What drug is used for spinal anesthesia. How and why is spinal anesthesia performed? Positive and negative aspects of the method

03.09.2020

These methods in essence relate to conduction anesthesia, since the analgesic effect is achieved mainly due to the blockade of the roots of the spinal cord, and not directly affecting it.

History.

The first step towards the development and implementation of these methods in practice should be considered the results of the study of Corning (1885), who studied the effect of a solution of cocaine on the conduction of the spinal nerves. During operations in clinical conditions, spinal (spinal) anesthesia was first used by M. Bier in 1898. In Russia, it was first used by Ya.B. Zel'dovich in 1899. The works of domestic surgeons, S. S. Yudin, contributed to the widespread introduction of this type of anesthesia. , A. G. Savinykh, B. A. Petrov, B. E. Frankenberg.

Although the efficacy of local anesthetics on the spinal cord roots in the subdural and epidural spaces is generally similar, surgeons preferred spinal anesthesia from the outset. The reason, apparently, was the more complex technique of injecting anesthetic into the epidural space.

Anatomy.

The spine, consisting of 7 cervical, 12 thoracic, 5 lumbar vertebrae, sacrum and coccyx, is a solid whole thanks to the ligaments that hold the vertebrae together. The main ones are supraspinous, interspinous and yellow. The first connects the spinous processes from the 7th cervical vertebra to the sacrum. The interspinous ligaments fasten all the vertebrae in the sagittal plane, and the intertransverse ones in the frontal plane. The yellow ligament, which runs between the inner edges of the vertebral arches, is very dense. It completely covers the back of the spinal canal. When puncture of the spinal canal, all these ligaments have to be overcome, except for the transverse ligament.

The spine does not occupy a strictly vertical position, but is curved in the sagittal plane: in the cervical and lumbar regions, the bends are convex forward, and in the thoracic and sacral regions, the convexity is backward. In spinal anesthesia, this is of practical importance, allowing one to predict the effect of gravity and the patient's body position on the spread of the anesthetic, and by changing the bend of the lumbar spine and body position to achieve the required level of anesthesia.

The physiological curves of the spine and the unequal shape of the vertebrae in its various parts also determine some uniqueness of the conditions for puncture of the spinal canal. The position of the spinous processes is of great importance in this respect. The cervical, two upper thoracic and lower lumbar spinous processes are located almost horizontally and in their level completely correspond to the vertebrae from which they depart. The spinous processes of the rest of the vertebrae are directed downward and are tiled overlapping one another. Therefore, their tops are almost at the level of the bodies of the underlying vertebrae, covering the yellow ligament behind. With the maximum flexion of the neck and trunk forward, the spinous processes move apart somewhat, which, during puncture, improves access to the spinal canal.

The epidural and subdural spaces are distinguished in the spinal canal. The first of them is an annular slit, bounded outside by the wall of the spinal canal, and from the inside by the dura mater. The epidural space vertically ends blindly at the top of the large foramen of the occipital bone, below - at the coccyx. It is filled with adipose tissue with elements of connective tissue. It contains lymphatic and blood vessels with a widely branched plexus located mainly behind. The width of the epidural space in the back in the cervical spine is 1 - 1.5 mm, in the middle thoracic region - 2.5-4.0 mm, in the lumbar - 5.0-6.0 mm. Through the lateral openings of the spinal canal, this space is connected to the paravertebral, where the spinal roots, merging, form segmental nerves.

The solution, injected into the epidural space, spreads not only up and down, but also quite freely penetrates the tissue surrounding the roots through the lateral openings into the paravertebral space.

The main place in the spinal canal is occupied by the spinal cord. Being a continuation of the medulla oblongata, it ends below at the level of the 2nd lumbar vertebra. The inconsistency between the length of the spinal cord and the size of the spine arising in the process of development of the organism is the reason for the increasing inconsistency of the discharge of the nerve roots with the level of the segments innervated by them from top to bottom. The outer shell of the spinal cord is the dura mater. It is a dense fibrous formation that creates a kind of sac, starting from the foramen magnum and ending at the lower edge of the second sacral vertebra. The hard shell wraps not only the spinal cord, but also its roots, gradually thinning on them, along the way through the lateral intervertebral foramen. The second sheath of the spinal cord is the arachnoid. It is very thin and quite close to the dura mater. The third shell is called soft. It directly covers the spinal cord. The space between the arachnoid and soft membranes is filled with cerebrospinal fluid.

If the spinal cord ends at the level of the 2nd lumbar, then the dural sac - at the level of the 2nd sacral vertebrae. Below the cone of the spinal cord, the roots in the so-called cauda equina stretch inside the subarachnoid space in the direction of the corresponding intervertebral foramen. The length of this path for passing roots is different: the underlying roots go further down it than the overlying ones. As a result, the general direction of the nerve fibers in the cauda equina is fan-shaped. The considered part of the subarachnoid space is the place where the largest amount of cerebrospinal fluid is concentrated, and therefore, in the aspect of spinal anesthesia, it is of greatest interest.

Execution technique.

Technique for performing spinal anesthesia. Epidural and spinal anesthesia methods in preparation for conduction and the technique of their implementation have much in common. When determining premedication, one must proceed from the need for reliable prevention of severe mental stress in patients, the reduction of which is facilitated by proper psychological preparation during the preoperative examination by an anesthesiologist. Along with this, direct drug preparation should to some extent increase the effectiveness of anesthesia. Benzodiazepines play an important role in achieving this goal.

An important condition for epidural and spinal anesthesia is a pre-prepared sterile placement. It should include: several large and small napkins, gauze balls, rubber gloves, cups for anesthetic solution and search solution, two tweezers, a set for epidural (spinal) anesthesia, syringes and needles for anesthesia of the skin, subcutaneous tissue and the introduction of the main anesthetic.

Due to the fact that with the considered methods of anesthesia, the possibility of complications in the form of severe respiratory and circulatory disorders cannot be excluded, everything necessary to eliminate these disorders must be provided.

Puncture of the spinal canal.

Puncture of the spinal canal with the considered method of anesthesia is carried out in the patient's sitting position or on his side. The latter position is used more often. The patient's back should be bent as much as possible, the head is brought to the chest, the hips are pulled up to the stomach. The skin in the area of \u200b\u200bthe puncture is treated as thoroughly as for the operation, after which it is covered with sterile linen.

There are two approaches to the spinal canal: median and lateral (paramedial). In the first case, the needle is inserted in the interval between the spinous processes, taking into account the angle formed by them in relation to the axis of the spine. With this access, the inserted needle, passing through the skin and subcutaneous tissue, meets resistance first of the supraspinatus and then the interspinous ligaments. In elderly and elderly patients, these ligaments are usually very dense and even calcified. In such cases, paramedial access is preferred.

For paramedial access, the needle is inserted from a point located 1.5-2 cm from the line of the spinous processes. The needle is guided somewhat medially in such a way that its tip comes out to the intercutaneous space along the midline.

The main stages of spinal anesthesia are: puncture of the subarachnoid space and the introduction of anesthetic; obtaining the required level of anesthesia. Monitoring the functions of the cardiovascular system and gas exchange, as well as the prevention and treatment of their possible disorders during the receipt and maintenance of anesthesia is a prerequisite. For spinal anesthesia, thin needles of 25.26G are mainly used. The use of needles with a larger diameter (up to 22G inclusive) is allowed only if it is necessary to overcome the ossified ligamentous apparatus of the spine. The use of thicker needles can lead to leakage of cerebrospinal fluid and the development of cerebral hypotension syndrome. The use of thinner needles is associated with the difficulty of inserting them and the need to use guide needles.

Spinal anesthesia technique. After cannulation of the vein and infusion of crystalloid solutions in a volume of 10-15 ml / kg of body weight in the position on the "diseased" side or sitting, the intervertebral spaces at the L2-S1 level are identified with the choice of the most convenient for puncture. Local anesthesia of the skin is performed in the center of the selected space. The fingers of the left hand are used to fix the skin at the puncture site. The needle is taken in the right hand in such a way that its pavilion is held in the palm of the hand by the little finger and ring fingers, and the index and thumb fixed the needle at a distance of 3-4 cm from its end. The needle is inserted strictly along the midline into the thickness of the interspinous ligament to a depth of 3 cm. After making sure that the direction is correct, the needle is advanced through the intervertebral foramen into the spinal canal with a forward movement of the index and thumb of the right hand. Attempts to overcome hard obstacles by force should be avoided, which can lead to the curvature of the needle. Changing the direction of the needle by re-insertion from the supraspinatus ligament in the sagittal direction usually allows atraumatic penetration into the spinal canal. With spinal anesthesia, there is no need for the precautions to prevent puncture of the dura, as is the case with epidural anesthesia. However, the needle must be passed through the yellow ligament carefully so that, overcoming the resistance of the ligament, it does not go deeply and does not damage the roots. Then, after removing the mandrel, check whether the cerebrospinal fluid comes from the lumen of the needle. If this is not the case, the needle with the mandrel inserted into it is advanced a little deeper, thus achieving the release of cerebrospinal fluid. Unstable and insufficient supply of it can be due to three reasons: incomplete penetration of the needle tip through the dura mater, covering the lumen of the needle with one of the nerve roots, or penetration of the needle tip into the anterior semicircle of the epidural space. In all these cases, a slight change in the position of the needle along the insertion depth or along the axis helps.

When performing spinal anesthesia, puncture of the subarachnoid space is usually performed at the level of the lumbar spine - the 3rd and 4th lumbar vertebrae.

The anesthetic is administered in hypo-, hyper- or isobaric, in relation to cerebrospinal fluid, solutions, often using the latter two. Isobaric solutions of anesthetic in some cases can manifest themselves as hypo- or hyperbaric, depending on the quantitative content of salt and glucose ions in the cerebrospinal fluid. Therefore, only the use of obviously hyperbaric solutions makes it possible to ensure control when obtaining the required level of anesthesia. By changing the position of the body and the bending of the lumbar spine, it can be moved a considerable distance from the injection site or anesthesia can be provided mainly on one side. The first is achieved by tilting the head or leg ends of the operating table in combination with giving the thoracic and lumbar spine an arched position by raising the brachiocephalic and pelvic parts of the body, while at the lowest point there should be a vertebra, spaced down from the desired upper level of anesthesia by 2-3 segments; the second - giving the patient a lateral position after the injection of the anesthetic, for the period of fixation with tissues (about 10-15 minutes). Once the spread of anesthesia cranially has reached the required level, the table is leveled. It should be emphasized that in order to ensure high-quality anesthesia during operations on the organs of the lower abdomen, the level of spinal anesthesia should not be lower than the Th6 segment. Hyperbaric solutions are prepared by adding 2 drops of 40% glucose solution to the official anesthetic solutions. The most commonly used anesthetics are listed in Table 1.

Table 1. Characteristics of local anesthetics used for spinal anesthesia

The duration of action of the same dose of the drug can vary significantly depending on the size of the anesthesia zone. With an increase in the area of \u200b\u200bdistribution of the anesthetic in the cerebrospinal fluid, the concentration of the latter decreases and the duration of action is shortened.

In recent years, along with spinal anesthesia, the method of spinal epidural anesthesia has become more widespread. Its advantage is obvious during long-term surgical interventions and is manifested in the fact that at the first stage of the operation such advantages of spinal anesthesia as its rapid onset and a small dose of anesthetic compared to epidural are realized, and the prolongation of the effect is provided by epidural administration of the drug. The method is used in cases where the duration of the operation may go beyond the capabilities of spinal anesthesia. When epidural anesthesia is used in these cases, the total anesthetic consumption can be significant.

The method can be implemented both by separate puncture of the epidural and subarachnoid spaces with epidural catheterization, and by puncture of the subarachnoid space through an epidural needle. In the latter case, after identification of the epidural space, a thin, longer spinal needle (26G, 4.5 inches) is inserted through the lumen of the epidural needle and advanced into the subarachnoid space. The moment the needle passes through the dura is usually well felt. After a drop of cerebrospinal fluid arrives, a dose of anesthetic is administered for spinal anesthesia, the spinal needle is removed and the epidural space is catheterized. In all cases, the puncture of the subarachnoid space should not be performed above the L2-L3 level.

Influenceepidural and spinal anesthesia on the functional systems of the body.

The considered methods of regional anesthesia have much in common not only in the technique of performing and manifesting the analgesic effect, but also in the effect on the functional state. With one and the other methods, the local anesthetic exerts its specific effect mainly at the level of the roots of the spinal cord. The nerve fibers passing through the roots are polymorphic, which causes a non-simultaneous onset of conduction blockade along them. First, thin vegetative fibers are blocked, and then, successively, fibers that carry temperature, pain, tactile sensitivity. The conductivity of the motor fibers is turned off last. To block the roots in the epidural space, a higher concentration of anesthetic is required than in the subarachnoid space. This is due to the fact that in the epidural space, the roots are partially covered with a dura mater.

In the subarachnoid space, the anesthetic solution, mixing with the cerebrospinal fluid, can diffuse quite widely from the injection site by diffusion. Moreover, with distance from it, the concentration of the anesthetic in the cerebrospinal fluid gradually decreases. A zone is formed where it blocks only sympathetic fibers, since they are the thinnest. As a result, the area of \u200b\u200bturning off the sympathetic innervation is 3-4 segments wider than the area of \u200b\u200banesthesia. With epidural anesthesia, this phenomenon is not significant.

The cardiovascular system during spinal anesthesia is influenced by a number of factors. The most significant is the blockade of sympathetic innervation in the area of \u200b\u200baction of the anesthetic on the roots of the spinal cord. This results in:

expansion of blood vessels in the area of \u200b\u200bdistribution of the anesthetic in the spinal canal, which leads to an increase in the capacity of the vascular bed;

with anesthesia above the level of the 5th thoracic segment, efferent sympathetic fibers are blocked, through which a central stimulating effect on the heart is realized, in particular the Bainbridge reflex, which arises due to a decrease in blood flow to the heart against the background of an increased capacity of the vascular bed. In addition, the local anesthetic that enters the blood as a result of resorption affects the cardiovascular system; it reduces the sensitivity of beta-adrenergic receptors. The blockade of sympathetic fibers at the root level is not accompanied by blockade of a-adrenergic receptors of peripheral blood vessels, maintaining their response to endo- and exogenous catecholamines, which plays an important role in the correction of vascular tone.

Thus, with spinal anesthesia, an inhibitory effect on the function of the cardiovascular system is mainly manifested. This is due to the wide area of \u200b\u200baction of the anesthetic on the sympathetic innervation. In addition, with spinal anesthesia, a blocking effect develops faster than with epidural anesthesia, which limits the mobilization of the adaptive mechanisms of the cardiovascular system. The points noted dictate the need for careful monitoring of the state of blood circulation in the immediate period after the administration of the anesthetic and the readiness to take urgent measures aimed at eliminating hemodynamic disturbances, if they arise.

External respiration is usually not adversely affected by spinal anesthesia under stable hemodynamic conditions. When the anesthetic spreads to the level of the cervical vertebrae, blockade of the phrenic nerve can also occur, which threatens the development of respiratory failure. Acute respiratory failure can also occur with profound hypotension associated with widespread spinal anesthesia.

The gastrointestinal tract under conditions of anesthesia in the lower thoracic and lumbar regions experiences a predominance of the tone of parasympathetic innervation, which is accompanied by increased motility and secretion. It is believed that this vegetative dystonia can be the cause of nausea and vomiting that sometimes occurs with the considered methods of anesthesia.

The most dangerous complication of the immediate period after the implementation of spinal anesthesia is deep collapse. The probability of its occurrence with a correct assessment of the initial state of patients, with rare exceptions, can be foreseen and the necessary preventive measures can be taken. However, there are also cases in which the development of this complication is unexpected for the anesthesiologist. The cause of severe collapse is more often the introduction of a significant amount of local anesthetic solution into the subarachnoid space. The result is a wide blockade of sympathetic innervation; its consequence is an increase in the capacity of the vascular bed and a decrease in resistance to blood flow, which leads to a decrease in venous return to the heart and cardiac output.

Considering that in the subarachnoid space the conditions for diffusion of the anesthetic along the spinal cord are much better than in the epidural, it is necessary not only to strictly observe the dosage of the anesthetic, but also to carefully monitor the area of \u200b\u200bits action.

Acute circulatory disorders associated with spinal anesthesia require very prompt and rational action from the anesthesiologist. The first, quickly feasible and quite effective technique is to give the operating table a position with a slightly lowered head end. In this way, an increase in blood flow to the heart is achieved very quickly. This should not be done only with spinal anesthesia, when a hyperbaric anesthetic solution is used. In this case, it is necessary to raise the foot end of the operating table. Urgent measures also include intensive infusion of blood substitutes, bolus administration of 5-10 mg of ephedrine, drip administration of norepinephrine (1 ml 0.2% per 250 ml of 5% glucose solution). For bradycardia, epinephrine should be used instead of norepinephrine. Since the collapse is often accompanied by respiratory depression, in some cases the transition to mechanical ventilation or assisted ventilation is indicated. In case of cardiac arrest, resuscitation measures are taken according to the generally accepted method.

Other possible complications relate to the postoperative period. The most dangerous of them are purulent-inflammatory processes in the spinal canal in the form of epiduritis or meningitis. They are usually the result of aseptic disorders. But against the background of sepsis, an inflammatory focus can occur here even in the absence of a local source of infection. Early diagnosis of this complication is difficult. To recognize it, the growing pain in the area of \u200b\u200bthe former puncture or the inserted catheter, symptoms of irritation of the meninges, and general manifestations of a purulent infection matter. Treatment begins with the introduction of large doses of antibiotics, including in the epidural space. If with their help it is not possible to extinguish the inflammatory process, an operation is undertaken to drain the epidural space.

A typical complication of spinal anesthesia is headache, which is a manifestation of cerebral hypotension syndrome. However, in recent years, due to the use of very thin needles for puncture of the subarachnoid space, this complication has become much less common. Compliance with bed rest for 3-5 days, drinking plenty of fluids or infusion of glucose-salt solutions usually lead to a cure.

Indications for epidural and spinal anesthesia. The indications, as well as contraindications to the methods under consideration, are largely similar. However, choosing one or the other should not be approached in the same way. The indications for epidural anesthesia are much wider than for spinal anesthesia, although both of these methods have become more common in recent years. The advantages of epidural anesthesia were clearly manifested after the introduction into practice of catheterization of the epidural space, which opened up the possibility of using the method for any long-term operation, as well as for postoperative analgesia.

Epidural and spinal anesthesia is used both in combination and without a combination with general anesthesia. The latter option is mainly used in operations on the lower extremities and in the pelvic area. Against the background of moderate sedation, in many cases it provides good conditions for operations on the abdominal organs, carried out against the background of spontaneous breathing. In operations on the chest and large-scale surgical interventions on the abdominal organs, a combination of general anesthesia with traditional epidural anesthesia or epidural analgesia with morphine is more acceptable. Spinal anesthesia for combination with general anesthesia is much less acceptable. It is not used at all for operations on the breast organs. It is also significant that spinal anesthesia is limited in time and, therefore, cannot be used for long-term operations.

In recent years, in connection with the improvement of the considered methods, it turned out that some previously established contraindications to them do not have sufficient grounds. In particular, this applies to a number of diseases of the cardiovascular system, lung pathology, and obese patients. Currently, epidural and spinal anesthesia is considered contraindicated in inflammatory processes in the tissues of the back, significant deformity of the spine, its previous injury or CNS disease, severe bleeding disorders, as well as against the background of shock and hypersensitivity to local anesthetics. Relative contraindications are severe exhaustion, insufficiently compensated blood loss, severe cardiovascular failure, the use of low molecular weight heparins. For epidural analgesiimorphine, contraindications are inflammation in the tissues of the back, deformities of the spine, its former injuries and diseases of the central nervous system. As for hemodynamic disorders associated with shock or cardiovascular pathology, they do not matter when determining the indications for this method of analgesia.

Any surgical operation or invasive examination is painful and cannot be performed without anesthesia (literally translated, the word means “pain off”). All existing types of local anesthesia and general anesthesia are designed to alleviate the suffering of a person during surgical interventions and diagnostic studies, to relieve the patient of pain. Thus, they make it possible to treat serious diseases that cannot be eliminated without surgical help.

There are two broad groups of anesthesia: general anesthesia and local anesthesia. The main difference between them is as follows. During general anesthesia with the help of special medications, consciousness and pain sensitivity in the whole body are turned off, the person is in a state of medication-induced deep sleep. Local anesthesia involves the elimination of pain sensitivity only in a specific area of \u200b\u200bthe body (where invasive intervention is planned). The patient's consciousness is preserved with such anesthesia.

Each type of pain relief has its own strict indications and contraindications. Modern anesthesia techniques are very effective but complex. Therefore, they are performed by specialists who have undergone a special training course - anesthesiologists.

Spinal anesthesia is used even during pregnancy

Types of local anesthesia

Small surgical interventions, as well as part of large-scale operations, can be performed not under general anesthesia, but under local anesthesia. For example, spinal anesthesia (a type of local anesthetic) is used to relieve pain during childbirth, during a cesarean section, and many other surgical procedures. It can also be used in patients for whom general anesthesia is contraindicated, in the elderly.

Depending on the place of the blockade of pain sensitivity, the following types of local anesthesia are distinguished:

(CA) - pain is eliminated by blocking sensitivity at the level of the spinal roots by injecting an anesthetic (drugs for local anesthesia) into the subarachnoid space (between the arachnoid and soft membranes of the spinal cord, where the spinal roots are freely located).
Epidural - pain disappears due to the blockade of the transmission of nerve impulses at the level of the spinal roots by injecting an anesthetic into the epidural space (the gap between the hard membrane of the spinal cord and the canal of the spine).
Combined spinal-epidural anesthesia - when the two procedures described above are performed simultaneously.
Conductive pain is eliminated by blocking the transmission of nerve impulses at the level of individual nerve trunks or plexuses.
Infiltrative - Pain relief is achieved by infiltration of soft tissues of anesthetics due to blockade of pain receptors and small nerve branches.
Contact - pain relief by irrigation or application of local anesthetics to the skin or mucous membrane.

Each of these types of local analgesia has its own indications and methodology. Spinal and epidural anesthesia can be used for complex surgical procedures. With their help, you can turn off the sensitivity at different levels (depending on the injection site of the anesthetic). Other types of regional anesthesia are used for smaller operations and diagnostic procedures.

Below we will talk about the features of this type of local anesthesia, such as spinal anesthesia.

Indications and contraindications

Spinal anesthesia is used in such cases:

surgical interventions below the level of the navel;
gynecological and urological operations;
surgical procedures on the lower extremities, for example, treatment of varicose veins;
surgery on the perineum;
pain relief during childbirth and caesarean section;
as an alternative to general anesthesia in case of contraindications to the latter (old age, somatic pathology, allergy to drugs for anesthesia, etc.).

Contraindications to this type of analgesia are absolute and relative.

With spinal anesthesia, the patient is awake

Absolute:

patient refusal;
blood diseases that are accompanied by increased bleeding, the use of anticoagulants before surgery (high risk of bleeding);
inflammatory lesions of the skin at the site of the proposed puncture;
the patient's serious condition (shock, acute blood loss, cardiovascular, pulmonary failure, sepsis, etc.);
allergy to local anesthetics used for analgesia;
infectious diseases of the nervous system (meningitis, arachnoiditis, encephalitis, myelitis);
intracranial hypertension;
exacerbation of herpes viral infection;
severe cardiac arrhythmias and blockages.

Relative:

deformity of the spinal column, which increases the risk of complications and makes anesthesia dangerous to life and health;
predicted volumetric blood loss during future surgery;
severe fetal distress when choosing a method of delivery;
signs of an infectious disease, fever;
some diseases of the NA (epilepsy, radiculitis with radicular syndrome, vascular lesions of the brain, poliomyelitis, chronic headache, multiple sclerosis);
emotional instability of the patient, mental disorders (persons who cannot lie still while surgeons perform the operation);
stenosis of the aortic valve of the heart;
therapy with acetylsalicylic acid and other antiplatelet agents (risk of bleeding);
history of spinal column injury;
possible expansion of the scope of the operation and lengthening of the time of its execution, for example, surgical removal of tumors, when the tactics of the surgeon may change depending on what was seen during the revision on the operating table;
childhood.

Various spinal deformities are an obstacle to spinal analgesia

Pros and cons

Each type of anesthesia has its own advantages and disadvantages. Consider the pros and cons of spinal pain relief.

Positive sides:

analgesia comes instantly;
the effect of medications on the child in case of pain relief during childbirth or cesarean section is completely excluded;
this type of anesthesia additionally provides muscle relaxation, which facilitates the work of the surgeon;
a lower dose of local anesthetics, in contrast to epidural anesthesia;
the needle is very thin, which minimizes damage to the tissues of the spinal cord;
minimal risk of drugs entering the systemic circulation and side effects such as toxic poisoning with local anesthetics;
no breathing problems, since the patient is conscious, and anesthesia does not affect the respiratory center of the brain;
during the operation, the surgeon and the anesthesiologist can communicate with the patient, which will significantly speed up the diagnosis in case of any complications;
the technique is simpler than in the case of epidural analgesia, which minimizes the risk of negative consequences after analgesia.

Negative sides:

a sharp drop in blood pressure during spinal analgesia (to prevent this, the patient is first given drugs that increase blood pressure);
limited time of the analgesic effect (if during epidural anesthesia it is possible to administer an additional dose of anesthetic, then in the case of spinal anesthesia, the drugs are administered once, and in the event that something goes wrong, the patient will be urgently transferred to general anesthesia, although today there are anesthetics, which last for about 6 hours);
a high risk of developing neurological complications, such as severe headaches.

Spinal anesthesia drugs

For spinal analgesia, local anesthetics and a number of drugs are used that are used as additives to anesthetics (adjuvants).

In theory, any local anesthetics can be used for CA, but today the following drugs are preferred.

Lidocaine

It is considered the “gold standard” of local anesthesia. It is an anesthetic of medium duration. The main disadvantage is the short and unpredictable duration of the anesthetic effect (45 to 90 minutes).

Among the disadvantages can be called the neurotoxicity of the drug, but this applies only to its concentrated solutions (5%), if 2% lidocaine is used, there is no toxic effect on the nervous system. Among the advantages of using lidocaine for intrathecal administration, one can note the rapid onset of action (5 minutes after injection), pronounced muscle relaxation, low cost, and wide availability of the anesthetic.

Bupivacaine (Blockcos)

It is the most widely used AS drug worldwide. Has a long-lasting analgesic effect (90-240 minutes). Of the main disadvantages of the drug, cardiotoxicity should be noted, but the use of low concentrations (0.5% solutions) and a small dose of anesthetic for spinal administration reduce such complications to a minimum. The drug is more expensive than lidocaine and more difficult to obtain.

The action of bupivacaine begins 5-8 minutes after administration, it is characterized by a low level of motor block (low degree of muscle relaxation).

Bupivacaine is the most commonly used local anesthetic for spinal anesthesia

Ropivacaine (Naropin)

This is a drug of the latest generation of local anesthetics, which was created a quarter of a century after bupivacaine (1963). For CA, a 0.75% solution of ropivacaine is used. The time of onset of analgesia ranges from 10-20 minutes, the duration of action is 2-6 hours. Has no cardiotoxic effect when administered intrathecally. During AS, ropivacaine can induce a controlled motor block, which cannot be done with bupivacaine. The main disadvantages are the high cost and low availability of the drug.

Only an anesthesiologist at the stage of preparation for the operation can answer the question of which drug is better to choose. The local anesthetic is chosen, first of all, depending on the type of surgery, its expected duration, individual characteristics and financial capabilities of the patient.

Opioids (morphine, fentanyl), epinephrine and clonidine can be used as adjuvants during spinal anesthesia.

Methodology

The main task of the anesthesiologist during SA is the introduction of a local anesthetic into the subarachnoid space of the spinal cord, which surrounds the spinal cord, is filled with CSF. It is here that the roots of the spinal cord are freely located, which must be blocked with the help of a local anesthetic. To get into the subarachnoid space, the anesthesiologist needs to pierce the skin, subcutaneous fatty tissue, a number of vertebral ligaments, epidural space, dura mater and arachnoid with a needle.

With spinal anesthesia, the anesthetic is injected from the subarachnoid space of the spinal cord, and with epidural, into the epidural

For a successful SA, the patient must be in the correct position - sitting with the spine flexed as much as possible, the head should be close to the chest with the chin, arms bent at the elbows and are on the knees. It is also possible to use the patient's position lying on his side with the spine bent and the knees tucked up to the stomach.

Important! Remain immobilized while performing spinal anesthesia. This will shorten the time it takes to complete the procedure and reduce the risk of some complications.

The choice of the injection site is made by the doctor. At the same time, he carefully feels the lumbar spine and looks for the necessary landmarks. As a rule, SA is performed between 2, 3, 4, 5 lumbar vertebrae. The optimal place is considered to be the interspinous space between the 2nd and 3rd lumbar vertebrae. The choice of the injection site is influenced by the anatomical features of the structure of the spine, the presence of deformities, injuries, and a history of operations.

After marking the site of the injection of the anesthetic, the doctor carefully treats the hands, since the SA takes place under strict aseptic and antiseptic conditions. The patient's skin at the puncture site is also treated with antiseptics.

For anesthesia, you need 2 syringes with an anesthetic. The first is used for infiltrative anesthesia of soft tissues along the way of insertion of a spinal needle, so that it does not hurt. The second contains a dose of the drug, which must be injected with a special needle into the subarachnoid space.

Spinal anesthesia can be performed with the patient sitting or lying on his side

After infiltrative anesthesia of the puncture site, the doctor inserts a long (13 cm) and thin (1 mm diameter) spinal needle. With the introduction of this needle, the back hurts a little, therefore, sometimes anesthesiologists do not perform preliminary infiltrative anesthesia.

The doctor advances the needle slowly through all the tissues. When the dura mater (a very dense membrane) is punctured, a “failure” is felt and the needle is not inserted further. This means that the end of the needle is located in the subarachnoid space.

Then the doctor removes the mandrel from the needle (a thin metal conductor that tightly closed the lumen of the spinal needle) and makes sure that the instrument is located correctly. In this case, droplets of transparent cerebrospinal fluid are released from the cannula, which fills the subarachnoid space.

Leakage of drops of cerebrospinal fluid from the cannula means that the needle is positioned correctly

Then the doctor attaches a syringe with an anesthetic to the needle and injects the required dose of the drug. The needle is slowly removed, the puncture site is sealed with a sterile bandage. Then the patient is placed on the operating table for surgical intervention.

Complications and side effects

Regional anesthesia has a less negative effect on the body than general anesthesia, and complications with such anesthesia are extremely rare. Among the most common are:

Postpuncture headache (PPH). This is the most common type of side effects of SA and the main argument of opponents of such pain relief. Previously, complaints of headaches after SA were common, but today this side effect is recorded in only 3% of patients. This was facilitated by new and safe anesthetics, as well as modern puncture needles.
Toxic effects of local anesthetics (on the brain, heart, liver, kidneys, etc.).
Epidural hemorrhage.
Infectious complications (meningitis).
Delayed urination.
Arterial hypotension.
Pain at the injection site.
Trauma to the spinal root or spinal cord tissue when punctured with a needle.
Adhesive arachnoiditis.

In order for SA to pass successfully and without complications, be sure to listen to your anesthesiologist and surgeon, follow all their recommendations. The specialist will give precise instructions on how to behave before, during and after anesthesia, after how long you can get up and do physical therapy, what you can eat and other tips necessary for a quick recovery.

The main task when performing spinal anesthesia is to inject the solution into the spinal (subarachnoid) space. This space surrounds the spinal cord and is filled with a colorless, transparent fluid called CSF (cerebrospinal fluid).

In order to get into the subarachnoid space, the needle must go through the skin, subcutaneous tissue, a number of intervertebral ligaments, the epidural space and the dura mater.

Large nerves pass through the subarachnoid space, transmitting a pain signal to the spinal cord. A local anesthetic solution injected into the subarachnoid space causes a blockage of signal transmission along these nerves, which leads to anesthesia () of a specific region of the patient's body.

Spinal anesthesia requires a spinal needle, syringe, and local anesthetic solution.

Before performing spinal anesthesia, he probes the patient's back to determine the optimal injection site. Typically, spinal anesthesia is performed at a point between the 3rd, 4th, or 5th lumbar vertebrae.

The hands are then carefully treated by the anesthetist, as spinal anesthesia requires strict sterile conditions.

Using disinfecting solutions, the anesthetist (assistant to the anesthesiologist) treats the site where spinal anesthesia will be administered.

After that, the anesthesiologist covers the area where the spinal anesthesia will be administered with sterile napkins.

Next, a solution of local anesthetic is drawn into two syringes. The first syringe will be used to pass the area through which the spinal needle will be inserted. Another syringe is designed to inject a local anesthetic solution through a spinal needle into the subarachnoid space.

The anesthetist helps to keep the patient in the correct body position.

The anesthesiologist will perform local anesthesia in the area where the spinal needle will be injected.

The spinal needle is very long and thin. The spinal needle is about 13 cm long and the outer diameter is less than one millimeter. The spinal needle prick is practically painless, so sometimes the anesthesiologists do not perform the preliminary local anesthesia described above.

The anesthesiologist makes an injection at the target point with a spinal needle and slowly conducts it between the vertebrae in the direction of the spinal cord, while passing through the skin, subcutaneous tissue, ligaments and dura mater.

The dura mater is a dense membrane that surrounds the spinal cord, enclosed in the cerebrospinal fluid. A puncture of the dura mater with the advancement of the spinal needle is felt by the anesthesiologist as a "failure".

After the sensation of "failure", the spinal needle is no longer held and the mandrel is removed from it, which is a thin metal conductor that tightly closes the lumen of the spinal needle.

The anesthesiologist makes sure that the tip of the spinal needle is correctly positioned. The end of the spinal needle should be located with the subarachnoid space, which, as we recall, is filled with transparent CSF (cerebrospinal fluid). The criterion for the correct location of the spinal needle is the leakage of the cerebrospinal fluid from the cannula of the spinal needle.

One of the most commonly used types of pain relief for lower body surgery is spinal anesthesia. This is the name of the type of anesthesia that allows surgical intervention below the level of the navel to a person who is conscious at this time. Such anesthesia requires experience and competence from the anesthesiologist. Its technique is a procedure in which an anesthetic is injected into the spinal canal using a special needle.

Spinal anesthesia is a technique that works on the nerve roots of the spinal cord. It completely blocks the transmission of nerve impulses, so the patient is not in pain during surgical treatment. Anesthesia is provided by the introduction of anesthetic into the spine (into the subarachnoid space), which gives the patient a feeling of comfort during surgery. Thanks to anesthesia, the patient gets rid of the state of panic and fear.

Anesthesiologist administers pain relief

The indications for the use of anesthesia are extensive, but it can be done only after careful preparation of the patient and with his consent. The method of injecting a drug into the spine requires a detailed history to be collected before starting the operation. Only competent preparation for the procedure will make the anesthesia safe and reliable, eliminating the likelihood of complications both during and after it.

The technique of performing spinal anesthesia differs from other similar procedures in that it uses ultra-thin needles about 130 mm long and less than 1 mm in diameter. In addition, spinal anesthesia is performed just below the level of the patient's spinal cord. The drug, which blocks the nerve roots, is taken in a small dose and sent directly to the point of the spinal canal where the cerebrospinal fluid is concentrated.

Spinal anesthesia, like any other anesthesia, has both indications for use and contraindications. A specialist anesthesiologist should make a conclusion about whether to prescribe this type of pain relief to a patient. The impact on the spine can be carried out only after collecting complete information about the patient's health (physical and mental). Proper preparation for this operation is also mandatory, the responsibility for which falls on the shoulders of the patient.

It is important to understand that not only doctors, but also patients contribute to the success of treatment. If there are indications for spinal anesthesia, the patient must prepare for the procedure taking into account the requirements and advice of the anesthesiologist.

Spinal anesthesia needle position

The main task of this type of pain relief is the introduction of a special anesthetic solution into the cerebrospinal fluid (cerebrospinal fluid). How many doses of the drug need to be administered is decided by the doctor in each case individually. The technique of the operation involves the following phased advancement of the needle:

through the skin and subcutaneous tissue;
through a number of intervertebral ligaments;
through the epidural zone;
through the meninges.

The endpoint of the needle is the subarachnoid space (cerebrospinal fluid) that surrounds the spinal cord. It is in the spinal zone that large nerves pass, which are responsible for the transmission of a pain impulse. Anesthetic injected into this space provides anesthesia by blocking nerve signals. This technique makes insensitive only a certain region of the patient's body, which is active during the operation, but at the same time he is insensitive and the patient does not hurt.

Stages of the

To perform anesthesia surgery, the anesthesiologist uses a special needle, syringe, and local anesthetic. The technique of the procedure requires the patient to take the correct body position. The best option is a sitting position. To avoid pain during and after the operation, the patient must fully follow the doctor's recommendations before and after anesthesia.

Correct patient positioning for spinal anesthesia:

it is desirable to sit, but it is also possible in a lying position on its side;
the collections must be brought closer to the chest;
the back should be strongly bent;
the arms bent at the elbows should lie on the knees.

Patient position during spinal anesthesia

Please note that while the spine is anesthetized, the patient must remain absolutely motionless. This is the only way to avoid possible complications during and after the surgery.

Spinal anesthesia is performed as follows:

between the vertebrae of the lower back, the best place for the injection is determined;
the procedure is sterile (the doctor's hands and the patient's skin surface are treated);
the injection site is covered with sterile films;
anesthetic is drawn in 2 syringes;
the first syringe is used to numb the area through which anesthesia will be administered;
the second syringe delivers the solution into the spinal canal.

During anesthesia, the correct position of the patient is assisted by the assistant anesthesiologist (nurse). This is done slowly and carefully. Subject to the necessary conditions and the prescribed technique of anesthesia, patients do not hurt. After this operation is completed, a bandage is applied to the spine at the injection site. After this procedure, the patient is immediately placed on the operating table in a position that is convenient for surgeons.

Indications

With spinal anesthesia, operations can be performed in the perineum, pelvic organs or lower extremities. In some cases, such anesthesia has certain advantages - indications that should be considered for the well-being of the patient. People of all ages can do anesthesia in the cerebrospinal fluid through the spine.

Main indications:

with hernia repair, gynecological operations and in urology;
during operations on the legs and in the perineum;
suppression of stress reactions of the body;
in obstetrics.

Anesthetic benefits during labor

If a pregnant woman is relatively healthy and her fetus is healthy, the indications for anesthesia are obvious. Thanks to such anesthesia, it does not hurt to give birth, and the woman herself participates in the process of childbirth and hears the first cry of her child. Therefore, today many expectant mothers, if there are no contraindications, insist on the use of spinal anesthesia during childbirth (cesarean section).

Additional indications for the use of spinal anesthesia are diseases of the lungs, stomach and intestines. In this case, the anesthesiologist takes into account the drugs used in the treatment of, for example, duodenal ulcer (Omez, etc.). So, given the interaction of the drug Omez with the anesthetic, the doctor determines the optimal dose of the solution for anesthesia, anticipating how long the anesthesia will last and how the patient will move away from it.

Contraindications

The indications for spinal anesthesia are surgery in the lower trunk. However, in some cases there are contraindications for the use of anesthesia in the spine. In each case, this issue is jointly decided by the anesthesiologist and the patient, or his representatives. Most doctors insist on using spinal anesthesia if general anesthesia can be dispensed with.

There are 2 types of contraindications for this type of pain relief:

relative contraindications;
absolute contraindications.

Relative contraindications can be defined as follows:

emotional and psychological lability of the patient;
the presence of mental and neurological pathologies;
oligophrenia (low level of intelligence);
some heart disease;
spinal anomalies;
unknown duration of surgery;
fetal death or fetal malformations (in obstetrics);
risk of bleeding.

Absolute contraindications:

the patient's categorical disagreement;
lack of prerequisites and equipment;
hypertension (persistent or episodic increase in blood pressure);
infectious skin lesions in the puncture area;
coagulopathy and other disorders of the blood coagulation system;
limb amputation;
the use of certain medications before surgery (an example is drug incompatibility).

Benefits of Spinal Anesthesia

Why is spinal anesthesia gaining popularity?

Anesthesia is an artificially induced loss of sensation. A person in a state of such numbness is not painful or scary. His body is provided with a stationary and comfortable position for surgeons, which increases the chances of a positive outcome of the operation. Patients who have undergone anesthesia testify that they were not in pain during the procedure.

If there is an indication for such pain relief, there is no need for general anesthesia. The technique for performing this anesthesia is simple and within the power of every practicing anesthesiologist. An experienced doctor knows how to administer anesthesia, how much anesthetic to inject and how long the pain relief will last. However, it is not always possible to predict exactly how the patient will move away from anesthesia, since everyone leaves him according to an individual scenario.

Modern methods of anesthesia contain enough funds that relate to local anesthesia. One of these is spinal (spinal) anesthesia. This type of pain relief has its own indications and contraindications.

Despite the fact that the method is considered more gentle for the patient's health in comparison with general anesthesia, there are cases when its use entails, up to the violation of some vital functions of a person.

To avoid complications after spinal anesthesia, you must first undergo a thorough examination by qualified specialists. The experience and skill of the physician in charge of anesthesia plays an important role.

Anesthesia in the back

Spinal anesthesia into the spine is performed for a variety of reasons. The most common use of this type of pain relief is childbirth. During the birth of a child, difficult situations often arise when the mother may need anesthesia, including during a planned or emergency caesarean section.

Spinal anesthesia is the most appropriate option in this case. It is subdivided into, spinal and combined analgesia, which includes both types of pain relief. All options refer to local methods of preventing pain during surgery. These methods differ only in that the blockade of nerve impulses occurs in different areas.

The epidural method involves the introduction of anesthetic drugs into a special space between the hard membrane of the spinal cord and the spinal canal. Spinal anesthesia is performed in a similar way, but the final site for administration of medications is the subarachnoid area filled with cerebrospinal fluid. This is the space between the arachnoid and soft membranes, which contains the roots of the spinal cord. It is at their level that pain is eliminated.

Indications for Spinal Anesthesia

In medical practice, there are many cases when you have to use local methods of anesthesia. Sometimes the cause is contraindications to general anesthesia. During some simple and relatively short surgical procedures, it is simply not necessary. Then local anesthesia is used. Its area of \u200b\u200bapplication is the spinal cord.

If the contact method does not sufficiently eliminate the pain that medical manipulations can deliver to the patient, then doctors, as a rule, use the introduction of anesthetics into the epidural or subarachnoid space.

Indications for spinal anesthesia:

difficult and painful childbirth;
cesarean section;
surgical interventions on organs below the waist;
gynecological and urological operations;
contraindications to general anesthesia for health reasons, age or individual drug intolerance;
surgical manipulations on the legs, including surgery to eliminate varicose veins.

In each specific case, a team of specialists led by the attending physician must carefully study the patient's medical history, conduct the necessary tests and evaluate what a spinal tap and a certain type of anesthetics will have for a person. To carry out this specific type of pain relief, it is imperative to obtain the patient's consent.

For whom is spinal anesthesia contraindicated?

The doctor chooses a specific method of pain relief depending on the type, potential complexity and duration of the upcoming operation. An important role is played by the general state of human health and the characteristics of his body.

If the patient has contraindications to the use of spinal anesthesia, it can be severe. Sometimes a person is not psychologically ready for a procedure such as a lumbar puncture, during which an anesthetic is injected. Even so, the doctor suggests a different method of pain relief. But besides the patient's disagreement, there are even more serious contraindications to spinal anesthesia:

The presence of at least one such factor implies a ban on spinal anesthesia. These types of contraindications are called absolute. In all other cases, the decision to use spinal analgesia is made by the doctor, evaluating.

Relative contraindications

There are situations in which a surgeon and anesthesiologist can take risks and perform an operation with spinal anesthesia, despite the presence of relative contraindications:

Modern medicine allows you to combine several types of anesthesia. If an abnormal situation arises during an operation, specialists can quickly make a decision and use a different, more appropriate method of pain relief.

Spinal anesthesia technique

Spinal anesthesia is a local type of analgesia, but unlike contact methods, which involve the external application of anesthetics to the surgical site, it requires a puncture in the lumbar back. The result of the procedure depends on how accurately the anesthesiologist chooses the injection site and makes an injection of high quality.

For spinal anesthesia, it is very important that the patient is in the correct posture and does not move. It is recommended to take a sitting position, bending your back as much as possible and clasping your knees with your hands. The chin should be lowered to the chest. A horizontal position is allowed if the patient lies on his side.

Since the anesthetic is injected into the subarachnoid space, the specialist needs to pierce not only the skin, soft tissues and fatty tissue, but also several vertebral ligaments, the epidural region, the arachnoid and the hard membranes of the spinal cord. This procedure is quite painful, so 2 types of pain relievers are used for it. First, the doctor injects to relieve the discomfort from the puncture, only then proceeds to the main manipulations, which require a lumbar puncture.

The anesthesiologist chooses the puncture site depending on the structure of the patient's spine, applies a special marking and inserts a thin needle 13 cm long, equipped with a mandrel - a guide that closes its lumen.

When the instrument reaches the subarachnoid space, the doctor takes out the mandrel. If drops of cerebrospinal fluid are released from the puncture through a special tube (cannula), the needle is inserted correctly. In this case, a syringe with the drug is attached to the needle and the anesthetic is injected. The hole on the patient's body is sealed with a sterile bandage after the procedure is completed. All manipulations are carried out under strict sterility conditions.

The effect of the pain reliever begins in 5-20 minutes, depending on the drug. First, the patient feels a surge of heat to the lower extremities, then this sensation is replaced by complete numbness of the body below the waist. The person is conscious during the operation, but does not feel pain.

Sensation in the legs is restored in about 2-4 hours. At first, the patient usually feels weak and dizzy. This condition can last for a day. One hour after surgery, you can already drink water and eat light food. The regimen and diet must be agreed with the attending physician.

Types of anesthetics used

The most common drug used for spinal anesthesia is lidocaine. This anesthetic effectively blocks nerve impulses that provoke pain. The advantages of the medication are that it is available, is inexpensive, relaxes the muscles of a person and has a high speed of action. The effect occurs approximately 5 minutes after drug administration.

However, lidocaine has a number of significant disadvantages:

This anesthetic belongs to the average duration of painkillers, but it acts on each person individually, so it is difficult to predict how quickly the blockade of the nerve roots will end. This does not allow the use of the drug for complex and lengthy operations.
Lidocaine is toxic to the nervous system. The use of its 5% solution provokes a number of complications; at a concentration of 2%, the risk of negative consequences is reduced, but still possible.

The world standard anesthetic for spinal pain relief is Bupivacaine. It is more expensive and less readily available. The drug in low concentrations practically does not cause complications from the nervous system. The duration of action of the drug ranges from 90 to 240 minutes. The analgesic effect occurs 8 minutes after the administration of the medication. However, Bupivacaine does not have a pronounced relaxing effect, which creates some difficulties for the surgeon during the operation.

The most modern anesthetic is Ropivacaine. The risk of complications from its use is practically reduced to zero. This remedy lasts up to 6 hours. The effect of blockade of pain impulses occurs 10-20 minutes after drug administration. The main disadvantage of Ropivacaine is its high cost. It is very difficult to obtain this anesthetic even in specialized pharmacies.

Potential complications of spinal pain relief

Local types of anesthesia, which include spinal anesthesia, are considered relatively safe compared to general anesthesia. Such anesthesia does not put a serious strain on the respiratory and cardiovascular systems.

The absence of side effects largely depends on the patient's general health and comorbidities in his anamnesis. The qualifications of the doctor administering the anesthesia and the patient's strict adherence to the instructions of the medical staff are essential.

However, this type of pain relief is not always without complications. Severe headache is the most common. Currently, this side effect occurs in 5% of patients. The use of new generation anesthetics is gradually decreasing this figure.

Often, incorrect needle insertion can provoke epidural bleeding or trauma to the nerve endings of the spinal cord. The consequences of such cases are different. Sometimes the patient even needs long-term rehabilitation.