Spinal anesthesia for caesarean section, contraindications, drugs. What is spinal anesthesia, why is it dangerous, pros and cons of Spinal anesthesia what

Spinal anesthesia is a common method of pain relief, in which tissues and organs located below the lower back lose sensitivity. This type of blockade was invented and first put into practice by August Beer back in 1897. It was a surgical intervention on the leg near the knee, which ended successfully. At the same time, the patient was not in pain during anesthesia, which became significant for continuing the study of the discovery.

After some modifications spinal anesthesia was officially introduced into the routine practice of anesthesiologist-resuscitator around the world.

So, let's figure out what this method is and how it works.

Spinal anesthesia is a method of anesthesia in which a local anesthetic is injected into the spinal space (subarachnoid space) to block nerve impulses and relieve pain in the lower torso and lower extremities during surgery. The result of anesthesia - numbness - occurs immediately after the anesthetic is introduced into the space. When an operation is performed under spinal anesthesia, the patient is usually conscious, sometimes, if the operation goes well for a long time, then for the patient’s comfort, the anesthesiologist performs so-called sedation.

Anesthesia kit and procedure technique

Before the intervention, the patient preparing for the operation signs the necessary documentation, which states his consent to the procedure and explains the technique of spinal anesthesia. The doctor examines the patient, finds out the details of concomitant diseases that interest him, the course of the underlying disease, and gets acquainted with the patient’s medical record. .

Medical kit for anesthesia:

• spinal needle and guide (introducer);
• syringe for spinal anesthesia;
• pain reliever;
• disposable gloves, cotton pads, bandages, tweezers, ethyl alcohol (70%), trays.

Spinal needle and sheath

Technique

When performing spinal anesthesia, the patient can be in several positions: lying on his side or sitting. First of all, it will depend on the clinical situation, and then on the preference of the anesthesiologist.

During spinal anesthesia, the patient is placed on his side in such a way that his knees are tucked as tightly as possible to his stomach and his chin to his chest. A small cushion is placed under women's sides; this is due to the anatomy of the women's spine and pelvis. This is a classic option.

In the sitting position, the patient sits on the edge of the table, with his feet placed on a stool. You are asked to cross your arms over your chest, or simply place them on your hips, or you are asked to hug a pillow or bolster, with your chin close to your chest and your back arched. You can often hear the following phrase from an anesthesiologist: “Arch your back like a cat!” Not to be confused with the word "bend".

The area where the spinal puncture will be performed is carefully treated with a skin antiseptic. The area is then wiped with a dry, sterile gauze pad.

In the classic version, you need to perform local anesthesia of the skin. The so-called “button” is made. A small amount of local anesthetic is injected subcutaneously, after which the spinal space is punctured and anesthesia is administered.

So, after “piercing” the skin, the needle is advanced between the spinous processes through the ligament until a loss of resistance or “failure” is felt. CSF (cerebrospinal fluid) will begin to leak from the spinal needle. Next, a syringe is attached and the anesthetic is injected into the space. At the moment of administration of the medicine, a feeling of warmth appears in the legs, tingling, then a feeling appears as if “the legs have served time.” After administering the medicine, the syringe and needle are removed, and a gauze pad is glued to the puncture site. The full development of anesthesia occurs after 5-8 minutes from the administration of the drug, sometimes it is necessary to wait up to 40 minutes, it is associated with the characteristics of the body, it happens quite rarely. Pain sensitivity is completely switched off, tactile sensations (sensation of touch) may remain.

Leakage of cerebrospinal fluid from the spinal needle

Attaching a syringe

Advantages and disadvantages of spinal anesthesia

Spinal anesthesia, like any anesthesia, has its advantages and disadvantages.

Pros of spinal anesthesia:

• rapid onset of anesthesia;
• According to the technique, it usually does not take much time
• minimal toxic effects on the body;
• There is no pain in the operation area for some time.

Disadvantages of spinal anesthesia:

• time limitation (3-4 hours)
• relative uncontrollability - having received any undesirable effect, the effect of the anesthetic cannot be stopped.

Indications for spinal anesthesia

The indication is to perform surgery on the abdominal organs below the diaphragm and lower extremities

• various hernia repairs;
• caesarean section (surgical expulsion of the fetus);
• operations on the vessels of the lower extremities
• prosthetics of joints of the lower extremities, various traumatological operations, amputation of limbs;
• obstetric and gynecological intervention (caesarean section, hysteroscopy, minor cesarean section, uterine amputation, surgery for uterine prolapse, etc.);
• urological interventions (surgeries on the kidneys, bladder, prostate gland, varicocele, etc.);
• Coloproctology (hemorrhoidectomy, removal of anal canal polyps, paraproctitis, excision of the epithelial coccygeal tract, etc.)

Contraindications to peridural (epidural) anesthesia.

So, contraindications can be absolute (the patient is not allowed to undergo anesthesia in 100% of cases) or relative (at the discretion of the doctor).

Absolute contraindications:

• patient refusal;
• skin diseases of the back with pronounced pustular abscesses and formations at the puncture site (injection);
• allergic reaction to local anesthetic;
• severe deformation spinal column(for example, Bechterov's disease);
• impaired blood clotting function (coagulopathy);
• clinically significant hypovolemia (dehydration, blood loss);
• cardiac conduction disturbances (AV block, sick sinus syndrome);

Relative contraindications:

• developmental anomalies and mild deformity of the spine;
• psychiatric diseases;
• low level of intelligence in the patient;
• treatment with antiplatelet agents and anticoagulants - blood thinning drugs (clopidogrel and its derivatives, warfarin, etc.);
• previous spinal surgeries;
• presence of a tattoo at the puncture site (injection);

Complications after anesthesia:

• Frequent (post-puncture headaches, back pain)
• Rare (total spinal block - high spread of anesthetic with clinical signs of respiratory and cardiac arrest, transient neurological disorders - pain in the lower back with radiation to the hips or buttocks, neuropathy - damage to the root during puncture, spinal or epidural hematoma)

Factors that increase the frequency of post-puncture headache:

• Young women have a higher incidence
• When using a needle with a large diameter, for example, more than 25G
• Pregnancy
• Increases with the number of puncture attempts

Factors that do not influence the frequency of post-puncture headache

• Extended spinal anesthesia
• Time frame for patient activation (bed rest 24 hours)

The main thing to remember is that these complications can manifest themselves, as a rule, either immediately after the end of spinal anesthesia, or after 1-2 days. Everything that appeared “a month after spinal anesthesia” does not mean due to it. In any case, you need to see a doctor.

Spinal anesthesia is a method of central neuraxial anesthesia, which consists of injecting a local anesthetic into the subarachnoid space.

History of the method

Spinal anesthesia in the form in which it is used now was first performed by A. Beer on August 16, 1897 during a resection of the ankle joint due to tuberculous lesions. A. Beer and his student A. Hildebrandt personally experienced the effects of a new method of anesthesia. Further new method pain relief attracted the attention of surgeons, and many began to widely use it in their practice. Mention should be made here of T. Tuffier, Ya.B. Zeldovich, S.S. Yudina. In obstetric practice, spinal anesthesia for the purpose of pain relief during labor was first used by O. Kreis in 1900.

Anatomy

The spinal canal runs from the foramen magnum to the sacral fissure, but the subarachnoid space usually ends at the level of the second sacral vertebra.

The spinal column consists of 7 cervical, 12 thoracic and 5 lumbar vertebrae with the adjacent sacrum and coccyx. It has several clinically significant bends. The greatest bends anteriorly (lordosis) are located at the levels C5 and L4-5, posteriorly - at the levels Th5 and S5. These anatomical features, together with the baricity of local anesthetics, play an important role in the segmental distribution of the level of spinal block. The vertebral bodies adjacent to each other are separated by intervertebral discs. The anterior longitudinal ligament (1) runs along the anterior surface of the vertebral bodies from the skull to the sacrum, which is rigidly fixed to the intervertebral discs and the edges of the vertebral bodies. The posterior longitudinal ligament (4) connects the posterior surfaces of the vertebral bodies and forms the anterior wall of the spinal canal . The vertebral plates are connected by the ligamentum flavum (3), and the posterior spinous processes by the interspinous ligaments (2). The supraspinous ligament (1) runs along the outer surface of the spinous processes C7 - S1. The pedicles of the vertebrae are not connected by ligaments, resulting in the formation of intervertebral foramina through which the spinal nerves exit.

The spinal canal has three connective tissue membranes that protect the spinal cord: the dura mater, the arachnoid mater, and the pia mater. These membranes participate in the formation of three spaces: epidural, subdural and subarachnoid. The spinal cord and roots are directly covered by a well-vascularized pia mater; the subarachnoid space is limited by two adjacent membranes - the arachnoid and dura mater.

On the image:

1.Spinal cord

2. Pia mater

3. Subarachnoid septum

4. Arachnoid membrane

5. Subdural space

6. Dura mater

7.Epidural space

8. Vertebra

9. Ligamentum flavum

10.Trabecula

11. Subarachnoid space.

The last figure clearly demonstrates the relative position of the epidural, subarachnoid space and spinal cord.

Indications:

1. Operations below the navel level

2. Gynecological and urological operations

3. Caesarean section

4. Surgeries on the lower extremities

5. Operations on the perineum.

Contraindications:

a) absolute

1. Patient refusal

2. Coagulopathy

3. Clinically significant hypovolemia

4. Pronounced signs of vagotonia

5. AV block, sick sinus syndrome

6. Skin infections at the puncture site, sepsis, meningitis

7. Exacerbation of herpes infection

8. Intracranial hypertension

9. Allergic reactions to local anesthetics of the amide group

b) relative

1. The urgency of the situation and the lack of time to prepare the patient and perform the manipulation

2. The patient’s psycho-emotional lability or low level of intelligence

3. Aortic stenosis, severe chronic heart failure

4. Real opportunity expanding the volume and increasing the time of intervention

5. Peripheral neuropathy

6. Demyelinating diseases of the central nervous system

7. Mental illness

8. Treatment with aspirin or other antiplatelet agents

9. Significant spinal deformity

10. Previous spinal injuries.

Equipment and materials

The main equipment for spinal anesthesia is represented by needles various types and sizes. Let us briefly describe the different types and sizes of needles. The main types of needles are shown below in the figure.

The first type is the Quincke needle, the standard for spinal anesthesia. The needle is well sharpened, which sometimes creates difficulties in tactile identification of the structures it passes through, at the same time, puncture with such needles is technically simpler than puncture with pencil-sharpened needles. The shape of the hole in the dura mater when Quincke needles are used resembles an opened tin can and is completely independent of the position of the needle cut relative to the axis of the spine.

It is a known fact that with a longitudinal (relative to the axis of the spine) orientation of the needle cut, a significantly smaller amount of post-puncture pain is observed. This fact has been explained for a long time by the expansion of the fibers of the dura mater. However, recent research allows us to confidently assert that this phenomenon is based on a completely different mechanism. In addition, when using Quincke needles, you should remember that thin needles of this type tend to deviate from a straight course when moving through dense tissue (ligaments), acting like the front wheels of a car. Sprott and Whitacre needles. They are combined into one group because they are pencil-type needles, and there is no fundamental difference between them. The main purpose of this shape of the end of these needles is to reduce the frequency of post-puncture pain, since it is believed that these needles injure the dura mater less, pushing it apart. However, data from electron microscopic studies cast doubt on this fact, since the microphotographs clearly show that the hole in the dura mater after the use of such needles has torn edges and does not collapse.

It is possible that the inflammatory edema that forms at the edges of such an opening plays a role in reducing the frequency of puncture pain, but the formation of a fibrin plug cannot be ruled out. In any case, this issue requires further clarification. The sizes of spinal needles are designated according to the international classification (outer diameter, G). It is quite clear that not only the technical ease of performing a puncture, but also the frequency of post-puncture headaches depends on the size. The smaller the needle gauge, the less often PPB occurs, and when using ultra-thin needles (29-32 G), their frequency tends to zero. Regarding the frequency of occurrence of post-puncture syndrome when using needles of various types and sizes, the average data of various authors are given below. So, the frequency of PPB when using Quincke needles of size 22 G was 36%, size 25 G - 3-25%, and size 27 G - 1. 5-5.6%. The frequency of PPB after using pencil-sharpened needles appears to be 0.6-4, 0-14.5 and 0%, respectively.

Drugs

To perform spinal anesthesia, local anesthetics and a number of drugs are used as additives to local anesthetics and are called adjuvants.

Local anesthetics. Almost all local anesthetics can theoretically be used for SA, but the use of ester drugs seems to be of only historical interest. It should be remembered that drugs intended for intrathecal administration must have appropriate labels on the packaging or in the instructions, which legally protects the doctor. To understand the mechanics of anesthetic spread in the subarachnoid space, it is necessary to understand the meaning of the following terms.

Density(specific gravity) is the main physical characteristic of a solution. This is the mass (in grams) of one milliliter of solution at a given temperature. Relative density is the ratio of the density of a solution to the density of water at a given temperature.

Baricity- the ratio of the density of the anesthetic to the density of the cerebrospinal fluid at a given temperature. This indicator is extremely important, as it allows one to judge how the anesthetic will behave when introduced into the subarachnoid space. From the point of view of baricity, hypo-, iso- and hyperbaric solutions of anesthetics are distinguished.

Hypobaric solutions are drugs that, when introduced into the subarachnoid space, “float” upward relative to the injection site, causing anesthesia at higher levels. These drugs include, for example, 0.5% lidocaine solution or 0.25% bupivacaine solution. Currently, spinal anesthesia with hypobaric solutions has extremely limited use (hemorrhoidectomy in the “jackknife” position).

Isobaric solutions, when introduced into the subarachnoid space, spread evenly in all directions, causing anesthesia of the segments exposed to the drug. These include 0.5% isobaric solution of bupivacaine (Marcaine-spinal), 2% solution of lidocaine. It should be remembered that the isobaricity of a solution depends on its temperature, and in the case of a slight increase in the density of the cerebrospinal fluid, isobaric solutions at body temperature can behave as slightly hypobaric, which is responsible for the unpredictable development of the block in some cases when they are used.

Hyperbaric solutions “sink” when mixed with cerebrospinal fluid, falling below the puncture site and causing anesthesia of the corresponding segments. The most popular solutions for SA around the world. With the patient in the supine position, hyperbaric solutions flow from the top lumbar lordosis in both directions, stopping at the level of T4 and S5, with the patient positioned on his side, they induce anesthesia of the corresponding side (do not forget that when the head is tilted, in this case the anesthetic spreads unhindered in the cranial direction!), and when performing a puncture in a sitting position and left in a sitting position for some time, the classic “saddle” block develops, widely used for perineal operations. Hyperbaric anesthetics include 0.5% hyperbaric solution of bupivacaine (Marcaine-heavy) and 5% solution of lidocaine. Hyperbaric solutions can be prepared by mixing anesthetic solutions with dextrose solutions.

In the CIS, the most commonly used drugs for SA are lidocaine and bupivacaine. Let's give brief description each of these drugs in the aspect of spinal anesthesia.

Lidocaine."Gold standard" among local anesthetics average duration actions. Amide group drug. For SA it is used in the form of a 2% isobaric solution and in the form of a 5% hyperbaric solution on dextrose. The main disadvantage of lidocaine is the short and unpredictable (from 45 to 90 minutes) duration of action, which, however, is easily solved by the use of adjuvants. The second dark spot in the reputation of lidocaine were reports of its neurotoxicity, which, however, as was later established, applies only to concentrated (5%) solutions. The drug has a rapid onset of action - as a rule, operating anesthesia with intrathecal administration develops in 5 minutes. Lidocaine also differs from bupivacaine in a more pronounced motor component of the block and significantly lower cost and wide availability in the CIS.

Bupivacaine. The most common drug for SA in the world. It has a long duration of action (90-240 minutes). Also belongs to the group of amide local anesthetics. Isobaric and hyperbaric) 0.5% solutions are used, in the USA - only hyperbaric. Bupivacaine does not appear to have any known cardiotoxicity. of great importance when performing spinal anesthesia due to small doses of the drug.

Adjuvants. The topic of using additives (adjuvants) during spinal anesthesia is quite painful for domestic anesthesiology. It is painful because for the legal use of adjuvants (the use of which throughout the civilized world has long become normal everyday practice) there is a serious bureaucratic obstacle in the form of the lack of permission for the intrathecal administration of any drugs other than local anesthetics and adrenaline. However, for anesthesiologists in countries with highly developed medicine, spinal anesthesia without the use of adjuvants is no longer popular and the number of studies on this issue is measured in the hundreds. The most commonly used adjuvants during SA are opioids (morphine, fentanyl), clonidine and epinephrine.

Morphine. A drug whose use as an additive to intraspinal administered local anesthetics has long become a classic of the genre. Morphine hydrochloride is a drug with pronounced hydrophilic properties, which explains its slow onset of action and duration of the analgesic effect. Morphine-induced postoperative analgesia does not have segmental boundaries, since the drug distributes evenly throughout the subarachnoid space. The use of morphine as an adjuvant for SA has, in general, one goal - to provide high-quality and long-lasting postoperative pain relief, the duration of which (as well as side effects) ranges from 6 to 24 hours. Side effects resulting from intrathecal administration of morphine include nausea, vomiting, bradycardia, skin itching, excessive sedation and delayed respiratory depression in the postoperative period. Morphine is also characterized by urinary retention and reactivation of herpes infection. From all of the above, it follows that morphine should be administered intrathecally in minimally sufficient doses, and the patient after its use should be adequately monitored for 24 days after administration of the drug. The average dose of morphine recommended for intrathecal administration is 0.1-0.3 mg, although the range of doses in various literature is very wide. Exceeding the specified dose does not increase the analgesic effect, but it greatly increases the risk of developing delayed respiratory depression and other side effects.

Fentanyl. Fentanyl is clearly recognized as the most popular adjuvant in the world. Unlike morphine, the drug has a pronounced lipophilicity, which allows it to have a quick and relatively short-lasting effect, being quickly absorbed into the blood from the injection site. The duration of the effect of fentanyl when administered subarachnoidally is 2-3 hours; residual postoperative analgesia lasts up to 4 hours, which allows the patient to adapt to the pain syndrome that occurs after the block is resolved. Fentanyl prolongs and significantly deepens anesthesia and gives a distinct sedative effect. Side effects include central respiratory depression that occurs when the dose is exceeded and sometimes a decrease in heart rate. Other side effects opiates (nausea, vomiting, urinary retention and itchy skin) are extremely rare when using fentanyl. Regarding doses, numerous studies have shown that the maximum possible analgesic effect with subarachnoid administration was provided by a dose of 6.25 mcg. Increasing the dose did not affect either the depth or duration of anesthesia, but it did increase the incidence of complications many times over. Thus, in practical work it is not recommended to go beyond 10-15 mcg, but we use fentanyl at a dose of 15 mcg (about 1/3 of 0.005% of the solution).

Clonidine. The drug is a stimulator of presynaptic adrenergic receptors and imidazoline receptors in the central nervous system. The cardinal difference between clonidine and opiates is that it inhibits the flow of all (and not just pain) nociceptive impulses. In general, in terms of its mechanism of action, clonidine has some similarities with cocaine, the first MA used for SA. Clonidine is also a lipophilic drug, so it is quickly absorbed from the injection site. The use of clonidine makes sense when using local anesthetics of medium duration of action (lidocaine) in order to deepen and prolong their effect. In addition, clonidine has a sedative effect and does not depress breathing at all. Of the side effects of clonidine, the first one is bradycardia, which can last several hours after administration of the drug, but rarely has clinical significance. Other side effects include clonidine's ability to cause hypotension and dry mouth. The range of doses of clonidine for intrathecal administration described in the world literature is quite wide and ranges from 15 to 200 mcg. In practical work, it is not recommended to go beyond 50 mcg.

Adrenalin. Theoretically, the addition of epinephrine aims to reduce the absorption of local anesthetic into the systemic circulation and thereby enhance and prolong anesthesia. However, if we remember the blood supply to the subarachnoid space, it becomes clear that it is extremely doubtful that adrenaline realizes its effect in a similar way. It is possible that the basis of the action of epinephrine is its own ability to enhance anesthesia by increasing the binding of MA molecules to sodium channels. However, despite this, the significant negative aspects of its intrathecal use cannot be ignored. Absorption of adrenaline itself can cause transient changes in the cardiovascular system of patients. Adding epinephrine to a local anesthetic solution may slightly reduce hypotension during spinal anesthesia, but does not prevent it. Moreover, there are sometimes reports of cases of a paradoxical sudden drop in blood pressure when using epinephrine in neuraxial anesthesia methods, which may be associated with the absorption of small doses of the drug. The most serious argument against the use of adrenaline as an adjuvant can be the cases of spinal conus ischemia described in the literature, sometimes caused by local vasospasm at the site of drug administration. Thus, in our opinion, the use of adrenaline as an additive to MA during SA should be excluded.

Distribution of local anesthetics in the subarachnoid space. Factors affecting the spread of local anesthetic

As noted earlier, the distribution of LA in the subarachnoid space is primarily influenced by the baricity of the MA drug. So, the density of the cerebrospinal fluid ranges from 1.004 to 1.009 with an average value of 1.007. A solution with a density of less than 1.003 is hypobaric for most patients. A solution with a density of 1.010 or more is considered hyperbaric for all patients. A solution with a density of 1.007 is isobaric, but may be hypobaric for one patient and hyperbaric for another, so it is difficult to predict whether a given solution will be isobaric for a given patient.

Patient position. Regardless of which anesthetic solution is chosen - hypo-, iso- or hyperbaric, the position of the patient after the injection is a factor that determines the zone of anesthesia. If a hyperbaric solution is selected and a high level of block is required, the anesthesiologist lowers the head end of the table below the foot end so that the heavy solution flows down the “hill.” On the other hand, if the solution is hypobaric and a high block is required, then the anesthesiologist places the patient in a position with the head end elevated, because It is believed that the hypobaric solution floats in the cerebrospinal fluid. Thus, there is no significant difference which solution the anesthesiologist chose to use, because he knows in advance the required level of the block, the density of the solution, the injection site and the position in which the patient must be placed to achieve the desired level. Currently, hypobaric solutions are almost out of use, and in some countries, for example, in the USA, their use is prohibited by law, since it is fraught with an unacceptably high prevalence of the block.

Speed ​​of solution introduction. The speed of insertion through a regular needle also affects the level of blockade, because turbulent flows promote wider distribution of the solution. A slow injection that does not cause significant turbulence results in a lower level of spinal block. To verify this, take a 5 ml syringe with a 22 gauge (22 G) needle, fill it with water, dip the tip of the needle under the water and quickly release the water from the syringe. Notice how the vortex flows generated by the jet cause the liquid to rotate. Repeat the experiment, but this time release the water from the syringe slowly - the degree of turbulence will decrease significantly. In practice, if you have performed a spinal puncture at a low level, quickly injecting the solution, creating eddy currents, will help send the anesthetic further away from the injection site. There is another way to increase the turbulence of the flow and send the anesthetic to a higher level: to do this, after administering the anesthetic, about 1 ml of cerebrospinal fluid should be aspirated and quickly injected again (i.e., bubbling). In practice, the direction of the needle when injecting a local anesthetic solution is not particularly important, but the angle between the needle and the spine of the subarachnoid space can determine the direction of flow of the local anesthetic. If the needle is directed cranially, then the flow of solution will spread in the same direction. Therefore, it must be borne in mind that the initial spread of the solution will be faster above the injection site. In some needles for spinal anesthesia, the bevel of the needle is positioned in such a way that it is possible to influence the direction of flow of the solution. For example, the Witacre needle has a blind-ended point and a hole in the side of the point. The point of the Tuohy needle ends blindly, and the end of the needle is curved so that the hole is in the middle of this angle. Both needles determine the angle at which the solution will flow out. In the first case, the angle will be 90°, and in the second - 45°. When using such needles, this circumstance must be taken into account.

Intra-abdominal pressure. For obese patients, pregnant women, patients with a large volume of ascitic fluid that stretches the abdomen, a smaller volume of anesthetic is required than usual. All these conditions limit the flow of blood through the inferior vena cava. To overcome this block, part of the blood from the inferior vena cava flows through the vertebral veins. It is believed that congested vertebral veins bulge into the space of the spinal canal and reduce the volume of cerebrospinal fluid. The usual volume of anesthetic solution under such conditions will lead to a higher block, so the dose of the drug and the volume of the solution are reduced by half or a third from the usual. Actually, the patient’s weight does not have any effect on the distribution of local anesthetic solutions. This process will be exactly the same for both a patient weighing 60 kilograms and a patient weighing 90 kilograms, provided that all other factors are the same. Theoretical arguments that the accumulation of fat in the epidural space in general obesity can reduce the volume of the subarachnoid space have not found practical confirmation.

Patient's height. The difference in the height of patients has important clinical significance during spinal anesthesia. The introduction of a local anesthetic solution into the subarachnoid space in small patients is accompanied by a more cranial spread of the anesthetic, and, consequently, a higher block than when the same dose of the drug is administered and at the same level tall patients. The distribution of identical doses of local anesthetic in the cerebrospinal fluid of a tall and short person occurs in the same way - over the same distance, at the same speed. However, in a small person, due to the shorter length of the spinal column, the upper limit of the zone of distribution of the anesthetic will correspond to the level of location of higher segments of the spinal cord. In addition, differences in the distribution of local anesthetic may be due to differences in the volume of cerebrospinal fluid in short and tall people. Larger volumes of the subarachnoid space, and therefore larger volumes of cerebrospinal fluid in tall people, will lead to a greater dilution of the local anesthetic solution. All this may explain the development of a lower level of block in patients with tall stature.

Patient's age. The volume of the epidural and subarachnoid space decreases with age, so when the same dose is administered to the elderly, the anesthetic spreads more cranially than to the young.

Dose and volume of local anesthetic. The dose of local anesthetic is also important factor, significantly affecting the quality of spinal anesthesia. The choice of dose depends on the properties of the anesthetic, the nature, and duration of the operation. In addition, the choice of dose may be influenced by the factors listed above - pregnancy, obesity, the position of the patient on the operating table. An increase in dose is accompanied by an increase in the segmental level of anesthesia. However, the volume and concentration of local anesthetic also plays a significant role.

Puncture level and anatomical factors. When choosing the location and level of the upcoming lumbar puncture, you must remember that the maximum convexity of the lumbar lordosis occurs at the lumbar vertebrae L3-L5. Therefore, at a low puncture level (L3-L4), migration of the hyperbaric solution of local anesthetic into the sacral region, followed by the development of a low block. Although in most cases this level of puncture allows achieving good quality anesthesia for surgery, such as caesarean section. And yet, the most rational level of puncture is considered to be the interspinous space L2-L3. In this situation, the convexity of the lumbar lordosis, on the contrary, will impede the caudal spread of the anesthetic. Pathological curves of the spine (scoliosis and kyphoscoliosis) can also have a significant impact on spinal anesthesia. Firstly, it technically complicates the puncture due to rotation and angular displacements of the vertebral bodies and spinous processes. Therefore, very often puncture is possible only from paramedian access. Secondly, severe kyphosis and kyphoscoliosis are combined with a decrease in the volume of cerebrospinal fluid, which sometimes leads to a higher blockade than expected. Anatomical factors influencing spinal anesthesia include previous operations on the spine and spinal cord. In these cases, it is also better to use a paramedian approach, or perform a puncture one intervertebral space cranial to the postoperative suture. Changes in the configuration of the subarachnoid space due to such anatomical factors increase the likelihood incomplete blockade, or discrepancies between the actual level of blockade and the expected one. The subarachnoid distribution of anesthetics is shown very clearly in the video lecture “Glass Back”; we strongly recommend that everyone watch this film.

Differentiated block for spinal anesthesia

A differentiated (differential, selective) block during spinal anesthesia is a phenomenon of selective blockade of nerve fibers depending on their thickness and the concentration of local anesthetic. The thicker the nerve fiber, the higher the threshold concentration of the anesthetic should be and the slower the block occurs. This phenomenon was discovered back in 1929 by D. Erlanger and G. Gasser. As is known, the nerve fibers that make up the spinal roots are heterogeneous and are represented by A-alpha, A-beta, A-gamma, A-sigma, B and C fibers.

As is known, A-alpha fibers are the largest in diameter, fully myelinated, and serve as a conductor of motor impulses to skeletal muscles and proprioceptive impulses to the spinal cord. This type of fiber is blocked only by high concentrations of anesthetics last. A-beta and gamma fibers are fully myelinated fibers, of the afferent type, responsible for non-painful proprio- and tactile sensitivity. A-sigma fibers are weakly myelinated and conduct pain impulses from mechano- and thermoreceptors; It is due to their blockade that the analgesic component of anesthesia is provided.

B fibers are the most poorly myelinated. They are responsible for conducting motor impulses of the sympathetic nervous system. As is well known, these fibers originate from the T1 - L2 segments. The blockade of these fibers causes all the hemodynamic effects of SA described below.

And finally, C-fibers contain no myelin sheath at all and are gray in color. These are sensitive conductors of the sympathetic nervous system. They are part of all the dorsal roots of the spinal cord.

The anesthesiologist has the opportunity to observe a differentiated block every time he performs SA or EA (except, of course, in cases of total spinal block). This phenomenon occurs in cases where part of the nerve fibers located in the area of ​​action of the anesthetic remains unblocked due to the concentration of the drug being insufficient for this type of fiber. So, after introducing a solution of MA into the subarachnoid space, the maximum concentration of the drug is created directly at the injection level - in this zone all nerve fibers are blocked and complete anesthesia and relaxation of the lower extremities occurs. Subsequently, the local anesthetic spreads in accordance with the laws of its distribution in the subarachnoid space, which leads to a gradual increase in the upper limit of anesthesia and muscle relaxation, but at the same time the anesthetic is gradually diluted with cerebrospinal fluid, its concentration decreases and becomes insufficient to block thick nerve fibers. Therefore, at this level, segments with working muscles are found, but with pain, temperature and other sensitivity turned off and the sympathetic efferent innervation of blood vessels is blocked. Further spread of the anesthetic in the subarachnoid space is accompanied by a progressive decrease in its concentration and further differentiation of the block. The last fibers that continue to be affected by minimal concentrations of local anesthetic are C-fibers, which, as already indicated, are fibers of sympathetic sensitivity. Subsequently, when the local anesthetic is absorbed into the systemic bloodstream, its concentration in the cerebrospinal fluid drops and functions are restored in reverse order(top down). A fairly common simplified rule in the literature is that it is generally accepted that the upper level of the somatic sensory block is determined to be two segments above the upper level of the motor block, and the upper level of the sympathetic block is two segments above the sensory block. Of course, in practice this ideal picture is not always observed. It should also be remembered that the map of dermatomes is not at all identical to the map of myotomes, and the scheme of splanchial innervation is not at all similar to these maps. The pictures below clearly demonstrate this.

Physiological effects of spinal anesthesia

It should always be remembered that spinal anesthesia, like any other method of anesthesia, is not strictly local, but affects, to one degree or another, all the organs and systems of the patient. In this section we will focus on discussing the clinical effects that inevitably arise when performing neuraxial blockade.

The cardiovascular system. Interruption of sympathetic impulses causes hemodynamic changes of varying severity. Sympathectomy leads to two characteristic phenomena - hypotension and bradycardia. It is quite difficult to draw a clear line between where the physiological effect of spinal anesthesia ends and where the pathology begins. Typical hemodynamic manifestations of spinal anesthesia include moderate decreases in blood pressure and heart rate, and, as a consequence, in SV and CO. The reasons for the hemodynamic effects of SA are sympathetic blockade, a decrease in peripheral vascular resistance and a shift in the balance of the autonomic nervous system towards the parasympathetic component. Of secondary importance are the activation of the mechanoreceptors of the left ventricle against the background of a decrease in its volume (Bezold-Jarisch reflex) and an increase in the activity of baroreceptors. On average, clinically significant bradycardia during SA occurs in 10-13% of cases, and arterial hypotension in 30%. Cases of cardiac arrest during SA have been described with a frequency of 0.004-1 per 10,000 performed SA.

Risk factors for the development of arterial hypotension in SA:

The sensor block is above the T5 level;

Initial systolic blood pressure less than 120 mm Hg. Art.;

Spinal puncture above the level of L3-L4;

Aortocaval compression syndrome;

Hypovolemia and hemoconcentration (Ht more than 35%).

Risk factors for the development of bradycardia in SA:

Initial heart rate less than 60/min;

Taking beta-blockers;

Elongation P-R interval on ECG;

The sensor block is above the T5 level.

Respiratory system. Effect of normal spinal anesthesia on function external respiration in healthy patients most often entail minimal clinical manifestations. There is a slight decrease in vital capacity due to a decrease in expiratory reserve volume, which is caused by paralysis of the muscles of the anterior abdominal wall. Impairment of the functions of the intercostal muscles depends on the height of the block, while the function of the diaphragm in SA is almost never impaired. A decrease in FRC and forced expiratory volume directly depends on the height of the block and decreased function of the abdominal and intercostal muscles; Excessively high blocks can naturally lead to decreased ventilation and the appearance of signs of respiratory failure. Respiratory arrests, which are observed during very high blocks, are usually caused by ischemia of the respiratory center due to arterial hypotension, which is catastrophic in such situations. Despite the fact that a decrease in the activity of the intercostal and abdominal muscles has virtually no effect on the condition of relatively healthy patients, a different picture is observed in patients with chronic obstructive pulmonary diseases, since they are forced to constantly use auxiliary muscles for active exhalation. In such patients, ventilation disturbances are quite possible, this should be remembered.

Gastrointestinal tract. Unlike general anesthesia, neuraxial blockades are characterized not only by preservation, but also by increased gastrointestinal motility due to activation of the parasympathetic nervous system. The incidence of nausea and vomiting in SA is 5-15%, in obstetrics - up to 60%. It is generally accepted that neuraxial anesthesia helps reduce the incidence of postoperative intestinal paresis by blocking nociceptive and sympathetic impulses, as well as reducing the need for narcotic analgesics.

Urinary system. Theoretically, one can assume a decrease in renal blood flow when performing SA, but this assumption is not confirmed in practice. The huge physiological reserve of the kidneys allows them to maintain their functions even with serious changes in homeostasis. Significant clinical aspects regarding urinary function during SA include urinary retention due to difficulty emptying the bladder. Paralysis of the bladder muscles is the cause of this unpleasant phenomenon, and it should be noted that it occurs with relatively low concentrations of local anesthetic. Treatment of this complication consists of timely catheterization of the bladder.

Thermoregulation. In everyday clinical practice, monitoring of body temperature during SA is usually not used. This leads to the fact that hypothermia, the incidence of which during SA is from 60 to 90%, remains unrecognized. It should be remembered that disturbances in temperature homeostasis occur with equal frequency during both general and regional anesthesia. It is known that risk factors for the development of intraoperative hypothermia are elderly age patients, low temperature in the operating room, reduced trophological status. Mechanisms that contribute to a decrease in body temperature in SA include sympathetic blockade and vasodilation, decreased tolerance to hypothermia, increased radiation heat loss, inhibition of spinal thermoregulatory centers, and infusion of cold solutions. Although monitoring of body temperature during neuraxial anesthesia has not yet entered into routine clinical practice, it should be mentioned that measuring core temperature is highly desirable in elderly patients and in cases of high spinal blocks. Of course, if hypothermia is detected, the patient must be warmed by any of the existing methods (infusion of heated solutions, use of a warming mattress or warm air).

Immune system. It is well known that general anesthesia serves as a powerful immunosuppressant due to the direct inhibition of lymphocyte function by general anesthetics, as well as due to the stress response. Unlike general anesthesia, neuraxial anesthesia helps preserve cellular and humoral immunity; in addition, the presence of low concentrations of amide group anesthetics in the blood gives some anti-inflammatory effect. There is every reason to believe that neuraxial methods of pain relief help reduce the incidence of purulent-septic complications in the postoperative period.

Consciousness. Despite the widespread belief among non-specialists that general and spinal anesthesia differ in the presence or absence of consciousness, this is far from the case. Spinal anesthesia, unlike general anesthesia, has a direct effect that leads to depression of consciousness. Numerous studies confirm the fact that the level of consciousness during spinal anesthesia is similar to that during the administration of sedatives. Possible mechanisms of depression of consciousness in SA include the ascending spread of local anesthetics and a decrease in the activity of the reticular formation due to interruption of afferent impulses. It is clear that the depth of sedation for SA depends on the height of the block. The sedative effect in SA develops in two phases. The first peak of action is observed when maximum spinal block is reached (20-30 minutes after administration of the anesthetic), and the second - approximately an hour after injection. The mechanism of the second peak is not yet clear.

Practical administration of spinal anesthesia

Preparation for spinal anesthesia. Preparation for SA includes a conversation with the patient, obtaining informed consent for SA, explaining the puncture procedure to the patient and establishing normal contact with him. Specific preparation includes the prevention of aspiration complications (in obstetrics and emergency surgery) and hemodynamic reactions, as well as the administration of premedication, if necessary. The latter usually involves oral administration of a drug from the group of tranquilizers the night before. Premedication can be enhanced by re-administering an IM tranquilizer one hour before surgery. The use of atropine as premedication does not prevent vagal reactions in SA.

Prevention of aspiration (in obstetrics) is routine. In the morning before a planned operation, food and liquid intake is prohibited. One hour before a planned cesarean section or immediately after making a decision about emergency surgery, 2 ml of a 0.5% solution of metoclopramide and 20 mg of quamatel are administered intravenously.

Prevention of hemodynamic disorders primarily involves installing a catheter of adequate diameter (16-18 G) in a peripheral vein. 400-600 ml of crystalloid solution (0.9% sodium chloride solution, Ringer's solution) is infused intravenously - the so-called pre-infusion. The question of its necessity is still open, however, there is no reason yet to completely abandon preinfusion. Colloidal solutions for preinfusion are used only when there are clear signs of hypovolemia. It is highly advisable to bandage the legs of patients undergoing a cesarean section with elastic bandages from the tips of the toes to the middle of the thighs. Prophylactic administration of vasopressors before CA is currently not recommended.

The SA kit should include the following items:

Spinal needle with or without sheath

Syringe for drug(s) for intrathecal administration

Syringe with a needle for anesthesia of the puncture site

A clamp and several gauze balls for cleaning the puncture site

Sterile gloves.

Patient position on the table To carry out subarachnoid blockade, three main positions of the patient are used: lying on his side, sitting and positioning in the “jackknife” position.

The side lying position is one of the most commonly used. The spine should be arched as much as possible - the knees and hips should be brought as close to the stomach as possible, and the chin should be pressed to the chest. The head should be in line with the spine. Your hips and shoulders should be perpendicular to the surface of the table. The patient's back is placed at the very edge of the operating table. This provision allows the use of sedation in patients before anesthesia without fear of orthostatic problems. It should be remembered that in this position there may be a slow flow of cerebrospinal fluid from the needle due to hydrostatic relations in the subarachnoid space.

The sitting position is considered the most comfortable for performing a spinal puncture. The patient is placed on the edge of the table, with his legs placed on a stand (chair). The neck should be bent as much as possible so that the chin touches the chest. The patient's arms are crossed on the stomach. The assistant should support the patient to prevent fainting.

The “jackknife” position is currently used only in proctological operations using hypobaric anesthetic solutions for spinal anesthesia. Due to the fact that in this position the sacrococcygeal region is the highest point of the spinal column, hypobaric anesthetics spread in this direction, that is, a sacral subarachnoid blockade develops. Among the features of this position, it should be mentioned that confirming the correct position of the needle in this case can be very difficult due to the low hydrostatic pressure of the cerebrospinal fluid in this position - careful aspiration with a syringe can help.

Spinal puncture technique

The choice of the interspinous space for puncture does not have a significant effect on the distribution of the anesthetic, if the puncture, of course, is performed in the lumbar region. The use of other parts of the spine for SA is currently of only historical interest. However, for safety reasons, when choosing a puncture site, one should take into account the fact that the spinal cord ends at the level of the first or second lumbar vertebra. But in approximately 5% of the general population of people, variants occur - the spinal cord can end at the level of the twelfth thoracic or third lumbar vertebra. Rare cases have also been described in the literature in which the spinal cord ends at the level of the sacrum. The second point that should be taken into account when choosing a puncture site is the fact that the greatest convexity of the lumbar lordosis occurs at L3-L4. Based on this, it should be remembered that it is theoretically possible for the anesthetic solution to flow into the sacral region when performing SA below this level, although, as has been repeatedly stated earlier, the height of the puncture site does not have a significant effect on the level of the block. In this regard, it is appropriate to recall the advice of Robert McIntosh: “The level of puncture does not matter, the main thing is that it is below L2. If the distances between the spinous processes are not the same, you can advise the anesthetist to choose the widest gap for the puncture.”

The puncture site must be treated with the utmost care. It is absolutely unacceptable to use antiseptics containing phenol for treatment; When using iodine- and chlorine-containing antiseptics, as well as surfactants, their residues should be removed dry from the skin surface with a dry sterile ball.

Anatomical landmarks for puncture. These include, firstly, Tuffier's line - a straight line connecting the upper points of the iliac crests and passing at the level of the 4th lumbar vertebra. The distance from the skin to the subarachnoid space is purely individual, and can range from 2.5 to 8 cm, on average 4-5 cm. The diameter of the subarachnoid space in the lumbar region is about 1.5 cm.

To reach the subarachnoid space, the puncture can be performed through a median or paramedian approach.

Puncture via median access:

Select the interval for puncture

Use your free hand to secure the skin at the puncture site.

Execute local anesthesia skin of the puncture site. To do this, it is advisable to use the remaining local anesthetic, diluting it with saline solution

The puncture point is located strictly in the middle of the distance between the spinous processes; it is necessary to ensure that the needle does not deviate from the line of the spine

When using a Quincke needle, its cut should be oriented along the line of the spine, which leads to a significant reduction in the incidence of post-puncture syndrome

The needle is passed until a loss of resistance is felt, which indicates the needle has passed through the ligamentum flavum, and then another 0.5-1 cm, which leads to its passage through the dura mater, puncture of which may be accompanied by a characteristic “click”

Remove the mandrin and wait for the cerebrospinal fluid needle to appear in the pavilion, remembering that when using thin needles, especially with pencil sharpening, this may take about one minute

If there is no cerebrospinal fluid, it is possible to advance it another 0.5 cm, try to rotate the needle around its axis, and pull the needle towards you (if it has gone too far)

If the needle rests on the bone at a shallow depth, this indicates that it has entered the arch of the lower vertebra. In this case, the needle is removed to the subcutaneous tissue and redirected more cranially. If the needle rests at a great depth, then this indicates that it has entered the vertebral body. In this case, the needle is carefully pulled back until cerebrospinal fluid appears. There is another way. If the needle rests on the bone, the depth of its insertion is noted, and then it is redirected more cephalad. If the same thing happens, then the depth of its penetration is compared with the previous one. If it is larger, there is contact of the needle with the upper edge of the spinous process, and it is necessary to redirect it even more cranially. If the depth of the obstacle is less than the previous one, then the needle has reached the lower edge of the spinous process and its direction changes to a more caudal one. If the needle rests at the same depth, then it deviates from the midline and hits the lateral plate of the vertebral body. In this case, the needle is directed strictly in the sagittal plane.

Puncture via paramedian access:

Less widely used

With this access, the incidence of post-puncture syndrome is significantly reduced, which allows the use of needles of a higher caliber (20-22 G), in addition, the hole required for the passage of the needle is wider and the puncture is technically simpler

No spinal flexion is required, which can be important in obstetrics and in the elderly

Local anesthesia of the skin is performed as in the case of a median approach

Strictly speaking, there is a lateral approach, in which the needle is inserted with a slight medial deviation, stepping back half a finger from the midline and directed with the usual cranial deviation; and paramedian (oblique lateral) approach, in which the needle is inserted at the level of the spinous process at the lower edge of the intervertebral space and is directed at an angle of 45° relative to the midline, as well as 45° in the cranial direction

The bevel of the needle during puncture should be facing the skin

If the needle rests on the bone structure at a great depth, then it must be redirected more cranially.

Administration of anesthetic:

The anesthetic can be injected only after the appearance of cerebrospinal fluid in the needle pavilion - in no case should the anesthetic be injected if the patient complains of ongoing paresthesia - in this case, the needle is pulled back a little and the puncture attempt is repeated - when injecting the anesthetic, and especially when attaching and detaching the syringe, you should always securely fix the needle with a hand resting on the patient’s back - when administering an anesthetic, the syringe scale should always be facing the doctor - the anesthetic injection rate is 0.2 ml/sec - 1 ml every 5 sec; do not overly force the introduction of the solution - after introducing the anesthetic, you should make sure that the end of the needle is in the subarachnoid space, which is achieved by disconnecting the syringe and controlling the flow of cerebrospinal fluid into the needle pavilion - after checking the position of the needle, a mandrel is inserted into it and the needle is removed, and the puncture site treated with a ball of alcohol and sealed with a narrow ball and adhesive tape.

Lumbosacral approach (Taylor's approach)

In case of unsuccessful attempts to penetrate into the subarachnoid space from the classical approach due to calcification or scar changes, the so-called Taylor access can help - access through the lumbosacral opening, which is the widest and for this reason may still be passable. To achieve this approach, the posterosuperior iliac spine is identified and 1 cm inferior and 1 cm medial are stepped back from it. After anesthetizing the skin, the needle is directed through this point at an angle of 45° in the cranial and 45° medial directions and is passed into the space between the fifth lumbar vertebra and the sacrum. The needle must be of sufficient length, 10-12 cm, since the trajectory with this access is longer. The tactile sensations that occur when the needle passes through the ligaments in this case are identical to those with a median approach.

Course of surgical anesthesia

After a spinal puncture, the patient is carefully placed in the position required for surgery. In obstetrics, the table with the patient is tilted slightly to the left - prevention of aortocaval compression. It is necessary to avoid sharp turns of the patient, especially around its own axis, as they can lead to a higher spread of the block. Care must also be taken to prevent the patient from becoming cold.

Required monitoring during CA includes continuous monitoring of the patient, non-invasive blood pressure measurement, HR calculation and pulse oximetry. The use of cardiac monitoring and, during long-term operations, body temperature monitoring is highly desirable. All patients receive oxygen inhalation through a face mask or nasal catheter.

The first sign of a developing blockade is the appearance of a feeling of warmth in the lower extremities when the anesthetic is administered or immediately after puncture, which is associated with vasodilation. Assessment of the level of the block is carried out on average 5 minutes after the puncture and includes an assessment of the level of sensory block and the degree of motor block. Sensory block is assessed by determining pain (pin test) or temperature (touching the skin with a ball moistened with alcohol or ether) sensitivity; the latter is preferable. According to the pattern of skin innervation (see above), the level of sensory block is determined and recorded in the anesthesia protocol. To quickly determine the level of the sensory block, it is enough to remember several anatomical landmarks:

T12-L1 - top edge pubis and inguinal folds;

T10 - navel;

T6 - xiphoid process;

T4 - nipples;

C7 - middle finger of the hand.

The motor block is assessed using the F.R. scale. Bromage:

0 - ability to move the hip, knee and ankle joints;

1 - ability to move only in the knee and ankle joints;

2 - ability to move only in the ankle joint;

3 - inability to move in all three joints.

The doctor’s free orientation in assessing the quality, level and depth of the block achieved is the basis for his timely and adequate treatment measures if any complications arise.

It should be remembered that the rate of development of surgical anesthesia is not the same for different drugs - for example, when using lidocaine, the block develops in 3-7 minutes, while when using bupivacaine its development can take up to 10-15 minutes.

Infusion therapy for spinal anesthesia is individual in nature. As a rule, the infusion rate is initially set to high (to prevent an episode of hypotension associated with the development of block), and then reduced to moderate. As a rule, crystalloids are used, the total volume of which (including preinfusion) is usually 1000 - 1500 ml.

Sedative therapy for spinal anesthesia is used according to indications (patients with severe emotional lability, mutilation, prolonged operations, etc.). Benzodiazepine drugs or propofol are usually used, but their doses must be reduced.

Problems and troubles

A doctor who has included neuraxial pain management techniques, especially SA, in his arsenal, is doomed from time to time to encounter various phenomena that cannot be called complications, but which can ruin the mood of both the doctor and the patient. One part of these phenomena is associated with the direct physiological effects of neuraxial blocks, while the other arises as a result of technical problems encountered during puncture. It would not be entirely correct to classify these phenomena as complications, since complications of SA are more serious things. So, let's look at the typical troubles of SA.

No anesthesia. As is known, spinal anesthesia is an “all or nothing” phenomenon, that is, if the right drug in the right dose into the right anatomical space, then anesthesia will develop in any case. Based on this, there can be two real reasons for the lack of anesthesia: - The drug was not introduced into the subarachnoid space, usually as a result of needle displacement or incorrect identification of the latter. - The drug, after being introduced into the subarachnoid space, flows down from the lumbar lordosis into the sacral region. In this case, the anesthesia covers only the lower extremities, which can be a problem if the surgical intervention was planned for more high level. The absence of anesthesia is manifested by the preservation of active movements in the lower extremities 5-7 minutes after administration of the drug and the presence of pain sensitivity in the surgical area. The best course of action in this case is to switch to general anesthesia.

Insufficient anesthesia. Anesthesia may be insufficient in depth, extent or duration. The reasons for insufficient anesthesia may be related to the quality of the drug itself, displacement of the needle during the injection of the latter, drainage of part of the anesthetic from the top of the lumbar lordosis, individual variations in the density of the cerebrospinal fluid, etc. In any case, a situation arises when the CA is not able to independently provide surgical anesthesia. The solution to the problem must be individual for each case, and ranges from inhalation of nitrous oxide with oxygen through the mask of the anesthesia machine to switching to full general anesthesia.

Nausea and vomiting. Occurs relatively often in SA. May be caused by the direct effect of the anesthetic and/or adjuvant on the vomiting center or by impaired cerebral perfusion due to a fall cardiac output with the development of hypotension and bradycardia. Treatment in the first case may include the administration of antiemetics; in the second case, eliminating the immediate cause.

Complications of spinal anesthesia

In this section we will consider those phenomena that, according to the definition of I.A. Shurygin - the author of one of the best books on spinal anesthesia in Russian - are functional deviations, organic changes or mechanical damage that arise in connection with a complex of anesthesiological benefits and can cause transient or persistent damage to the patient’s health or cause death.

You should always remember that spinal anesthesia is a special state of the body, which has its own patterns and logic, which is fundamentally different from the state of general anesthesia. It is in relation to this state that such a concept as the norm of a method can be fully attributed. For example, a decrease in heart rate to 50 beats per minute in another situation usually serves as a signal for immediate action, but in the case of spinal anesthesia, if the patient’s condition is satisfactory, such an indicator should not cause any active action by the doctor. A similar situation is observed with arterial hypotension. The criterion for active intervention should be the patient’s well-being and the presence real threat his life and health. One of the catchphrases in anesthesiology, “take care of the patient, not the monitor,” fully applies to spinal anesthesia.

As a rule, the cause of most complications of SA is sympathetic blockade, the degree and prevalence of which is completely impossible to predict. Also, complications of SA can be caused by a high spinal block (primarily motor), but such complications are quite rare. For convenience of consideration, we will divide all complications of SA into circulatory disorders, respiratory disorders and neurological complications, recognizing the fact that the developing complication to one degree or another affects all organs and systems of the patient.

Circulatory disorders- the most common group of complications of SA. All circulatory disorders have one single pathophysiological cause - sympathetic blockade and resulting bradycardia and hypotension, and at their core - a decrease in CO and IOC. Hemodynamic disturbances in SA can develop gradually, or they can be of a landslide nature, but all of them, as a rule, can be corrected quite well if it is started in a timely manner. There are three hemodynamic complications of SA: hypotension, bradycardia and cardiac arrest.

Arterial hypotension is the most common complication of SA, but there are a number of nuances. First, what should be considered arterial hypotension? The mass of criteria for this condition found in modern medical literature only suggests that there is no consensus as to what blood pressure numbers should be considered a complication and correction should begin. It seems to us that it is much more important to use the patient’s well-being as a criterion rather than rely entirely on objective indicators. Typically, a decrease in systolic blood pressure to 90-80 mm Hg. Art. is completely tolerated by young people, relatively healthy people, which cannot be said about elderly patients with atherosclerotic lesions of cerebral vessels. If hypotension causes severe circulatory disorders, then the symptoms are quite demonstrative: the patient begins to complain of weakness, dizziness and nausea (!). As hypotension worsens, signs of cerebral ischemia begin to progress - a feeling of lightheadedness, darkening of the eyes, vomiting, depression of consciousness. Correction of arterial hypotension is carried out by generally accepted methods: elimination of hypovolemia (if it occurs) and the use of vasopressors. Of course, you should not wait for signs of cerebral ischemia, but start correcting hypotension earlier, especially if there is a rapid rate of decrease in blood pressure, a combination of hypotension with bradycardia, alternating pulse, nausea, and complaints of deterioration of well-being. Correction of arterial hypotension consists of the following actions:

Increasing O2 supply to 6-7 l/min;

Increasing the rate of infusion (colloid transfusions are usually required infrequently);

Raising the foot end of the table;

The use of vasopressors (ephedrine around the world is now slightly inferior in this regard to mezatone, which before use is diluted at the rate of 1 ml of 1% mezatone solution per 20 ml of 0.9% solution sodium chloride and injected slowly in 1-4 ml increments; bradycardia due to the administration of mezatone is easily relieved by atropine).

Bradycardia is the second most common complication of SA. Currently, it is believed that bradycardia in SA should be considered a heart rate decrease of less than 50 beats/min. The causes of bradycardia are well known - blockade of the efferent sympathetic innervation of the heart and cardiac reflexes. The prophylactic use of atropine as premedication is useless. Correction of bradycardia is generally accepted - the administration of atropine and ephedrine, sometimes the use of adrenaline may be required. It should be remembered that with a progressive drop in heart rate, atropine should be administered ahead of schedule. Subarachnoid use of opiates or clonidine deepens and increases the frequency of bradycardia.

Cardiac arrest is a rare complication of SA. Can develop at any stage of anesthesia. It is not related to the height of the block - it can develop even with a saddle block. Most often associated with a sudden change in body position. As a rule, if asystole is detected immediately and conduction is started immediately resuscitation measures, then cardiac activity is restored very quickly.

Such a specific hemodynamic complication of SA as vasovagal syncope deserves special mention. According to its mechanism, it is a fainting episode that develops against the background emotional lability patient; but developed under conditions of almost total sympathetic blockade, which makes it catastrophic. The clinical picture of vasovagal syncope during SA develops within 1-2 minutes. Severe weakness and dizziness appear, almost instantly followed by yawning, nausea, retching and pallor skin. Objectively, a rapidly progressive decrease in blood pressure and severe bradycardia are noted. Subsequently, the pupils dilate and loss of consciousness occurs. Assistance should be provided immediately and include manual ventilation with 100% oxygen, elevation of the lower extremities, administration of atropine along with vasopressors, or epinephrine. After hemodynamic recovery, the operation is continued under sedation or superficial anesthesia.

Breathing disorders include ventilation DN (oppression of the respiratory center or weakness of the respiratory muscles) and separation of ventilation and blood flow in the lungs due to hypotension, leading to a decrease in pressure in the pulmonary circulation. As a rule, breathing disorders in AS respond well to correction.

Depression of the respiratory center usually occurs due to:

Acute ischemia of the respiratory center;

Drug depression DC;

Depression of the DC during spinal anesthesia against the background of sedation;

Hypoventilation due to high spinal block.

In the first case, the cause of DC inhibition is hemodynamic disorders. In this case, a clinical picture of respiratory failure is observed against the background of deep arterial hypotension and general signs of decreased cerebral blood flow (lethargy, loss of consciousness, hyporeflexia). Treatment of complications includes providing oxygenation (from giving oxygen to tracheal intubation and transferring the patient to mechanical ventilation) and measures to normalize hemodynamics.

Drug-induced depression DC occurs when drugs are used as adjuvants narcotic analgesics. It occurs quite often, but clinically significant hypoventilation occurs, as a rule, when safe doses of drugs are exceeded. With this type of hypoventilation, patients do not feel discomfort or lack of air, they are drowsy, facial skin hyperemia develops, and breathing is significantly reduced. Monitoring may not immediately reveal a decrease in saturation if the patient is breathing a mixture with a high percentage of oxygen, this should be kept in mind. Severe drug-induced depression in DC may require full respiratory support. Depression of the respiratory center, which occurs during sedation during SA, usually occurs during intravenous administration tranquilizers or propofol. The risk of complications is proportional to the dose of the drug. Diagnosis and treatment of this complication does not differ from those for respiratory depression caused by narcotic analgesics.

Hypoventilation with a high spinal block develops when the roots innervating the diaphragm are blocked (C3-C5). This is usually preceded by patient complaints of numbness in the hands and weakness. Then the patient's reaction is pronounced emotional character- complaints of lack of air and difficulty breathing appear, then real panic develops. Help must be provided quickly and clearly. The patient is calmed down and oxygen inhalation is continued. Stabilize hemodynamics if necessary. With further development of respiratory failure clinics, careful auxiliary ventilation with oxygen is performed through the mask of the anesthesia machine in rhythm with the patient’s respiratory movements. The question of the need for tracheal intubation and switching to automatic ventilation is decided individually.

Delayed and late complications of spinal anesthesia

This group of complications includes neurological disorders, including traumatic injuries of the roots or spinal cord with a needle, infectious complications, neurotoxic disorders, ischemic disorders and post-puncture syndrome.

Traumatic injuries usually occur when the spinal cord or roots are damaged by a needle. The signs of this are very characteristic - sudden shooting pain during puncture and the appearance of paresthesia when injecting the drug. When these symptoms appear, the needle is pulled back 0.5-1 cm and the puncture is repeated.

In addition to needle damage to roots or nerves, the category of traumatic complications also includes such a rare complication of SA as an epidural hematoma. The risk of such a complication is estimated at 7 per 1 million anesthetics. Usually, this complication develops during treatment with anticoagulants and/or antiplatelet agents. Recommendations for performing regional pain management techniques in patients taking drugs that affect hemostasis are posted on our website. The clinical picture of epidural hematomas includes patient complaints of unbearable back pain, followed by various motor and sensory disorders and dysfunction of the pelvic organs. The anesthesiologist should always be wary of cases of prolonged block. In this aspect, prolonged epidural analgesia with local anesthetics requires regular monitoring of tendon reflexes. A developed epidural hematoma requires immediate surgical intervention. An even rarer (2 cases per 1 million anesthesia) complication of SA is subdural intracranial hematoma, the main clinical symptom of which is the patient’s complaints of prolonged persistent headache, which is often mistaken for post-puncture headache. The triggering factor for the development of a hematoma is a leak of cerebrospinal fluid, which leads to a decrease in ICP and a displacement of the brain in the caudal direction with tension in the veins of the dura mater and their subsequent rupture. The main differential diagnostic point is the fact that with subdural intracranial hematoma, headache is not associated with body position, unlike post-puncture syndrome. Tactics for such complications are well known.

Infectious complications SAs are quite rare. These include epidural abscess and bacterial meningitis. The clinical picture of these complications is well known, as is therapeutic tactics. Separate mention should be made of aseptic meningitis associated with the entry of detergents or iodine into the subarachnoid space.

Neurotoxic disorders associated with toxic effects on nerve fibers of local anesthetics, adjuvants or their preservatives. In general, the main problems of local anesthetic neurotoxicity are associated with the use of lidocaine, especially at concentrations above 5%. Bupivacaine causes damage to nerve fibers ten times less often. Clinically, neurotoxic disorders can manifest as weakness, numbness, peresthesia, radicular pain in the lower extremities, cauda equina syndrome, and urinary retention. As a rule, all these symptoms disappear within a week and only in some cases can last up to 6 months.

Ischemic disorders associated with the use of adrenaline as an adjuvant, which we discussed above. We believe that the use of epinephrine as a supplement with MA for SA does not make any practical sense, carries a risk of ischemic and hemodynamic complications and should therefore be excluded.

Post-puncture syndrome overshadowed SA from the first days of its existence as a method, since the first who had to experience it were A. Beer and A. Hildebrandt. S.S. Yudin wrote: “Of all the shadow sides of spinal anesthesia, this is the most painful and unpleasant. We still cannot reliably eliminate the occurrence of headaches.” The cause of post-puncture syndrome is clearly established - leakage of cerebrospinal fluid through a defect in the dura mater, which entails tension meninges when moving the patient into a vertical position due to brain dislocation, and, as a result, causes headache, nausea, vomiting and dizziness. However, many facts in this area have not yet received a satisfactory explanation. We previously mentioned some measures to prevent PPS, we will systematize them.

1) Use of thin needles for puncture (optimally 25-27 G, in some cases - 22 G).

2) Orientation of the Quincke needle cut along the spine.

3) Using pencil sharpened needles (Whitacre and Sprotte needles).

4) Strive to complete the puncture on the first try.

5) Avoidance of double puncture of the dura mater. I would especially like to note that the often recommended adherence to bed rest after SA for the purpose of preventing PPS has no value, since PPS can develop after a few days of lying in bed. This recommendation negates one of the advantages of SA - the possibility of early activation of the patient.

The symptoms of PPS are very demonstrative. The main symptom is headache, sometimes radiating to the neck or shoulder girdle. In some cases, there are symptoms associated with tension of the cranial nerves - nausea, vomiting, dizziness, diplopia. The time frame for the development of PPS can be very different - from less than a day to 5-7 days. The main differential diagnostic significance is the relationship between pain and vertical position bodies.

Treatment for PPS should be started immediately. This is the anesthesiologist's responsibility, without a doubt. The first step is to establish the presence of PPS as such and explain to the patient what is going on. There are two treatment options for PPS.

Passive tactics - limiting the patient’s suffering until the dural defect is closed (on average 3-10 days):

Bed rest;

Infusion therapy in a volume of 1-1.5 liters daily;

Drink plenty of fluids;

Prescription of NSAIDs;

Purpose of caffeine;

Symptomatic and sedative therapy.

Active tactics involve eliminating the dura mater defect by filling the epidural space with autologous blood. The effectiveness of the method is close to 100%. In countries with highly developed medicine, epidural blood patch is the main method of treating PPS. The essence is to inject 10-20 ml of autologous blood into the epidural space at the level of the previous puncture or the lower of the used spaces, and at least 24 hours must pass from the moment of spinal anesthesia.

No special patient preparation is required;

The patient is placed on his side; puncture the peripheral vein;

A puncture of the epidural space is performed with a Tuohy needle, and they try to use a minimum amount of saline solution to identify it.

20 ml of autologous blood is drawn into a dry syringe and the blood is injected into the epidural space; in most cases, 15 ml is sufficient.

The patient is observed for 30-40 minutes and then sent to the ward;

If the filling effect is insufficient (which is relatively rare), the procedure is repeated.

Immediate postoperative period

After the operation, performed under spinal anesthesia, the patient can be transferred to the general postoperative ward. Indications for monitoring the patient in the department (ward) intensive care serve as: - unstable hemodynamics requiring infusion and/or vasopressors; - ventilation disturbances of any severity. IN further patient can be transferred to a specialized department after stabilization of the condition, if there are no orthostatic disorders, hemodynamics are stable, there is no dysfunction of the pelvic organs and post-puncture syndrome. If any neurological complications develop, consultation with a neurologist is required as early as possible.

Anesthesia plays a huge role in modern medicine. After all, thanks to it, doctors have the opportunity to perform operations and a number of special examinations that are accompanied by pain.

Modern anesthesia involves rather complex pain relief techniques. Therefore, for these purposes there is a certain doctor, who is called an anesthesiologist.

The largest percentage of pain relief occurs under general anesthesia, that is, anesthesia. However, it is also possible to perform local anesthesia. This type of loss of sensitivity involves anesthesia of only certain areas of the human body.

However, if there is certain situations and individual indications, another type of anesthesia is often performed, the name of which is “spinal anesthesia”.

This analgesic technique represents a regional loss of sensation in the patient. In this case, there is a complete temporary “switching off” of any sensations in the area of ​​the body located below the navel. This type anesthesia is an excellent replacement for general anesthesia. Patient input process spinal anesthesia It is performed by injecting a certain drug into the back, which turns off the nerves responsible for pain.

Pros this method pain relief are:

• minimal blood loss during the operation;
• the risk of postoperative blood clots and pulmonary thromboembolism is significantly reduced;
• reducing negative effects on the lungs and heart;
• no nausea or weakness;
• absence painful sensations in the postoperative period;
• the possibility of direct contact with the doctor during surgery;
• the opportunity to eat well after surgery.

Technology of anesthesia

To ensure complete painlessness, anesthesia is administered into the cavity of the spinal column, located between the membranes of the brain and spinal cord. This area is filled with cerebrospinal fluid - cerebrospinal fluid. Thanks to the anesthetic entering this space, a complete “switching off” of the lower body is achieved. This result is achieved by blocking nerve impulses emanating from the nerve roots of the spine to the brain. Therefore, a person does not feel anything during the action of the drug.

Administering spinal anesthesia requires specialist technical skill as the process is not easy. In addition, spinal anesthesia is performed using medical instruments that reduce the risk of complications after anesthesia.

Such tools include:

• alcohol disinfecting cotton swabs for antiseptic procedures;
• two syringes, one of which contains a local anesthetic for a less sensitive spinal puncture. And the second syringe is filled directly with an analgesic agent for spinal anesthesia;
• a special needle for performing a spinal puncture. By the way, it is much thinner than the one used for epidural anesthesia.

Preparing the patient

For an anesthesiologist to effectively administer spinal anesthesia, the patient must follow a number of recommendations:

• when conducting elective surgery the patient must limit himself to eating and drinking liquids;
• You must first inform the specialist about the patient’s allergic reactions to medications, if any;
• undergo laboratory blood tests (group and Rh factor, general analysis, coagulogram).

The process of spinal anesthesia

After completing all the above doctor’s instructions, you can proceed directly to the anesthetic injection. To do this, the patient must provide the doctor with good access to the spine, taking a position lying on your side, or sitting, with your back bent as much as possible.

This is followed by treatment of the anesthesia injection area with antiseptic drugs and an injection of local anesthetic from the first syringe. Then the anesthesiologist administers the anesthetic, based on the rules for the technique of administering this anesthesia - specifically into the subarachnoid space.

The required dosage of the drug is calculated by the anesthesiologist in advance. It is determined based on the analysis individual characteristics human body: height, weight, age.

It is worth noting that the puncture site is usually located between the II and III vertebrae of the lumbar spinal column, but it is also acceptable to administer an anesthetic up to the V vertebra. The choice of location for spinal anesthesia depends on the individual structure of the spine, the presence of previous injuries or surgical interventions.

Feel

After direct administration of the drug, a person gradually begins to feel heaviness in the legs or a slight tingling sensation. This indicates that the administered drug is beginning to work. After a few minutes, sensitivity completely disappears. Before surgery, the doctor must test for loss of sensitivity. If suddenly a person feels an unpleasant sensation, more like an electric shock, you should immediately tell a doctor about it.

In some situations, longer spinal anesthesia may be required. In this case, a special instrument, a catheter, is placed in place of the previous puncture for additional administration of the medicine.

Anesthetics for anesthesia

For spinal anesthesia, agents with various properties are used. Each of these drugs gives a different effect in terms of duration of exposure. Patients with allergic diseases There is no need to worry: there are a lot of options for administered medications, and the doctor will definitely replace a drug that is unsuitable for the individual body with one that has a similar effect. Here are some of the medications that are used for spinal anesthesia: Narolin, Novocaine, Mezaton, Fraxiparine, Lidocaine, Bupivacaine and many others.

For your information, the table below shows the active ingredients used in spinal anesthesia drugs, their dosages and the duration of action of each of them. Thanks to this table, the patient can determine whether he is allergic to a particular drug and whether the dosage is appropriate for him.

Medicine	Concentration of solutions, (%)	Maximum dose, (mg)	Duration of action (minutes)
Procaine hydrochloride	0.25 or 0.5	500	40-60
Lidocaine	2-5 (hyperbaric solution)	15-100	60-90
Tetracaine hydrochloride	0.5 (hypobaric, isobaric or hyperbaric solution)	5-20	from 180 (hyperbaric solution) to 270 (hypobaric solution)
Bupivacaine hydrochloride	0.5 (isobaric or hyperbaric solution	10-20	90-150
Artikain	5 (hyperbaric solution)	100-150	up to 120

Advantages of the method

1. The rapid onset of the effect of loss of sensitivity and blocking of nerve impulses.
2. Successfully used when caesarean section or to ease labor pains. Thanks to the safe effect on the patient’s body, the mother in labor does not have to worry about the health of the baby.
3. A much smaller dose of the drug enters the patient’s body compared to other types of anesthesia.
4. By using a thin needle when injecting the drug, the risk of internal damage is minimized.
5. This anesthesia technique involves the muscles being as relaxed as possible, which greatly helps the surgeon during the operation.
6. There is minimal intoxication of the body when the drug is administered, since the percentage of the anesthetic entering the blood is in isolated cases.
7. The analgesic effect does not affect the respiratory system; therefore, problems associated with the lungs are automatically excluded, as is the case with general anesthesia.
8. The patient remains conscious, which helps to immediately eliminate complications, since direct contact is maintained between doctors and the patient during the entire surgical process.
9. Minimal risk of complications after puncture due to the simplicity of the anesthetic injection technique.

Negative consequences of spinal anesthesia

In order for the patient to decide to undergo spinal anesthesia, he needs to familiarize himself in advance with information about the disadvantages of this method of pain relief.

1. During the medication administration process, the patient's blood pressure may drop sharply. Therefore, hypotensive patients are given drugs that increase blood pressure in advance - of course, if necessary. For hypertensive patients, this consequence can only have a positive effect.
2. The time of loss of sensitivity is directly related to the dose of the drug. If sensitivity returns before the required time, and there is not enough time to complete the operation, the patient is immediately placed under general anesthesia. The spinal anesthesia method does not involve constant support of the anesthetic in the body; most often it is administered once. However, do not worry, since modern medicine uses medications that last up to six hours, which in most cases allows the surgeon to carry out all the manipulations on time.
3. Headaches are a frequent companion of the patient after recovery from anesthesia.

Indications for using spinal anesthesia technique

1. Surgery of the legs or perineum.
2. Reducing the risk of thrombosis in older people during leg surgery.
3. Due to the impossibility of administering general anesthesia for lung diseases, both acute and chronic stages.
4. The need to reduce tone muscle tissue intestines during operations on the gastrointestinal tract.
5. The need to relax the walls blood vessels in people with heart problems, with the exception of hypertensive patients and patients with heart valve problems.

Indications for general anesthesia

In some cases, patients are prescribed only general anesthesia. Such situations include large-scale surgical operations when the doctor is unable to complete them in a short period of time. In cases of dental treatment, general anesthesia is prescribed when the patient needs to have a large number of teeth removed or many implants installed.

Important! Along with this, this anesthesia is prescribed to people with allergies to local anesthetics, patients with a gag reflex during dental therapy, as well as those patients who will undergo surgery on organs above the navel.

Contraindications to the use of spinal anesthesia

Complete contraindications for spinal anesthesia are:

• direct refusal of the person to undergo the procedure;
• problems with blood clotting - to exclude volumetric blood loss;
• infection or inflammation at the site of future anesthesia injection;
• critical conditions of the patient in the form of shock, major blood loss, sepsis, pulmonary and cardiac dysfunction;
• allergy to all types of anesthetics used for puncture;
• meningitis and other infectious diseases of the nerves;
• hypertension;
• herpes;
• arrhythmia.

Relative contraindications, when the benefit significantly outweighs the harm caused to the patient by spinal anesthesia, include:

• changes in the structure of the spine, both congenital and acquired due to injury;
• the patient was given a pre-prognosis for heavy blood loss during surgery;
• fever associated with infectious diseases;
• multiple sclerosis, epilepsy and other diseases of the nervous system;
• mental disorders (when there is a possibility that the patient will not be able to lie still during surgery);
• use of aspirin shortly before the appointment of spinal anesthesia due to an increased risk of blood loss due to the properties of this drug;
• the likelihood of increased surgical time;
• childhood.

Frequently asked questions from patients before agreeing to spinal anesthesia

How will I feel after the anesthesia is administered?

Answer. A couple of minutes after the injection of spinal anesthesia, heaviness in the lower extremities, slight numbness and warmth may be felt. After 15 minutes, the legs will be completely motionless.

What will myHow do you feel during surgery?

Answer. During a prolonged operation, a feeling of discomfort may occur due to the long static posture of the body. However, no pain will be felt. Also, discomfort during surgery can be caused by strong touches, stretching of the legs during the doctor's manipulations, or ambient noise. At the request of the patient, the anesthesiologist can put him into a state of light sleep for better comfort. At the same time, the specialist monitors his physical indicators: pulse, blood pressure, breathing and consciousness.

What will myHow do you feel after surgery?

Answer. For several hours (usually six), you will feel a slight numbness in your legs, and minor pain may occur at the injection site. Mobility of the lower extremities will soon be restored. The main recommendation after surgery is to remain in bed for 24 hours.

Possible side effects of spinal anesthesia

First of all, it should be noted that the number of side effects with this type of anesthesia is much less than after general anesthesia. Therefore, the risk of complications is reduced to a minimum and is extremely rare.

Possible complications are associated with pathologies present in the patient’s body, as well as age and bad habits.

We should not forget that all manipulations in anesthesiology, up to the installation of a regular IV, carry a certain risk. However, by strictly adhering to all doctor’s prescriptions, a person in most cases manages to avoid negative consequences.

Possible complications after anesthesia include:

• headache. This negative consequence most often appears due to the fact that after anesthesia a person begins to actively move. Statistics show 1% of the total number of complications. Such pain syndrome goes away on its own in a couple of days. However, during this period it would not be amiss to measure blood pressure and act based on the tonometer readings. The main rule in this case is compliance with bed rest in the postoperative period;
• decrease in blood pressure. The negative factor caused by the administration of an anesthetic. As a rule, it does not last long. To normalize pressure, special intravenous solutions and recommend drinking more fluids. This condition occurs in 1% of patients;
• pain in the anesthesia puncture area. The discomfort goes away within 24 hours and does not require additional treatment. If the patient cannot tolerate the pain, then you can take a Paracetamol or Diclofenac tablet;
• delay in the process of urination. A common occurrence that does not require therapy and usually resolves on the second day after surgery;
• neurological complications. An extremely rare phenomenon characterized by loss of sensation, muscle weakness and tingling in the lower part of the body lasting up to two days. If this problem persists for more than three days, you should consult a doctor.

Preventing complications

In order to eliminate the risk of developing negative consequences, it is necessary to strictly follow the recommendations of the anesthesiologist.

1. 6-8 hours before surgery, do not eat or drink any liquids.
2. Do not smoke tobacco products 6 hours before surgery.
3. Do not wear makeup or polish your nails before surgery.
4. Remove contact lenses from your eyes and remove them from oral cavity all removable dentures, if any. It is necessary to inform the anesthesiologist in advance about the presence of ocular prostheses if they are worn.
5. Remove rings from your fingers, earrings from your ears, chains from your neck, as well as other jewelry items. For believers, it is permissible to leave the cross on the body, but not on a chain, but on a braid.

The main thing is that the patient informs the anesthesiologist about all his diseases, previous injuries and surgical interventions, and also talks about the presence of possible allergies to medications or intolerance to any drugs. The specialist also needs to know whether the patient is taking medications. Collecting this information is the key to successful spinal anesthesia. This will also help prevent negative side effects after anesthesia.

Before the operation, the patient should rest well and get enough sleep. It would be a good idea to spend some time in the fresh air and calm down. These simple steps will help you psychologically tune in to a positive wave, which will greatly facilitate the process of surgical intervention, and will also help the body recover faster after its completion.

Let's sum it up

Spinal anesthesia is an extremely safe method of pain relief. If the patient is faced with a choice between spinal and general anesthesia, then it is worth giving preference to the first - firstly, it does not require long preparation, and secondly, the recovery period after such anesthesia is short and, moreover, quite comfortable. There is no need to be afraid of this type of anesthesia - after a few hours, sensitivity is completely restored, and the patient can forget about any discomfort.

Video - Personal experience: spinal anesthesia - does it hurt or not?

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One of the commonly used types of anesthesia for operations in the lower part of the patient's body 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 the time. Such anesthesia requires the anesthesiologist to have experience and competence. The technique is a procedure in which an anesthetic substance is injected into the spinal canal using a special needle.

Spinal anesthesia is a technique that helps to influence the nerve roots of the spinal cord. It completely blocks the transmission of nerve impulses, so the patient does not experience any pain during surgical treatment. Anesthesia is provided by injecting an 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 only be done after careful preparation of the patient and with his consent. The method of introducing a medicinal substance into the spine requires collecting a detailed medical history before starting the operation. Only competent preparation for the procedure will make 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 given 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 in the spinal canal where the cerebrospinal fluid is concentrated.

Spinal anesthesia, like any other anesthesia, has both indications for use and contraindications. An anesthesiologist must make a conclusion about whether to prescribe this type of anesthesia to a patient. Impact on the spine can be carried out only after collecting complete information about the patient’s health status (physical and mental). Proper preparation for this operation is also mandatory, a 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.

Needle position for spinal anesthesia

The main task of this type of anesthesia is the introduction of a special anesthetic solution into the cerebrospinal fluid (CSF). 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 step-by-step advancement of the needle:

• through the skin and subcutaneous tissue;
• through a number of intervertebral ligaments;
• through the epidural zone;
• through the dura mater.

The final target of the needle is the subarachnoid space (cerebrospinal fluid), which surrounds the spinal cord. It is in the spinal zone that the large nerves responsible for transmitting the pain impulse pass. An anesthetic injected into this space provides anesthesia by blocking nerve signals. This technique makes only a certain region of the patient’s body insensitive, which is active during the operation, but is insensitive to it and does not hurt the patient.

Stages of implementation

To perform anesthesia surgery, the anesthesiologist uses a special needle, syringe and local anesthetic. The technique of the procedure requires that the patient assume the correct body position. The best option is a sitting position. To ensure that the patient does not experience pain during and after the operation, he must fully follow the doctor’s recommendations before and after anesthesia.

Correct positioning of the patient during spinal anesthesia:

• It is advisable to sit, but you can also lie on your side;
• the selections must be brought closer to the chest;
• your back should be bent strongly;
• The arms bent at the elbows should rest on the knees.

Patient position during spinal anesthesia

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

Spinal anesthesia is performed as follows:

• between the lumbar vertebrae is determined the best place for injection;
• the procedure is ensured sterility (the doctor’s hands and the surface of the patient’s skin are treated);
• the injection site is covered with sterile films;
• Anesthetic is drawn into 2 syringes;
• the first syringe is used to numb the area through which anesthesia will be administered;
• the second syringe ensures that the solution enters the spinal canal.

During anesthesia, the anesthesiologist's assistant (nurse) helps keep the patient in the correct position. This anesthesia is carried out slowly and carefully. If the necessary conditions and the prescribed anesthesia technique are observed, patients are not in pain. 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 the surgeons.

Indications

Thanks to spinal anesthesia, it is possible to perform operations in the perineal area, on the pelvic organs or lower extremities. In some cases, such anesthesia has certain advantages - indications that should be taken into account for the sake of the patient's well-being. Anesthesia in the cerebrospinal fluid through the spine can be administered to people of different ages.

Main indications:

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

Anesthetic assistance during childbirth

If the pregnant woman is relatively healthy and her fetus is healthy, the indication for anesthesia is obvious. Thanks to such anesthesia, giving birth is not painful, and the woman herself participates in the birth process and hears the first cry of her child. Therefore, today many expectant mothers, if there are no contraindications, insist on using spinal anesthesia during childbirth (caesarean 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 those used in treatment, for example, peptic ulcer duodenal preparations (Omez, etc.). So, taking into account the interaction of the drug Omez with the anesthetic, the doctor determines the optimal dose of the anesthesia solution, anticipating how long the anesthesia will last and how the patient will recover from it.

Contraindications

Indications for spinal anesthesia are surgical operations in the lower part of the body. However, in some cases there are contraindications for the use of anesthesia in the spine. In each case, this issue is decided jointly by the anesthesiologist and the patient, or his representatives. Most doctors insist on using spinal anesthesia if general anesthesia can be avoided.

There are 2 types of contraindications for this type of anesthesia:

• 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 diseases;
• spinal abnormalities;
• unknown duration of surgery;
• death of the fetus or the presence of developmental defects in the fetus (in obstetrics);
• risk of bleeding.

Absolute contraindications:

• patient's categorical disagreement;
• lack of mandatory conditions 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 in pain or afraid. 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 are indications for such anesthesia, there is no need to do general anesthesia. The technique for performing this anesthesia is simple and within the capabilities of every practicing anesthesiologist. An experienced doctor knows how to administer anesthesia, how much anesthetic to administer, and how long the pain relief will last. However, it is not always possible to predict exactly how a patient will recover from anesthesia, since everyone recovers from it according to an individual scenario.

Spinal, also known as spinal anesthesia, is a method of local anesthesia used for surgical interventions in the lower segments of the body (lower limbs, bladder, genitourinary and reproductive systems). In everyday life, this method is referred to as “spine anesthesia,” which quite accurately reflects its essence.. The procedure is performed by injecting an anesthetic into the subarachnoid space.

Therefore, in some sources, back pain relief is called subarachnoid or lumbar. So what is spinal anesthesia? What are its pros and cons? What indications for its use exist?

Types of anesthesia

Spinal anesthesia is just one type of local anesthesia. All of them are based on local blocking of nerve conduction and are not accompanied by a loss of consciousness of the patient.

There are the following types of disabling pain sensitivity at the local level:

1. Application - the drug is administered transdermally (lubrication, spraying, using an adhesive plaster with an anesthetic). It is used for dental anesthesia of the injection site, in ophthalmology, and also before bronchoscopy and gastroscopy.
2. Infiltration – tissues are impregnated with anesthetic layer by layer (creeping infiltrate according to Vishnevsky). It is used for tissue anesthesia during minor operations (with the exception of purulent and oncological operations).
3. Conductive - the anesthetic is injected in close proximity to the nerve trunk.

Local conduction anesthesia also includes cerebrospinal (spinal) anesthesia. The method allows you to block the anterior and posterior roots of the spinal cord, which leads to the loss of pain, thermal and tactile sensitivity, and causes muscle relaxation. When performing anesthesia, lumbar puncture is performed 15-20 minutes before the start of the intervention.

How is spinal anesthesia different from epidural?

Spinal anesthesia can be of two types: epidural and subarachnoid. In the first case medicinal product is introduced into the epidural space, located above the dura mater of the spinal cord. The principle of operation of this type of anesthesia is the same as that of the spinal variety, however, the anesthetic penetrates the spinal cord through perfusion.

The method is actively used for long-term interventions, when long-term continuous administration of an anesthetic is necessary. To do this, a silicone catheter is inserted into the spine.

With spinal (subarachnoid) anesthesia, the anesthesiologist inserts a needle directly under the subarachnoid membrane, where the spinal cord is located. The drug is injected into the cerebrospinal fluid, mixed with it and washes the necessary areas of the central nervous system. In this way, an analgesic effect is achieved. The lumbar type of anesthesia allows for rapid and strong blocking of sensitivity, but its implementation is associated with a high risk of complications.

Preparations for spinal anesthesia

Drugs for spinal anesthesia do not differ from those used for other types of local anesthesia.

The most popular anesthetics include:

1. Lidocaine - the 5% solution used disables pain sensitivity for 1-1.5 hours. The volume of the drug for a patient weighing 70 kg and height 165-175 cm is 1.2 ml. The dose is increased if the patient’s body weight differs from the nominal by more than 10 kg, and height by 15 cm. The drug slows down heart contractions, therefore cannot be used for pain relief for people suffering from bradycardia.
2. Tetracaine is a 0.5% medicine for spinal anesthesia. Causes loss of sensation for up to 3 hours. The dose of the drug for a patient with the parameters specified in the previous paragraph is 2.4 ml.
3. Omnicaine is one of the strongest, but also most toxic anesthetics for spinal anesthesia. A 0.5% solution is used, the duration of which is up to 4 hours, administered in a dose of 3 ml.

In order to enhance and prolong the effect, drugs for spinal anesthesia are mixed with adrenaline (0.2 ml of a 0.1% solution) or mesaton (0.2 ml of a 1% solution). This allows the anesthesia time to be increased by half, often eliminating the need for repeated injections. Vasoconstrictors must be added immediately before administration.

Note: it should be borne in mind that the addition of vasoconstrictors increases the time for the development of the anesthetic effect. When anesthetizing with such a mixture, the period from the moment of administration of the drug to the start of the operation must be doubled. There is no such need when using omnicaine (bupivacaine).

Technique of spinal anesthesia

Preparation for spinal anesthesia is carried out immediately before the start of the procedure. The doctor selects a needle to administer the product, positions or positions the patient correctly, and prepares the necessary solutions. The classic technique of spinal anesthesia involves spinal needles with a diameter of 22-25 G. Thicker needles are elastic and are easily inserted into the required area. At the same time, they damage a large number of fibers of the meninges, which subsequently causes headaches. Thin needles require the use of a guidewire but reduce the risk of postoperative headaches.

Modern spinal needles have a sharpening point that resembles a pencil tip. Thanks to this, they do not cut, but push apart the fibers of the meninges. Headaches after this are extremely rare. The number of such cases tends to zero. There is a direct

There may be a relationship between what and how spinal anesthesia is administered and how often complications of this type of anesthesia develop.

During the procedure, the patient sits or lies in a bent position. The supine position is used to provide low access in gynecological and urological clinics, as well as for pain relief in obese patients. The sitting position is standard and avoids vertical spread of the medication along the spinal cord.

The puncture is performed at the level of L 3 -L 4 L 2 -L 3 vertebrae. The injection site is treated with alcohol, iodine and again with alcohol, after which it is thoroughly dried with sterile wipes. Local infiltration anesthesia is performed, after which a puncture needle is inserted. The passage into the subdural space is through the interspinous ligament. Evidence of a hit is a feeling of failure and aspiration of cerebrospinal fluid into the syringe. Before the final administration of the medicine, a test dose is administered, after which the patient’s condition is carefully monitored for 2-3 minutes. At normal indicators saturation, heart rate, blood pressure and respiratory rate, the remaining volume of the drug is administered.

Note: the puncture site is determined by the ridge ilium, which corresponds to the L 4 vertebra. To do this, the anesthesiologist assistant places his palm with the edge on the edge of the ilium perpendicular to the spine.

Advantages and disadvantages of spinal cord anesthesia

Like any other invasive treatment method, spinal anesthesia during surgery has its advantages and disadvantages.

Advantages include:

• ease of implementation compared to the introduction of general anesthesia;
• low risk of complications of spinal anesthesia after surgery;
• the possibility of the patient remaining conscious;
• ease of monitoring the patient's condition;
• high speed onset of analgesic effect.

The disadvantages of lumbar anesthesia are quite few. The list includes time limitations (the operation time depends on how long the spinal anesthesia wears off), the uncontrollability of the effect (the effect of the anesthetic cannot be reversed) and the impossibility of using the technique for anesthesia of the upper parts of the body. The latter is due to the fact that local spinal anesthesia in women is used mainly in gynecology and obstetrics. For men, spinal anesthesia is the main method of pain relief during urological operations.

Indications for spinal anesthesia

Indications for the use of spinal anesthesia are all surgical interventions in which the surgeon works below the line of the L 2 vertebra. As a rule, this method of pain relief is used for major gynecological, urological, and trauma surgeries. Subarachnoid administration of an anesthetic during labor is justified only with an extremely low pain threshold of the woman in labor, as well as during the transition to a cesarean section.

During surgical expulsion of the fetus, anesthesia injected into the spine is used only until the newborn is removed. Before sanitation of the uterine cavity and suturing, the woman’s consciousness is switched off by using intravenous anesthetics (sodium thiopental, propofol). Ventilation of the lungs is carried out using a non-invasive method (through a mask).

Contraindications

Contraindications to spinal anesthesia can be absolute or relative. Their absolute variety completely excludes the possibility of pain relief using the method in question. In the presence of relative contraindications, the intravertebral method of pain relief is possible if the benefits to the patient outweigh the risks.

Absolute

Subarachnoid anesthesia is avoided if there is absolute contraindications, since anesthetics can cause severe postoperative complications. Contraindications to the spinal type of anesthesia, which completely exclude the possibility of its implementation, include in the list:

• lack of patient consent;
• infectious processes in the area of ​​the intended anesthetic injection in the back;
• sepsis;
• coagulopathies;
• high intracranial pressure;
• allergic reactions history of anesthetics.

If there are absolute contraindications, the operation is performed under general anesthesia or, if possible, under local infiltration anesthesia.

Relative

Spinal anesthesia is relatively contraindicated in:

• availability skin infection near the injection site;
• hypovolemia;
• back pain;
• decreased blood clotting;
• diseases of the central nervous system;
• mental disorders in the patient (without prior drug suppression of consciousness).

If the patient has relative contraindications, spinal anesthesia can be performed only if it is impossible to use other methods of switching off sensitivity.

Complications and side effects

Side effects and complications after spinal anesthesia can develop both immediately after the administration of the anesthetic and some time after the end of the operation.

From the point of view of immediate complications, spinal anesthesia is dangerous:

• the risk of developing dyspnea or apnea - a complication occurs when the anesthetic is administered too high, which leads to blocking of the areas responsible for the functioning of the respiratory muscles. The problem is solved with the help of artificial ventilation until spontaneous breathing is restored (the duration of the anesthetic).
• Paresthesia - occurs as a result of irritation of nerve endings during needle insertion. They pass on their own medical intervention not required.
• Nausea or vomiting - the problem appears as a result of hypotension, which occurs during irritation vagus nerve. The patient's condition can be normalized with the help of drugs that increase blood pressure.

Generally, there are no other risks of regional anesthesia. After the effect of the anesthetic wears off, the patient may experience such side effects anesthesia, like:

• Headache;
• Urinary retention;
• Meningitis;
• Arachnoiditis;
• Infectious processes;
• Neurological disorders;
• Back pain.

Most complications are resolved by conservative treatment. Patients with headaches are prescribed bed rest, given an infusion of saline solutions, and caffeine is administered. Such people can get up only when the effects of spinal anesthesia have completely disappeared. Inflammatory processes require antibacterial and anti-inflammatory therapy, neurological processes require consultation with a neurologist and the fastest possible detection of the causes of their development (direct needle injury, hematoma).

Lumbar anesthesia – great way pain relief, considered one of the safest. Complications after spinal anesthesia are rare and can be successfully treated in most cases.