutions are not recommended for use, since even traces of it brought into the subarachnoid space can cause aseptic arachnoiditis (spinal and epidural anesthesia require careful asepsis and antisepsis. An indispensable condition is to work with gloves, and for long-term (with a catheter) anesthesia - the use of bacterial filters).
Anesthesia of the puncture area is carried out either using EMLA cream two hours before the procedure, or, immediately before the procedure, local anesthesia.
A thick needle (15G) is used to pierce the skin. The needle for spinal anesthesia (Fig. 1) is passed strictly along the midline between the spinous processes at a slight angle (no more than 15-20 degrees) in accordance with the inclination of the spinous processes. The depth to which the needle must be inserted ranges from 4.5 to 6.0 cm, with an average of 5.5 cm; the sizes of needles for spinal anesthesia are presented in Table 6.
Table 6 Outer diameters and color code of needles for epidural and spinal anesthesia
Olive Brown 10G; 3.4mm.
Yellow-green 11G;3.0 mm.
Pale blue 12G;2.7 mm.
Purple 13G;2.4 mm.
Light green 14G;2.1 mm.
Gray-blue 15G; 1.8 mm.
White 16G; 1.6 mm.
Red-violet 17G; 1.4 mm.
Pink 18G; 1.2 mm.
Cream 19G; 1.1 mm.
Yellow 20G;0.9 mm.
Dark Green 21G; 0.8 mm.
Black 22G; 0.7 mm.
Dark blue 23G; 0.6 mm.
Lilac 24G; 0.55 mm.
Orange 25G; 0.5 mm.
Brown 26G; 0.45 mm.
Gray 27G; 0.4 mm.
Turquoise 28G; 0.36 mm.
Red 29G; 0.33 mm.
Yellow 30G; 0.3 mm.

When the needle is slowly passed through the ligamentous apparatus, resistance from dense tissue is felt, which suddenly disappears after puncturing the ligamentum flavum. After this, the mandrel is removed and the needle is advanced 2-3 mm, piercing the dura mater.
By the time the dura mater is punctured, the plane of the needle cut should be directed longitudinally to the fibers of the dura mater. The needle should push the fibers apart, not cut them. Leakage of cerebrospinal fluid from the needle pavilion - absolute sign its exact localization in the subarachnoid space.
Puncture of the subarachnoid space with thin (25-26G) needles presents certain technical difficulties associated with high probability bending of the needle, up to its fracture, when passing through dense ossified ligaments or when entering the bone formations of the spine.
To facilitate subarachnoid puncture, introducers (conductors) were proposed, which are short thick needles measuring 18-20G) with Crawford sharpening, first described by J.L. Corning (1894). Later, L.S.Sise (1928) and J.S.Lundy (1942) proposed their own versions of introducers. Currently, introducers are included in sets for spinal, spinal-epidural, and long-term spinal anesthesia manufactured by Sims Portex and Braun. In the absence of a standard introducer, the use of infusion needles measuring 18 - 20G and 40 mm long is allowed.
The introducer is inserted strictly along the midline in the interspinous space to a depth of 3 - 4 cm, passing the skin, subcutaneous tissue, supraspinous ligament and stops in the thickness of the interspinous ligament. Then, through the lumen of the introducer, the subarachnoid space is punctured with a needle for spinal anesthesia. If the needle rests on a bone formation, it is necessary to remove it, change the direction of the introducer and repeat the puncture.
In another option, using a longer introducer, a syringe with an isotonic sodium chloride solution and an air bubble is attached to the latter, and the epidural space is punctured, entry into which is determined by the “loss of resistance” and “air bubble” methods. After this, the syringe is disconnected and a puncture of the subarachnoid space is performed through the lumen of the introducer.
For spinal anesthesia, a paramedian approach can be used. At the level of the interspinous space, retreating 1.5-2.0 cm from the line of the spinous processes, a needle is inserted at an angle of 25 degrees to the sagittal plane. If necessary, the movement of the needle end can be changed both in the cranial and caudal directions. A variant of the paramedian approach is the lumbosacral one, described by T.A. Taylor in 1940. The puncture is performed at the L5-S1 level. The needle is inserted 1 cm medially and 1 cm caudally from the point of projection onto the skin of the posterosuperior spine of the iliac crest (Fig. 3).

Rice. 3. Lumbosacral access according to T.A. Taylor
The advantages of the paramedian approach are the absence of dense ligaments along the way, a clearer sensation of a puncture of the dura mater and a reduced risk of injury to the venous plexus spinalis posterioris, the largest branch of which is embedded in the tissue between the bony wall of the spine and the dura mater, just along the midline. The main disadvantage is the possibility of the needle entering the abdominal cavity if it deviates from the required trajectory of movement.
Insufficient flow of cerebrospinal fluid from the needle may be due to for the following reasons. Firstly, it is possible that not the entire needle section has passed through the dura mater of the spinal cord. In this case, the needle should be moved forward 1-2 mm. Secondly, it is possible that the needle tip passed through the subarachnoid space and, having pierced the dura mater, passed to the vertebral body. In this case, the venous network is usually injured, and the cerebrospinal fluid becomes stained with blood. In this case, the needle is pulled back 1-2 mm and 1-2 ml of cerebrospinal fluid is released until it is cleared of blood impurities. Perhaps the cut of the needle, located in the subarachnoid space, is covered by the nerve root. In these cases, the needle must be rotated around its own axis.
If there is no cerebrospinal fluid, it is recommended to clear the needle with a mandrel, ask the patient to cough, or try to aspirate the cerebrospinal fluid with a syringe.
If, despite the measures taken, cerebrospinal fluid does not appear from the needle pavilion, you should either change the access and direction, or perform a puncture of the spinal space in the adjacent intervertebral space.
Puncture of the spinal space must be performed anatomically due to the danger of traumatic injuries to the spinal cord and its roots, manifested by paresthesia, acute pain, muscle twitching or sudden movements of the lower extremities. A correctly performed spinal puncture should not be accompanied by any unpleasant sensations for the patient.
Before removing the spinal needle, a mandrel must be inserted into its lumen. Performing this simple technique helps reduce the incidence of post-puncture syndrome (Vilming, 1988).
It should be noted that recently high and medium spinal anesthesia (in the sense of puncture) is practically not used due to the risk of spinal cord injury. To block segments of the spinal cord above the Th12 level, a puncture of the subarachnoid space is performed at a level below L1, a hyperbaric solution of local anesthetic is administered (Baricity is the ratio of the mass of 1 ml of local anesthetic solution to the mass of 1 ml of cerebrospinal fluid at a temperature of 4 ° C.), the patient is placed on his back and head end operating table lowered 10 degrees. After achieving the desired level of anesthesia, the patient is returned to a horizontal position.
Traditionally, solutions of local anesthetics for spinal anesthesia, depending on the specific gravity, are divided into hyperbaric, isobaric and hypobaric (Table 6).
Table 6 Characteristics of local anesthetics used for spinal anesthesia
Hyperbaric solutions
Lidocaine
Concentration 5% in 7.5% glucose solution
Dosage 60 mg (1.2 ml)
Duration of action (hours) 0.75 - 1.5
Bupivacaine
Concentration 0.75% in 8.25% glucose solution
Dosage 9 mg (1.2 ml)
Tetracaine
Concentration 0.5% in 5% glucose solution
Dosage 12 mg (2.4 ml)
Duration of action (hours) 2.0 - 3.0
Isobaric solutions
Lidocaine
Concentration 2% aqueous solution
Dosage 60 mg (3.0 ml)
Duration of action (hours) 1.0 - 2.0
Bupivacaine
Dosage 15 mg (3.0 ml)
Duration of action (hours) 2.0 - 4.0
Tetracaine
Concentration 0.5% aqueous solution
Dosage 15 mg (3.0 ml)
Hypobaric solutions
Tetracaine
Concentration 0.1% aqueous solution
Dosage 10 mg (10 ml)
Duration of action (hours) 3.0 - 5.0

When introducing solutions with different specific gravity, their hydrodynamic properties must be taken into account.
in the subarachnoid space. Thus, in the Trendelenburg position, the hypobaric solution will spread caudally, and the hyperbaric solution - cranially; with the head end of the operating table raised, the hypobaric solution will spread cranially, and the hyperbaric solution - caudally (Fig. 4)

IN recent years Combined spinal anesthesia is increasingly being used, including the administration of narcotic analgesics and central adrenergic agonists along with local anesthetics. (Table 7).
Table 7 Dosages of narcotic analgesics and clonidine for spinal anesthesia
Morphine 1 - 2 mg
Fentanyl 50 - 100 mcg
Pethidine 1.0 mg/kg
Clonidine 50 - 100 mcg

Their most rational combinations are presented in Table 8.
Table 8 rational combinations of drugs for spinal anesthesia
2 ml 5% lidocaine solution + 50 mcg fentanyl
Duration of the operation is up to 90 minutes
duration of postoperative analgesia 60 - 70 min
2 ml 5% lidocaine solution + 75 mcg clonidine
Duration of operation up to 120 minutes
duration of postoperative analgesia 4 - 5 hours
2 ml 5% lidocaine solution + 50 mcg fentanyl + 75 mcg clonidine
Duration of the operation is up to 180 minutes
duration of postoperative analgesia 6.0 - 6.5 hours

A feature of spinal anesthesia is the blockade of preganglionic sympathetic fibers passing through the anterior roots. At the same time, arterioles and venules expand, total peripheral resistance decreases (by 5-20%), venous return and cardiac output (by 10-30%). Decline cardiac output may also be due to a decrease in heart rate and myocardial contractility.
This usually occurs with a high level of spinal block (above Th IV. Blood pressure decreases by 15-30%. In patients with hypertension or hypovolemia, the decrease in blood pressure is more pronounced than in patients with normal blood pressure or normovolemia.
Spinal anesthesia does not have a clinically significant effect on tidal volume, respiratory rate, minute ventilation, partial pressure of CO 2 in the alveolar air, PaCO 2 and PaO 2. Oxygen demand is reduced by 10%, CO 2 production is also reduced due to a decrease in the activity of metabolic processes in the muscles.
It is advisable to use bupivacaine (Marcaine, Anecaine) in the form of a 0.5% solution as an anesthetic. The initial dose is 15-20 mg. The sensory block develops after 7-8 minutes, the motor block a little later. A repeated dose of the drug must be administered, as a rule, after 3-3.5 hours; it is 0.5-0.75 of the original. During the operation, which lasts 7-8 hours, no more than 40 mg of bupivacaine is consumed.
Hemodynamic stabilization is carried out according to the general rules for spinal anesthesia: infusion support in combination with clinical titration of ephedrine.
Emotional comfort, which is very necessary during long-term and traumatic interventions, should be provided with midazolam (dormicum) - a water-soluble benzodiazepine with a short half-life, which has excellent sedative, anxiolytic, and amnestic effects.
Pain relief in the postoperative period.
Patients with a catheter in the subarachnoid space should only be kept in the intensive care unit under the supervision of an anesthesiologist.
For the purpose of analgesia, three types of drugs are used: local anesthetics, narcotic analgesics and clonidine.
Local anesthetics are used in a concentration half as much as for surgical anesthesia. Marcaine in the form of a 0.25% or even 0.125% solution, lidocaine in the form of a 1% solution. It is more advisable to use bupivacaine, as it is long-acting and has a less pronounced property than lidocaine to create a motor block, which is not necessary in the postoperative period. The initial dose of bupivacaine is 3.0 - 4.0 ml, repeated doses of the same volume are administered after 3.5 - 4 hours. During the day, 50 - 60 mg of anesthetic is consumed, within two days - no more than 110 mg. Such doses practically eliminate the possibility of developing intoxication. When using 0.25% bupivacaine, the analgesia is complete, but some limitation of movements in the legs is possible; when working with a 0.125% solution, there are no motor disturbances. The use of solutions of local anesthetics with reduced concentrations in the postoperative period does not cause noticeable changes in hemodynamics, however, access to the vein should be permanent due to the possibility of increased sympathetic block and the development of hypotension.
Of the opioids, it is preferable to use fentanyl at a dose of 50 mcg, which creates adequate analgesia for 3-5 hours. Analgesia is not accompanied by respiratory and movement disorders. The development of urinary retention, nausea and vomiting, and skin itching, characteristic of the use of morphine, is not typical.
Clonidine in a dose of 50-75 mcg creates sufficient analgesia, lasting 5-6 hours, which is not accompanied by hemodynamic and respiratory disorders.
Against the background of prolonged spinal analgesia, intestinal motility is restored early, and gases begin to escape. Coughing and sputum evacuation are effective, which prevents complications in the bronchopulmonary system. This option for postoperative pain relief avoids the use of large doses of opiates, which have known negative effects.
It appears that extended spinal anesthesia has some advantages over the more common extended epidural due to:
– use of thin and low-traumatic instruments,
– significantly lower doses of drugs, therefore lower toxicity and cost,
– high intensity anesthesia and analgesia,
– a rare “mosaic” of anesthesia.

Chapter IV. LONG-TERM SPINAL ANESTHESIA

Long-term spinal anesthesia was first described by the London surgeon N.P.Dean (1907), then it was used by Aburel E. (1931), Lemman W.T. (11940), Tuochy E. (1944), Mostovy M.I. (1949).
The anesthesia technique involved inserting a needle into the subarachnoid space and attaching a flexible tube to it to inject local anesthetic. The patient was placed on the operating table, which had a special cutout for a spinal needle.
The use of this method of anesthesia was limited not only by technical difficulties (a special operating table), but also by the high, up to 20%, incidence of post-puncture headaches.
In 1944, E. Tuochy described the technique of catheterization of the subarachnoid space using a ureteral catheter. With the advent of plastic catheters, interest in long-term spinal anesthesia has revived. Through 22-23G needles, a 28G catheter was inserted into the subarachnoid space (Harley R.J., Lambert D.H., 1990). However, due to the development of severe complications in the form of cauda equina syndrome (Rigler et al., 1991), the use of microcatheters for long-term spinal anesthesia has been prohibited by the US Food and Drug Administration since 1992. Other countries followed the US example, resulting in a significant decrease in the number of studies on long-term spinal anesthesia. It was later determined that it was not the microcatheter that was the cause of this complication, but the 5% hyperbaric lidocaine solution used.
Currently, long-term spinal anesthesia in the clinic is being replaced by the method of spinal-epidural anesthesia.
Indications for prolonged spinal anesthesia are surgical interventions of any duration and traumaticity, performed in the zone of innervation Th 10-S 5: on the colon, bladder, female genital organs, perineum, aorta and iliac vessels, lower extremities, during kidney transplantation. The need for high-quality postoperative pain relief is also an indication for this method of regional anesthesia.
Contraindications do not differ from those for routine spinal anesthesia.

Technique for catheterization of the subarachnoid space

In a sitting or lateral position at a level below L, an introducer is inserted into the interspinous ligament. Through the introducer, the subarachnoid space is punctured with a Crawford needle, which is verified by the appearance of cerebrospinal fluid in the needle pavilion. Given its small diameter, some patience should be exercised. The microcatheter is inserted 3 cm distal to the end of the needle, after which the needle and mandrel are removed from the catheter. The proximal end of the catheter is connected to the adapter and filter. It should be borne in mind that for free insertion of the microcatheter it is necessary to position the end of the Crauford needle as close as possible to the dorsal wall of the dural sac, otherwise the catheter will rest against the ventral wall. It is strictly forbidden to remove an already inserted catheter through the needle due to the danger of cutting it off.
Anesthesia begins when there is access to the venous bed and a volume load of 1000.0-1500.0 ml of crystalloids is created. The exception is the contingent of patients with chronic renal failure undergoing kidney transplantation who are in a state of hyperhydration.

Two-segment method
Spinal and epidural anesthesia are performed in different interspinous spaces. First, puncture and catheterization of the epidural space are performed, the effect of the test dose is assessed, then spinal anesthesia is performed below at the appropriate level.
To provide the spinal component of spinal epidural anesthesia, 2% aqueous solutions of lidocaine, 1% hyperbaric solutions of lidocaine, 0.5% solutions of bupivacaine, a combination of solutions of lidocaine with fentanyl (100 µg) and/or clonidine (100 µg) are used.
If it is necessary to expand the anesthesia zone, local anesthetic solutions (5-8 ml of a 2% lidocaine solution) are administered epidurally in fractional doses. It is characteristic that expanding the anesthesia zone by one segment requires less
doses of anesthetic than with conventional epidural anesthesia (E. Yu. Gallinger, 1995).
An essential feature of spinal-epidural anesthesia is the reduction in the incidence of post-puncture headaches to 1.3% (L.E.S.Carrie, 1990). This is due, on the one hand, to the fact that the epidural catheter “splints” the dura mater to the arachnoid mater, and on the other hand, the introduction of a local anesthetic solution into the epidural space prevents the outflow of cerebrospinal fluid from the subarachnoid space.
Thus, spinal-epidural anesthesia allows you to obtain a reliable spinal block, quickly begin surgery, and extend anesthesia, if necessary, both during surgery and in the postoperative period.
Clinical application of spinal epidural anesthesia. Combined combined spinal-epidural anesthesia for abdominal operations
Indications for spinal-epidural anesthesia in abdominal surgery are surgical interventions on the stomach, pancreas, biliary tract, intestines, and large ventral hernias.
First, the epidural space is catheterized at the level of Th 7-8 and the catheter is fixed with an adhesive plaster, then 8-12 ml of a 2% solution of lidocaine in combination with 100 μg of fentanyl and 100 μg of clonidine is injected intrathecally at the level of L 2-3. After 5-7 minutes, sensory blockade develops, reaching a level of Th 2-4. The operation is performed against a background of 70-100 mg/kg of GHB under mechanical ventilation (MOD-70-75 ml/kg, FiO, "0.3). Maintaining central hemodynamic parameters at an adequate, stable level is carried out by infusion-transfusion therapy, giving the patient a Trendelenburg position (10-15°), administration of anticholinergics and, according to indications (bradycardia, lowering blood pressure), adrenergic metics (V.I. Strashnov et al. ., 1997).
The duration of combined spinal anesthesia is 3.5-4.5 hours. As drugs for epidural anesthesia, l - 2% solutions of lidocaine or its combination with 50 mcg of clonidine and 50 mcg of fentanyl are used. It is possible to use a combination of 0.25% - 0.125% solution of bupivacaine with fentanyl (50 mcg of fentanyl per 50 ml of local anesthetic solution), administered continuously with a dosing syringe at a rate of 6-8 ml/hour.

Chapter V. EPIDURAL ANESTHESIA AND ANALGESIA

Indications for epidural anesthesia and analgesia

1. Surgical interventions on the chest, abdominal organs, urological, proctological, obstetric and gynecological, operations on the lower extremities.
2. Surgical interventions in patients with severe concomitant pathology (obesity, cardiovascular and pulmonary diseases, dysfunction of the liver and kidneys, deformation of the upper respiratory tract), in elderly and senile people, in patients with a “full” stomach.
3. Component of combined anesthesia.
4. Severe combined skeletal injuries (multiple fractures of the ribs, pelvic bones, lower extremities).
5. Postoperative pain relief.
6. Component of therapy for pancreatitis, peritonitis, intestinal obstruction, status asthmaticus.
7. Fighting chronic pain syndrome.
Relative contraindications to epidural anesthesia and analgesia
1. Deformation of the spine (kyphosis, scoliosis, etc.), making it difficult to puncture the epidural space.
2. Diseases of the nervous system.
3. Hypovolemia.
4. Arterial hypotension.
5. Epidural administration of narcotic analgesics is not indicated in patients in the postoperative period with a high risk of developing anastomotic leakage (gastric resection for cancer).
Absolute contraindications to epidural anesthesia and analgesia
1. Inflammatory skin lesions in the area of ​​the proposed epidural puncture.
2. Severe shock.
3. Reluctance of the patient to undergo epidural anesthesia.
4. Sepsis and septic conditions.
5. Violation of the blood coagulation system (danger of epidural hematoma).
6. Increased intracranial pressure.
7. Hypersensitivity to local anesthetics or narcotic analgesics.
Psychological preparation patient for epidural anesthesia includes a mandatory confidential conversation with the patient before the operation, in which the anesthesiologist must explain to him in a simple and tactful manner why this particular method was chosen for pain relief, how anesthesia will be performed, what sensations may arise and how the patient will have to behave. Lack of awareness of the patient about the possibilities and advantages of epidural anesthesia, personal negative experience, negative attitude of people around the patient often lead to the patient’s wary attitude towards this type of pain relief. However, experience shows that, as a rule, negative attitude it is possible to overcome the risk of epidural anesthesia after a confidential conversation, especially in elderly, balanced patients, in people with high intelligence, in those who have been ill for a long time. In general, establishing trusting contact between the anesthesiologist and the patient seems extremely important.
Medication preparation includes prescribing sleeping pills, antihistamines and minor tranquilizers at night. 30 minutes before transporting the patient to the operating room, Dormicum is administered intramuscularly in doses of 0.1 mg/kg, which creates a good background for anesthesia, since the drug has excellent anxiolytic, amnestic and sedative effects. Narcotic analgesics (promedol) are not recommended for use due to their pronounced sedative effect. Atropine, if appropriate indications arise, is best used on the operating table.
We consider it most appropriate to perform puncture and catheterization of the epidural space not on the day of surgery, but the day before. In this case, a calm atmosphere is created, the anesthesiologist is not limited in time, which allows him to carefully, without haste, perform all the necessary manipulations. Lack of time on the day of surgery, haste, surgeons waiting for surgery to begin, and the risk of a decrease in personal “rating” in the eyes of the operating staff due to ineffective epidural anesthesia do not contribute to the provision of high-quality anesthesia care.

Epidural anesthesia technique

Puncture of the epidural space is performed with the patient sitting or lying on his side.
Sitting position: the patient sits on the operating table, lower limbs bent at right angles at the hip and knee joints, the torso is bent forward as much as possible, the head is lowered down, the chin touches the chest, the hands are on the knees.
Lying position on your side: lower limbs bent as far as possible hip joints, knees are brought to the stomach, the head is bent, the chin is pressed to the chest, the lower corners of the shoulder blades are located on the same vertical axis. The assistant must hold the patient in this position and at the same time monitor his condition.
The skin in the area of ​​the intended puncture and the anesthesiologist's hands should be treated more thoroughly than surgeons do (it is important for the surgeon to avoid infection of the wound, for the anesthesiologist - epiduritis or meningitis!).
The level of epidural puncture is selected depending on the area of ​​surgical intervention (Table 9) and the corresponding segmental innervation of organs (Fig. 8).
Table 9 Level of epidural anesthesia depending on the area of ​​surgery
Th 2- Th 4 Chest (heart, lungs)
Th 5- Th 7 Stomach, duodenum, gallbladder, pancreas
Th 7- Th 9 Jejunum and ileum
Th 8- Th 10 Blind and ascending colon
Th 10- Th 12 Descending colon, sigmoid colon
L 2- L 5 Rectum, perineum
Th 10- L 1Uterus, kidneys, ureters
L 2- L 4 Prostate gland, bladder
L 2- L 5 Lower limbs

Rice. 8. Scheme of segmental innervation of the skin.
Anatomical and topographical landmarks when choosing the puncture level are presented in Table 10.
Table 10. Anatomical landmarks during puncture
C 7 spinous process of VII cervical vertebra
Th 2 connection of the body and the manubrium of the sternum
Th 4 nipple of the mammary gland
Th 7 - 8 line connecting the lower angles of the scapulae, xiphoid process
Th 10navel
Th 12XII pair of ribs
L 1 pubic symphysis
L 4 - 5 line connecting the crests of the wings of the ilium
After treating the puncture site with an antiseptic solution, anesthesia of the skin and underlying tissues is performed with a 0.5% solution of novocaine. Only the skin is anesthetized subcutaneous tissue and supraspinous ligament. Further along the course there are almost no pain receptors, and the introduction of novocaine into the interspinous ligament can create the appearance of a loss of resistance when performing the Dogliotti test as the Tuohy needle moves towards the epidural space. The skin is punctured with a thick needle. The needle for epidural anesthesia is inserted strictly along the midline, adhering to the sagittal plane. Depending on the level of puncture, the direction of the needle should correspond to the direction of the spinous processes. If in the lumbar region the angle formed by the needle and the surface of the skin is about 90°, then in the lower thoracic region it is up to 50°, and in the upper thoracic region it reaches 30°-40°. To reach the epidural space, the needle passes the skin, subcutaneous tissue, supraspinous, interspinous and yellow ligaments.
The distance between the skin surface and the epidural space is on average 5 cm. In obese patients it increases, sometimes up to 7-8 cm.
The dimensions of the epidural space in different parts of the spine are different (Table 11).
Table 11 Dimensions of the epidural space in various parts of the spine, mm
Neck 1.0 - 1.5
Upper thoracic 2.5 - 3.0
Nizhnegorodny 4.0 - 5.0
Lumbar 5.0 - 6.0

Identification of the epidural space

1. Sign of loss of resistance. When carefully moving the needle with an attached saline or air-filled syringe through the ligamentum flavum, a slight click or dip is felt. Free forward movement of the syringe piston indicates that the needle has entered the epidural space.
2. Air bubble. There is a small air bubble in the saline syringe attached to the puncture needle. During puncture, periodic pressure on the piston compresses the bubble. When it enters the epidural space, the springy effect of the bubble disappears, because the solution passes through the needle without resistance.
3. Epidural space indicator. The indicator is a piece of a standard intravenous catheter about 15 cm long. The indicator is filled with 1 ml of anesthetic or isotonic sodium chloride solution, then gently shaken so that the liquid column turns into drops mixed with air bubbles. After this, the indicator is connected to a puncture needle inserted into the interspinous ligament, and the needle is passed further through the ligamentum flavum into the epidural space. When the tip of the needle enters the epidural space, it is accompanied by a sharp movement of air bubbles towards the needle. The column of liquid and air in the indicator begins to oscillate synchronously with heart contractions. Sometimes fluctuations of greater amplitude are observed in rhythm with the patient's breathing.
4. Sign of a suspended drop. As the needle passes through the thickness of the ligamentum flavum, a drop of local anesthetic solution is placed on the needle pavilion. When it enters the epidural space, due to the negative pressure in it, the drop is drawn into the lumen of the needle, especially during inspiration.
5. If, during puncture of the epidural space, cerebrospinal fluid begins to be released from the needle, the needle should be pulled back 2-3 mm until the release of cerebrospinal fluid stops, which indicates that the tip of the needle is in the epidural space. During catheterization, the likelihood that the catheter enters the subarachnoid space is low, because The direction of movement of the catheter is determined by the bevel of the needle.
In elderly and senile patients due to degenerative changes in the interspinous ligaments, cavities are formed, entering which with a needle is felt as a loss of resistance, simulating a puncture of the epidural space. In this case, a test with “reverse filling of the syringe” is useful: 1 ml of saline and 1.0 -1.5 ml of air are quickly injected through the puncture needle, immediately after which the finger is removed from the piston. If the needle is positioned correctly, there will be no backflow of liquid or its amount does not exceed 0.2 ml. It is also possible to perform a trial catheterization, because the passage of the catheter into the epidural space is characterized by specific tactile sensations in the form of light elastic resistance.
Use to identify the epidural space various devices(indicators, capillary tubes, etc.) are not widely used in practice.
After making sure that the puncture needle is correctly positioned, a catheter is inserted through its lumen. As the catheter tip enters the epidural space, slight resistance is felt. The catheter is advanced to a depth of 3-5 cm (Fig. 9), after which the puncture needle is carefully removed, and the catheter is placed along the spine and brought out into the subclavian region, secured with adhesive tape along its entire length.
A special adapter is attached to the end of the catheter, or a thin needle is inserted into its lumen to connect to a syringe. The administration of local anesthetic solutions should be carried out through a bacterial microfilter.
To clarify the nature of the location of the catheter in the epidural space, radiography is used, introducing water-soluble radiopaque agents (urografin) into the catheter in a volume of 0.6-0.9 ml. An x-ray allows you to clearly trace the outer part of the catheter, the place where the catheter passes through the tissue, inner part located in the epidural space. Some epidural anesthesia kits contain radiopaque catheters, which makes it much easier to determine the location of the catheter. If there is any doubt that the catheter is located in the epidural space, it should be removed only together with the needle. Otherwise, the tip of the catheter may be cut off and remain in the tissues, including the epidural space, which will require prompt removal.

Fig.9. Determination of the length of the catheter in the epidural space.
Example No. 1. The full length of the epidural needle is 11.5 cm. The catheter is passed through the lumen of the needle to the throne mark (at 15 cm). Length of the catheter in the epidural space: 15-11.5 = 3.5 cm.
1 - epdural catheter. 2-puncture needle. 3- skin. 4- subcutaneous tissue. 5- supraspinous ligament, 6- spinous process, 7- ligamentum flavum. 8 - epndural space, 9 - outer layer of the dura mater. 10 - subarachnoid space.
After catheterization of the epidural space, a “test dose” of local anesthetic is administered in a volume of 2.0-3.0 ml. Careful observation of the patient for 5 minutes allows us to identify signs of a developing spinal block (see Chapter IV). In the absence of evidence for the development of spinal anesthesia, the main dose of local anesthetic is administered.
Dosage of local anesthetics for epidural anesthesia
I. Calculation according to the nomogram Dose /ml/segm./

Calculation example: Patient 55 years old, height 180 cm.
Operation - elimination of inguinal hernia. Innervation: Th 8 - 122 - 5 dermatomes
L I - 5- 5 dermatomes
S I - 5- 5 dermatomes
Total: 15 dermatomes
Anesthetic volume (ml) = 15 x 1.1 = 16.5

II Calculation using the formula
V per 1 segment = 3.113 - 0.0252 x age (years)

III Estimated body weight
V= 15 - 17 mg/kg/hour
Table 11 Segmental dosage of 2% lidocaine solution
V= ml/segment x number of segments
20 - 30 years 1.75 - 1.6 ml/segm
40 - 50 years 1.50 - 1.4 ml/segm
60 - 70 years 1.25 - 1.1ml/segm
80 years 1.0 ml/segm

IV. Dosage of local anesthetics in children
Table 13 Dosage of trimecaine for epidural anesthesia in children
Newborns 0.5%; 5 - 7 ml; 10 - 15 mg/kg
Less 1 year 1.0%; 4 - 9 ml; 8 - 15 mg/kg
1 - 4 year 2.0%; age + 2 ml; 4 - 6 mg/kg
5 - 9 years 2.0%; age + 1 ml; 4 - 6 mg/kg
9 - 13 years 2.0%; up to 10 ml; 4 - 6 mg/kg

Features of the use of some local anesthetics for epidural anesthesia

The maximum single dose of lidocaine without adrenaline for epidural anesthesia is 400 mg (4.5 mg/kg), with adrenaline - 500 mg (7 mg/kg). For anesthesia in the thoracic spine, use 10-15 ml of a 2% lidocaine solution (200-300 mg). In the lumbar region, a 2% lidocaine solution is used in a volume of 15-20 ml (300-400 mg), 1.5 ° lidocaine solution - 20-25 ml (300-375 mg).
The maximum single dose of bupivacaine is 150 mg, and in combination with adrenaline - 200 mg. The maximum daily dose is 400 mg. When using a 0.75% bupivacaine solution, the first injection of the drug is carried out in a volume of 10-20 ml (75-150 mg), repeated injections - 3-5 ml. The duration of anesthesia reaches 6-9 hours. When using a 0.25-0.5% solution of bupivacaine, the onset of action is noted at 10-12 minutes, the duration of anesthesia reaches 4-6 hours. In the postoperative period, the interval between injections should be at least 3 hours.
Mepivacaine for epidural anesthesia is used in 1%, 1.5% and 2% solutions. The maximum single dose of the drug is 400 mg, the daily dose is 1000 mg. The onset of action of a 2% mepivacaine solution is observed at 7-15 minutes, the duration of anesthesia is up to 3-5 hours. The interval between administrations should not be less than 1.5 hours.
A single dose of nezacaine is 800 mg, and in combination with adrenaline - 1000 mg. For epidural anesthesia in the thoracic region, 1.5-2.0 ml/segm is used. (30-60 mg), in the lumbar region - 2.0-2.5 ml/segm. (40-75 mg) 2-3% nezacaine solution. Repeated administration of the drug in a dose 3-6 ml less than the initial one is performed 40-50 minutes after the first injection. The total volume of the solution is 15-25 ml (300-750 mg). The duration of anesthesia with nezacaine is 30-60 minutes, and when combined with adrenaline, 60-90 minutes.
A single dose of 1% etidocaine solution is 300 mg (4.0 mg/kg), when using adrenaline - 450 mg (5.5 mg/kg).
The commonly used dosage is 0.7-1.7 ml/segm. Repeated administration of the drug is performed 2-3 hours after the first injection.
General characteristics of local anesthetics are presented in Table 14.
Table 14 Characteristics of local anesthetics used for epidural anesthesia
Lidocaine 2%
Max. single dose (mg) 400
Strength 1.0
Toxicity 1.0
Start (min) 8 - 12
Duration (hours) up to 1.3
Trimecaine 2.5%
Max. single dose (mg) 400
Strength 0.45
Toxicity 1.0
Start (min) 7 - 10
Duration (hours) 1.0 - 1.5
Bupivacaine 0.5%
Max. single dose (mg) 150
Strength 4.0
Toxicity 2.0
Start (min) 10 - 12
Prilocaine 2%
Max. single dose (mg) 900
Strength 0.65
Toxicity 0.77
Start (min) 10 - 13
Duration (hours) 2.0 - 3.0
Mepivacaine 2%
Max. single dose (mg) 400
Strength 1.0
Toxicity 1.8
Start (min) 7 - 15
Duration (hours) 3.0 - 5.0
Etidocaine 1%
Max. single dose (mg) 300
Strength 4.0
Toxicity 5.5
Start (min) 10 - 12
Duration (hours) 4.0 - 6.0
Azacaine 0.75%
Max. single dose (mg) 420
Strength 3.5
Toxicity 3.6
Start (min) 25 - 30
Duration (hours) 5.0 - 10.0
Nezacaine 2%
Max. single dose (mg) 800
Strength 0.5
Toxicity 0.3
Start (min) 1 - 2
Duration (hours) 0.5 - 1.0
Ropivacaine
Max. single dose (mg) 150
Strength 4.0
Toxicity 2.0
Start (min) 10 - 12
Duration (hours) 3.0 - 3.5

However, local anesthetics are not without their drawbacks. The duration of action of the most common of them (trimecaine, lidocaine) is quite short, which increases the burden on medical staff, as well as the likelihood of infection of the epidural space with frequent administrations in the postoperative period. The initial administration of large doses of drugs and an increase in the number of patients with multiple concomitant diseases leads to the development of severe complications, mainly deep arterial hypotension.
Clinical experience in recent years has shown that the use of narcotic analgesics for epidural analgesia provides a powerful and long-lasting analgesic effect. The maximum duration of analgesia is provided by morphine (up to 24 hours or more), the minimum by fentanyl (up to 4 hours). The effectiveness of postoperative epidural analgesia depends on accurate identification of the epidural space and delivery of analgesic to the affected spinal cord segments. The choice of drug dose is also of great importance (Table 15).
Table 15 Dosage of narcotic analgesics used for epidural analgesia
Morphine 2 mg - 0.1 mg/kg
Fentanyl 100 - 200 µg
Pethidine 25 - 100 mg
Alfentanil 15 - 30 µg
Lofentanil 5 mcg
Methadone 4 - 6 mg
Buprenorphine 60 - 300 mcg
Butorphanol 1 - 4 mg
Phenopyridine 2 mg
Nalbuphine 5 mg
Omnopon 10mg
Pentazocine 0.2 - 0.4 mg/kg
Stayed on 5 - 10 mg
Promedol 20 mg

In patients with chronic pain syndrome, 2-3 mg of morphine is sufficient; in patients with acute pain in the postoperative period, 4-5 mg.
It is noteworthy that complications that arise during epidural analgesia with narcotic analgesics are dose-dependent. When using morphine in a dose of 5 mg, 60% of patients experience urinary retention, and when using 7 mg - in 100%.
It should be noted that morphine and fentanyl are approved by the Russian Pharmacopoeia for epidural use.
A decrease in the analgesic activity of epidurally administered morphine was also noted, which was practically ineffective on days 6-7.
Epidural analgesia with clonidine, which is used in a dose of 100-200 mcg, does not have such disadvantages.
The onset of action of clonidine is noted at 5-6 minutes, sufficient analgesia develops after 15-30 minutes. The analgesic effect of clonidine lasts from 3.5 to 24 hours, with an average of 8.5 hours. Moreover, the duration of analgesia and its quality remained the same on days 5-6 of administration. Good results of epidural analgesia with clonidine were achieved in 83-90% of cases.
Epidurally administered clonidine reduced systolic blood pressure by 10-15% after 15 minutes, the maximum reduction occurred at 60 minutes - by 15-18%. Average dynamic pressure decreases by 6.1%, heart rate by 8.6%, and total peripheral resistance by 8.9%. Cardiac minute volume, stroke volume and cardiac index do not change. Respiratory frequency decreases by 19%, tidal volume increases by 31% and vital capacity of the lungs by 50%. PaO 2 increases by 8%, PaCO2 decreases by 9.5%.
Thus, changes in hemodynamic and respiratory parameters during epidural analgesia with clonidine are normalizing in nature and contribute to a smooth course of the postoperative period.

Chapter VI. THERAPEUTIC USE OF EPIDURAL ANALGESIA

The effects of epidural analgesia are not limited to the switching off of conduction in the spinal roots as a result of the administration of a local anesthetic drug or narcotic. Under the influence of an epidural blockade, various and complex physiological reactions of many organs and systems occur in the body, the therapeutic effects of which are much wider and deeper than the analgesic properties.
The use of epidural analgesia in therapy is a relatively new approach to treatment serious illnesses and conditions based on smooth muscle spasm (bronchiolospasm, sphincter spasm, arteriospasm, etc.), based on segmental desympathy of organs and systems in combination with other specific methods of influencing the main links in the pathogenesis of suffering. Blockade of nociceptive afferentation has both a general effect, normalizing the ratio of the adrenergic and cholinergic systems of the body, and a local effect in the form of vasodilation and increased blood flow, relaxation of smooth muscles and bronchodilation, relaxation of sphincters and gland ducts.
Epidural analgesia for status asthmaticus
Sympathetic blockade caused by epidural analgesia in patients with status asthmaticus increases intrapulmonary blood flow, improves gas exchange in the lungs, and reduces arterial hypoxemia. The bronchodilating effect of analgesia is based on the Cannon-Rosenblutt law: “as a result of denervation of an organ, its sensitive structures become many times more sensitive to their mediator” (Cannon W., Rosenbluth A., 1951).
Puncture and catheterization of the epidural space is performed at the level of Th 3 - 4. The volume of injected local anesthetic (2% lidocaine solution) is determined by the need to block 7-8 upper thoracic segments (from C 7 to Th 6 -8) at the rate of 1 ml/segment, i.e. . 6-8ml. 30-40 minutes after the administration of the local anesthetic, the patients' breathing becomes freer, shortness of breath decreases, exhalation becomes more complete, sputum discharge becomes easier, airway resistance decreases, hypoxia decreases, and the work of breathing decreases sharply. Against the background of epidural analgesia, patients increase tidal volume by 50%, minute respiratory volume by 45%, and vital lung capacity by 126%. pH and PaO 2 increase, PaCO 2 decreases. Hemodynamic parameters normalize: blood pressure decreases by 22.5%, heart rate decreases by 25%, stroke volume, cardiac output and cardiac index increase by 22.3%, respectively, 13 % and 37%. Total peripheral resistance decreases by 13.7%.

Epidural analgesia in patients with acute myocardial infarction

Perform catheterization of the epidural space in patients with acute heart attack myocardium should be performed before starting therapy with anticoagulants and fibrinolytics. Otherwise, it is absolutely contraindicated. Epidural analgesia in patients with acute myocardial infarction causes interruption of afferent pathological impulses, accompanied by dilatation of arteries and arterioles, a decrease in total peripheral resistance, pressure in the right atrium and large veins, myocardial function, the frequency of arrhythmias and fibrillations.
The indication for the use of epidural analgesia in patients with acute myocardial infarction is persistent pain that is not relieved by narcotic analgesics.
Puncture and catheterization of the epidural space is performed at the level Th 3 - 4. A 2% lidocaine solution is used as an analgesic drug at a dose of 0.5-1.0 ml/segment. For blockade of 8 segments (C 5-Th 5), 5-8 ml of local anesthetic solution is usually used. The duration of the analgesic effect is 4 - 5 hours. With the combined use of a local anesthetic solution with 3-4 mg of morphine, the duration of analgesia increases to 8-12 hours.

Epidural analgesia in patients with pancreatitis

In patients with pancreatitis, epidural analgesia completely relieves pain, relieves visceral vasospasm, spasm of the sphincter of Oddi, pancreatic and bile ducts, thereby increasing the outflow of pancreatic secretions and bile, increasing perfusion of the pancreas, and accelerating the normalization of blood and urine amylase.
Patients with pancreatitis who are supposed to undergo epidural analgesia, first of all, need to compensate for the deficit of BCC by infusion of colloid and crystalloid solutions until the central venous pressure and hematocrit normalize.
Puncture and catheterization of the epidural space is performed at the level of Th 7-8. The dose of the administered anesthetic is determined by the need to block 7-8 segments of the spinal cord (Th 5 - 12) at the rate of 1.2-2.0 ml/segment. Typically, 6-10 ml of a 2% lidocaine solution is used. To increase the duration of the effect, 50-100 mg of fentanyl is added to the local anesthetic solution.
Epidural analgesia for radicular pain syndrome
The indication for the use of epidural analgesia is persistent, severe radicular pain syndrome that is not amenable to conventional methods of conservative treatment.
Under local anesthesia at the L 1 -2 level, the epidural space is punctured and a mixture consisting of 5-6 ml of a 2% lidocaine solution or a 0.5% marcaine solution, 50-100 mcg of fentanyl and 100-200 mcg of clonidine, and then a glucocorticoid is injected. Methylprednisolone (60-120 mg), hydrocortisone (100-150 mg) are used as the latter.
or triamcinolone (75-50 mg). Before administration, the corticosteroid is diluted in 5-10 ml of isotonic sodium chloride solution.
Before removal from the epidural space, the needle must be washed to avoid the formation of fistulas, because even trace concentrations of corticosteroids contribute to their formation.
The pain syndrome is relieved 15-20 minutes after the epidural injection. If necessary, repeated administration of the above mixture of drugs is performed after 24-48 hours. Usually 1-2 injections are enough.

Epidural anesthesia and analgesia in patients with obliterating endarteritis and ischemic disorders in the lower extremities

Epidural blockade in patients with obliterating endarteritis turns off pathological impulses from the affected area, improves local blood flow, relieves spasm of arterioles and smooth muscles, which leads to breaking the vicious circle: spasm - ischemia - pain - spasm.
Indications for epidural anesthesia and analgesia in patients with obliterating endarteritis:
1. C therapeutic purpose- in the spastic stage of the disease.
2. For prognostic purposes - when determining indications for sympathectomy. If there is a positive effect (warming of the limb, disappearance of pain, improvement in skin color, etc.), sympathectomy is indicated, but if epidural anesthesia is not effective, sympathectomy is not indicated.
3. Preparing patients for surgery on the vessels of the lower extremities (epidural blockade effectively relieves severe pain, improves blood flow in the lower extremities, trophic processes, relieves psycho-emotional stress, and normalizes sleep).
4. Anesthesia during surgery.
5. Postoperative analgesia.
Puncture and catheterization of the epidural space is performed at the L1-2 level. In the spastic stage of the disease, 15 ml of a 2% lidocaine solution is administered epidurally, and in the first 2-3 days the injection interval is 4 hours, then every 6 hours for 7-10 days. For preoperative preparation, use epidurally 3-7 mg of morphine in a daily dose of at least 10 mg, clonidine 100-200 mcg in a daily dose of at least 400 mcg, or a combination of 4 mg of morphine with 50-100 mcg of clonidine. During the operation, solutions of local anesthetics are used together with clonidine.
In the postoperative period, a good analgesic effect was obtained after administration of 5-7 mg of morphine, 100-200 mcg of clonidine or a combination of 4 mg of morphine and 50-100 mcg of clonidine. It is noteworthy that clonidine, both after the first epidural administration and on days 5-6 of continuous use, did not change the severity and duration of the analgesic effect. On average, the analgesic effect of clonidine lasts 5 hours.

Epidural anesthesia in patients with diabetes mellitus

Epidural anesthesia, without causing stress production of counter-insular hormones, pronounced glycogenolysis and inhibition of the insulin-producing function of the pancreas, prevents an excessive catabolic reaction in response to surgical aggression and preserves rational adaptive mechanisms of carbohydrate metabolism. All of the above is the basis for the use of epidural anesthesia during surgical interventions in patients with diabetes.
Indications for the use of epidural anesthesia in this category of patients are long-term traumatic operations in the lower abdominal cavity and lower extremities.
After installing the catheter at the appropriate level in the epidural space and administering the test dose, the main dose of local anesthetic is administered fractionally in two stages. At the first stage, the volume of a 2% lidocaine solution is 7-10 ml, at the second, after 10-15 minutes - 5-7 ml.
The two-stage administration of the main dose of local anesthetic allows for timely replenishment of blood volume, selecting the optimal dose of local anesthetic and avoiding arterial hypotension.
Anesthesia is maintained during the intraoperative period by administering 5-7 ml of a 2° lidocaine solution at intervals of 1.0-1.5 hours. For analgesia in the postoperative period, it is advisable to use a combination of narcotic analgesics with central adrenergic agonists.

Epidural analgesia in the postoperative period

The pain syndrome is supported by four sources of pain impulses - cutaneous, deep somatic, visceral and humoral, and they, in turn, cause reflex vascular spasm, forming a vicious circle that ultimately leads to general and organ physical inactivity and the development of various kinds of complications.
According to its mechanism of action, epidural analgesia can completely prevent the influence of the first components, which significantly affects the course of the postoperative period. In conditions of effective epidural analgesia, the pain syndrome is completely relieved, the motor activity of patients increases, they can breathe freely and cough up sputum, and take care of themselves independently. Makes it easier to carry out breathing exercises.
The sympatholytic effects of epidural analgesia help relieve reflex vasospasm, enhance intestinal motility, and increase perfusion of organs and tissues.
The level of puncture and catheterization of the epidural space is performed depending on the area of ​​surgical intervention. Solutions of local anesthetics, narcotic analgesics, and central adrenergic drugs are used as drugs for analgesia.
It is noteworthy that preoperative epidural administration of narcotic analgesics, which cause blockade of the modulation of nociceptive impulses in the neurons of the dorsal horn of the spinal cord, is accompanied by longer postoperative analgesia than with the administration of opiates after surgery. So, with epidural administration of 4 mg of morphine over 45-60 minutes. before surgery, the duration of postoperative analgesia is 15-20 hours or more, while the same dose of morphine administered immediately after the end of the operation causes pain relief for about 10-12 hours.
Epidural analgesia is the most physiological method of p/o pain relief, its effectiveness is significantly superior to routine parenteral administration narcotic analgesics and has a normalizing effect on respiration and blood circulation, reducing the number of postoperative complications and facilitating the postoperative period.

Epidural analgesia for labor pain relief

Indications for the use of epidural analgesia are any childbirth in the absence of contraindications to this type of anesthesia, especially childbirth with discoordinated uterine contractions, twin births, delivery using obstetric forceps, with late toxicosis of pregnant women, as well as in the presence of severe concomitant extragenital pathology (sugar diabetes, liver disease, kidney disease, heart defects, hypertension). Epidural anesthesia is also used for caesarean section.
Transplacental permeability of local anesthetics is presented in Table 16.
Table 16 Transplacental permeability of local anesthetics
Lidocaine 0.45 - 0.7
Trimecaine 0.46 - 0.67
Bupnvacaine 0.26 - 0.45
Mepivacaine 0.7
Prilocaine 1.0 - 1.2
Etidocaine 0.14 - 0.35
To relieve labor pain, puncture and catheterization of the epidural space is performed at level L 3-4. Analgesia begins when the uterine pharynx is dilated by 5-6 cm. In the first stage of labor, 10-12 ml of a 1% lidocaine solution is administered. Upon completion of flexion and internal rotation of the fetal head, an additional 10-12 ml of a 2% lidocaine solution is injected.
During a cesarean section, the volume of local anesthetic administered should be sufficient to block the segments from T5 to L5.

Epidural analgesia for chronic pain syndrome in cancer patients

To combat pain in incurable cancer, in addition to narcotic analgesics, epidural chemical denervation is used.
Technique of epidural chemical denervation.
– Catheterization of the epidural space
– After administering a test dose of local anesthetic, the boundaries of skin anesthesia are determined.
– 30 minutes after administration usual dose local anesthetic is injected epidurally (slowly!) 1-2 ml of 96 alcohol.
The disappearance or significant reduction of pain occurs within 5-7 days. If pain persists, the alcohol injection is repeated. Usually 2-3 injections of alcohol are enough.

Chapter VII. COMPLICATIONS OF EPIDURAL AND SPINAL ANESTHESIA AND ANALGESIA

When performed correctly, epidural and spinal anesthesia are simple and safe methods of pain relief. The main reason for the development of complications during their implementation is the low qualifications of the anesthesiologist, who, in addition to the desire to master these methods, must have deep theoretical knowledge of epidural and spinal anesthesia, as well as be fluent in the technique of resuscitation measures. Practice shows that with the accumulation of experience, the frequency of failures and complications when performing regional anesthesia is significantly reduced.

Complications of epidural anesthesia

Perforation of the dura mater occurs in 0.4 - 0.8% of cases and is diagnosed by the leakage of warm cerebrospinal fluid from the needle pavilion. The risk of this complication is minimal if it is diagnosed in time. In this case, it is possible either to refuse to perform epidural anesthesia, or to carry out long-term spinal anesthesia, or to perform a puncture of the epidural space one segment higher, or, by pulling the needle 2 mm back until the flow of cerebrospinal fluid stops, catheterize the epidural space and treat the anesthesia as spinal (a test dose is administered in a volume of 2-3ml and, if spinal anesthesia does not develop within 10-15 minutes, the main calculated dose of local anesthetic is administered). Perforation of the dura mater in any case dictates the need to abandon epidural use of morphine. It is permissible to use fentanyl in a dose of no more than 50 mcg.
Complications from the catheter. The optimal depth of catheter insertion during catheterization of the epidural space is 3-5 cm. With deep catheterization, the likelihood of catheter displacement into the anterolateral sections of the epidural space, its exit through the intervertebral foramina beyond the epidural space, and damage to the venous plexuses increases. In many cases, this determines the development of mosaic, inadequate anesthesia, and one-sided anesthesia. Deep catheterization of the epidural space is fraught with the danger of kinking and knotting of the catheter. When the catheter is passed at a distance of less than 2 cm, it may exit the epidural space, especially when the patient’s body position changes.
Arterial hypotension. A decrease in blood pressure by more than 30% of the initial value is regarded as a complication that occurs in 9% of patients operated on under epidural anesthesia. Arterial hypotension more often occurs in patients with reduced compensatory capabilities of the cardiovascular system (patients in old age, weakened, exhausted, with initial hypovolemia).
The immediate causes of hypotension are:
– Injection of a relatively large dose of local anesthetic blocking more than 10 segments of the spinal cord.
– Injection of a local anesthetic solution against the background of an unnoticed perforation of the dura mater and penetration of the anesthetic into the subarachnoid space.
As a result of widespread sympathetic blockade, vascular tone and general peripheral resistance decrease, the capacity of the vascular bed increases, which leads to the development of severe hypotension.
Subarachnoid ingestion of a local anesthetic in a dose significantly higher than that used for spinal anesthesia leads to the development of severe hypotension within 2-5 minutes, a pronounced “scaphoid abdomen”, diaphragmatic breathing followed by apnea, loss of consciousness, paralysis of the lower extremities. This condition is called total spinal block.
The essence of the changes that occur in the patient’s body during the development of a total spinal block is explained by the fact that the anesthetic, spreading in the cranial direction, consistently blocks the roots spinal nerves, which include preganglionic sympathetic fibers and fibers innervating the intercostal respiratory muscles. As a result, hypogenia develops, the severity of which depends on the degree of vasodilation. When the anesthetic reaches the Th 1 level, the innervation of all intercostal muscles is switched off and breathing is supported by one diaphragm. The sympathetic innervation of the heart is also switched off, which leads to bradycardia, a decrease in myocardial contractility and cardiac output.
Preventive measures to combat the negative manifestations of epidural anesthesia include careful selection of patients, precise dosage of local anesthetics (blockade of no more than 10 segments), and infusion therapy in the hypervolemic hemodilution mode in the pre- and intraoperative periods. From the standpoint of the pathogenesis of hypotension, which is a consequence of desympatization of the heart and extensive vascular regions of the abdominal cavity and lower extremities, it is most advisable to use the mixed adrenergic agonist ephedrine, which eliminates the deficiency of venous return, eliminates bradycardia and has a positive inotropic effect.
Significantly less effective in the development of arterial hypotension is the “pure” β-adrenergic agonist mezaton, which does not increase either venous return or stroke volume and, in addition, contributes to the development of bradycardia.
IN critical situations The drug of choice is adrenaline, which is able to restore blood circulation even when cardiac activity has stopped.
The use of vasopressors provides the anesthesiologist with time for a primary diagnosis, allows the initiation of massive infusion therapy, and, in the case of the development of a total spinal block, mechanical ventilation. If treatment measures are started in a timely manner, the prognosis is usually favorable.
A specific complication of epidural anesthesia during childbirth is the development of Bernard-Horner syndrome, which is manifested by miosis, narrowing of the palpebral fissure, enophthalmos, as well as impaired lacrimation, anisocoria, injection of scleral vessels, skin hyperemia, sweating with simultaneous anesthesia of certain areas of the skin of the upper extremities and motor disorders in them on the side of the blockade. This complication is associated with a wide distribution of the anesthetic throughout the reduced epidural space and blockade of the sympathetic innervation of the cervical segments. The decrease in the volume of the epidural space is due to compression of the vessels of the inferior vena cava by the uterus, expansion of the venous plexuses of the epidural space, preventing the outflow of anesthetic through the intervertebral foramina, and the use of oxytocin to intensify contractions.
In the supine position, pregnant women may develop aortocaval compression syndrome, in which venous return to the heart is impaired. The synergy of the inferior vena cava syndrome and epidural anesthesia leads to severe hemodynamic disturbances, and therefore, during the period of delivery, it is recommended to turn the woman in labor on her left side or place a cushion under the right buttock.
During puncture, the needle may damage the veins of the epidural space, which can lead to hemorrhage and the development of a hematoma. Although blood, as a rule, freely leaves the epidural space through the intervertebral foramina, there is a danger of compression of the spinal cord by the hematoma with severe neurological consequences in the form of persistent paralysis and paresis.
Allergic reactions to local anesthetics are relatively rare and are mainly in the form of skin rashes (hives, blisters). Mostly these reactions occur after the administration of ether-type anesthetics. Rare allergic reactions that occur in response to the administration of amide anesthetics are most often associated not with the anesthetic itself, but with the stabilizer in the solution (sodium metabisulfite), the concentration of which can reach up to 2 mg/ml (J. Levy, 1990).
Patients with a history of allergic reactions to local anesthetics or patients with multiple allergies are recommended to perform skin tests to determine which drugs are safe for them.
The test is carried out one month after the allergic reaction. The patient should not take antihistamines, sympathomimetic drugs, methylxanthines, cough and cold remedies. Local anesthetics are diluted immediately before use in an isotonic sodium chloride solution. The skin of the forearm is treated with alcohol and cells measuring 2.5x2.5 cm are applied using a ballpoint pen or felt-tip pen.
Medicines are injected intradermally into the center of the square until a blister of 1-2 mm in size appears (0.01-0.02 ml of solution). If the results are negative, solutions of local anesthetics having a 10 times higher concentration are prepared and administered (Table 17).
Table 17 Doses of local anesthetics administered during skin tests
Intradermal 0.02 ml 1:100
Subcutaneous 0.1 ml 1:100
Subcutaneous 0.1 ml 1:10
Subcutaneous 0.1 ml undiluted
Subcutaneous 0.5 ml undiluted
Subcutaneous 1.0 ml undiluted

The reaction is considered positive when an infiltrate with a diameter of at least 7 mm appears within the first 10 minutes and persists for at least 30 minutes, when foci of skin hyperemia appear and persist for 30 minutes, and with generalized skin reactions (itching).
The most serious complication of epidural analgesia with opiates is respiratory depression (up to 0.4% of cases). It can develop for the first time 30-60 minutes (early depression) and 6-48 hours later (delayed depression). Most authors note that the most dangerous period is 6-12 hours after epidural microinjection.
The cause of the development of respiratory depression is undetected perforation of the dura mater during puncture of the epidural space, epidural administration of excessive doses of opiates, and the use of opiates against the background of epidural analgesia with narcotic analgesics.
The mechanism of development of respiratory depression is that an epidurally administered narcotic analgesic penetrates into the posterior parts of the subarachnoid space, rises in the rostral direction with the flow of cerebrospinal fluid and binds to opiate receptors in the area respiratory center.
Clinically, respiratory depression is manifested by the patient’s state of doubt, the presence of pinpoint “morphine” pupils and a gradual decrease in breathing to 4-6 per minute, up to apnea.
Respiratory depression caused by epidurally administered morphine is eliminated by infusion of naloxone at a dose of 5 mcg/kg.h, and weakening of analgesia occurs only when the dose of naloxone is increased to 10 mcg/kg.h. It is noteworthy that naloxone at a dose of 5-10 mcg/kg.h not only eliminates respiratory disorders, but also significantly reduces the depth of analgesia with epidurally administered fentanyl.
Acute respiratory distress is treated with a bolus of 0.4 mg naloxone. If necessary, 0.4 mg of naloxone is administered again after 2-3 minutes. In extreme cases, after short-term mask ventilation, the patient is intubated and transferred to mechanical ventilation.
When performing epidural analgesia with opiates, it is advisable to follow the following rules:
1. If damage to the dura mater is suspected, morphine should be avoided. If necessary, 25-50 mcg of fentanyl can be used.
2. No attempt should be made to enhance epidural analgesia with opiates by parenteral administration narcotic analgesics.
3. Do not exceed the calculated doses of epidurally administered narcotic analgesics.
“Minor” complications of epidural analgesia with narcotic analgesics include skin itching (up to 8% of cases), nausea and vomiting (up to 12% of cases).
Skin itching may be limited to the zone of segmental analgesia, however, it is more often observed on the face, neck, torso, and is sometimes generalized. The frequency of itching increases sharply when using morphine at a dose of 5 mg or more. The duration and intensity of skin itching varies from several tens of minutes to many hours.
Nausea and vomiting typically occur after the onset of pruritus, with nausea occurring 4 and vomiting 6 hours after epidural microinjection.
Skin itching, nausea and vomiting special treatment not required.
Transient urination disorder during epidural analgesia with morphine in a dose of 5 mg or more is observed in 60% of patients, however, this is not a complex problem, since in intensive care units, most patients with severe pathology undergo bladder catheterization to record diuresis.
The frequency of manifestations of the general toxic effect of drugs used for regional anesthesia is 1-5% and is associated either with an overdose of a local anesthetic or with its intravascular administration during accidental catheterization of the veins of the epidural space. Particularly dangerous is the intravascular administration of bupivacaine, which causes cardiac arrest that is resistant to therapy.

Clinical manifestations of local anesthetic toxicity.

Easy degree gravity. Patients complain of dizziness, tinnitus, and numbness around the mouth. Confusion, dilated pupils, nausea, hypertension, tachycardia, and respiratory depression are noted.
Moderate severity. The patient experiences twitching of the facial muscles, grimaces, then develops generalized tonic-clonic convulsions, vomiting, tachycardia, a decrease in blood pressure to 60-80 mm Hg, and respiratory failure (up to apnea).
Severe degree. The patient's consciousness is lost to coma, mydriasis, respiratory arrest, deep hypotension, sinus bradycardia, impaired myocardial conduction, development of ventricular extrasystoles with subsequent cardiac arrest.
Treatment of toxic manifestations of local anesthetics consists primarily of the use of anticonvulsants(barbiturates), tracheal intubation and mechanical ventilation at FiO2=l.0, massive infusion of blood substitutes, administration of hormones (prednisolate up to 30 mg/kg). When bradycardia develops, atropine is used (0.5 - 1.0 - 1.5 mg). In case of cardiac arrest, resuscitation measures are carried out. It should be remembered that in case of cardiac arrest caused by the toxic effects of bupivacaine, cardiopulmonary-cerebral resuscitation should be carried out for at least 60 minutes.
It is not recommended to leave the catheter in the patient for more than 4-7 days, since the risk of infection of the epidural space increases in proportion to the increase in this period.
One of the most dangerous complications of epidural and spinal anesthesia is the development of purulent epiduritis. The first signs of this complication occur 3-7 days after the start of anesthesia and are manifested by weakness, headache, hyperthermia, pain in the area where the catheter or puncture is located during movements, when tapping the spinous processes, when administering a local anesthetic or narcotic. In a later period, the pain is diffuse in nature, and the appearance of skin hyperthesia is noted. As the process progresses, skin sensitivity decreases, due to compression of the roots, reflexes decrease, and sometimes Kernig's symptom occurs. In some cases, there is the development of paraparesis with decreased sensitivity and dysfunction pelvic organs.
If purulent epiduritis is suspected, the catheter must be removed and its microbiological examination performed. The diagnosis and localization of epiduritis is clarified by epidural puncture, for which the three-needle technique is used (V.I. Kostyunin, 1977). One needle is inserted into the place of the previous injection, the second is one vertebra higher, the third is lower one vertebra. The insertion of needles should be very careful, the needle pitch should not be more than 1.5-2.0 mm. To identify the epidural space, you should use a syringe filled with air (an isotonic sodium chloride solution, expanding the epidural space, destroys the inflammatory barrier, which, as a rule, limits the spread of the purulent process). The presence of thick pus indicates the development of an epidural abscess, cloudy fluid - purulent epiduritis.
After evacuation of the discharge, antibiotics of the aminoglycoside group are administered into the epidural space (1 g kanamycin or 80 mg gentamicin or 3 mg/kg netilmicin). The administration of antibiotics is repeated 2-3 times every 2-3 days. In addition, a course of massive antibacterial therapy is carried out, including the appointment of cephalosporins of the 2nd - 3rd generation in combination with 2-3 generation aminoglycosides, in maximum doses.
In the initial period of the disease, such patients should be examined by a neurosurgeon, since the optimal period for surgical intervention is the period of local soreness and radicular pain before the development of symptoms of spinal dysfunction (I.M. Irger, 1988).

Complications of spinal anesthesia

Hypotension is an integral component of the course of spinal anesthesia. The degree of its severity is determined by the level of anesthesia and the implementation of appropriate preventive measures. Carrying out preoperative infusion "support" (M. Dobson, 1989), intraoperative infusion therapy in the mode of hypervolemic hemodilution, the use of ephedrine, and slow introduction of an anesthetic into the subarachnoid space exclude the development of severe hemodynamic disorders.
In the case of the development of severe hypotension and the inability to significantly increase the rate and volume of infusion therapy, intravenous jet administration of 3.0-3.5 ml/kg of patient's body weight of a 7.5% sodium chloride solution is indicated for 3-5 minutes. A rapid increase in plasma sodium levels creates a high transmembrane gradient and, by mobilizing fluid from the interstitial space, increases intravascular volume, effectively correcting hypotension.
If preventive measures are not taken, then in 80% of cases during spinal anesthesia, deep hypotension suddenly develops, requiring correction by immediate administration of colloid solutions and adrenergic agonists.
When narcotic analgesics are used for spinal anesthesia, respiratory depression may develop. The respiratory-depressive effect of morphine is proportional to its administered dose and is pronounced after intrathecal injection of more than 1-2 mg.
To prevent respiratory depression, the dosage of narcotic analgesics should be strictly observed and the patient should be placed in a semi-sitting position. Naloxone (0.4 mg) is used as a morphine antagonist, which eliminates unwanted effects opiates. According to indications, the patient is transferred to mechanical ventilation until spontaneous breathing is restored.
One of the main factors causing the development of neurological complications during spinal anesthesia is injury to the spinal cord or its roots during puncture. Injury to the spinal cord root by a needle is accompanied by the appearance of sharp pain along the nerve trunks in the form of “shots” in the lower extremities, which should always be alarming, as this can lead to serious neurological consequences such as radiculitis with paresthesia, residual paralysis or cauda equina syndrome.
Interspinous ligamentosis is manifested by severe back pain (not only in the puncture area, but throughout the entire spinal column). The development of this complication is associated with traumatic manipulations, repeated punctures, and aseptic inflammation. As a rule, back pain does not require special treatment and disappears on its own by 5-7 days. For persistent pain, darsanvalization of the puncture site or magnesium electrophoresis is effective.
To avoid such complications, one should strictly observe maximum caution and anatomy when puncturing the subarachnoid space.
Headache after spinal anesthesia occurs in 1.5% to 14% of cases. The pathophysiological basis of headache is considered to be a gross puncture of the dura mater and the associated liquorrhea (S.S. Yudin, 1925, B.A. Petrov, P.C. Lund, 1969). The causes of headaches in the postpuncture period may be a decrease in cerebrospinal fluid pressure and irritation of the meninges.
Post-puncture headache three times more common in patients suffering from headaches before spinal anesthesia. The frequency of cephalgia increases markedly in women aged 18 to 30 years, especially those with a low body mass index (weight/height ratio) and endocrine diseases. When the needle cut is directed perpendicular to the longitudinal fibers of the dura mater, the frequency of post-puncture headaches reaches 16.1%, while when the needle cut is directed longitudinally relative to the fibers of the dura mater, it is only 0.24% (Morris M.C. et al, 1989). When performing punctures with needles of 22G or more gauge, headache occurs in 10-15%. The anesthetic used also plays a role in the development of cephalgia: lidocaine, bupivacaine, tetracaine (Naulty J.S. et al, 1985). Our experience shows that the use of combinations of local anesthetics with narcotic analgesics and clonidine significantly reduces the frequency of headaches and their intensity.
To prevent post-puncture headache, small-diameter puncture needles (25 G or less), such as “pencil point”, should be used. After administration of the local anesthetic, the needle is removed 0.5-0.6 cm until the flow of cerebrospinal fluid from the pavilion stops, and 10-15 ml of isotonic sodium chloride solution is injected epidurally (isotonic sodium chloride solution corrects the negative pressure in the epidural space and thereby prevents the leakage of cerebrospinal fluid ).
Headaches may occur 2-3 days after the surgical period and last no more than 1-2 days. They usually respond well to drinking plenty of fluids. In case of persistent headaches that get worse in an upright position, in addition to drink plenty of fluids, infusion therapy is prescribed in a volume of 1.5-2.0 liters per day, analgesics, antispasmodics, B vitamins, intravenous administration of 40% glucose solution, 20% caffeine solution, 25% magnesium sulfate solution, 20% piracetam solution.
A good effect is shown with intravenous administration of 500-1000 mg of caffeine in 1000 ml of Ringer's solution, leading in 80% of cases to a decrease in the intensity of headaches (Cammann W.R. et al, 1990).
For severe cephalgia that cannot be controlled conservative methods treatment, in order to reduce liquorrhea, epidural administration of “sealing” solutions, which use autologous blood, is indicated. The epidural space is punctured with a Tuohy needle at the level of the previous lumbar puncture and 15-20 ml of autologous blood is injected epidurally (Gormley J.B., 1960). The effectiveness of “filling” with autologous blood reaches 90% (Choi A. et al, 1996).
For persistent headaches, good results have been obtained from the use of physiotherapeutic procedures: endonasal glutamic acid electrophoresis, magnesium electrophoresis in the cervical spine, and the use of sinusoidal modulated current in the area of ​​the cervical sympathetic nodes (L.A. Rybakov, 1996).
The leading method in the prevention of headaches in the postpuncture period is the use of needles of the smallest diameter (22-28G) for spinal anesthesia and the prevention of excessive leakage of cerebrospinal fluid from the needle.
It is noteworthy that with the paramedian approach, the puncture holes in the dura mater and the arachnoid mater do not coincide, which prevents liquorrhea.
Sometimes, a headache of the nature of cephalalgia is accompanied by visual and hearing impairment. This is due to the fact that when the pressure of the cerebrospinal fluid decreases, the cerebellum and the pons of the brain shift slightly, which causes tension on the abducens nerve, which is fixed in the petrous part of the temporal bone. Paresis of the abducens nerve leads to the development of convergent strabismus and diplopia.
After spinal anesthesia, deafness may develop, accompanied by vestibular disorders, including unilateral ones. This is explained by a decrease in liquor pressure and, accordingly, a decrease in pressure in the inner ear.
The method of treating these complications is “sealing” the epidural space with autologous blood and infusion therapy.
Aseptic meningitis is manifested by hyperthermia, headache, rigidity neck muscles, photophobia. Symptoms of aseptic meningitis occur within 24 hours after spinal anesthesia and last no more than a week.
Cauda equina syndrome. In 90% of cases, the development of this complication is preceded by the occurrence of paresthesia during a spinal puncture. Clinically, the syndrome is manifested by loss of sensitivity in the perineal area, varying degrees of paresis of the lower extremities, urinary and fecal incontinence. The syndrome occurs after the end of anesthesia and gradually regresses over a period of several weeks to several months.
Adhesive arachnoiditis is a more serious complication of spinal anesthesia, which develops gradually, several weeks after anesthesia. There is weakness, loss of sensation in the lower extremities and, ultimately, complete paraplegia develops.
Neurological problems usually resolve within a few days, but if symptoms persist for 6-12 months, full recovery functions of the nervous system seem doubtful.
Quite rare complications of spinal anesthesia include hair loss, blurred vision with the development of scotoma, and sudden delayed cardiac arrest.

Spinal anesthesia is performed according to the following scheme:

Before surgery: a catheter is installed in a peripheral vein and infusion support begins, which is carried out either in the form of pre-infusion with crystalloids in a volume of 1000 ml or synthetic colloids (HES, gelatin) in a volume of 500 ml, or infusion is carried out after regional anesthesia in the same composition. In any case, the administration of the infusion should not delay the operation (ASA recommendations, 2007). Infusion does not completely prevent the development of arterial hypotension(aortocaval compression).

Bladder catheterization is performed.

Non-invasive monitoring (BP, HR SpO2, ECG)

Premedication includes an anticholinergic agent (atropine 0.5 mg), antihistamine(diphenhydramine 10 mg)

Spinal anesthesia technique: The patient’s position is sitting with her legs down or lying on her side with her back arched. The puncture site is treated (from the coccyx to the lower angle of the shoulder blades) and through a pre-inserted introducer at level LII-LIII, a puncture of the subarachnoid space is performed. Only needles of size 25-29 G should be used and preferably “pencil-point” sharpening. The entry of a needle into the subarachnoid space is determined by the appearance of cerebrospinal fluid in the transparent cannula of the needle. After administration of the local anesthetic, the needle is immediately removed and a sterile napkin is applied to the puncture site.

Technique for performing epidural anesthesia: Initial measures are similar to those for spinal anesthesia.

After treatment with an antiseptic, the puncture site is anesthetized: 1% is usually used lidocaine solution 3-5 ml.

The Tuohy needle is inserted between the spinous processes of L2-L3 or L3-L4 in a horizontal position on the side or in a sitting position. Any access option can be used - medial, paramedian or lateral. The needle with mandrel moves forward slowly and carefully to avoid accidental puncture of the dura mater. Entry of the needle lumen into the epidural space is identified using the following signs:

• feeling of needle “failure”
• loss of resistance (Sicara and Forestier) - no sensation of resistance when introducing liquid with a syringe through a needle, the air bubble in the syringe does not deform
• no leakage of cerebrospinal fluid or blood
• free passage of the catheter beyond the needle

After installing the catheter, an aspiration test is required.

After administration of a “test dose” of local anesthetic there are no signs of spinal anesthesia. Carrying out a “test dose” is mandatory!

After identifying the epidural space, the catheter is advanced 3 cm upward and secured to the skin along its entire length with an adhesive tape or other fixative. During epidural anesthesia during labor, the patient should avoid the supine position to prevent aortocaval compression.

Next, the patient is placed in the position for surgery: on her back with a tilt to the left - 150, placing a bolster or changing the angle of the operating table to reduce the degree of aortocaval compression. The horizontal position of the operating table must be carefully monitored, especially during spinal anesthesia and the use of a hyperbaric local anesthetic solution. It is unacceptable to use the provisions of Fowler and Trendelenburg.

To sedate the patient during surgery, intravenous anesthetics such as sodium tipopental 1-3 mg/kg and propofol 1-3 mg/kg can be used. The latter also has an antiemetic effect, which is especially important for the development of nausea and vomiting during spinal anesthesia.

Thus, the following schemes of spinal anesthesia for cesarean section can be proposed:

1. Marcain Spinal 10.0-12.5 mg intrathecally.
2. Marcain Spinal 10.0-12.5 mg intrathecally + sedation intravenously sodium thiopental 50-100 mg, propofol 50-100 mg.

Epidural anesthesia regimensduring a cesarean section (it is optimal to inject the local anesthetic into the epidural space in fractions):

1. Ropivacaine 0.75% – 15-20 ml
2. Bupivacaine 0.5% – 15-20 ml

The first experiments in the use of spinal anesthesia date back to 1898, but this method of pain relief became widespread much later. To use this method the doctor must have certain knowledge in the field of anatomy of the spinal cord and its membranes.

Epidural and spinal anesthesia

These methods of pain relief are regional. During these procedures, an anesthetic substance is injected into a special area located near the spinal cord. Thanks to this, the lower half of the body is “frozen”. Many people do not know whether there is a difference between spinal and epidural anesthesia.

The preparation procedure and anesthesia with these methods are similar. After all, in both cases an injection is given in the back. The fundamental difference is that spinal anesthesia is a single injection, while epidural anesthesia is the installation of a special thin tube through which an anesthetic is administered over a certain period of time.

But the technique of execution is not the only difference between these two methods of pain relief. Spinal anesthesia is used in cases where it is necessary to achieve a short-term effect. Depending on the type of drugs used, the duration of pain relief can vary from 1 to 4 hours. Epidural anesthesia is not limited in time. Pain relief will continue as long as the anesthetic is supplied to the body through the installed catheter. This method is often used to relieve the patient from pain not only during surgery, but also in the postoperative period.

Operating principle

Peridural and epidural anesthesia are regional anesthesia in which drugs are injected into the epidural space of the spine. The principle of its action is based on the fact that the drugs used enter the subarachnoid space through the dural couplings. As a result, impulses traveling along the root nerves to the spinal cord are blocked.

After all, the drug is administered in close proximity to the trunk with nerve cells. Namely, they are responsible for the appearance of pain in various parts of the body and transmitting it to the brain.

Depending on the site of administration of the drug, it is possible to disable motor activity and sensitivity in certain areas of the body. Most often, epidural anesthesia is used to “switch off” the lower half of the body. To do this, it is necessary to inject an anesthetic into the intervertebral space between T10-T11. To numb the chest area, the drug is injected into the area between T2 and T3; the upper half of the abdomen can be numbed by injecting into the area of ​​the T7-T8 vertebrae. The area of ​​the pelvic organs is “switched off” after the introduction of an anesthetic into the space between L1-L4, the lower limbs - L3-L4.

Indications for the use of regional anesthesia

Epidural and spinal anesthesia can be used either separately or in combination with general anesthesia. The latter option is used in cases where thoracic operations (on the chest) or long-term surgical interventions in the abdominal area are planned. Their combination and the use of anesthetics can minimize the patient's need for opioids.

Separately, epidural anesthesia can be used in the following situations:

Pain relief after surgery;

Local anesthesia during childbirth;

The need for operations on the legs and other parts of the lower half of the body;

Carrying out a caesarean section.

In some cases, epidural anesthesia is used exclusively. It is used when it is necessary to carry out operations:

On the pelvis, thigh, ankle, large;

For hip or knee replacement;

For hernia removal.

Spinal anesthesia may be used as a treatment option for back pain. It is often done after operations. It is also used in vascular surgery in cases where it is necessary to perform intervention in the lower extremities.

Pain relief for childbirth

More and more women are using epidural or spinal anesthesia to avoid painful contractions. When the anesthetic is administered, the pain sensations disappear, but consciousness is retained in full.

Epidural anesthesia for childbirth is often used in developed countries. According to statistics, it is used by about 70% of women giving birth. This type of anesthesia allows you to numb the entire birth process. However, this does not affect the fetus in any way.

Despite the fact that childbirth is a natural physiological process that does not require outside intervention, more and more women insist on being given anesthesia. Although during childbirth, the body produces a shock dose of endorphins. They promote natural pain relief, because these hormones can provide emotional uplift and suppress feelings of fear and pain.

True, the mechanism for producing endorphins depends on the condition and mood of the woman. For example, a prolonged labor with severe pain negatively affects both the woman in labor and the unborn baby. In addition, a woman may experience increased blood pressure, loss of strength, and disturbances in the functioning of the main muscle - the heart. In such cases, pain relief is necessary.

But only on a planned basis can epidural anesthesia be performed. Contraindications to its implementation are quite common. But in emergency cases it is not used also because its effect does not occur instantly. It may take half an hour from the start of the administration of anesthetics to complete anesthesia.

Nuances of preparation

If possible, the patient is pre-prepared for pain relief. If epidural (peridural), spinal anesthesia is planned, then in the evening the patient is given up to 0.15 g of Phenobarbital. If necessary, a tranquilizer may also be prescribed. As a rule, doctors use the drugs “Diazepam” or “Chlozepid”. In addition, about an hour before the introduction of anesthesia, intramuscular injections of Diazepam or Diprazine are indicated; Morphine and Atropine or Fentaline may also be prescribed.

Also an obligatory step is the preparation of sterile installation. To carry it out, you need napkins (both large and small), sterile rubber gloves, gauze balls, needles, syringes, catheters, two tweezers and two glasses for anesthetic solutions. It is also important to prepare everything necessary to be able to eliminate possible complications. With such anesthesia, the possibility of severe disruptions in the functioning of the circulatory and respiratory systems cannot be ruled out.

2 syringes are pre-prepared, one of which should have a volume of 5 ml, and the second - 10 ml. The medical staff also prepares 4 needles, 2 of which are needed to anesthetize the area of ​​skin where the main injection will be made. Another one is needed to inject the anesthetic and pass the catheter, and the last one is needed to withdraw the anesthetic medication into a syringe.

Carrying out pain relief

Spinal and epidural anesthesia is given to the patient who is sitting or lying on his side. As a rule, the latter provision is used much more often. In this case, the patient should bend his back as much as possible, pull his hips towards his stomach, and press his head to his chest.

The skin in the injection area is carefully treated and covered with sterile napkins. This is done in the same way as before the operation. The skin at the planned puncture site is anesthetized. In addition, to make it easier to pass the needle through the skin, it is recommended to make a small puncture with a narrow scalpel.

Experts distinguish two methods of how access to the epidural spinal space can be achieved: median and paramedian. In the first case, the needle is inserted into the space between the spinous processes. After passing through the skin and fatty tissue, it first abuts the supraspinous and then the interspinous ligament. In elderly patients, they may become calcified, which makes inserting the needle much more difficult.

The lateral, or paramedian method provides that the injection is made into the border area located between the vertebrae. It is carried out from a point located 1.5 or 2 cm from the spinous processes. But this method is used when it is not possible to puncture the canal using the median method. It is recommended for obese patients with sclerotic ligaments.

Features of the “epidural”

Before planned operations, patients and their anesthesiologist decide what kind of anesthesia will be used. But many patients want to figure out for themselves what epidural and epidural anesthesia are. What is the difference between these methods cannot be found out. After all, these are two names for the same method of pain relief, in which the anesthetic is gradually introduced into the body through a catheter.

The doctor must know the nuances of the puncture. For example, to administer an epidural, the needle must pass through the ligamentum flavum. To do this, remove the mandrin and attach a syringe containing a solution of sodium chloride, so that an air bubble remains. Once the needle enters the ligament, the air bubble will appear compressed. But it straightens out as soon as the tip enters the epidural area.

The anesthesiologist should also be aware of other methods of checking whether the needle is positioned correctly. The fact that everything is normal is indicated by the absence of cerebrospinal fluid in the needle after its patency was checked with a mandrel. Also ensure that the small amount of saline injected does not flow back through the needle after the syringe is disconnected. But this is not a complete list of verification methods. The doctor must carry out a comprehensive diagnosis to ensure that the needle is positioned correctly.

Epidural anesthesia requires the use of a catheter. Its introduction, as a rule, does not present any difficulties. Once selected and checked for patency, it is advanced through the needle into the epidural space. After this, the needle is gradually removed, and the catheter is fixed, covering the exit site with a bactericidal patch or sterile bandage.

Medicines used

To minimize possible complications during epidural anesthesia, it is important to select the correct dose of anesthetic and correctly carry out the puncture procedure itself. For pain relief, purified solutions of anesthetics that do not contain preservatives are used.

In some cases, lidocaine is used for epidural anesthesia. But they also use drugs such as Ropivacaine and Bupivacaine. Under the supervision of a highly qualified, experienced physician and when indicated, medications related to opiates may be added. These may be medications such as Morphine, Promedol. But the dosage of these drugs is minimal. It cannot even be compared with the one that is used for

When an anesthetic is introduced into the epidural area, the latter spreads along it in various directions. It passes up, down and into the paravertebral tissue through the intervertebral lateral foramina. At the same time, when figuring out what the concentration of “Dicain” should be for epidural anesthesia, one must remember that the anesthesia zone will depend on the amount of solution, intensity of administration and dosage. In addition to the above, they can also use the products “Xikain”, “Trimekain”, “Markain”. For complete anesthesia, about 25-30 ml of solutions of these anesthetics can be used. But this number is considered the maximum.

Necessary restrictions

Despite the fact that epidural anesthesia is considered one of the safest, it still has contraindications. These include:

Tuberculous spondylitis;

Pustules on the back;

Traumatic shock;

Organic lesions of the central nervous system;

Complex spinal deformities, diseases and pathological injuries;

Intestinal obstruction;

Cardiovascular collapse resulting from peritonitis;

General serious condition of the patient;

Decompensation of the heart;

Childhood;

Hypersensitivity to anesthetic components;

Exhaustion of the body.

Possible problems

But do not forget that epidural anesthesia is not always painless and without consequences. Contraindications and complications that may occur must be clarified before going on the operating table.

You must understand that the technique of performing such anesthesia is complex, so the qualifications of the doctor are crucial. The most dangerous is the occurrence of deep collapse after spinal or epidural anesthesia. Most often, this condition occurs when the dura mater is damaged. Because of this, a blockade of sympathetic innervation occurs, as a result, vascular tone decreases, and severe hypotension develops. However, this condition can also develop if anesthesia is performed correctly in cases where a large proportion of the anesthetic is administered, hoping to anesthetize a wide area.

But problems can also develop in the postoperative period. These include:

The onset of an inflammatory purulent process in the spinal cord canal (the cause, as a rule, is a violation of antiseptic rules);

Headache and discomfort in the back area;

Pelvic organs (can develop due to needle damage to the spinal cord roots).

If patients are given anesthesia using Morphine, they should be monitored more closely. Indeed, sometimes such epidural anesthesia leads to respiratory depression. There are no separate contraindications for using this method. But it is worth remembering that the risk of respiratory depression increases with increasing morphine dose.

Features of spinal anesthesia

Despite the similarities, there are significant differences between epidural and spinal anesthesia. For example, the position of the needle after a puncture is not so important. As soon as the needle passes the dura mater, the doctor feels a sinking feeling of the needle. A catheter is not installed for this type of anesthesia.

When making a puncture, care must be taken to ensure that the needle does not go too far and damage the roots of the spinal cord. The fact that the tip has already entered the subarachnoid space can be confirmed by removing the mandrin. At the same time, the needle will begin to discharge. If it flows intermittently or in insufficient quantities, then its position must be slightly changed by rotation. After correct installation of the needle, the administration of analgesics begins. Their dosage is less than that of epidural anesthesia.

The technique of performing anesthesia is similar to performing spinal anesthesia, but it is necessary to perform a puncture so as not to puncture the dura mater. A special Tuohy needle is used, which makes it easy to pass the catheter into the epidural tissue.

After anesthesia of the skin of the subcutaneous tissue, the supraspinous and interspinous ligaments are pierced with a needle and mandrel, i.e. to a depth of about 5 cm. Next, the mandrin is removed from the needle and a spitz with a 0.9% sodium chloride solution is attached. It is impossible to fill the syringe with an anesthetic solution, since an erroneous puncture of the dura mater can accidentally introduce an unacceptably large dose of anesthetic into the subarachnoid space.

Sign of “loss of resistance”. When the needle passes through the ligamentum flavum, pressing on the syringe piston causes a feeling of springy resistance; when the tip of the needle enters the epidural tissue, a sensation of “failure” occurs, the piston moves freely forward.

Air bubble. There is a small air bubble in the saline syringe attached to the puncture needle. During the passage of the ligaments, pressing on the piston compresses the bubble. The piston exerts spring resistance. When it enters the epidural space, the bubble immediately stops compressing and the spring resistance disappears.

Hanging drop sign. A drop of saline solution is suspended from the needle pavilion. When the tip of the needle enters the epidural tissue during inspiration, the drop is drawn into the needle. You can do the same by attaching a thin transparent tube (venous catheter) with a column of liquid to the needle.

Immediately after identifying the epidural space, the advancement of the needle must be stopped and, after making sure that there is no flow of blood and cerebrospinal fluid through the needle, the anesthetic must be administered. The flow of blood through the needle indicates a wound to the venous plexus. In this case, it is necessary to repeat the puncture 1 vertebra higher or lower. The flow of cerebrospinal fluid through the needle indicates a puncture of the subarachnoid space. In this case, according to some authors, it is possible (and in most cases rational) to perform spinal anesthesia. Other experts believe that the needle can be pulled out a few millimeters until the flow of cerebrospinal fluid stops, and then catheterization of the epidural space should be performed. The probability of the catheter and the injected anesthetic getting into the puncture of the dura mater, in their opinion, is extremely small

According to the level of puncture, they are distinguished:

high epidural anesthesia (in the thoracic region): the puncture level between Th2 and Th3 gives anesthesia of the chest; between Th7 and Th8 - the upper half of the abdomen; between Th10 and Th11 - the lower half of the abdomen;

moderate epidural anesthesia (upper lumbar region): puncture between L1 and L2 gives anesthesia to the lower half of the abdominal cavity;

lower epidural (lower lumbar): injection of anesthetic between L3 and L4 produces anesthesia of the perineum and lower extremities.

After identifying the entry of the Tuohy needle into the epidural space, a plastic catheter is inserted along it, which is advanced 3-5 cm in the cranial direction, after which the needle is carefully removed. Many branded disposable epidural sets include catheters with a radiopaque marker on the end that allows you to monitor the catheter's position if necessary. The catheter is fixed to the skin along the spine with an adhesive tape, and its end is brought out to the area of ​​the shoulder girdle. An adapter is attached to the end of the catheter. Medications are administered into the catheter only through a bacterial filter.

After catheterization, a test dose of local anesthetic (2-3 ml) is administered to eliminate the possibility of the catheter getting into the subarachnoid space. If after 3 minutes a spinal block does not develop, administer the main dose of the drug (see Table 2) in 15-20 ml of solution; when performing several punctures to obtain a larger area of ​​anesthesia, the total amount of solution should not exceed 20-30 ml. When adrenaline (1:2000) is added to anesthetic solutions, due to slower adsorption, the duration of their action increases by 1.5-2 times, and the maximum dose can be increased by 20-25%.

Table 2.

Local anesthetics for epidural anesthesia

The catheter can remain in the epidural space for 3-5 days. The method is especially valuable during major operations on the abdominal cavity, since it contributes to the rapid resolution of intestinal paresis.

In recent years, narcotic analgesics have begun to be used for epidural anesthesia (Fnetanil 100-200 mcg, less often morphine up to 2 mg/kg). It was found that they quickly diffuse into the subarachnoid space and interact with opiate receptors in the spinal cord. Narcotic analgesics can be combined with local anesthetics or used alone. The use of clonidine (100-200 mcg per injection) for epidural anesthesia is promising. The analgesic effect lasts on average 8.5 hours.