POTENTIZED LOCAL ANESTHESIA (PRE-MEDICATION)

An anesthetic drug is usually used in dental practice and other branches of medicine. Without painkillers, it is impossible to perform surgery and other medicinal procedures. This group of drugs has several types. It should also be noted that some patients suffer from allergies to painkillers.

In order to analgese a specific area of soft tissue, local anesthetics are used. They effectively reduce the excitation of sensitive nerve endings. As a rule, such medications are used in dental practice. It should be noted that the first anesthetic was Cocaine. It was used in various forms for local and general anesthesia.

Basically, an analgesic for local anesthesia is used in the form of injections. One of the most popular medications in this group is Lidocaine. Prilocaine is not as strong and toxic.

Generations of anesthesia drugs

To administer anesthesia, drugs can be used in different ways. In pharmacology, the classification of local anesthetics by use will be as follows:

Inhalation agents - “Sevoran”, “Propofol”, “Diprivan”, “Ftorotan”, “Ether”. Such anesthetic drugs help relax skeletal muscles and suppress pain. In this case, the person loses consciousness for some time.
Intravenous drugs - “Ketamine”, “Hexanal”, “Fentanyl”, “Relanium”, “Seduxen”, “Droperidol”, “Sodium oxybutyrate”. These medications have a quick effect. The patient loses consciousness after about twenty minutes.

Before use, the doctor must exclude the presence of allergic reactions in the patient to a certain component.

Requirements for anesthetic medications

Any drug has certain requirements that it must meet. Here are some of them:

The presence of increased selectivity of action.
Such drugs should have a resorptive effect. This reduces the likelihood of side effects.
No irritating influence.
The analgesic drug must have an immediate and long-lasting effect.
Medicines must be soluble and not subject to destruction during sterilization and storage.

Anesthesia can only be administered with drugs that meet all of the above points.

Pharmacology: classification of local anesthetics

All groups of drugs need to be classified. Medicines for superficial pain relief are called local. They suppress the sensitivity of nerve endings in a certain part of the body. In this case, the patient is conscious. Local anesthetics:

"Lidocaine."
"Dikain".
"Anestezin."
"Pyromecaine".

This type of anesthetic partially blocks and weakens nerve endings. In this regard, it is used only topically, usually in dentistry. What is the mechanism of action of local anesthetics?

Local infiltration anesthesia according to Vishnevsky.

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Local infiltration anesthesia according to Vishnevsky.

Indications: Used as a method of pain relief during surgical treatment of wounds; at the initial stages of conduction anesthesia and blockade of cellular spaces; during puncture of serous cavities and pathological space-occupying formations; when opening post-injection abscesses, boils and suppurating atheromas; when removing benign tumors of the skin and subcutaneous fat (papillomas, lipomas, fibromas), removing various types of granulomas. This method can also be used as a method of “hydraulic preparation” of tissue (for example, when isolating a hernial sac).

Contraindications: diffuse purulent inflammation, neuropsychiatric diseases and disorders.

Pathogenetic rationale: The method of infiltration anesthesia according to Vishnevsky is based on the teaching of N. I. Pirogov about the case structure of the human body. In his works, A. V. Vishnevsky writes “During the operation, strictly layer-by-layer and anatomical administration of weak solutions of novocaine in the form of a creeping infiltrate under the skin, fascial sheaths, aponeuroses, preperitoneal tissue, as well as duplication of the peritoneum, the goal is to block the nerve endings by direct contact with them of the anesthetic solution, which accelerates the onset of the analgesic effect.”

Technique: Layer-by-layer infiltration anesthesia involves alternating a scalpel and a syringe with an anesthetic solution during the operation. First, along the line of the intended incision, the skin is anesthetized by forming an intradermal novocaine nodule (creating a “lemon peel” - Fig. 1), then a tight novocaine infiltrate is created in the subcutaneous fat fiber. In this case, it is necessary to observe the principle “the end of the needle follows the stream of novocaine.”

Rice. 1. Lemon peel type skin anesthesia.

The intradermal position of the needle allows you to change its direction within 360˚ and inject the anesthetic in a fan-shaped manner. If you need to refill the syringe with novocaine, you should not remove the needle, just remove the syringe from the needle. When pain relief is performed correctly, the patient only feels the first injection. After anesthesia of the subcutaneous fat tissue, if necessary, anesthesia of the deeper-lying fascial sheaths is also performed by means of a tight creeping infiltrate and, as a rule, after dissection of the skin and subcutaneous tissue.

Tool kit and medications necessary to perform the practical skill: antiseptic for skin treatment; 0.25% novocaine solution; syringe; sterile gloves.

Anesthesia (blockade) of the site of a tubular bone fracture.

Indications: closed fractures of long bones.

The method refers to local infiltration anesthesia, while peripheral pain analyzers are blocked.

Technique: The skin over the site of a closed fracture is anesthetized in a “lemon peel” manner. The needle insertion site should be away from the projection of the great vessels and nerve trunks and only through intact skin. The hematoma is punctured with a needle, as evidenced by the flow of blood into the syringe during the reverse stroke of the piston, and 10-50 ml of a 1-2% anesthetic solution is injected. Do not insert a needle into a place where bone fragments are located directly under the skin. In case of multiple fractures, each segment is anesthetized separately, taking into account the total amount of anesthetic, reducing its concentration accordingly.

Tool kit and medications necessary to perform the practical skill: antiseptic for skin treatment; syringe; sterile gloves; ampoules with 1-2% anesthetic solution for infiltration anesthesia (novocaine, lidocaine, prilocaine, trimecaine, chloroprocaine).

Spinal anesthesia.

Indications: Spinal anesthesia is used for surgical interventions on the lower half of the body: the lower floor of the peritoneal cavity, perineum, lower extremities (for example, for hernia repair, hip replacement, appendectomy, uterine amputation, venectomy of the lower extremities, etc.).

Contraindications: There are absolute and relative contraindications to spinal anesthesia:

Absolute contraindications: increased intracranial and spinal pressure; diseases of the central nervous system; skin infection at the puncture site; severe hypovolemia; severe arterial hypotension (below 90 mm Hg); sepsis.

Relative contraindications: previous spinal surgeries; spinal column deformities; back pain, psycho-emotional lability of the patient; hypertensive crisis .

Pathogenetic rationale: In this case, it is necessary to recall some anatomical issues. The spinal cord is located in the spinal canal, formed by the posterior surface of the vertebral bodies and their arches and surrounded by membranes. Between the arachnoid membrane, directly adjacent to the spinal cord, and the dura mater, a space is formed filled with cerebrospinal fluid (CSF). The dura mater is impermeable to fluid and performs a protective function for the spinal cord. In the cranial direction, the dura mater of the spinal cord passes into the dura mater of the brain, forming a common closed space for the brain and spinal cord.

Spinal anesthesia is based on the injection of an anesthetic into the subarochnoid (subdural) space after a lumbar puncture. The selected anesthetic (novocaine, lidocaine, trimicaine) is mixed with cerebrospinal fluid (CSF) and affects the spinal cord: blocking its posterior roots leads to loss of pain, tactile, temperature sensitivity, and the anterior ¾ of motor paralysis (myorelaxation). The level of blockade depends on the location of the spinal puncture, the spread of the anesthetic through the subarochnoid space, depending on the position of the patient, the amount of anesthetic, and cerebrospinal fluid pressure.

Spinal anesthesia was first described by Beer in 1899. Over a century, this method of regional anesthesia has experienced both periods of complete oblivion and surges in popularity, which is associated with the emergence of new low-toxic local anesthetics and improvements in the technique of spinal puncture.

Technique: The spinal anesthesia procedure begins with premedication. The basis for this is an explanation, accessible to the patient, of the nature of the procedure itself and possible complications. Sedatives (Seduxen, Relanium) can be used as medicinal premedication, and atropine can be used for abdominal operations. After obtaining the patient’s consent to this type of anesthesia, its implementation begins.

The patient takes a forced position on the operating table (sitting or lying on his side) with his knees brought to the stomach and his head lowered (“fetal position”), which creates a convexity of the spinal column with an increase in the distance between the spinous processes. The puncture site is determined (Fig. 2). The optimal intervertebral gap is between L IV – LV, which corresponds to the horizontal line between the posterior iliac spines.

Rice. 2. Position of the patient on the operating table and

determination of the level of spinal puncture.

The surgical field is treated with an antiseptic and protected with sterile sheets. It must be remembered that when treating the surgical field with iodine preparations, they must be removed before puncture. The entry of iodide preparations into the subarochnoid space is unacceptable. At the level of the selected intervertebral, strictly along the midline between the spinous processes, the skin and underlying layers are anesthetized with an anesthetic (Novocaine, Lidocaine). After local infiltration anesthesia has been performed, they proceed directly to puncture of the subarochnoid space. This is done with a special needle with a mandrel (Fig. 3), which is inserted strictly in the sagittal plane between the spinous processes of the lumbar vertebrae at an angle of no more than 5-10˚ in accordance with the inclination of the spinous processes.

Rice. 3. Needles with mandrel for spinal anesthesia

As the needle advances, resistance is felt due to passing through the interspinous and yellow ligament, after which the needle falls into the suborochnoid space, as evidenced by the release of clear fluid (CSF) from the needle pavelion after removal of the mandrel (Fig. 4).

Rice. 4. The appearance of cerebrospinal fluid in the needle pavelion.

After removing 5 ml of cerebrospinal fluid, an adequate amount of the selected anesthetic is injected. Anesthesia occurs in 10-15 minutes, lasting up to 2-2.5 hours.

Complications of spinal anesthesia are associated with the technique of performing the procedure:

1. Damage to the spinal cord due to a needle during high punctures.

2. Infection of the cerebrospinal fluid resulting in myelitis and meningitis.

3. The effect of the anesthetic on the high segments of the spinal or longitudinal cord (drop in blood pressure, respiratory arrest).

All complications of spinal anesthesia can be avoided with strict adherence to the rules of asepsis and antisepsis, correct choice of the site of spinal puncture and strict dosage of the anesthetic substance.

Instrumental set and medications necessary to perform the practical skill: Spinal anesthesia is carried out in an operating room with strict adherence to the rules of asepsis and antisepsis. For spinal puncture, a special needle is required, the peculiarity of which is a bluntly beveled end and the presence of a mandrel; the needle is 10-12 cm long, with a diameter of no more than 5 mm. 4 ml of 5% novocaine solution is used as an anesthetic; 5 ml of 2% trimecaine solution, 5 ml of 2% lidocaine solution, 5 ml of 1% ropivacaine solution, 5 ml of 0.5% marcaine. It is necessary to have means to relieve possible complications: vasoconstrictor drugs, respiratory analeptics (lobeline, cardamine, cititon, caffeine), atropine, ventilator. To prevent hypotension, ephedrine is administered intramuscularly 15 minutes before spinal anesthesia.

Paravertebral blockade.

Indications: intercostal neuralgia of various etiologies, degenerative-dystrophic diseases of the lumbar spine with radicular syndrome.

With the patient lying or sitting, the line of the spinous processes is determined. Stepping 3-3.5 cm below and 1-1.5 cm caudal to the corresponding spinous process, a needle is inserted and passed vertically in relation to the skin, infiltrating with anesthetic. At a depth of 4 cm, the needle rests on the transverse process. Having slightly changed the direction, the needle is passed along the upper or lower edge of the transverse process to a depth of 1 cm and 10-15 ml of 0.5 - 1% novocaine solution is injected. Thus, the branches of the posterior branch of the spinal nerve, which innervate the facet joints, muscles and ligaments of the dorsal surface of the body, are blocked.

Intercostal novocaine blockade.

Indications: single and multiple rib fractures, chest bruises, intercostal neuralgia.

Technique: Position the patient on the healthy side or sitting. At the most painful point or 3-4 cm away from the site of crepitation of bone fragments towards the spine, insert the needle all the way into the lower edge of the rib, infiltrating the soft tissue with a 1% novocaine solution. Then, tilting the needle tip caudally and sliding off the lower edge of the rib, an aspiration test is performed and another 5-10 ml of anesthetic is injected. To enhance the effect of the anesthetic, medical alcohol can be added to it in a ratio of 4:1.

Local infiltration anesthesia according to Vishnevsky.

Contraindications: diffuse purulent inflammation, neuropsychiatric diseases and disorders.

Rice. 1. Lemon peel type skin anesthesia.

Tool kit and medications necessary to perform the practical skill: antiseptic for skin treatment; 0.25% novocaine solution; syringe; sterile gloves.

Anesthesia (blockade) of the site of a tubular bone fracture.

Indications: closed fractures of long bones.

The method refers to local infiltration anesthesia, while peripheral pain analyzers are blocked.

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Classification by duration of action

This is important to consider when planning the operation. The painkiller has varying degrees of action. Classification of local anesthetics:

Short-acting - up to 30-50 minutes - “Novocain”.
Average duration of action - up to 45-90 minutes - Mepivacaine, Lidocaine.
Long-acting - up to 90 minutes or more - Bupivacaine.

It should be noted that the stronger the anesthetic, the more toxic it is.

“Articaine”, as well as “Lidocaine”, “Mepivacaine” - the hydrolysis of these drugs goes well, the effect occurs quickly (after five minutes, depending on the method of anesthesia.

These painkillers are considered weak bases, they are poorly soluble in water, and are used in the form of water-soluble salts, which are convenient for use. For the local anesthetic effect to manifest itself in the tissues at the injection site, solvolysis with water must occur to form an anesthetic drug that is highly soluble in lipids.

There is a classification of local anesthetics based on their chemical structure. This will be discussed further.

Local anesthesia

Much credit for the development of local anesthesia belongs to Russian scientists: V.K. Anrep, who discovered the local anesthetic properties of cocaine in 1880, A.I. Lukashevich, who began performing operations under conduction anesthesia in 1886, and especially A.V. Vishnevsky ( 1874—1948). He was a wonderful surgeon who did a lot for the development of general and military surgery. He developed the safest method of local anesthesia, thanks to which hundreds of thousands of wounded during the war were provided with the full necessary surgical care.

MECHANISM OF LOCAL ANESTHESIA

The main differences between local anesthesia and general anesthesia are the preservation of consciousness and the creation of an obstacle to the path of pain impulses below the brain or, more precisely, not above the thoracic spinal cord. On this path, you can achieve both pain relief and eliminate other sensations - heat and cold, touch and pressure.

Anesthesia can be performed in the following areas: 1) the surface of the laryngeal mucosa. trachea, bronchi, urethra and bladder (this is superficial, or terminal, anesthesia); 2) turning off pain receptors in the skin and other organs (infiltration and regional anesthesia); 3) along the course of a large nerve or nerve plexus (conductor anesthesia); 4) along the nerve roots outside the dura mater (epidural anesthesia); 5) at the level of nerve cells that conduct sensitivity in the spinal cord itself (spinal or spinal anesthesia).

PREPARATIONS FOR LOCAL ANESTHESIA

We will focus on several of the most commonly used substances.

Novocaine (procaine). White powder with a bitter taste, highly soluble in water and alcohol. Novocaine is selectively absorbed by nervous tissue and consistently turns off the feeling of cold, heat, pain and, finally, pressure. Active in alkaline tissue reactions. With inflammation (acid reaction in tissues), its activity decreases.

In the form of a 5-10% solution, it is used for anesthesia of mucous membranes, and a 1-2% solution for conduction anesthesia. It is practically not used for epidural and spinal anesthesia due to insufficient effectiveness.

Novocaine is most often used for infiltration anesthesia according to A.V. Vishnevsky.

Dicaine (pantocaine). It is 15 times stronger, but almost as many times more toxic than novocaine. It is used for anesthesia of mucous membranes in the form of 0.25; 0.5; 1 or 2% solutions, less often - for epidural anesthesia: 0.3% solution in fractional doses of 3-5 ml (but not more than 20 ml). The maximum single dose is 0.07 g.

Lidocaine (xylocaine). The drug is 2 times more toxic, but 4 times stronger and acts longer (up to 5 hours) than novocaine. For anesthesia of mucous membranes, 4-10% solutions are used, in ophthalmic practice - 2% solution, for conduction anesthesia - 0.5-2% solution (up to 50 ml), for epidural anesthesia - 2% solution (up to 20 ml), for infiltration anesthesia - 0.5-0.25% solutions (500 and 1000 ml, respectively). Maximum dose 15 mg/kg.

Trimecaine (mesocaine). 1.5 times more toxic and 3 times stronger than novocaine. For infiltration anesthesia, 0.25% and 0.5% solutions of 800 and 400 ml are used, respectively. For conduction anesthesia - 1% (100 ml) or 2% (no more than 20 ml due to sharp potentiation!) solutions. In the form of a 2.5-3% solution in an amount of 7-10 ml, it is used for epidural anesthesia, and for spinal anesthesia, 2-3 ml of a 5% solution is sufficient. The maximum dose is 10-12 mg/kg.

Bupivacaine (marcaine, anecaine). It is the most powerful and long-acting anesthetic of those discussed above (2-3 times greater than lidocaine). For epidural anesthesia it is usually used as a 0.5% solution. The main dose is 40-50 mg, with a maintenance dose of 15-40 mg. Available in 20 ml bottles (1 ml contains 2.5 or 5 mg of the drug) and 1 ml ampoules (contains 5 mg).

Naropin (ropivacaine). One of the most modern anesthetics. The drug is produced in polypropylene ampoules containing 10 or 20 ml of a solution of various concentrations (0.2%, 0.75% and 1%), as well as infusion containers of 100 or 200 ml of 0.2% ropivacaine. Duration of action - up to 5 hours. Used for conduction and epidural anesthesia.

Ultracaine DC Forte . 1 ml of the drug contains 40 mg of articaine hydrochloride and 12 mcg of adrenaline hydrochloride. The drug has low toxicity. Although the drug is intended for use in dental practice, there is currently experience with its use for epidural anesthesia.

PREPARATION OF THE PATIENT

The patient must be examined to exclude contraindications to local anesthesia (excitement, low contact, etc.). When clarifying the medical history, it is necessary to find out whether there have been previous reactions to local anesthesia.

It is necessary to prepare the patient psychologically: the safety and effectiveness of local anesthesia are explained to him.

It is necessary to carry out medication preparation, as with general anesthesia; It is advisable to include sedatives and antihistamines. Dentures are removed and the time of the last meal is checked. They prepare everything necessary to eliminate complications: anticonvulsants, a ventilator, an internal infusion system and vasoconstrictors.

ANESTHESIA OF THE MUCOUS (TERMINAL ANESTHESIA)

This method is often used in ophthalmology, otorhinolaryngology, pulmonology, urology; They are also used during tracheal intubation to prevent reflex reactions. For anesthesia, 4-8 drops are instilled into the conjunctiva and cornea, and 2-8 drops of a 2-5% trimecaine solution are instilled into the nasal mucosa. For anesthesia of the mucous membranes of the bronchial tree, 3 ml of a 3% dicaine solution is sufficient.

CONDUCTION ANESTHESIA

Brachial plexus block . The patient lies on his back with a pad placed under his neck. The head is turned in the direction opposite to the blockade site. The needle point is 1 cm above the middle of the collarbone. The needle is inserted in the direction of the first rib. When the tip of the needle hits the nerve plexus, there is a feeling of a “shot” in the arm. After this, the needle must be pulled back 0.5 cm to avoid intraneural administration of the drug. For anesthesia, 40-60 ml of a 1% lidocaine solution or 0.25% marcaine solution is administered.

Sciatic nerve block . The patient is placed on the edge of the table. The solution is injected into a point located midway between the greater trochanter of the tibia and the tip of the coccyx.

Intercostal nerve block . After puncturing the skin, the needle is directed to the lower edge of the overlying rib and immediately, as soon as the tip of the needle touches it, the direction is shifted downward so as not to damage the vein and artery, but to inject the drug into the area of the nerve located below them.

PARAVERTEBRAL ANESTHESIA

This is a type of regional local anesthesia. The essence of the method is to block the nerve trunks at the point where they exit the intervertebral foramina with a local anesthetic. It is necessary to anesthetize not only the affected segment, for example with intercostal neuralgia, but also two segments above and below it. A local anesthetic solution is injected separately into each segment. 5-10 ml of 0.5% novocaine solution is injected into the point chosen for injection. First, the skin and subcutaneous tissue are anesthetized. Then the needle is directed 4-5 cm lateral and slightly below the intended spinous process until it stops at the transverse process or rib. The needle is slightly removed and again moved forward and downward 1 cm under the rib towards the vertebral body. A local anesthetic is injected here.

With this method, you can get a needle into the pleura or abdominal cavity, injure the spleen or get into the subdural space. Therefore, you should carefully monitor the patient’s reactions and be prepared to deal with complications. But this method can be very useful for eliminating pain after lung surgery and multiple rib fractures.

EPIDURAL ANESTHESIA

The epidural space is located between the dura mater of the spinal cord and the inner surface of the spinal canal. It is filled with loose connective tissue in which the venous plexuses are located; The posterior (sensory) and anterior (motor) roots of the spinal nerves pass through this space. They need to be anesthetized.

The patient is placed on his side, with his legs brought to his stomach (the puncture can also be performed in a sitting position; in this case, a stand is placed under the legs, and the back is bent as much as possible). Depending on the desired level of anesthesia, the injection site is chosen: for anesthesia of the chest - Th2 - Th3, the upper half of the abdomen - Th7 - Th8, the lower half of the abdomen - Th10 - Th11, the pelvis - L1 - L2, the lower extremities - L3 - L4.

The puncture site is treated twice with alcohol (but not iodine!) and covered with sterile linen. A thin needle is used to anesthetize the skin and subcutaneous tissue. Then the epidural anesthesia needle with an attached syringe filled with isotonic sodium chloride solution is inserted strictly along the midline in the intervertebral space. The needle is advanced without violence, only by pressing the 1st finger on the syringe plunger. While the needle passes through the ligaments, despite the pressure, the solution does not flow out of the syringe, but as soon as the end of the needle enters the epidural space, the resistance disappears and the solution begins to leave the syringe. Inject 1-2 ml of isotonic sodium chloride solution, disconnect the syringe from the needle and make sure that it is positioned correctly (no blood or liquid should leak from it). After this, 4 ml of local anesthetic solution (test dose) is administered, carefully observing the patient’s breathing, pulse and consciousness. 5 minutes after administration of the test dose, if there are no signs of spinal anesthesia, the main dose is administered, which is determined by the doctor individually for each patient.

For long-term anesthesia, special needles are used (for example, a Tuohy needle), through which a polyethylene or fluoroplastic catheter is inserted 2-4 cm upward into the epidural space. A solution of local anesthetic is injected through it during the operation as needed.

To prolong the effect of the local anesthetic, 1-2 drops of a 0.01% adrenaline solution are often added per 10 ml of solution. In recent years, to enhance the effect of the local anesthetic, small doses of narcotic analgesics (morphine, promedol, fentanyl) have been added to the solution. This allows you to reduce the dosage of local anesthetic and provide long-term postoperative analgesia.

Anesthesia after the administration of a local anesthetic does not occur immediately, but after a certain period of time, called the hidden or latent period. This interval varies for different local anesthetics, for example, for lidocaine or trimecaine it is 10-15 minutes, and for dicaine or bupivacaine it can reach 20-25 minutes.

The clinical picture of epidural blockade develops in the following sequence.

At first, the patient feels a feeling of warmth in the lower extremities, then a feeling of numbness, crawling “pins and needles” appears, and, finally, motor blockade occurs when the patient cannot lift his leg. True, this does not happen in all cases, more often in older people. The degree of development of the blockade is determined by injections with an injection needle. Anesthesia is considered sufficient when the patient ceases to distinguish between sharp and dull touch.

The effect of epidural anesthesia on the body.

Central nervous system. Epidural anesthesia does not directly affect the central nervous system. However, the shutdown of a certain part of the body that occurs during it leads to the development of so-called deafferentation of the brain, i.e. removing the exciting effect of sensitive impulses coming from the periphery. As a result, brain inhibition occurs, which is manifested by drowsiness and a feeling of calm.

The cardiovascular system . By the time anesthesia sets in, a decrease in blood pressure usually occurs. This is a natural manifestation of epidural anesthesia, caused by the blockade of sympathetic nerve fibers, leading to vasodilation and vascular capacity. As a result, relative hypovolemia occurs, which leads to the development of hypotension. With high epidural blockade, bradycardia may develop as a result of inhibition of the sympathetic nerves of the heart.

Respiratory system. With high epidural anesthesia, some respiratory depression is possible due to blockade of the intercostal muscles.

Epidural blockade has a bronchodilator effect, which is used in the treatment of status asthmaticus.

Digestive system . As a result of the sympathetic blockade that occurs during epidural anesthesia, intestinal motility increases. This effect is used in the treatment of intestinal paresis. On the other hand, this dictates the need for thorough cleansing of the intestines before a planned operation, because involuntary defecation is possible.

From the urinary system, urinary retention is possible. True, such complications are quite rare, and are more often caused by the action of narcotic analgesics, especially morphine.

SPINAL ANESTHESIA

A local anesthetic solution is injected with the patient sitting or on his side into the subarachnoid space. Use special thin (No. 24-26) needles. The puncture is usually performed in the space between the III and IV lumbar vertebrae. The needle passes through the same anatomical formations as with epidural anesthesia, but in addition it is necessary to puncture the dura mater. Entry into the subarachnoid space is determined by the flow of cerebrospinal fluid from the needle. After this, a local anesthetic solution is injected. Use a 5% solution of lidocaine (1.5 ml) or a 0.25-0.5% solution of bupivacaine (2-3 ml).

The clinical picture and effect on the body of spinal and epidural anesthesia are largely similar. Unlike epidural, the speed of blockade development during spinal anesthesia is higher (no more than 3-5 minutes). Failures and incomplete anesthesia occur less frequently. Spinal anesthesia gives very good muscle relaxation.

During spinal anesthesia, the density of the injected local anesthetic is important. If it is less than the density of the cerebrospinal fluid, the solution is called hypobaric; if it is equal to it, it is isobaric; if it is greater than the density of the cerebrospinal fluid, it is called hyperbaric. Knowing the density of the solution allows you to determine in which direction the local anesthetic will spread. Hypobaric solutions spread upward from the injection site, hyperbaric solutions spread downward, and isobaric solutions remain at the injection level.

INDICATIONS AND CONTRAINDICATIONS FOR EPIDURAL AND SPINAL ANESTHESIA.

Indications for epidural and spinal anesthesia in its “pure form” are operations on the lower extremities, pelvic bones, pelvic organs, and anterior abdominal wall.

In combination with multicomponent anesthesia, they can be used for extensive and traumatic operations on the upper floor of the abdominal cavity and chest organs.

Epidural and spinal anesthesia are of great importance for the treatment of various pain syndromes in oncology, traumatology, cardiology, etc.

Contraindications are divided into absolute and relative. Absolute symptoms include intolerance to local anesthetics, hypocoagulation, purulent skin diseases at the puncture site, shock, hypovolemia, and hypotension. Relative contraindications are spinal deformities, obesity, and some diseases of the nervous system.

COMPLICATIONS

I. Complications caused by the action of local anesthetic.

These complications can occur with any type of local anesthesia. Three types of complications are most likely to occur: damage to the central nervous system, cardiac conduction system and allergic reactions, as well as their combination. The occurrence and severity of complications depend on the following factors: 1 - the nature of the local anesthetic; 2 - its dose; 3 - type of local anesthesia; 4 - adding vasoconstrictor drugs to the solution.

The stronger the local anesthetic, the more dangerous it is: its strength decreases in the sequence sovcaine - dicaine - trimecaine - lidocaine - novocaine. The most dangerous are spinal, then epidural and regional anesthesia, performed near large vessels (plexus anesthesia).

CNS lesions . The patient becomes restless (less often drowsy), complains of dizziness, ringing in the ears, speech becomes slurred, a metallic taste appears in the mouth, and nystagmus can often be detected. Convulsive twitching of individual muscles occurs, and in the most severe cases - general convulsions. The latter are especially pronounced in respiratory and metabolic acidosis.

Hemodynamic disorders . The conduction system of the heart and vascular tone (sympathetic blockade) are most affected. Therefore, bradycardia appears (up to cardiac arrest) and blood pressure sharply decreases (up to cardiovascular collapse).

Allergic reactions. There may be allergic dermatitis: the appearance of many red spots on the skin, sometimes on an edematous basis, itching, an attack of bronchial asthma, and in the most severe cases - anaphylactic shock.

Prevention . The main thing is to carefully collect anamnesis. At the slightest suspicion of intolerance to local anesthetics, you should either abandon this method altogether, or use antihistamines, benzodiazepines (Sibazon, Relanium) and phenobarbital in the preparation. It is very important to use a test dose of local anesthetic (introduce it intradermally and evaluate the reaction), not exceed a single maximum dose and stop anesthesia if there is a suspicion of entry into a large vessel (conductor anesthesia, epidural anesthesia) or into the cerebrospinal fluid tract (epidural anesthesia, paravertebral anesthesia) .

Intensive therapy . If the central nervous system is predominantly affected, 2.5-5 mg of sibazone or (carefully!) 2% sodium thiopental solution is administered intravenously until the seizures are eliminated.

If hemodynamic disturbances occur, the patient is transferred to the Trendelenburg position and vigorous infusion therapy is administered. If necessary, vasoconstrictor drugs and glucocorticoid hormones (12 mg dexazone, 60 mg prednisolone) are administered.

In case of cardiac arrest, the entire complex of cardiopulmonary resuscitation is performed.

II. Complications of epidural and spinal anesthesia.

Complications of a traumatic nature. The mildest of them are injuries to the periosteum and spinal ligaments. Manifested by pain at the puncture site. They usually go away on their own within a few days. More serious complications include damage to the vessel with possible formation of an epidural hematoma, damage to the nerve root, puncture of the dura mater. A puncture of the dura mater, if diagnosed in a timely manner, usually does not lead to any serious health problems for the patient, with the exception of headaches that last for several days and are caused by the leakage of cerebrospinal fluid and a decrease in intracranial pressure.

Breathing disorders . This often happens with high epidural and spinal anesthesia, when the roots of the intercostal nerves are blocked. In this case, the only breathing muscle remains the diaphragm. In these conditions, assisted ventilation is sometimes required.

Hemodynamic disorders . As mentioned above, hypotension is an almost constant companion to epidural and spinal anesthesia. A decrease in blood pressure by less than 40% of the initial value is not considered a complication and can be easily stopped by accelerating the infusion rate. When blood pressure decreases by more than 40%, it is necessary to take more vigorous measures: massive infusion therapy, and if it is ineffective, the introduction of vasoconstrictor drugs, preferably ephedrine in a dose of 0.2-0.3 ml.

If the dura mater is punctured unnoticed and a full dose of local anesthetic is administered, a terrible complication can develop - a total spinal block, which is characterized by a sharp decrease in blood pressure and respiratory arrest. If immediate action is not taken, death may occur. It is necessary to transfer the patient to mechanical ventilation. administration of vasopressors. powerful infusion therapy.

Purulent complications . If the principles of asepsis are not observed, the development of purulent epiduritis and meningitis is possible. Powerful antibacterial therapy is indicated, and in some cases, surgical intervention to open and drain the purulent focus.

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What's included

The structure of painkillers includes the following:

anesthetic;
vasoconstrictor;
additives;
preservative;
vasoconstrictor stabilizer.

Chemical classification of local anesthetics by structure is:

Esters - “Novocain”, “Dicain”, “Anestezin”.
Amides - “Atricaine”, “Lidocaine”, “Metevacaine”, “Prilocaine”, “Trimecaine”, “Bupivacaine”, “Etidocaine”.

A vasoconstrictor is needed to enhance the effect of the anesthetic. Additional components are sodium sulfate and edetate. Methylparaben acts as a preservative.

Pharmacological properties

The mechanism of action of local anesthetics is based on disruption of nerve sensitivity. Anesthesia blocks pain sensations. It is important to note that the effect of the drug depends on its solubility in water and fat.

General anesthesia is a strong anesthesia, due to which the body completely loses pain sensitivity and reflexes for a certain period of time. This relaxes the skeletal muscles. Its use is only possible when performing complex and painful surgical interventions.

Amides

In order to provide the patient with high-quality anesthesia, doctors use anesthetics from the Amide group, because they are better absorbed by the tissues at the injection site and act much faster and longer than ethers.

Pyromecaine is a white or brownish powder that easily dissolves in water and alcohol. Used for topical anesthesia. The drug can be found in the form of an application or 5% ointment.
Lidocaine is a white crystalline powder, soluble in water and alcohol. Well absorbed by tissues. It is 4 times better than Novocain, but at the same time 2 times more toxic.
Prilocaine is a drug in many ways similar to Lidocaine, but not as effective.
Mepivacaine has many similar properties to lidocaine, but is not as toxic.
Articaine - in addition to pain relief, has an antispasmodic effect and lowers blood pressure. It acts faster than all other drugs, since the effect is observed already from 30 seconds. It is 2 times more powerful than Lidocaine, less toxic and is eliminated from the body faster.
Trimecaine - in terms of pharmacological properties, it has many similarities with Lidocaine, it is 2-3 times more effective than Novocaine, due to the rapid onset of the analgesic effect and prolonged action. But a huge disadvantage is its toxicity.

When are anesthetics used?

Painkillers are prescribed locally in the form of superficial and injection administration. The first type of anesthesia is applied to the mucous membrane or wound. As a rule, in such situations, Benzocaine and Lidocaine are used. Such anesthetic medications are also used to block various inflammatory processes, as well as infections and neurological diseases.

Dentists do not use large doses of anesthesia. For superficial anesthesia, creams, as well as gels, ointments and solutions are used. There is a large list of painkillers that dentists use. The doctor must select a safe medicine that will not cause an allergy.

Indications for general and local anesthesia:

Any surgical interventions.
Catheterization (a type of instrumental research often used for the diagnosis and treatment of bladder pathologies).
Probing (a method of examining the gastrointestinal tract, a diagnostic procedure).
Intubation (ensuring normal airway patency by introducing a special tube into the trachea).
Osteosynthesis (surgical reposition of bone fragments using various fixing structures that ensure long-term elimination of their mobility).
Neurological blockades (a medical procedure to relieve muscle spasms).
Spinal anesthesia (an anesthetic method in which a blocking agent is injected directly into the cerebrospinal fluid).

Such anesthesia is usually used when cleaning a dental canal. The classification of local anesthetics in dentistry is no different from the usual classification of these drugs. The following means are used:

"Ultracaine".
"Ubistezin".
"Septanest".
"Scandonest".

Local anesthetics

II. 1. Drugs acting on the peripheral nervous system

In the peripheral nervous system, afferent and efferent parts are distinguished. Nerve fibers that conduct excitation from organs and tissues to the central nervous system (CNS) are called afferent, and fibers that conduct excitation from the DNS to organs and tissues are called efferent.

Substances affecting afferent innervation

Afferent innervation includes sensory nerve endings and sensory nerve fibers. Sensitive nerve endings (sensitive receptors) are located in organs and tissues and are capable of perceiving various types of irritations. There are pain receptors, temperature receptors, receptors of touch (tactile), smell, and taste.

Chapter 5. Substances that depress sensory nerve endings or prevent the action of irritants on them

Substances that reduce the sensitivity of the endings of afferent fibers include local anesthetics, and substances that prevent the action of irritants on them include astringents and adsorbents.

Local anesthetics

Local anesthetics are substances that can temporarily, reversibly block sensory receptors. First of all, pain receptors are blocked, and then olfactory, gustatory, temperature and tactile.

In addition, local anesthetics disrupt the conduction of excitation along nerve fibers. First of all, the conduction along sensitive nerve fibers is disrupted. At higher concentrations, local anesthetics can also block motor fibers.

The mechanism of action of local anesthetics is due to the blockade of Na+ channels in the membranes of nerve fibers. Due to the blockade of Na+ channels, the processes of depolarization of the membrane of nerve fibers, the occurrence and propagation of action potentials are disrupted.

The binding sites for local anesthetics are located in the cytoplasmic part of the Na+ channels. Local anesthetics are weak bases. The non-ionized (non-protonated) part of the substance molecules penetrates into the nerve fibers and affects the cytoplasmic part of the Na+ channels. In an acidic environment, local anesthetics are significantly ionized and do not penetrate the nerve fibers. Therefore, in an acidic environment, in particular during tissue inflammation, the effect of local anesthetics is weakened.

According to their chemical structure, local anesthetics are represented by amides or esters.

Amides

(lidocaine, trimecaine, bupivacaine, mepivacaine, articaine, ropivacaine) are metabolized in the liver under the influence of cytochrome P450 isoenzymes (mixed-function oxidase).

Ethers

(procaine, tetracaine, cocaine) are hydrolyzed by plasma cholinesterase, and therefore are more suitable as local anesthetics in patients with liver diseases.

Local anesthetics have a depressant effect on myocardial contractility, dilate blood vessels (direct effect associated with blockade of Na+ channels, as well as a depressant effect on sympathetic innervation), and reduce blood pressure.

The exception is cocaine, which strengthens and increases heart rate, constricts blood vessels, and increases blood pressure.

With the resorptive effect of local anesthetics, their effect on the central nervous system may appear. In this case, local anesthetics can cause dizziness, headache, nausea, flashing spots before the eyes, tinnitus, drowsiness, euphoria, and anxiety. In severe cases, tremors, clonicotonic convulsions, a drop in blood pressure, cardiac arrhythmias, respiratory depression, and loss of consciousness are possible. For convulsions, diazepam is administered intravenously, and ephedrine is administered to increase blood pressure.

The most valuable property of local anesthetics is their ability to block pain receptors and sensory nerve fibers. In this regard, they are used for local anesthesia (local anesthesia) during surgical operations and painful diagnostic procedures.

Types of anesthesia. Superficial anesthesia

(terminal, topical anesthesia) – mainly anesthesia of the mucous membranes (eyes, nose, nasopharynx, etc.). When an anesthetic is applied to the mucous membrane, it becomes insensitive because the anesthetic blocks the sensory nerve endings (terminals) in the mucous membrane.

Surface anesthesia is used in ophthalmic practice (for example, when removing foreign particles from the cornea), in otolaryngology (for operations on the nasal mucosa, nasopharynx), as well as during intubation, insertion of bronchoscopes, esophagoscopes, etc.

Local anesthetics are used in the form of solutions, ointments, creams, and gels.

When applying local anesthetics to mucous membranes, partial absorption of substances and the manifestation of their resorptive toxic effect are possible. To reduce the absorption of anesthetics, vasoconstrictors, such as adrenaline (epinephrine), are added to their solutions.

Preventing the absorption of anesthetics not only reduces their toxicity, but also prolongs their effect.

In ophthalmology, solutions of tetracaine (0.3%), lidocaine (2–4%), and bumecaine (0.5%) are used for anesthesia of the conjunctiva and cornea (for example, when removing a foreign particle).

For anesthesia of the nasal mucosa, solutions of tetracaine (0.5%), lidocaine (2–4%), and bumecaine (1–2%) are used.

For anesthesia of the mucous membrane of the oral cavity, nasopharynx, larynx, respiratory tract, esophagus, rectum, urinary tract, vagina, solutions of lidocaine (2%) or bumecaine (0.5–2%) are used.

Conduction anesthesia

(regional anesthesia). If a local anesthetic solution is injected into the tissue surrounding a nerve that contains sensory fibers, the sensory nerve fibers are blocked at the site of injection of the anesthetic. In this regard, the entire area innervated by this nerve loses sensitivity. This type of local anesthesia is called conduction anesthesia (nerve blockade).

Since with this type of anesthesia the local anesthetic is injected into the tissues and partially enters the general bloodstream, its resorptive effect is possible. Therefore, toxic anesthetics (for example, tetracaine) cannot be used for conduction anesthesia. To reduce absorption and prolong the action of local anesthetics, vasoconstrictors (adrenaline, etc.) are added to their solutions. Conduction anesthesia is used for surgical operations on the extremities, in dental practice, etc.

For conduction anesthesia, 1–2% solutions of procaine, lidocaine, trimecaine, as well as solutions of articaine (2%), bupivacaine (0.25–0.5%) are used.

A type of conduction anesthesia is epidural anesthesia. The anesthetic solution is injected into the epidural space (between the dura mater and the inner surface of the spinal canal). In this case, the sensory fibers of the spinal nerve roots are blocked. Epidural anesthesia is used for operations on the lower extremities and pelvic organs. In particular, epidural anesthesia is used for caesarean section.

For epidural anesthesia, solutions of lidocaine (2%), trimecaine (2%), bupivacaine (0.5–0.75%), and ropivacaine (0.75%) are used.

Subarachnoid anesthesia

(spinal anesthesia, spinal anesthesia). The anesthetic solution is injected into the cerebrospinal fluid at the level of the lumbar spinal cord. In this case, the sensory fibers entering the lumbosacral spinal cord are blocked, and anesthesia of the lower extremities and lower half of the body, including internal organs, develops. Subarachnoid anesthesia is usually used for operations on the pelvic organs and lower extremities.

For subarachnoid anesthesia, solutions of lidocaine (5%), trimecaine (5%), and bupivacaine (0.5%) are used.

Infiltration anesthesia

. A solution of local anesthetic of low concentration (0.25–0.5%), but in large quantities (200–500 ml) is injected under pressure into the tissues: skin, subcutaneous tissue, muscles, tissues of internal organs. The tissues are “impregnated” (infiltrated) with the anesthetic solution. In this case, sensitive nerve endings and sensitive nerve fibers that are in the area of action of the anesthetic are blocked.

Infiltration anesthesia is used during surgical operations, including operations on internal organs. Just as for conduction anesthesia, toxic anesthetics cannot be used for infiltration anesthesia, since they enter the general bloodstream and can have a resorptive toxic effect.

Anesthetics for infiltration anesthesia are usually dissolved in hypotonic (0.6%) or isotonic (0.9%) sodium chloride solutions. To reduce the absorption of anesthetics and prolong their action, adrenaline (epinephrine) is usually added to their solutions.

For infiltration anesthesia, solutions of procaine (0.25–0.5%), lidocaine (0.5%), trimecaine (0.125–0.25%), and bupivacaine (0.25%) are used.

Of course, for conduction, spinal and infiltration anesthesia, only sterile anesthetic solutions are used.

For superficial anesthesia , cocaine, tetracaine, benzocaine, proximetacaine, oxybuprocaine, bumecaine, and mepivacaine are used.

Cocaine , an alkaloid from the Erythroxylon Sosa shrub, native to South America, was the first local anesthetic. Cocaine solutions are sometimes used for superficial anesthesia. However, cocaine has now been largely replaced by more active and less toxic anesthetics.

Cocaine disrupts the neuronal reuptake of norepinephrine at noradrenergic synapses. This leads to activation of noradrenergic transmission of excitation. At dopaminergic synapses, cocaine disrupts the neuronal reuptake of dopamine. The stimulation of dopaminergic synapses in the central nervous system is associated with the euphoria caused by cocaine.

The resorptive effect of cocaine manifests itself in the stimulation of the central nervous system. Cocaine's ability to excite the central nervous system, elevate mood, and cause a feeling of vivacity and a surge of strength has proven to be the cause of abuse of this substance. When taking cocaine systematically, a person develops a strong need to re-use the drug, while in its absence, a feeling of lethargy, weakness appears, and mood sharply decreases, that is, drug addiction develops (cocaineism).

The peripheral effect of cocaine is manifested by activation of the influences of sympathetic (noradrenergic) innervation: the frequency and strength of heart contractions increase; blood vessels narrow; blood pressure rises. In large doses, cocaine causes tremors, convulsions, and hyperpyrexia; the stimulating effect is replaced by depression of the central nervous system (death in cocaine poisoning occurs due to paralysis of the respiratory center).

Tetracaine (Dicaine) is an active and toxic local anesthetic. Due to its high toxicity, tetracaine is used mainly for superficial anesthesia: anesthesia of the mucous membranes of the eyes (0.3%), nose and nasopharynx (0.5–1%). The highest single dose of tetracaine for anesthesia of the upper respiratory tract is 3 ml of a 3% solution. The duration of action of tetracaine is 2–3 hours.

In case of an overdose of the drug, even when applied topically, tetracaine can be absorbed through the mucous membranes and have a resorptive toxic effect. In this case, excitation of the central nervous system develops, which in severe cases is replaced by its paralysis; death occurs from paralysis of the respiratory center. To reduce the absorption of tetracaine, adrenaline (epinephrine) is added to its solutions.

Benzocaine (anesthetic), unlike other local anesthetics, is slightly soluble in water; soluble in alcohol and fatty oils. In this regard, benzocaine is used exclusively for surface anesthesia in oil solutions (for example, for acute inflammation of the middle ear, pain in the external auditory canal), ointments, pastes (5%), powders (for example, for skin diseases accompanied by severe itching) , rectal suppositories and oil solutions for lesions of the rectum (hemorrhoids, fissures). Oral benzocaine is prescribed for increased sensitivity of the esophagus, stomach pain, and vomiting.

Proxymetacaine and oxybuprocaine (inocaine) are used in ophthalmology for short-term manipulations (conjunctival anesthesia, corneal anesthesia for determining intraocular pressure, removing foreign particles).

Bumecaine (Bumecaine; pyromecaine) is used as a local anesthetic in ophthalmology (0.5% solution), as well as for surface anesthesia of the oral mucosa (1–2% solutions), nose, nasopharynx, larynx, esophagus, rectum, respiratory and urinary tract. In dentistry, 5% bumecaine ointment is also used.

Mepivacaine is used topically in dentistry, as well as for anesthesia during tracheal intubation, bronchoscopy, esophagoscopy, and tonsillectomy.

for conduction and infiltration anesthesia .

Procaine (Procaine; novocaine) is an active anesthetic whose action lasts 30–60 minutes (hydrolyzed by plasma cholinesterase). The drug is highly soluble in water and can be sterilized using conventional methods. With certain precautions (adding a solution of adrenaline, observing the dosage), the toxicity of procaine is low.

Procaine solutions are used for infiltration (0.25–0.5%), conduction and epidural (1–2%) anesthesia. To prevent the absorption of procaine, a 0.1% solution of adrenaline (epinephrine) is added to its solutions. Procaine is sometimes used for spinal anesthesia (5%), and in high concentrations (10%) for superficial anesthesia.

Bupivacaine (marcaine) is one of the most active and long-acting amide-type local anesthetics. The action of bupivacaine is characterized by a latent period (up to 20 minutes). For infiltration anesthesia, a 0.25% solution is used, for conduction anesthesia - 0.25–0.5% solutions, for epidural anesthesia - a 0.75% solution, and for spinal anesthesia - 0.5%. The duration of epidural or spinal anesthesia is 3–4 hours.

The resorptive effect of bupivacaine can be manifested by symptoms such as headache, dizziness, blurred vision, nausea, vomiting, ventricular tachyarrhythmias, atrioventricular block.

Articain (ultracaine) is an amide-type local anesthetic. It is used for infiltration, conduction, epidural and subarachnoid anesthesia; lasts 1–2 hours.

Ropivacain (naropin) – amide. They are used mainly for epidural anesthesia (in particular, during caesarean section, for the relief of acute pain), as well as for conduction and subarachnoid anesthesia. Ropivacaine differs in its duration of action; With epidural anesthesia, the analgesic effect lasts 6–12 hours.

For all types of anesthesia, lidocaine is used - an amide-type local anesthetic. In the form of eye drops, 2 and 4% solutions of lidocaine are used. For superficial anesthesia of the mucous membrane of the oral cavity, nasopharynx, larynx, esophagus, rectum, respiratory and urinary tract, 1-2% solutions are used, for infiltration anesthesia - 0.25-0.5%, for conduction anesthesia - 1-2%, for epidural anesthesia - 2% solution, for spinal anesthesia - 5%. In dentistry, otolaryngology, and also during endoscopy, a 10% dosed aerosol of lidocaine is used, which is sprayed onto the mucous membranes.

The toxicity of lidocaine is slightly higher than that of procaine, especially when used in high concentrations (1–2%). To reduce the resorptive effect of lidocaine, adrenaline (epinephrine) is added to its solutions.

Lidocaine is also used as an antiarrhythmic drug[1].

Trimecaine is similar in chemical structure, indications for use and applied concentrations of solutions to lidocaine. Lasts longer.

In addition to these drugs, ethyl chloride (chlorethyl) is used for local anesthesia, a volatile liquid produced in ampoules. When applied to the skin, ethyl chloride evaporates quickly. In this case, tissue cooling and loss of sensitivity occur.

Ethyl chloride is used for pain relief during minor skin operations, bruises, sprains of ligaments, tendons (for example, during sports competitions), neuritis, radiculitis.

Contraindications and adverse reactions

Therapy using an anesthetic is carried out only after prohibitions on use have been eliminated. The use of local anesthesia is contraindicated in the presence of the following conditions:

Surgical intervention for obesity.
Operations for gas exchange disorders.
Allergic symptom.
Mental disorders, pathologies of the hearing aid, a state of severe intoxication.
The patient is unconscious.
Epilepsy (a chronic neurological disease manifested in the body’s predisposition to the sudden onset of seizures).
Panic state of the patient, refusal of local anesthesia.
Children under ten years of age.
Sepsis (a severe infectious disease that develops with the progression and spread of the infectious process throughout the body through the blood).
Hemorrhagic symptom (tendency to increased bleeding of the skin, mucous membranes and internal organs due to pathology of the hemostatic system).
Anemia (a group of clinical and hematological syndromes, the common point of which is a decrease in the concentration of hemoglobin in the blood, often with a simultaneous decrease in the number of red blood cells).
Heart failure.

The doctor must select local anesthesia in dental practice on an individual basis. This anesthetic can be used during lactation. Adverse reactions of anesthetics usually occur due to improper use.

In most situations, the following negative effects appear:

Tachycardia (increased heart rate (HR) from 90 beats per minute).
Fainting.
Swelling at the injection site.
Congestion in the ears.
Anaphylaxis (an immediate allergic reaction, a state of sharply increased sensitivity of the body).

In addition, such symptoms can be observed when allergies appear.

POTENTIZED LOCAL ANESTHESIA (PRE-MEDICATION)

Local anesthetics eliminate the sensory component of pain, but do not affect its emotional and autonomic components. Most patients at a dentist's appointment experience feelings of anxiety, fear, restlessness, and are sometimes in a state of apathy or depression, which is a manifestation of mental stress or emotional stress. In this case, psychovegetative complications arise, manifested by tachycardia, hypertension, hyperglycemia, asthmatic attack, angina pectoris, fainting or collapse.

Under the influence of negative emotions, significant changes occur in the system of regulation of vital functions of the body.

ma: the content of catecholamines, histamine, and | vasospasm occurs, metabolic processes are disrupted (possible;

energy consumption will decrease). The frequency of general complications during outpatient operations depends not so much on the nature of the intervention, but on the severity of psycho-emotional tension (stress) in the patient. Therefore, before dental operations, in order to preserve adaptation mechanisms and prevent general complications, medicinal preparation is necessary with a predominant effect on the psycho-emotional sphere of the patient. The drugs used for this purpose act on different parts of the central nervous system and different levels of pain sensitivity. Without enhancing the local anesthetic effect of the local anesthetic, they significantly improve the analgesic effect. Turning off pain sensitivity in a surgical wound with the help of local anesthesia, carried out against the background of drug preparation (pre-medication), which provides a decrease in the body's reactivity and general analgesia, is called potentiated local anesthesia.

When determining the psycho-emotional state of a patient based on clinical signs, 5 types of reactions are distinguished (according to A.F. Bizyaev): asthenic, depressive, anxious, hypochondriacal, hysterical.

The asthenic reaction is characterized by autonomic lability, headaches, increased fatigue, irritability, and tearfulness. With a depressive reaction, a depressed mood, a low voice, a lack of confidence in the success of treatment, and the patient is laconic are noted. An anxious reaction is manifested by anxiety, excitement, fear, fear of an unsuccessful outcome, poor sleep, and increased heart rate. With a hypochondriacal reaction, the patient makes many complaints, details them, describes in detail sensations and events in chronological order, and is willing to be examined; There is a discrepancy between the abundance of complaints and the identified pathological changes. Hysterical are vegetative reactions (lump in the throat, lack of air, tremor of the fingers, red spots on the skin of the face and neck). The behavior of such patients is characterized by demonstrativeness, theatricality, and a desire to attract attention and evoke sympathy. The latter are more common in women.

The reaction may be absent, mild, moderate, or severe. With a mild degree, the symptoms are inconsistent, their identification is possible only with a targeted interview, and there are no significant changes in behavior. Moderate is characterized by constant and pronounced signs of psycho-emotional reactions; these reactions predominate in behavior. When the reaction is pronounced, the patient has poor control over his actions; psychoemotional disorder is the main factor determining his behavior and condition. It has been established that during planned dental operations, patients are more often diagnosed with mild, and with

urgent - moderate degree of severity of psycho-emotional stress.

Premedication is carried out taking into account the type and severity of the psycho-emotional reaction. In a clinic setting, the use of the tranquilizer Seduxen, the narcotic analgesic Lexir, and the non-narcotic analgesic Analgin is effective. In patients with concomitant diseases, in addition to these drugs, the use of the antispasmodic baralgin, the β-adrenergic blocker obzidan (anaprilin) and the anticholinergic atropine is justified (A.F. Bizyaev).

In patients without concomitant diseases with mild to moderate severity of the psycho-emotional state, the use of seduxen orally (0.3 mg/kg) 30-40 minutes before local anesthesia is effective; in cases of severe severity (except for cases of hysterical reaction), administration of 0.5 is indicated % solution of seduxen in the same dosage with 0.1% solution of atropine (0.6-0.8 ml) in one syringe intravenously. In case of severe tachycardia, it is better not to administer atropine.

For patients with a hysterical reaction and a pronounced degree of psycho-emotional state, intravenous administration of Seduxen (0.3 mg/kg) and Lexir (0.5 mg/kg) is indicated. When administering an atropine solution, monitoring the pulse rate is necessary. Premedication in the clinic for patients with concomitant diseases is given in the next section of the textbook.

In the hospital, preparation is carried out on the eve of the day of surgery or (if indicated) several days in advance. At night, sleeping pills, antihistamines, and minor tranquilizers are prescribed in generally accepted therapeutic dosages. These drugs are given again 3 hours before surgery. Additionally, drugs and vitamins (groups B, C) are administered intramuscularly. 45 minutes before surgery, a “cocktail” is administered intramuscularly, consisting of solutions of the drug, antihistamines, and M-anticholinergic. Instead of these drugs (sometimes together with them), you can administer seduxen or drugs used for neuroleptanalgesia (droperidol, fentanyl). Depending on the nature of the intervention, its traumatic nature, and the general condition of the patient, the dose of the drug is selected individually. Traumatic surgical interventions performed under local anesthesia are preferably performed in combination with neuroleptanalgesia or ataralgesia.

It should be emphasized that any drug preparation does not exclude the need for careful local anesthesia.

Complications

Carrying out local anesthesia requires some experience and compliance with all rules. Complications can be caused by various factors that the doctor allows during the anesthesia process. These include:

Damage to soft tissues caused by an injection needle or solution.
Broken injection needle.
Pain syndrome.
Paresthesia (one of the types of sensitivity disorder, characterized by spontaneously occurring sensations of burning, tingling, crawling).
Trismus (tonic spasm of the masticatory muscles, leading to limitation of movements in the temporomandibular joint).
Hematoma.
Development of infection.
Necrosis (a pathological process expressed in local death of tissue in a living organism as a result of any exo- or endogenous damage).
Facial nerve paresis (a neurological disease characterized by weakness of the facial muscles).
Allergic manifestations.
Toxic reaction.
Emotional stress due to fear of pain.

Each person may experience different complications after the administration of the anesthetic. Therefore, before using the medicine, if the patient has allergic reactions, this must be reported to a medical specialist.

Anesthetics also have certain disadvantages, for example:

Neurotoxicity.
Cardiotoxicity.

The anesthetic causes toxicity in any situation. It all depends on the dosage and group of anesthesia that is used. Neurotoxicity may manifest as:

Impaired motor and sensory functions.
Emotional stress.
Integrative functions of the brain (complete or partial memory loss).
Visual and hearing impairments.
Muscle weakness.
Paresis (neurological syndrome, decreased strength caused by damage to the motor pathway of the nervous system).
Paralysis (complete absence of voluntary movements, due to the same reasons as in the case of paresis).

One of the most severe consequences of local anesthesia in dental practice is facial nerve paresis.

Local anesthetics cause cardiotoxicity only in overdose. This complication is extremely rare. This reduces the conduction of nerve impulses and the expansion of capillaries.

Chemical properties

Structure. All local anesthetics used for nerve blocks consist of a hydrophobic aromatic ring connected to a tertiary amino group by a carbon chain. The length of the hydrocarbon chain varies from 6 to 9 A; drugs with a longer or shorter chain are ineffective. Benzocaine, used only for topical anesthesia, does not have a tertiary amino group and does not have a hydrogen, which is replaced at physiological pH (pKa = 3.5).
Esters and amides. Local anesthetics are divided into esters and amides depending on whether the carbon chain is attached to the benzene moiety by an ester or amide bond. The type of bond is important in determining which pathway a drug will take to be metabolized.
Isomers. Many local anesthetics have at least one asymmetric carbon atom and thus exist as two or more enanthomers. Most of them are used clinically as racemic mixtures containing both enantomers. The exceptions are ropivacaine and levobupivacaine: they are supplied as a single enantomer because in clinical practice it is more potent and less toxic than the racemate.

What to do if you have an allergy

The impact of painkillers on the human body in most cases is accompanied by the occurrence of allergic manifestations. But not all anesthetics can provoke such a reaction.

Before anesthesia, a test should be done to rule out intolerance or allergy to a particular drug. The healthcare professional will then administer safe pain-relieving medications.

Before giving anesthesia, you need to carry out a list of tests to exclude allergic reactions. A blood test for detecting negative reactions to an anesthetic in this situation is not considered effective.

"Lidocaine"

The drug is used for conduction, as well as infiltration and terminal anesthesia. The anesthetic has a local anesthetic and antiarrhythmic effect. As a pain reliever, it works by suppressing nerve conduction by blocking sodium channels in nerve fibers and endings.

The medicine is significantly superior to Procaine, its effect occurs faster, and it lasts longer - up to 75 minutes (together with Epinephrine - more than two hours). When used locally, the anesthetic expands capillaries and does not have a local irritating effect.

The antiarrhythmic effect of the drug is due to the ability to increase the permeability of membranes to potassium, block sodium channels, and stabilize cell membranes. "Lidocaine" does not have a significant effect on myocardial contractility and conductivity (it affects only in large doses).

The level of absorption of Lidocaine when administered locally depends on the dosage of the drug and the site of treatment. After intramuscular injections, the maximum content is reached five to fifteen minutes after application.

"Benzocaine"

The active component has an analgesic effect, preventing the development of pain. When used externally and applied to mucous cavities, the effect of Benzocaine occurs immediately and lasts for fifteen to twenty minutes.

Benzocaine is a widely used local anesthetic. The solution is produced as part of medications for topical use or for oral use.

The drug is a white powder that does not have a specific aroma, but has a bitter taste. If you apply the drug to the tip of your tongue, you will experience a feeling of numbness.

When using the drug topically and orally, a minimum of the active component is absorbed. After applying the medication to the mucous membrane, the effect of Benzocaine begins within one minute and lasts up to twenty minutes.

What it is

Local anesthesia is a method of pain relief in which an area of skin and some tissues are deprived of sensitivity at a certain depth, depending on the complexity of the operation. For example, applying cream to the leg before waxing is local anesthesia, but also deep anesthesia of the entire lower jaw (along with the bone) by administering just one injection.

Sometimes they talk about local anesthesia, meaning that this is the same method of anesthetizing a specific area. Although it would be more correct to call it local anesthesia, because anesthesia is still a shutdown of the patient’s consciousness.

"Novocaine"

The active component of the injection solution has a local anesthetic effect; it leads to a decrease in all types of tissue sensitivity in the area of application. The pharmacological action occurs by blocking sodium channels in the walls of peripheral nerves, which prevents the conduction of nerve impulses in sensitive tissues.

After absorption of procaine (the active substance) into the general bloodstream, it blocks the transmission of impulses in the autonomic ganglia, and also reduces the excitability of the peripheral cholinergic structures of the central nervous system. In addition, the anesthetic reduces muscle spasm, reduces the excitability of the motor structures of the cerebral cortex and heart muscles.

The duration of action of the Novocaine injection solution is short and ranges from thirty minutes to half an hour.

After introducing the drug into the tissue, the active component accumulates in the injection area and is then absorbed into the systemic bloodstream. The rate of absorption depends on the area of application of the medication. The active substance is exchanged in the liver with the formation of inactive breakdown products, which are eliminated from the body with urine. The time for removing half of the entire dosage of the drug after absorption of the drug is fifty seconds.

POTENTIZED LOCAL ANESTHESIA

Local anesthetics do not affect the emotional and autonomic components of pain, which causes the patient to lose appetite, sleep disturbance, fear, noticeable anxiety (screaming, crying, etc.), fearfulness, irritability, and also affects changes in various organs and systems — the glucocorticoid function of the adrenal cortex increases, blood pressure and body temperature increase, hemodynamics changes, etc.

This led to the use of premedication, i.e. medications that eliminate the previously listed changes in the patient’s body and improve the performance of surgery under local anesthesia. Potentiation is an enhancement of the pharmacological action of an anesthetic by other substances, more significant than the summation of the separate effects of these drugs.

Neuroleptanalgesia (neuroleptics + analgesia)

- a method of pain relief based on the combined use of neuroleptic drugs and narcotic analgesics.
Neuroleptic drugs are medicinal substances that have an inhibitory effect on the functions of the central nervous system, without disturbing consciousness, and can eliminate delusions, hallucinations and some other symptoms of psychosis. Neuroleptics
include the following drugs: chlorpromazine, etapyrazine, haloperidol, droperidol, etc.
Narcotic analgesics include
omnopon, codeine, morphine, promedol, fentanyl, etc.

Ataralgesia (ataractics - tranquilizers + analgesics) -

a state of depression of consciousness and pain sensitivity caused by the combined effect of analgesics and tranquilizers.
Tranquilizers, unlike neuroleptic drugs, do not have a pronounced antipsychotic effect. Tranquilizers mezepam
(rudotel), meprobamate, trioxazine, grandaxin, etc.

Based on what was said earlier, we present some schemes of neuroleptanalgesia and aralgesia that have found application in maxillofacial surgery in a hospital and clinic.

Premedication according to the schemes of A.A. Tsigani

• Children aged 1 year to 8-10 years are administered calypsol (at a dose of 5 mg/kg) and atropine (0.1 mg/kg or 0.1 ml of 1% solution per 10 kg) in the ward and taken to the operating room on a gurney. tion.

• For children aged 7 to 15 years, premedication at night may not be prescribed, because they do not realize the seriousness of the upcoming operation. In the morning

30-60 minutes before surgery, 0.1 ml of a 0.1% atropine solution is administered intramuscularly. In the presence of mental agitation or pain (with insufficient local anesthesia), ketamine is additionally administered intramuscularly at the rate of 5 mg/kg in the operating room.

• Patients aged 15 years and older the evening

and at 6.00 am the following drugs are prescribed: phenobarbital (0.15 mg/kg), diazepam (Seduxen) - 0.15 mg/kg, pipolfen - 0.5 mg/kg.
60 minutes before surgery,
a 1% solution of atropine (0.1 mg/kg), seduxen (Sibazon) - 0.2 mg/kg, 1% solution of diphenhydramine (0.4 ml per 10 kg), fentanyl (0.02 mg) is administered intramuscularly. /kg) or 1% morphine solution (0.2 mg/kg).

• Patients over 15 years of age with heart defects and diseases and with an increased coronary risk are prescribed:

the night before

(at 22.00) and in
the morning
(6.00) sleeping pills (phenobarbital - 0.5-1 mg/kg or Noxiron - 1.5 mg), antipsychotics (pipolfen - 0.5 mg/kg), tranquilizers (seduxen - 0.05- 0.15 mg/kg), narcotic analgesics (1% morphine solution - 0.1 mg/kg or 2% promedol solution - 0.2 mg/kg or 0.005% fentanyl solution - 0.01 mg/kg).

— in the morning 60 minutes before surgery

1% solution of atropine (0.1 mg/kg), seduxen or relanium (0.2 mg/kg), 1% solution of morphine (0.2 mg/kg) or 2% solution of promedol (0.4 mg) is administered intramuscularly. /kg) or 0.005% fentanyl solution (0.02 mg/kg)

— in the presence of arterial hypertension, patients are additionally prescribed weak antihypertensive drugs (papaverine, dibazole) intramuscularly.

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3. PAIN RELIEF IN ORAL AND MAXILLOFACIAL SURGERY AND SURGICAL DENTISTRY

Premedication according to the scheme I.A. Shugailova

1 hour before surgery, the following are administered intramuscularly: seduxen at a rate of 0.2 mg per 1 kg of patient weight, droperidol at a rate of 0.1 mg/kg in combination with 0.5-1.0 ml of a 0.1% atropine solution. The result is patient calm, general relaxation, and a state of easily interrupted sleep throughout the entire operation.

This premedication has a normalizing effect on all components of the pain response, which makes it possible to perform the operation under local anesthesia in a hospital setting.