Theory of general anesthesia. General anesthesia

All types of pain relief divided into 2 groups:

1). General anesthesia (anesthesia).

2). Local anesthesia.

Narcosis is an artificially induced reversible inhibition of the central nervous system caused by the administration of narcotic drugs, accompanied by loss of consciousness, all types of sensitivity, muscle tone, all conditioned and some unconditioned reflexes.

From the history of anesthesia:

In 1844, H. Wells used inhalation of nitrous oxide for tooth extraction. In the same year, Ya.A. Chistovich used ether anesthesia for hip amputation. The first public demonstration of the use of anesthesia during surgery took place in Boston (USA) in 1846: dentist W. Morton gave ether anesthesia to a patient. Soon W. Squire designed an apparatus for ether anesthesia. In Russia, ether was first used in 1847 by F.I. Inozemtsev.

• 1857 - C. Bernard demonstrated the effect of curare on the neuromuscular synapse.
• 1909 - intravenous anesthesia with hedonal was used for the first time (N.P. Kravkov, S.P. Fedorov).
• 1910 - tracheal intubation was used for the first time.
• 1920 - Description of the signs of anesthesia (Guedel).
• 1933 - Sodium thiopental was introduced into clinical practice.
• 1951 - Suckling synthesized fluorothane. In 1956, it was first used in the clinic.
• 1966 - Enflurane was used for the first time.

Theories of anesthesia

1). Coagulation theory(Kühn, 1864): Drugs cause the coagulation of intracellular proteins in neurons, which leads to disruption of their function.

2). Lipid theory(Hermann, 1866, Meyer, 1899): most narcotic substances are lipotropic, as a result of which they block the membranes of neurons, disrupting their metabolism.

3). Theory surface tension (adsorption theory, Traube, 1904): the anesthetic reduces the force of surface tension at the level of neuronal membranes.

4). Redox theory(Verworn, 1912): narcotic substances inhibit redox processes in neurons.

5). Hypoxic theory(1920): anesthetics cause hypoxia of the central nervous system.

6). Theory of water microcrystals(Pauling, 1961): drugs in aqueous solution form microcrystals that prevent the formation and propagation of action potentials along nerve fibers.

7). Membrane theory(Hober, 1907, Winterstein, 1916): Drugs cause disruption of the transport of ions across the neuronal membrane, thereby blocking the occurrence of an action potential.

None of the proposed theories fully explains the mechanism of anesthesia.

Modern representations : Currently, most scientists, based on the teachings of N.E. Vvedensky, A.A. Ukhtomsky and I.P. Pavlov, believe that anesthesia is a kind of functional inhibition of the central nervous system ( physiological theory of central nervous system inhibition- V.S.Galkin). According to P.A. Anokhin, the reticular formation of the brain is most sensitive to the effects of narcotic substances, which leads to a decrease in its ascending influence on the cerebral cortex.

Classification of anesthesia

1). According to factors affecting the central nervous system:

• Pharmacodynamic anesthesia- the effect of narcotic substances.
• Electronarcosis- action of the electric field.
• Hypnonarcosis- the effect of hypnosis.

2). According to the method of introducing the drug into the body:

• Inhalation:

Mask.

Endotracheal (ETN).

Endobronchial.

• Non-inhalation:

Intravenous.

Intramuscular (rarely used).

Rectal (usually only in children).

3). By quantity of narcotic drugs:

• Mononarcosis- 1 drug is used.
• Mixed anesthesia- several drugs are used at the same time.
• Combined anesthesia- use of various narcotic substances at different stages of the operation; or a combination of drugs with drugs that selectively act on other body functions (muscle relaxants, ganglion blockers, analgesics, etc.).

4). Depending on the stage of the operation:

• Introductory anesthesia- short-term, occurs without an excitation phase. Used for rapid induction of anesthesia.
• Maintenance anesthesia- used throughout the entire operation.
• Basic anesthesia- this is like the background against which the main anesthesia is carried out. The effect of basic anesthesia begins shortly before the operation and lasts for some time after its completion.
• Additional anesthesia- against the background of maintenance anesthesia, other drugs are administered to reduce the dose of the main anesthetic.

Inhalation anesthesia

Preparations for inhalation anesthesia

1). Liquid anesthetics- when they evaporate, they have a narcotic effect:

• Ftorotan (narcotan, halothane) - used in most domestic devices.
• Enflurane (ethrane), methoxyflurane (ingalan, pentrane) are used less frequently.
• Isoflurane, sevoflurane, desflurane are new modern anesthetics (used abroad).

Modern anesthetics have a strong narcotic, antisecretory, bronchodilator, ganglion-blocking and muscle relaxant effect, rapid induction of anesthesia with a short excitation phase and rapid awakening. They do not irritate the mucous membranes of the respiratory tract.

Side effects fluorotane: possibility of oppression respiratory system, drop in blood pressure, bradycardia, hepatotoxicity, increases the sensitivity of the myocardium to adrenaline (therefore, these drugs should not be used during fluorotane anesthesia).

Ether, chloroform and trichlorethylene are not currently used.

2). Gaseous anesthetics:

The most common is nitrous oxide, because it causes rapid induction of anesthesia with virtually no arousal phase and rapid awakening. Used only in combination with oxygen: 1:1, 2:1, 3:1 and 4:1. It is impossible to reduce the oxygen content in the mixture below 20% due to the development of severe hypoxia.

Disadvantage is that it causes superficial anesthesia, weakly inhibits reflexes and causes insufficient muscle relaxation. Therefore, it is used only for short-term operations that do not penetrate the body cavities, and also as induction anesthesia for major operations. It is possible to use nitrous oxide for maintenance anesthesia (in combination with other drugs).

Cyclopropane is currently practically not used due to the possibility of respiratory and cardiac depression.

The principle of anesthesia machines

Any anesthesia machine contains the main components:

1). Dosimeter - used for precise dosing of narcotic substances. Rotary dosimeters of the float type are most often used (the displacement of the float indicates the gas flow in liters per minute).

2). Vaporizer - serves to convert liquid narcotic substances into vapor and is a container into which the anesthetic is poured.

3). Cylinders for gaseous substances- oxygen (blue cylinders), nitrous oxide (gray cylinders), etc.

4). Breathing block- consists of several parts:

• Breathing bag- used for manual ventilation, as well as as a reservoir for the accumulation of excess narcotic substances.
• Adsorber- serves to absorb excess carbon dioxide from exhaled air. Requires replacement every 40-60 minutes of operation.
• Valves- serve for one-way movement of the narcotic substance: inhalation valve, exhalation valve, safety valve (for releasing excess narcotic substances into external environment) and a non-reversible valve (to separate the flow of inhaled and exhaled narcotic substances)
  At least 8-10 liters of air should be supplied to the patient per minute (of which at least 20% is oxygen).

Depending on the principle of operation of the breathing unit, there are 4 breathing circuits:

1). Open circuit:

Inhalation - from atmospheric air through the evaporator.

Exhale into the external environment.

2). Semi-open circuit:

Inhale - from the apparatus.

Exhale into the external environment.

Disadvantages of open and semi-open circuits are air pollution in the operating room and high consumption of narcotic substances.

3). Semi-closed circuit:

Inhale - from the apparatus.

Exhale - partly into the external environment, partly back into the apparatus.

4). Closed circuit:

Inhale - from the apparatus.

Exhale into the apparatus.

When using semi-closed and closed circuits, the air, passing through the adsorber, is freed from excess carbon dioxide and again enters the patient. The only one disadvantage of these two circuits is the possibility of developing hypercapnia due to failure of the adsorber. Its performance must be regularly monitored (a sign of its operation is some heating, since the process of absorption of carbon dioxide occurs with the release of heat).

Currently in use anesthesia machines Polynarcon-2, -4 and -5, which provide the ability to breathe along any of the 4 circuits. Modern anesthesia rooms are combined with ventilators (RO-5, RO-6, PHASE-5). They allow you to adjust:

• Tidal and minute volume of the lungs.
• The concentration of gases in inhaled and exhaled air.
• The ratio of inhalation and exhalation time.
• Outlet pressure.

The most popular imported devices are Omega, Draeger and others.

Stages of anesthesia(Gwedel, 1920):

1). Analgesia stage(lasts 3-8 minutes): gradual depression of consciousness, sharp decrease in pain sensitivity; however, catch reflexes, as well as temperature and tactile sensitivity are preserved. Respiration and hemodynamic parameters (pulse, blood pressure) are normal.

In the stage of analgesia, 3 phases are distinguished (Artusio, 1954):

• Initial phase- no analgesia or amnesia yet.
• Phase of complete analgesia and partial amnesia.
• Phase of complete analgesia and complete amnesia.

2). Excitation stage(lasts 1-5 minutes): it was especially pronounced during the use of ether anesthesia. Immediately after loss of consciousness, motor and speech excitation begins, which is associated with excitation of the subcortex. Breathing quickens, blood pressure rises slightly, and tachycardia develops.

3). Narcotic sleep stage (surgical stage):

There are 4 levels in it:

I - U level of eyeball movement: the eyeballs make smooth movements. The pupils are constricted, the reaction to light is preserved. Reflexes and muscle tone are preserved. Hemodynamic parameters and breathing are normal.

II - Level of absence of corneal reflex: eyeballs are motionless. The pupils are constricted, the reaction to light is preserved. Reflexes (including corneal) are absent. Muscle tone begins to decrease. Breathing is slow. Hemodynamic parameters are normal.

III - Pupil dilation level: pupils are dilated, their reaction to light is weak. A sharp decrease in muscle tone, the root of the tongue can sink and block the airways. The pulse increases, the pressure decreases. Shortness of breath up to 30 per minute (diaphragmatic breathing begins to predominate over costal breathing, exhalation is longer than inhalation).

IV - Diaphragmatic breathing level: pupils are dilated, there is no reaction to light. The pulse is frequent, thread-like, the pressure is sharply reduced. Breathing is shallow, arrhythmic, completely diaphragmatic. Subsequently, paralysis of the respiratory and vasomotor centers of the brain occurs. Thus, the fourth level is a sign of a drug overdose and often leads to death.

Depth of anesthesia when using inhalation mononarcosis, it should not exceed the I-II level of the surgical stage; only for a short time it can be deepened to level III. When using combined anesthesia, its depth usually does not exceed 1 level of the surgical stage. It is proposed to operate during the anesthesia stage (rausch anesthesia): short-term superficial interventions can be performed, and when using muscle relaxants, almost any operation can be performed.

4). Awakening stage(lasts from several minutes to several hours, depending on the dose received and the patient’s condition): occurs after stopping the supply of the narcotic substance and is characterized by the gradual restoration of consciousness of other body functions in reverse order.

This classification is rarely used for intravenous anesthesia because the surgical stage is reached very quickly and premedication with narcotic analgesics or atropine can significantly alter pupillary response.

Mask anesthesia

Mask anesthesia is used:

• For short operations.
• If it is impossible to perform tracheal intubation (anatomical features of the patient, trauma).
• When injected into anesthesia.
• Before tracheal intubation.

Technique:

1). The patient's head is tilted back (this is necessary to ensure greater patency of the upper respiratory tract).

2). Apply the mask so that it covers the mouth and nose. The anesthesiologist must maintain the mask throughout the anesthesia.

3). The patient is allowed to take a few breaths through a mask, then pure oxygen is connected, and only after that the drug is given (gradually increasing the dose).

4). After anesthesia enters the surgical stage (level 1-2), the dose of the drug is no longer increased and is kept at an individual level for each person. When deepening anesthesia to the 3rd level of the surgical stage, the anesthesiologist must bring the patient’s lower jaw forward and hold it in this position (to prevent tongue retraction).

Endotracheal anesthesia

It is used more often than others, mainly during long-term abdominal operations, as well as during operations on the neck organs. Intubation anesthesia was first used in an experiment by N.I. Pirogov in 1847, during operations - by K.A. Rauchfuss in 1890

The advantages of ETN over others are:

• Precise dosing of narcotic substances.
• Reliable patency of the upper respiratory tract.
• Aspiration is virtually eliminated.

Tracheal intubation technique:

The prerequisites for starting intubation are: lack of consciousness, sufficient muscle relaxation.

1). Maximum extension of the patient's head is performed. The lower jaw is brought forward.

2). A laryngoscope (with a straight or curved blade) is inserted into the patient's mouth, on the side of the tongue, and is used to lift the epiglottis. An examination is carried out: if the vocal cords move, then intubation cannot be performed, because you can hurt them.

3). Under the control of a laryngoscope, an endotracheal tube of the required diameter is inserted into the larynx and then into the trachea (for adults, usually No. 7-12) and fixed there by dosed inflation of a special cuff included in the tube. Too much inflation of the cuff can lead to bedsores of the tracheal wall, and too little inflation will break the seal.

4). After this, it is necessary to listen to breathing over both lungs using a phonendoscope. If intubation is too deep, the tube may enter the thicker right bronchus. In this case, breathing on the left will be weakened. If the tube rests on the bifurcation of the trachea, there will be no breathing sounds anywhere. If the tube gets into the stomach, in the absence of respiratory sounds, the epigastrium begins to swell.

Recently, it is increasingly used laryngeal mask. This is a special tube with a device for supplying the respiratory mixture to the entrance to the larynx. Its main advantage is ease of use.

Endobronchial anesthesia

used in lung surgeries when only one lung needs to be ventilated; or both lungs, but in different modes. Intubation of both one and both main bronchi is used.

Indications :

1). Absolute (anesthetic):

• Threat of respiratory tract infection from bronchiectasis, lung abscesses or empyema.
• Gas leak. It can occur when a bronchus ruptures.

2). Relative (surgical): improvement of surgical access to the lung, esophagus, anterior surface of the spine and large vessels.

Collapsed lung on the surgical side, it improves surgical access, reduces trauma to the lung tissue, allows the surgeon to work on the bronchi without air leakage, and limits the spread of infection with blood and sputum to the opposite lung.

For endobronchial anesthesia the following are used:

• Endobronchial obturators
• Double-lumen tubes (right-sided and left-sided).

Expansion of a collapsed lung after surgery:

The bronchi of the collapsed lung should be cleared of sputum by the end of the operation. Even with an open pleural cavity at the end of the operation, it is necessary to inflate the collapsed lung using manual ventilation under visual control. Physiotherapy and oxygen therapy are prescribed for the postoperative period.

The concept of adequacy of anesthesia

The main criteria for the adequacy of anesthesia are:

• Complete loss of consciousness.
• The skin is dry and of normal color.
• Stable hemodynamics (pulse and pressure).
• Diuresis is not lower than 30-50 ml/hour.
• Absence of pathological changes on the ECG (if monitoring is carried out).
• Normal volume indicators of pulmonary ventilation (determined using an anesthesia machine).
• Normal levels of oxygen and carbon dioxide in the blood (determined using a pulse oximeter, which is placed on the patient’s finger).

Premedication

This is the administration of medications before surgery in order to reduce the likelihood of intraoperative and postoperative complications.

Objectives of premedication:

1). Reduced emotional arousal and feelings of fear before surgery. Hypnotics (phenobarbital) and tranquilizers (diazepan, phenazepam) are used.

2). Stabilization of the autonomic nervous system. Neuroleptics are used (aminazine, droperidol).

3). Prevention of allergic reactions. Antihistamines are used (diphenhydramine, suprastin, pipolfen).

4). Decreased secretion of glands. Anticholinergics (atropine, metacin) are used.

5). Strengthening the effect of anesthetics. Narcotic analgesics (promedol, omnopon, fentanyl) are used.

Many premedication regimens have been proposed.

Scheme of premedication before emergency surgery:

• Promedol 2% - 1 ml IM.
• Atropine - 0.01 mg/kg s.c.
• Diphenhydramine 1% - 1-2 ml IM or (according to indications) droperidol.

Scheme of premedication before planned surgery:

1). The night before bed, take a sleeping pill (phenobarbital) or a tranquilizer (phenazepam).

2). In the morning, 2-3 hours before surgery - an antipsychotic (droperidol) and a tranquilizer (phenazepam).

3). 30 minutes before surgery:

• Promedol 2% - 1 ml IM.
• Atropine - 0.01 mg/kg s.c.
• Diphenhydramine 1% - 1-2 ml IM.

Intravenous anesthesia

This is anesthesia caused by intravenous administration of narcotic drugs.

Main advantages intravenous anesthesia are:

1). Quick induction of anesthesia, pleasant for the patient, with virtually no stage of excitement.

2). Technical ease of implementation.

3). Possibility of strict accounting of narcotic substances.

4). Reliability.

However, the method is not without shortcomings:

1). Lasts for a short time (usually 10-20 minutes).

2). Does not allow complete muscle relaxation.

3). There is a greater risk of overdose compared to inhalation anesthesia.

Therefore, intravenous anesthesia is rarely used independently (in the form of mononarcosis).

The mechanism of action of almost all drugs for intravenous anesthesia is to turn off consciousness and deep inhibition of the central nervous system, while suppression of sensitivity occurs secondary. An exception is ketamine, the effect of which is characterized by sufficient pain relief with partially or completely preserved consciousness.

The main drugs used for intravenous anesthesia

1). Barbiturates:

• Sodium thiopental is the main drug.
• Hexenal, thiaminal - are used less frequently.

Are used for introductory anesthesia and for short-term anesthesia during minor operations. The mechanism of action is explained by the inhibitory effect on the reticular formation of the brain.

The solution is prepared before surgery: 1 bottle (1 gram) is dissolved in 100 ml of saline (a 1% solution is obtained) and administered intravenously at a rate of approximately 5 ml per minute. 1-2 minutes after the start of administration, unexpressed speech excitation usually occurs (disinhibition of subcortical structures). Motor agitation is not typical. After another 1 minute, consciousness completely turns off and the patient enters the surgical stage of anesthesia, which lasts 10-15 minutes. A long duration of anesthesia is achieved by fractional administration of 0.1-0.2 g of the drug (i.e. 10-20 ml of solution). The total dose of the drug is no more than 1 g.

Possible side effects: respiratory and cardiac depression, drop in blood pressure. Barbiturates are contraindicated in acute liver failure.

2). Ketamine (ketalar, calypsol).

Used for short-term anesthesia, as well as as a component in combined anesthesia (in the maintenance phase of anesthesia) and in ataralgesia (together with tranquilizers).

Mechanism of action This drug is based on the temporary disconnection of nerve connections between different parts of the brain. Has low toxicity. It can be administered either intravenously or intramuscularly. The general dose is 1-2 mg/kg (intravenous) or 10 mg/kg (intramuscular).

Analgesia occurs 1-2 minutes after administration, but consciousness is preserved and you can talk with the patient. After the operation, the patient does not remember anything due to the development of retrograde amnesia.

This is the only anesthetic that stimulates the cardiovascular system, therefore it can be used in patients with heart failure and hypovolemia; Contraindicated in patients with hypertension.

Possible side effects: increased blood pressure, tachycardia, increased sensitivity of the heart to catecholamines, nausea and vomiting. Frightening hallucinations are characteristic (especially upon awakening). To prevent them, tranquilizers are administered in the preoperative period.

Ketamine is contraindicated in cases of increased ICP, hypertension, angina pectoris, and glaucoma.

3). Deprivan (propofol). Ampoules 20 ml 1% solution.

One of the most modern drugs. It has a short action and therefore usually requires combination with other drugs. It is the drug of choice for introductory anesthesia, but can also be used for long-term anesthesia. A single dose is 2-2.5 mg/kg; after administration, anesthesia lasts 5-7 minutes.

Possible side effects are very rare: short-term apnea (up to 20 seconds), bradycardia, allergic reactions.

4). Sodium hydroxybutyrate(GHB - gamma-hydroxybutyric acid).

Used for induction of anesthesia. The drug has low toxicity, therefore it is the drug of choice for weakened and elderly patients. In addition, GHB also has an antihypoxic effect on the brain. The drug must be administered very slowly. The general dose is 100-150 mg/kg.

Its only disadvantage is that it does not cause complete analgesia and muscle relaxation, which forces it to be combined with other drugs.

5).Etomidate - is used mainly for induction of anesthesia and for short-term anesthesia. A single dose (it lasts for 5 minutes) is 0.2-0.3 mg/kg (can be re-administered no more than 2 times). The advantage of this drug is that it does not affect the cardiovascular system.

Side effects: Nausea and vomiting in 30% of adults and involuntary movements immediately after administration of the drug.

6). Propanidid (epontol, sombrevin).

It is used mainly for induction of anesthesia, as well as for short-term operations. Anesthesia occurs “at the end of the needle”, awakening is very fast (after 5 minutes).

7). Viadryl (predion).

Used in combination with nitrous oxide for induction of anesthesia, as well as during endoscopic examinations.

Propanidid and Viadryl have practically not been used in the last few years.

Muscle relaxants

There are 2 groups of muscle relaxants:

1). Antidepolarizing(long-acting - 40-60 minutes): diplacin, anatruxonium, dioxonium, arduan. The mechanism of their action is the blockade of cholinergic receptors, as a result of which depolarization does not occur and the muscles do not contract. The antagonist of these drugs is cholinesterase inhibitors (prozerin), because Cholinesterase stops destroying acetylcholine, which accumulates in the amount necessary to overcome the blockade.

2). Depolarizing(short-acting - 5-7 minutes): ditilin (listenone, myorelaxin). At a dose of 20-30 mg it causes muscle relaxation, at a dose of 40-60 mg it stops breathing.

The mechanism of action is similar to acetylcholine, i.e. they cause long-term persistent depolarization of membranes, preventing repolarization. The antagonist is pseudocholinesterase (found in freshly citrated blood). Prozerin cannot be used, because due to the inhibition of cholinesterase, it enhances the effect of ditilin.

If both groups of muscle relaxants are used simultaneously, then a “double block” is possible - ditilin acquires the properties of drugs of the first group, resulting in prolonged cessation of breathing.

Narcotic analgesics

reduce the excitability of pain receptors, cause euphoria, anti-shock, hypnotic, antiemetic effects, decreased gastrointestinal secretion.

Side effects:

depression of the respiratory center, decreased peristalsis and gastrointestinal secretion, nausea and vomiting. Addiction quickly sets in. To reduce side effects, combine with anticholinergics (atropine, metacin).

Are used for premedication, in the postoperative period, and also as a component of combined anesthesia.

Contraindications: general exhaustion, insufficiency of the respiratory center. It is not used for labor pain relief.

1). Omnopon (Pantopon) - a mixture of opium alkaloids (contains up to 50% morphine).

2). Promedol - compared to morphine and omnopon, has fewer side effects and is therefore the drug of choice for premedication and central analgesia. The analgesic effect lasts 3-4 hours.

3). Fentanyl has a strong but short-term (15-30 minutes) effect, therefore it is the drug of choice for neuroleptanalgesia.

In case of an overdose of narcotic analgesics, naloxone (an opiate antagonist) is used.

Classification of intravenous anesthesia

1). Central analgesia.

2). Neuroleptanalgesia.

3). Ataralgesia.

Central analgesia

Through the administration of narcotic analgesics (promedol, omnopon, fentanyl), pronounced analgesia is achieved, which plays a major role. Narcotic analgesics are usually combined with muscle relaxants and other drugs (deprivan, ketamine).

However, high doses of drugs can lead to respiratory depression, which often requires the use of mechanical ventilation.

Neuroleptanalgesia (NLA)

The method is based on the combined use of:

1). Narcotic analgesics (fentanyl), which provide pain relief.

2). Neuroleptics (droperidol), which suppress autonomic reactions and cause a feeling of indifference in the patient.

A combination drug containing both substances (thalamonal) is also used.

Advantages of the method is the rapid onset of indifference to everything around; reduction of vegetative and metabolic changes caused by the operation.

Most often, NLA is used in combination with local anesthesia, and also as a component of combined anesthesia (fentanyl with droperidol is administered against the background of nitrous oxide anesthesia). In the latter case, the drugs are administered in fractions every 15-20 minutes: fentanyl - for increased heart rate, droperidol - for increased blood pressure.

Ataralgesia

This is a method that uses a combination of drugs from 2 groups:

1). Tranquilizers and sedatives.

2). Narcotic analgesics (promedol, fentanyl).

As a result, a state of ataraxia (“deprivation”) occurs.

Ataralgesia is usually used for minor superficial operations, and also as a component of combined anesthesia. In the latter case, the following drugs are added to the above drugs:

• Ketamine - to potentiate the narcotic effect.
• Neuroleptics (droperidol) - for neurovegetative protection.
• Muscle relaxants - to reduce muscle tone.
• Nitrous oxide - to deepen anesthesia.

The concept of combined anesthesia

Combined intubation anesthesia is currently the most reliable, controlled and universal method of anesthesia. Using several drugs allows you to reduce the dose of each of them and thereby reduce the likelihood of complications. Therefore, it is the method of choice for major traumatic operations.

Advantages of combined anesthesia:

• Rapid induction of anesthesia with virtually no arousal phase.
• Reducing the toxicity of anesthesia.
• The addition of muscle relaxants and neuroleptics allows you to operate at the 1st level of the surgical stage of anesthesia, and sometimes even during the analgesia stage. This reduces the dose of the main anesthetic and thereby reduces the risk of anesthesia complications.
• Endotracheal administration of the respiratory mixture also has its advantages: rapid management of anesthesia, good airway patency, prevention of aspiration complications, and the possibility of airway sanitation.

Stages of combined anesthesia:

1). Induction anesthesia:

Typically one of the following drugs is used:

• Barbiturates (sodium thiopental);
• Sodium hydroxybutyrate.
• Deprivan.
• Propanidide in combination with a narcotic analgesic (fentanyl, promedol) is rarely used.

At the end of induction anesthesia, respiratory depression may occur. In this case, it is necessary to start mechanical ventilation using a mask.

2). Tracheal intubation:

Before intubation, short-acting muscle relaxants (ditylin) are administered intravenously, while mechanical ventilation is continued through a mask for 1-2 minutes with pure oxygen. Then intubation is performed, stopping mechanical ventilation for this time (there is no breathing, so intubation should not take more than 30-40 seconds).

3). Basic (maintenance) anesthesia:

Basic anesthesia is carried out in 2 main ways:

• Inhalation anesthetics are used (fluorothane; or nitrous oxide in combination with oxygen).
• Neuroleptanalgesia (fentanyl with droperidol) is also used, alone or in combination with nitrous oxide.

Anesthesia is maintained at the 1st-2nd level of the surgical stage. To relax the muscles, the anesthesia is not deepened to level 3, but short-acting (ditilin) ​​or long-acting muscle relaxants (arduan) are administered. However, muscle relaxants cause paresis of all muscles, including respiratory ones, so after their administration they always switch to mechanical ventilation.

To reduce the dose of the main anesthetic, antipsychotics and sodium hydroxybutyrate are additionally used.

4). Recovery from anesthesia:

Towards the end of the operation, the administration of narcotic drugs is gradually stopped. The patient begins to breathe on his own (in this case, the anesthesiologist removes the endotracheal tube) and regains consciousness; all functions are gradually restored. If spontaneous breathing does not recover for a long time (for example, after using long-acting muscle relaxants), then decurarization is carried out with the help of antagonists - cholinesterase inhibitors (prozerin). To stimulate the respiratory and vasomotor centers, analeptics (cordiamin, bemegride, lobeline) are administered.

Monitoring the administration of anesthesia

During anesthesia, the anesthesiologist constantly monitors the following parameters:

1). Blood pressure and pulse rate are measured every 10-15 minutes. It is advisable to monitor the central venous pressure.

2). In people with heart disease, ECG monitoring is performed.

3). They control the parameters of mechanical ventilation (tidal volume, minute volume of breathing, etc.), as well as the partial tension of oxygen and carbon dioxide in the inhaled, exhaled air and in the blood.

4). Monitor indicators of acid-base status.

5). Every 15-20 minutes, the anesthesiologist performs auscultation of the lungs (to monitor the position of the endotracheal tube), and also checks the patency of the tube with a special catheter. If the tightness of the tube to the trachea is broken (as a result of relaxation of the tracheal muscles), it is necessary to pump air into the cuff.

The anesthesiological nurse keeps an anesthesia card, which notes all the listed parameters, as well as narcotic drugs and their doses (taking into account the stage of anesthesia they were administered). The anesthesia card is included in the patient's medical history.

The era of modern surgery began in 1846, when chemist C. T. Jackson and dentist W. T. G. Morton discovered the anesthetic properties of ether vapor and performed the first tooth extraction under general anesthesia. Somewhat later, surgeon M. Warren performed the world's first operation (removal of a neck tumor) under inhalation anesthesia using ether. In Russia, the introduction of anesthesia techniques was facilitated by the work of F. I. Inozemtsev and N. I. Pirogov. The work of the latter (he performed about 10 thousand anesthesia during the Crimean War) played an exceptional role big role. Since that time, the technique of anesthesia has become many times more complex and improved, opening the surgeon up to unusually complex interventions. But the question still remains open about what anesthesia sleep is and what are the mechanisms of its occurrence. To explain the phenomenon of anesthesia, a large number of theories have been put forward, many of which have not stood the test of time and are of purely historical interest. These are, for example:

1) Bernard's coagulation theory(according to his ideas, the drugs used to induce anesthesia caused coagulation of the protoplasm of neurons and a change in their metabolism); 2) lipoid theory(according to her ideas, narcotics dissolve the lipid substances of the membranes of nerve cells and, penetrating inside, cause a change in their metabolism);3) protein theory(drugs bind to enzyme proteins in nerve cells and cause disruption oxidative processes in them);4) adsorption theory(in the light of this theory, drug molecules are adsorbed on the surface of cells and cause a change in the properties of membranes and, consequently, the physiology of nervous tissue);5) theory of noble gases;6) neurophysiological theory(most fully answers all the questions of researchers, explains the development of anesthesia sleep under the influence of certain drugs by phasic changes in the activity of the reticular formation, which leads to inhibition of the central nervous system).

Anesthesia. Stages and levels.

Anesthesia is a deep, drug-induced sleep, accompanied by: switching off consciousness, severe anesthesia, relaxation of skeletal muscles and inhibition of reflex activity. By way of analgesic, the routes of its administration are distinguished: non-inhalation anesthesia, when drugs for anesthesia are administered intravenously; and inhalation anesthesia, when substances for anesthesia delivered into the respiratory tract through special devices. The following are used as air ducts for inhalation anesthesia: masks - mask anesthesia; intubation tubes that are inserted either into the trachea - endotracheal anesthesia, or into the bronchi - endobronchial anesthesia (it uses special tubes for one- or two-lung anesthesia. Mononarcosis is carried out with one of the drugs, mixed anesthesia - with the simultaneous use of several analgesics and anesthetics, and combined differs by their sequential administration.According to the effectiveness of their action on the central nervous system, anesthetic drugs can be: powerful anesthetics, i.e. induce sleep or induce a euphoric state, but be weak analgesics, i.e. give a low analgesic effect (nitrous oxide, sodium hydroxybutyrate) ;be effective analgesics, but weak anesthetics (all narcotic drugs); combine both properties to the same extent - most drugs for anesthesia are placed in the gas circulation circle. STAGES AND LEVELS OF NARCOSIS1 - stage of analgesia, in which (according to Artusio) there are three levels: 1) - absence of analgesia and amnesia (the patient is conscious, speech is coherent); 2) - partial analgesia and amnesia (excited speech without awareness); 3) - complete analgesia and amnesia.2 - stage of motor excitation: from with a complete loss of consciousness, the patient becomes highly agitated; the face is bright red, the veins of the neck are tense, the eyelids are tightly compressed, the pupils are wide. The stage is characteristic only for ether anesthesia.3 - surgical sleep stage: determined by the transition of breathing to automatic, uniform; the patient calms down. There are four levels:

1) - level of movement of the eyeballs: the eyelids are closed, but not compressed; the eyeballs “float”, the pupil is narrow; fixation of the eyeballs indicates a transition to the second level; 2) - the level of the corneal reflex: the eyelids are half-open, the eyeballs are fixed, the pupils are narrow, the corneal reflex is determined, its disappearance indicates a transition to the third level; 3) - the level of pupil dilation is the optimal level for surgical intervention; but he is already on the verge of an overdose, so you immediately need to reduce the amount of anesthetic; 4) - the level of diaphragmatic breathing develops only with an overdose of the drug: the eyes are wide open, the pupils are very wide; breathing is shallow, arrhythmic; hemodynamic depression with decreased blood pressure and tachycardia. 4 - stage of awakening - s a reverse development of the whole picture, but without excitement.

19. Modern combined intubation anesthesia (sequence of implementation, advantages)

Conducting combined intubation anesthesia is the competence of a trained anesthesiologist. Combined anesthesia belongs to the category of complex, but most advanced. It is absolutely controllable, is carried out using mechanical ventilation, special tubes with cuffs are used to prevent regurgitation, sanitation of the bronchial tree is possible during anesthesia, there is the possibility of combined use of anesthetics in any modifications that enhance each other, complete relaxation of the muscles (relaxation) is achieved. Combined intubation anesthesia carried out in stages, the phasing is carried out strictly, the choice of techniques is determined by the anesthesiologist. The main steps performed during combined anesthesia are as follows. 1. Carrying out introductory anesthesia (induction). They are produced with anesthetics for intravenous anesthesia, preference is given to calypsol and other short-acting anesthetics, more often hexenal Sombrevin is used with caution, due to a possible allergic reaction. If the analgesic effect of one drug is low, it is potentiated.

2. Muscle relaxation - relaxation of skeletal and respiratory muscles. Two types of muscle relaxants are used: central action; and peripheral action. They are divided into three groups: depolarizing - ditilin, with a duration of 5-7 minutes; non-depolarizing - tubocurarine, arduan, anatruxonium, diplacin, tracrium, with a relaxation period of 20-60 minutes; mixed type - dioxonium, cyclobutonium, with a relaxation period of up to 40-60 minutes. Peripheral-acting drugs in anesthesiology are used very widely, because controlled by the relaxation period, non-toxic - they break down in the body into gas, water and metabolites. The technique of muscle relaxation is simple: the diluted drug is administered slowly until convulsive contractions of the peripheral muscles (tremor) appear. The administration of the drug is stopped, the same dose is re-administered after the first dose has expired. Muscle relaxation can be carried out only in the presence of mechanical ventilation. Centrally acting muscle relaxants that do not affect neuromuscular conduction and direct excitability of skeletal muscles (dandrolene, etc.) are used in neurology and neurosurgery; they are not used in anesthesiology. 3. Tracheal intubation. It is performed using a laryngoscope, a tube with a disposable cuff. After inserting the endotracheal tube to the bifurcation of the trachea, the cuff is inflated with air from a syringe. This creates a high-quality delimitation of the airways, prevention of regurgitation during vomiting, optimal conditions for mechanical ventilation and sanitation of the bronchial tree during surgery. 4. Basic anesthesia. It can be carried out in various ways chosen by the anesthesiologist for a given situation, most often with an azeotropic mixture. Other combinations of anesthetics may be selected. Various modifications are discussed in the course of subordination and internship in anesthesiology and resuscitation.5. Elimination - withdrawal from anesthesia. As with the introduction of anesthesia, it is carried out in stages: with continued mechanical ventilation, the effect of the muscle relaxant ceases; anesthetics are turned off, but mechanical ventilation is continued in the hyperventilation mode (the MVR is increased due to the respiratory rate) to accelerate the leaching of anesthetics from the blood. Extubation is performed only after restoration of spontaneous breathing, reflexes and the appearance of elements of consciousness. Otherwise, accompanied by an anesthesiologist, the patient is transported to the intensive care unit with ongoing mechanical ventilation with a respirator, to be connected to prolonged mechanical ventilation.

20. Complications of anesthesia (vomiting, aspiration, asphyxia, cardiac arrest). Prevention, emergency care.

Complications of general anesthesia can occur at any stage of anesthesia. According to L.V. Usenko, at the stage of premedication 8% of complications are formed, at the stage of induction of anesthesia - up to 50%, with basic anesthesia - up to 20%, upon awakening - up to 17%, after the end of anesthesia - up to 5% of complications.

During the period of premedication, allergic reactions to drugs mainly develop; psychomotor agitation may occur due to fear, hypotension with an overdose of droperidol, especially with low initial blood pressure values, complications of the underlying disease are less common. At the stage of induction of anesthesia, allergic reactions may develop, up to anaphylactic shock, hypoxic and hypercapnic conditions, acute cardiac and respiratory failure, vomiting, regurgitation, convulsive syndrome.

At the stage of basic anesthesia, complications in the form of respiratory hypoxia caused by retraction of the tongue during early extubation, allergic reactions, hemodynamic disorders in the form of arrhythmias, blood pressure disorders, pulmonary edema, cardiac arrest, embolism and vascular thrombosis are most likely. Recurrence is rare, due to the release of curare-like drugs from the depot, with repeated cessation of breathing. In the post-anesthesia period, the following may develop: asphyxia due to retraction of the tongue, vomiting with regurgitation, cardiovascular disorders and hemodynamic disorders.

Prevention of these complications is carried out by including vasolytic drugs in premedication, successfully conducting induction of anesthesia before the surgical stage, while avoiding any irritants.
Treatment of these conditions consists of eliminating the cause (check the condition of the oral cavity), oxygenation by insufflation of oxygen, and, if necessary, deepening anesthesia and even curarization and intubation (leptocurare). In case of circulatory arrest, immediately stop the supply of general anesthetics, perform tracheal intubation, mechanical ventilation in the mode of moderate hyperventilation with 80% oxygen, closed cardiac massage, intravenous jet adrenaline, atropine, prednisolone, sodium bicarbonate, infusion therapy with crystalloids, and, if indicated, electric pulse therapy

21. Epidural anesthesia. Indications, contraindications, technique, complications. Epidural anesthesia- a type of conduction anesthesia. The analgesic effect is achieved by blocking the spinal cord roots with an anesthetic drug injected into the epidural space between the dura mater and the periosteum of the vertebrae (Fig. 20). This type of anesthesia has all positive qualities spinal anesthesia and is free from its disadvantages. Puncture technique The epidural space is similar to that of the subdural space during spinal anesthesia. The puncture can be performed at any level of the spinal column, depending on the nature of the operation. You should remember about the possibility of puncturing the dura mater and getting the anesthetic into the subarachnoid space, which is fraught with serious complications. The puncture is performed with a needle placed on a syringe with an isotonic sodium chloride solution. The advancement of the needle is accompanied by resistance when pressure is applied to the piston. As soon as the needle penetrates through the ligaments into the epidural space, resistance when pressing the piston disappears, and the solution is easily injected; the needle is felt to fall. Another sign of a correctly performed puncture is the absence of cerebrospinal fluid leakage from the needle pavilion; when a water pressure gauge is connected to the needle, the pressure detected should be negative. The anesthetic agent can be administered through a needle or catheter passed through the lumen of the needle and left in place. long time. To prolong anesthesia, drugs can be delivered through the catheter in fractions. For epidural anesthesia, a 2% lidocaine solution, a 0.5% bupivacaine solution, and a 0.75% ropivacaine solution are used. To enhance the analgesic effect during traumatic operations, narcotic analgesics (morphine and fentanyl) are injected into the epidural space. In the postoperative period, long-term epidural blockade is used as effective method pain relief, allowing to reduce the dose of narcotic analgesics. Epidural anesthesia is used for traumatological and orthopedic operations on the lower extremities, operations on the abdominal organs, pelvis. This type of pain relief is indicated for elderly and senile people, patients with severe diseases of the cardiovascular and respiratory systems, and metabolic disorders (obesity, diabetes). Complications rarely occur. Possible arterial hypotension and respiratory problems, nausea, vomiting, and seizures. In 5% of cases, anesthesia does not occur, which is due to the presence of jumpers in the epidural space, limiting the spread of the anesthetic solution.

22. Intravenous anesthesia (indications, technique, course). The advantages of intravenous general anesthesia are quick induction of anesthesia, lack of excitement, and a pleasant fall asleep for the patient. However, narcotic drugs for intravenous administration create short-term anesthesia, which makes it impossible to use them in their pure form for long-term surgical interventions. Barbituric acid derivatives- sodium thiopental and hexobarbital cause rapid onset of narcotic sleep. There is no arousal stage, awakening is quick. The clinical picture of anesthesia when using sodium thiopental and hexobarbital is identical. Hexobarbital causes less respiratory depression. Use freshly prepared solutions of barbiturates. To do this, the contents of the bottle (1 g of the drug) before starting anesthesia are dissolved in 100 ml isotonic solution sodium chloride (1% solution). The vein is punctured and the solution is slowly injected at a rate of 1 ml in 10-15 s. After injecting 3-5 ml of solution within 30 seconds, the patient’s sensitivity to barbiturates is determined, then the administration of the drug is continued until the surgical stage of anesthesia. The duration of anesthesia is 10-15 minutes from the onset of narcotic sleep after a single administration of the drug. To increase the duration of anesthesia, fractional administration of 100-200 mg of the drug is used. Its total dose should not exceed 1000 mg. At this time, the nurse monitors pulse, blood pressure and respiration. To determine the level of anesthesia, the anesthesiologist monitors the condition of the pupils, the movement of the eyeballs, and the presence of the corneal reflex. Barbiturates, especially sodium thiopental, are characterized by respiratory depression, and therefore, when using it for anesthesia, a breathing apparatus is required. When apnea occurs, you need to start mechanical ventilation using a breathing apparatus mask. Rapid administration of sodium thiopental can lead to a decrease in blood pressure and depression of cardiac activity. In this case, it is necessary to stop administering the drug. Sodium thiopental is contraindicated in acute liver failure. In surgical practice, barbiturate anesthesia is used for short-term operations lasting 10-20 minutes (opening abscesses, cellulitis, reducing dislocations, repositioning bone fragments). Barbiturates are also used for induction of anesthesia. Sodium hydroxydione succinate used at a dose of 15 mg/kg, the total dose on average is 1000 mg. Sodium hydroxybutyrate administered intravenously very slowly. The average dose is 100-150 mg/kg. Propofol- short-acting intravenous anesthetic agent.

23. Local anesthesia. (types, indications, contraindications)Local anesthesia - reversible elimination of pain sensitivity in a certain part of the body caused by the action of special medications. Indications for local anesthesia are determined by its advantages: no special long-term preoperative preparation is required; it can be used in cases where there are contraindications to anesthesia; the patient does not need constant postoperative monitoring, as after anesthesia. Operations are performed on an outpatient basis under local anesthesia. Local anesthesia is indicated in cases where performing an operation under intubation anesthesia is associated with a great risk to the patient's life. This group of patients includes elderly and senile people, exhausted, suffering from respiratory and cardiovascular failure. In these cases, anesthesia can be more dangerous than the operation itself. Contraindications for local anesthesia: 1) patient intolerance to anesthetics due to increased individual sensitivity; 2) age younger than 10 years; 3) the presence of mental disorders in patients, increased nervous excitability; 4) the presence of inflammatory or scar changes in tissues that prevent the performance of infiltration anesthesia; 5 ) ongoing internal bleeding, which requires urgent surgery to stop.

24. Characteristics of anesthetic substances (novocaine, tremecaine, lidocaine, dicaine). Application area.Agents used primarily for infiltrative and conduction anesthesiaNovocaine– is one of the least toxic local anesthetics, its effect lasts from 30 minutes to an hour. Novocaine penetrates poorly through mucous membranes, and therefore its use for surface anesthesia is limited (only in ENT practice is its 10% alcohol solution used). Novocaine does not affect blood vessels, so to narrow them, some adrenergic agonist (for example, adrenaline) is added to novocaine. At the same time, adrenaline prolongs the effect of novocaine and reduces its toxicity. The resorptive effect of novocaine is expressed in the inhibition of visceral and somatic reflexes, the development of hypotension and antiarrhythmic action. For infiltration anesthesia, novocaine is used in low concentrations (0.25-0.5%) and in large volumes (hundreds of ml). For conduction anesthesia, the volume of the anesthetic solution is significantly smaller, but its concentration increases (1.2% in a volume of 5, 10, 20 ml). Novocaine is mostly used for intramuscular injections, often in cases where the injected drug is painful. Here, the drug and novocaine are diluted in a syringe in controlled proportions and administered to the patient. Trimekain exceeds novocaine in duration of action by 3-4 times. Trimecaine has slightly less toxicity than novocaine and does not irritate tissues. The general effect on the body is a depressant effect on the cerebral cortex, as well as a sedative, hypnotic and anticonvulsant effect. When administered intravenously, trimecaine has an antiarrhythmic effect. Application area Conduction anesthesia – 1% and 2% solutions. Infiltration anesthesia – 0.25% and 0.5% solutions Agents used for all types of anesthesia Lidocaine has an analgesic potency 2.5 times greater than that of novocaine. Lidocaine in combination with adrenaline acts for 2-4 hours. Its toxicity is almost the same as that of novocaine. The local anesthetic does not irritate surrounding tissue. When administered intravenously, lidocaine has an antiarrhythmic effect. Application area Application (superficial anesthesia) – 10% spray. Infiltration anesthesia – 0.125%, 0.25%, 0.5% solutions. Conduction anesthesia – 1%, 2% solutions. Dicaine- a strong local anesthetic. It is significantly more active than Novocain and cocaine, but has high toxicity, 2 times greater than the toxicity of cocaine and 10 times greater than Novocaine, which requires caution when using the drug. Well absorbed through mucous membranes. Application area Anesthesia of the oral mucosa - 0.25-1% solutions. Superficial anesthesia – 1% and 2% solutions

Classification of bleeding.

Bleeding (haemorrhagia) is the leakage of blood from a blood vessel into the external environment or cavities and tissues of the body. By the appearance of a bleeding vessel. 1. Arterial.2. Venous.3. Arteriovenous.4. Capillary.5. Parenchymatous. According to the clinical picture. 1. External (blood from the vessel enters the external environment). 2. Internal (blood flowing from the vessel is located in the tissues (with hemorrhages, hematomas), hollow organs or body cavities).3. Hidden (without a clear clinical picture). For internal bleeding there is an additional classification.1. Bleeding into tissue: 1) hemorrhages in the tissue (blood flows into the tissue in such a way that they cannot be separated morphologically. The so-called impregnation occurs); 2) subcutaneous (bruising); 3) submucosal; 4) subarachnoid; 5) subserous.2. Hematomas (massive bleeding into the tissue). They can be removed using a puncture. According to the morphological picture. 1. Interstitial (blood spreads through the interstitial spaces). 2. Interstitial (bleeding occurs with tissue destruction and cavity formation). According to clinical manifestations. 1. Pulsating hematomas (in the case of communication between the hematoma cavity and the arterial trunk).2. Non-pulsating hematomas. Intracavitary bleeding is also distinguished.1. Outflow of blood into natural body cavities: 1) abdominal (hemoperitoneum); 2) cavity of the heart sac (hemopericardium); 3) pleural cavity (hemothorax); 4) joint cavity (hemarthrosis). 2. Blood leakage into hollow organs: gastrointestinal tract (GIT), urinary tract, etc.According to the rate of bleeding. 1. Acute (from large vessels, a large amount of blood is lost within minutes). 2. Acute (within an hour).3. Subacute (within 24 hours).4. Chronic (over weeks, months, years). By time of occurrence. 1. Primary.2. Secondary. Pathological classification. 1. Bleeding resulting from mechanical destruction of the walls of blood vessels, as well as from thermal injuries.2. Arrosive bleeding resulting from the destruction of the vessel wall by a pathological process (tumor disintegration, bedsores, purulent melting, etc.).3. Diapedetic bleeding (when the permeability of blood vessels is impaired).

26. Internal and external bleeding. Clinic, diagnosis, first aid. External bleeding: The main sign of a wound is external bleeding. The color of the blood can be different: scarlet for arterial bleeding, dark cherry for venous bleeding. Bleeding not only from the aorta, but also from the femoral or axillary artery can lead to death within a few minutes after injury. Damage to large veins can also quickly cause death. If large veins of the neck and chest are damaged, a dangerous complication such as an air embolism may occur. This complication develops as a result of air entering through a wound in a vein (into the right side of the heart, and then into the pulmonary artery) and blockage of its large or small branches. Internal bleeding: In the event of traumatic injury or the development of a pathological process in the area of ​​the vessel, internal bleeding occurs. Recognizing such bleeding is more difficult than external bleeding. The clinical picture consists of general symptoms caused by blood loss and local signs depending on the location of the source of bleeding. In case of acutely developed anemia (for example, a disturbed ectopic pregnancy or rupture of the splenic capsule in the presence of a subcapsular hematoma), pallor of the skin and visible mucous membranes, darkening in the eyes, dizziness, thirst, drowsiness are observed, and fainting may occur. The pulse is frequent - 120-140 per minute, blood pressure is low. With slow bleeding, signs of blood loss develop gradually.

27. Acute blood loss. Degrees of blood loss, diagnosis, dangers and complications. Acute blood loss - This is a sudden release of blood from the vascular bed. The main clinical symptoms of the resulting decrease in blood volume (hypovolemia) are pallor of the skin and visible mucous membranes, tachycardia and arterial hypotension. Cause of acute blood loss There may be trauma, spontaneous bleeding, or surgery. Great importance have the rate and volume of blood loss. When slow loss even large volumes of blood (1000-1500 ml) compensatory mechanisms have time to turn on, hemodynamic disturbances arise gradually and are not very serious. Against, heavy bleeding with the loss of less blood volume leads to severe hemodynamic disturbances and, as a consequence, to hemorrhagic shock. The following stages of hemorrhagic shock are distinguished: Stage 1 (compensated shock), when blood loss is 15-25% of the bcc, the patient’s consciousness is preserved, the skin is pale, cold, blood pressure is moderately reduced, the pulse is weak, moderate tachycardia is up to 90-110 beats/min. Stage 2 (decompensated shock) is characterized by an increase in cardiovascular disorders, and the body’s compensatory mechanisms fail. Blood loss is 25-40% of the bcc, impaired consciousness to the point of soporosis, acrocyanosis, cold extremities, blood pressure is sharply reduced, tachycardia 120-140 beats/min, pulse is weak, thread-like, shortness of breath, oliguria up to 20 ml/hour. Stage 3 (irreversible shock) is a relative concept and largely depends on the resuscitation methods used. The patient's condition is extremely serious. Consciousness is sharply depressed to the point of complete loss, the skin is pale, the skin is “marbled”, systolic pressure is below 60 mmHg, the pulse is determined only in the main vessels, sharp tachycardia up to 140-160 beats/min. How express diagnostics To assess the severity of shock, the concept of shock index is used - SI - the ratio of heart rate to systolic pressure. For 1st degree shock, CI = 1 (100/100), 2nd degree shock - 1.5 (120/80), 3rd degree shock - 2 (140/70). Hemorrhagic shock is characterized by general serious condition body, insufficient blood circulation, hypoxia, metabolic disorders and organ functions. The pathogenesis of shock is based on hypotension, hypoperfusion (decreased gas exchange) and hypoxia of organs and tissues. The leading damaging factor is circulatory hypoxia. A relatively rapid loss of 60% of the bcc is considered fatal for a person, blood loss of 50% of the bcc leads to a breakdown of the compensation mechanism, blood loss of 25% of the bcc is almost completely compensated by the body. The ratio of the amount of blood loss and its clinical manifestations: Blood loss of 10-15% BCC (450-500 ml), no hypovolemia, blood pressure not reduced; Blood loss 15-25% of the bcc (700-1300 ml), mild hypovolemia, blood pressure reduced by 10%, moderate tachycardia, pale skin, cold extremities; Blood loss 25-35% of the bcc (1300-1800 ml), moderate severity of hypovolemia , blood pressure is reduced to 100-90, tachycardia to 120 beats/min, pale skin, cold sweat, oliguria; Blood loss up to 50% of the volume of blood volume (2000-2500 ml), severe hypovolemia, blood pressure reduced to 60 mm. Hg, thready pulse, absent or confused consciousness, severe pallor, cold sweat, anuria; Blood loss of 60% of the blood volume is fatal. The danger of blood loss is associated with the development of hemorrhagic shock.

28. Treatment of acute blood loss. Timely start treatment can prevent the development of hemorrhagic shock, so it should be started as quickly as possible. In case of severe blood loss, they immediately begin to administer blood replacement fluids, the use of which is based on the fact that the loss of plasma and, consequently, a decrease in blood volume is tolerated by the body much more difficultly than the loss of red blood cells. Albumin, protein, dextran [cf. they say weight 50,000-70,000] are well retained in the bloodstream. If necessary, crystalloid solutions can be used, but remember that they quickly leave the vascular bed. Low molecular weight dextrans (dextran [average molecular weight 30,000-40,000]) replenish the volume of intravascular fluid, improve microcirculation and rheological properties of blood. Transfusion of blood products is necessary when the hemoglobin level decreases below 80 g/l and the hematocrit is less than 30. In case of severe acute blood loss, treatment begins with a jet infusion into one, two or three veins and only after the SBP rises above 80 mm Hg. switch to drip infusion. To eliminate anemia, infusions of red blood cells are used; it is more advisable to administer it after the infusion of blood substitutes, as this improves capillary blood flow and reduces the deposition of blood cells.

29. Hemorrhagic shock. Causes, clinic, treatment. Hemorrhagic shock - an emergency condition of the body that develops during acute blood loss. In the first place among the causes of acute bleeding are injuries. There are open and closed vascular injuries. In second place are profuse (strong and voluminous) bleeding as a result of various diseases: disseminated coagulation syndrome at the last stage, disintegration of a cancerous tumor, uterine bleeding, perforation of a stomach ulcer, etc. Manifestations of hemorrhagic shock directly depend on degree of blood loss. That is, the amount by which the circulating blood volume (CBV) decreases in a fairly short time. It should be recalled that blood loss of up to 0.5 liters (on average 25-30%) over several weeks will not lead to shock. The clinical picture of anemia will gradually develop. So, when the total volume of blood volume decreases to 10%, hemorrhagic shock does not develop. The patient may only be concerned about weakness and decreased tolerance to physical activity. In other words, it becomes more difficult for a person to bear loads that were previously easy for him. The fact is that such a volume of blood loss can be replenished with reserves from deposited (in other words, not participating in the general circulation) blood. Hemorrhagic shock begins to develop when the volume of lost blood is 500 ml or more. This amounts to 10-15% of the bcc. A loss of more than 3.5 liters of blood, which is equal to 70% of the blood volume, is considered fatal. Therefore, in the clinic, for calculating the volume of medical care, it is customary to distinguish three degrees of severity. With the first degree of severity (it is observed with a loss of 10 to 25% of blood volume), a moderate decrease in blood pressure and increased respiration are observed. The skin becomes pale. The patient complains of dry mouth and a feeling of thirst. Weakness forces such patients to move as little as possible. Otherwise, there is dizziness and even a short-term loss of consciousness - syncope. Moderate severity is observed with blood loss from 25 to 45% of the bcc, or from one to two liters of blood. More pronounced weakness is noted here. Consciousness becomes confused. Breathing is frequent and noisy. The heart rate reaches 150 and arrhythmias may occur. “Cracks” begin to appear on a dry tongue. This is how its natural folds manifest. A severe degree of hemorrhagic shock develops with a loss of 40-65% of the blood volume (2.5-3 liters). Consciousness is always depressed, even to the point of coma. Paleness of the skin is pronounced. Breathing is shallow and not rhythmic. With the loss of 3 liters of blood, it becomes pathological - alternating respiratory movements and pauses in breathing. Heart sounds are barely audible and are always arrhythmic. The pulse is weak, even in the carotid arteries. A loss of 70% (3.5-4 liters) is fatal. Coma and death occur almost instantly. Although, sometimes, there is a short period of agony, which can be regarded by non-specialists as a short-term improvement. The principles of resuscitation and intensive care in patients with acute blood loss and in a state of hemorrhagic shock at the prehospital stage are as follows: 1. Reduction or elimination of existing phenomena of acute respiratory failure -ness (ODN), the cause of which may be aspiration of knocked out teeth, blood, vomit, or cerebrospinal fluid due to a fracture of the base of the skull. This complication is especially often observed in patients with confused or absent consciousness and, as a rule, is combined with retraction of the root of the tongue.
Treatment comes down to mechanical release of the mouth and oropharynx, aspiration of contents using suction. Transportation can be carried out with an inserted airway or endotracheal tube and mechanical ventilation through them. 2. Carrying out pain relief with medications that do not depress breathing and blood circulation. Among the central narcotic analgesics, devoid of the side effects of opiates, you can use Lexir, Fortral, Tramal. Non-narcotic analgesics (analgin, baralgin) can be combined with antihistamines. There are options for nitrous-oxygen analgesia, intravenous administration of subnarcotic doses of ketamine (calypsol, ketalar), but these are purely anesthetic aids that require an anesthesiologist and the necessary equipment. 3. Reduction or elimination of hemodynamic disorders, primarily hypovolemia. In the first minutes after severe injury, the main cause of hypovolemia and hemodynamic disorders is blood loss. Prevention of cardiac arrest and all other serious disorders is the immediate and maximum possible elimination of hypovolemia. The main therapeutic measure should be massive and rapid infusion therapy. Of course, stopping external bleeding should precede infusion therapy.
Resuscitation in the event of clinical death due to acute blood loss is carried out according to generally accepted rules. The main task in case of acute blood loss and hemorrhagic shock at the hospital stage is to carry out a set of measures in a certain relationship and sequence. Transfusion therapy is only part of this complex and is aimed at replenishing blood volume. In carrying out intensive care for acute blood loss, it is necessary to reliably provide continuous transfusion therapy with a rational combination of available funds. It is equally important to observe a certain stage in treatment, speed and adequacy of assistance in the most difficult situations.

Currently, there is no theory of anesthesia that clearly defines the mechanism of the narcotic action of anesthetic substances. Among the existing theories, the following are of greatest importance.

Lipid theory proposed by G. Meyer (1899) and C. Overton (1901), who associated the effect of narcotic drugs with their ability to dissolve in fat-like substances of the membranes of nerve cells and thereby disrupt their activity, which leads to a narcotic effect. The narcotic power of anesthetics is directly dependent on their ability to dissolve fats.

According to adsorption theory Traube (1904) and O. Warburg (1914), the narcotic substance accumulates on the surface of cell membranes in the central nervous system, thereby changing physicochemical characteristics cells and disrupts their functions, which causes a state of anesthesia.

In accordance with theory of inhibition of oxidative processes Verworn (1912), the narcotic drug blocks enzymes that regulate redox processes in brain tissue cells.

According to coagulation theory Bernard (1875), Bancroft and Richter (1931), narcotic drugs cause reversible coagulation of the protoplasm of nerve cells, which lose the ability to excite, which leads to the occurrence of narcotic sleep.

The essence physiological theory anesthesia B.C. Galkin (1953), based on the teachings of I.M. Sechenova, I.P. Pavlova, N.E. Vvedensky, comes down to explaining narcotic sleep from the standpoint of inhibition of the central nervous system that occurs under the influence of narcotic substances. The reticular formation of the brain is most sensitive to the action of an anesthetic (Anokhin P.A.).

Thus, the physiological mechanisms of narcotic sleep correspond to modern principles of neurophysiology, and the direct mechanism of action of a narcotic drug on a nerve cell is based on one of the chemical or physical processes: the effect on cell colloids, cell membranes, lipid dissolution, etc.

Stages of anesthesia

Narcotics cause characteristic changes in all organs and systems. During the period of saturation of the body with a narcotic drug, a certain pattern (stages) is noted in changes in consciousness, breathing, and blood circulation. In this regard, stages are distinguished that characterize the depth of anesthesia. The stages appear especially clearly during ether anesthesia.

There are four stages: I - analgesia, II - excitement, III - surgical stage, divided into 4 levels, IV - awakening.

Analgesia stage (I)

The patient is conscious, but lethargic, dozing, and answers questions in monosyllables. There is no superficial pain sensitivity, but tactile and thermal sensitivity is preserved. During this period, it is possible to perform short-term interventions (opening phlegmons, ulcers, diagnostic studies). The stage is short-term, lasting 3-4 minutes.

Excitation stage (II)

At this stage, inhibition of the centers of the cerebral cortex occurs, but the subcortical centers are in a state of excitement: there is no consciousness, motor and speech excitation is expressed. The patients scream and try to get up from the operating table. The skin is hyperemic, the pulse is frequent, and blood pressure is elevated. The pupils are wide, but react to light, and lacrimation is noted. Often there is a cough, increased bronchial secretion, and vomiting is possible. Surgical manipulations cannot be performed against a background of agitation. During this period, it is necessary to continue saturating the body with a narcotic drug to deepen anesthesia. The duration of the stage depends on the patient’s condition and the experience of the anesthesiologist. Excitation usually lasts 7-15 minutes.

The mechanism of anesthesia has interested researchers since the discovery of ether anesthesia, but the first theories based on the study of changes in brain cells appeared at the beginning of the 20th century.

The most common ones explain anesthesia in terms of physical and chemical properties narcotic substance. With the development of the physiology of the central nervous system and higher nervous activity, the emphasis in the search for an acceptable hypothesis was placed on changes in the physiological state of different parts of the brain. As it turned out, the mechanisms of cellular anesthesia and anesthesia in a highly organized organism are fundamentally different.

Another G1.M. Sechenov believed that in a state of anesthesia, a targeted inhibition of the brain occurs, which spreads to lower parts and the spinal cord. NOT. Vvedensky (1903) showed that inhibition develops under conditions of prolonged exposure to extremely strong stimuli, and excessive stimuli are those that exceed the limit of functional mobility (lability) of the cell. The narcotic substance sharply reduces the lability of neurons, and narcotic inhibition develops in them.

B.C. Galkin (1953) developed a theory according to which the effect of a drug on the central nervous system is expressed in successive inhibition of the cortex, and then subcortical formations. In his opinion, at the first stage there is active inhibition in the cerebral cortex, at the second - inhibition of the cortex with the release of the subcortex with its possible positive induction, which is manifested by the stage of excitation, at the third - inhibition of both the cortex and subcortex - the phase of narcotic sleep.

CHAPTER XI. ANESTHESIA

PC. Anokhin connected the mechanism of anesthesia with the reticular formation of the brain stem. The hypothesis he proposed is based on the unequal sensitivity of different parts of the brain to a narcotic substance, where the reticular formation is the most sensitive. The reticular formation is connected with many centers of the cerebral cortex and supracortical structures. Under the influence of the drug, its activating effect on the cortex and subcortical structures decreases; a narcotic sleep ensues.

2.2. STAGE OF SINGLE-COMPONENT NARCOSIS

In the clinical course of one-component anesthesia (using ether as an example), four stages are distinguished.

/ stage(analgesia) occurs gradually after 3-5 minutes from the onset of anesthesia. Consciousness fades until it turns off. At this stage, the highest nervous activity is subjected to the greatest test, a subjective attitude of patients towards anesthesia is created.

All parameters look the same as before the start of anesthesia: the color of the skin is normal, hemodynamic and respiratory parameters are at the initial level. Reflexes are usually increased. The patient reacts to any irritation more sharply than usual. All complications during this period are of a reflex nature: bronchospasm, laryngospasm, reflex arrest of breathing and heart. As the patient is euthanized, the feeling of pain is progressively suppressed and complete analgesia occurs. This is the stage of rausch anesthesia (stunning), which is used as an independent anesthetic aid for short-term interventions (reduction of dislocations, opening of an abscess, tooth extraction).

// stage(excitement) occurs from the moment of loss of consciousness, for ether usually after 6-8 minutes. This stage is characterized by pronounced motor excitement, rapid breathing, tachycardia, increased blood pressure, and hyperemia of the skin. The pupils are dilated and do not respond to light. There could be vomiting. Any irritation (operation) during the log period is undesirable, as it causes uncontrollable actions on the part of the patient.

Stage III(surgical) allows you to perform surgical interventions and is the task of general anesthesia. The classic division of the surgical stage of anesthesia into four levels (Gwedel, 1937). All sublevels of stage III anesthesia in their pure form are unique and differ from one another in the state of breathing, cardiovascular activity, degree of relaxation of skeletal muscles and reflexes.

CHAPTER XI. ANESTHESIA

Since the time of H.II. Pirogov, the levels of the surgical stage of anesthesia are most conveniently determined by eye reflexes. These include involuntary mobility of the eyeballs, the corneal reflex, and the reaction of the pupil to light. EGP reflexes are associated with the oculomotor center of the medulla oblongata, located near the centers of respiration and blood circulation, therefore, with their help, one can indirectly judge the degree of depression of breathing and cardiac activity.

The 1st level of anesthesia is called the level of movement of the eyeballs (by the end of this level, the involuntary movement of the eyeballs stops and they occupy a central position); 2nd - level of the corneal reflex (the end of this level is marked by the disappearance of the corneal reflex); 3rd - level of pupil dilation; and, finally, the 4th - paralysis of ocular reflexes, in which there is also complete inhibition of diaphragmatic breathing. As anesthesia deepens, paralysis of the respiratory and vasomotor centers and death occur.

IV stage- awakening. Recovery from ether anesthesia occurs in reverse order introduction to anesthesia. However, the awakening process is longer.

2.3. PREPARING THE PATIENT FOR ANESTHESIA

Particular attention should be paid to preparing patients for anesthesia. It begins with personal contact between the anesgesiologist and the patient. First, the anesthesiologist needs to familiarize himself with the medical history and clarify the indications for the operation, and he must find out all the questions that interest him personally.

During planned operations, the anesthesiologist begins examining and getting to know the patient several days before the operation. In cases of emergency interventions, the examination is carried out immediately before the operation.

The anesthesiologist is obliged to know the patient’s occupation, whether his food activity is associated with harmful production (nuclear energy, chemical industry, etc.). The patient’s life history is of great importance: past diseases (sugar diabetes, coronary artery disease and myocardial infarction, hypertension) , regularly taken medications (glucocorticoid hormones, insulin, antihypertensive drugs).You should especially find out the tolerability of medications (allergic history).

The doctor performing anesthesia must be well aware of the state of the cardiovascular system, lungs, and liver. Among the mandatory

CHAPTER XI. ANESTHESIA

The main methods of examining the patient before surgery include: blood and urine samples, biochemical blood test, blood coagulation (coagulation). IN mandatory blood type and Rh affiliation must be determined. Electrocardiography is also performed. The use of inhalation anesthesia forces us to pay special attention to the study of the functional state of the respiratory system; spirography is performed, I determine! Stange and Soobraze tests: the time for which the patient can hold his breath while inhaling and exhaling. In the preoperative period during planned operations, it is necessary, if possible, to correct existing disturbances in homeostasis. In emergency cases, preparation is carried out to a limited extent

After assessing the patient's condition, the anesthesiologist determines the degree of surgical risk and selects the method of pain relief. The level of surgical risk reflects the prognosis of the course of the anesthesia and immediate post-anesthesia periods. The best known risk assessment is that proposed by N.N. Malinovsky (1973). It is based on a scoring principle for assessing the volume of the proposed intervention, surgical pathology, concomitant diseases and age. In accordance with the number of points, there are small degrees of risk (I-I1), moderate risk (III) and high risk (IV-V degrees).

A person who is about to have an operation is naturally worried, so a sympathetic attitude towards him and an explanation of the need for the operation are necessary. Such a conversation can be more effective than the effect of sedatives. However, not all anesthesiologists can communicate equally convincingly with patients. The state of anxiety in a patient before surgery is accompanied by the release of adrenaline from the adrenal medulla, an increase in metabolism, which makes it difficult to administer anesthesia and increases the risk of developing cardiac arrhythmias. Therefore, all patients are prescribed premedication before surgery. It is carried out taking into account the psycho-emotional state of the patient, his reaction to the disease and the upcoming operation, the characteristics of the operation itself and its duration, as well as age, constitution and life history.

Premedication for planned surgery begins several days before surgery with oral administration of tranquilizers or barbiturates. In case of emergency surgery, it is advisable to administer premedication directly on the operating table under the supervision of an anesthesiologist. On the day of surgery, the patient is not fed. Before surgery, you should empty your stomach, intestines, and bladder. In emergency cases, this is done using a gastric tube or urinary catheter. If the patient has dentures, they must be removed

GPAVAH1. ANESTHESIA

Before anesthesia, an asacid substance can be administered once to prevent aspiration of gastric contents. To reduce the volume of gastric secretion and acidity, instead of antacids, you can use a blocker of H2-histamine receptors of the stomach (tsgshetidia,

ranshgshbia) or hydrogen pump (omsprazole, amez etc.).

Immediately before the operation, direct premedication is prescribed. It pursues the following goals:

Sedation and amnesia - effective premedication suppresses the increase in cortisone in the blood during stress. Most versatile morphine and its derivatives, bepzodpazepnny (diazepill. tazepam etc.), neuroleptics (droperidote).

Analgesia - it is especially important in the case of pain present before surgery. Narcotic analgesics are used.

Inhibition of the parasympathetic nervous system - prevention of vagal cardiac arrest. It is achieved by using atropine. In patients suffering from glaucoma, atropine is replaced metaci-iom.

Premedication should include antihistamines (diphenhydramine, tiulfen, passionate) taking into account the fact that any operation and violation of tissue integrity cause the release of histampone, and this can lead to undesirable reactions (bronchospasm, tachycardia, decreased blood pressure). The sedative effect of antihypertensive drugs is used to potentiate anesthesia.

The drugs are usually administered intramuscularly 30-60 minutes before the administration of anesthesin.

All patients who have undergone premedication are taken to the operating room on a gurney, accompanied by medical staff.

2.4. INHALATION N\RCOS

Inhalation anesthesia basicpn on the introduction of general anesthetics in the form of vapor or 1aza through the respiratory tract, followed by diffusion from the alveoli into the blood. The saturation of the body with an inhalational anesthetic and the release of the latter depend on the drug, its concentration in the inhaled mixture, solubility in the blood and tissues, as well as on the state of breathing and circulation of the patient.

There are mask and non-masked methods of inhalation anesthesia. The mask method can be applied either using a simple Esmarch mask or using special anesthesia equipment. He came

CHAPTER XI. ANESTHESIA

changes during short operations and manipulations that do not require controlled breathing and muscle relaxation

Nitrous oxide and cyclopropane are used as gaseous anesgetics; the most commonly used liquid volatile anesthetics are ether, fluorogan, and trichlorethylene (trilene).

Ether It is a clear, colorless liquid with a specific pungent odor. It decomposes under the influence of light and air, so it is stored in dark bottles with a ground-in lid. Ether vapors mixed with oxygen are explosive. The positive properties of ether include its large therapeutic sprat - the difference between the dose that causes the chronic stage of anesthesia and the toxic dose, as well as the ability to use it in poorly adapted conditions. Negative properties: euthanasia takes a long time and is poorly tolerated by the patient; the stage of excitement is very pronounced; ether causes irritation of the upper respiratory tract, stimulates the sympathoadrenal system; The awakening stage is also very long.

Ftorotai - clear liquid with a sweetish odor. Not explosive. It is much stronger than ether, therefore it requires special equipment for its use. It has a small therapeutic breadth; an overdose of ftorotan is manifested by bradycardia and a decrease in blood pressure. Being more an anesthetic than an analgesic, it is often used as an element of mixed (with nitrous oxide and oxygen) and combined anesthesia.

Nitrous oxide- a colorless inert gas with a pleasant sweetish odor. It does not ignite, but in combination with ether and oxygen it supports combustion, and in a mixture with chloroethyl, ether, cyclopropane in certain concentrations it is explosive. The negative properties of nitrous oxide include low narcotic power, so it is more often used as a component of mixed or combined general anesthesia. To avoid hypoxia, the content of nitrous oxide in the inhaled mixture should not exceed 80° o. Nitrous oxide in commonly accepted concentrations does not have a toxic effect. There are no contraindications to anesthesia with nitrous oxide.

Trichlorethylene has a pronounced analgesic effect. Changes in the stages of anesthesia occur quickly. Does not irritate the mucous membrane of the respiratory tract. It has great anesthetic power and easy controllability of the level of anesthesia.

In its pure form it is not used for long-term operations, since in large doses it causes arrhythmia, respiratory depression and cardiac activity. Trichloroethylene is used only in open and semi-open

CHAPTER XI. PAIN RELIEF

this contours, since upon contact with soda lime it decomposes to form carbon monoxide and phosgene.

Cyclopropane - colorless gas with a characteristic odor. With cyclopropane anesthesia, anesthesia occurs quickly and without excitement, and there is no adverse effect on hemodynamics. Recovery from anesthesia lasts 5-7 minutes. The widespread use of cyclopropane in the clinic is limited by its explosiveness and high cost.

The combination of cyclopropane with nitrous oxide and oxygen is called the Shepna-Ashmaia mixture.

Equipment and methods of inhalation anesthesia. The main purpose of inhalation anesthesia devices is to deliver dy- the patient's hagel pathways of narcotic drugs in the gas or vapor phase as part of a gas mixture containing at least 20% oxygen and practically devoid of CO 2 - The load on the patient's respiratory system should be minimal. The current level of development of anesthesiology and international standards impose additional requirements on the equipment: the presence of a backup source of oxygen, an alarm for a decrease in oxygen pressure, blocking the supply of nitrous oxide when the oxygen pressure decreases, ensuring the disassembly of the breathing circuit for subsequent disinfection and sterilization, increasing the safety of the device for patients and operators personnel.

A modern anesthesia machine consists of four parts: 1 - high-pressure systems (cylinders with reducers); 2 - dosimeter systems For gaseous substances; 3 - evaporators for volatiles liquid anesthetics; 4 - breathing circuit.

The cylinders contain gases used in anesthesia: oxygen - at a pressure of 150 atm, nitrous oxide - 50 atm and cyclopropane - 6 atm. For safety reasons, the cylinders are painted in different colors: for oxygen - blue, for nitrous oxide - gray, for cyclopropane - red. In foreign countries, different colors of cylinders are accepted.

Reducers reduce the pressure of the gas supplied to the anesthesia machine. Up to 3-4 atm. They are equipped with pressure gauges indicating the pressure in the allope. The amount of oxygen in the cylinder can be determined by the readings of the pressure gauge on the reducer. To do this, it is enough to multiply the volume of the cylinder (usually 40 or 10 liters) by the pressure. The result corresponds to the number of liters of oxygen gas. Since the nitrous oxide in the cylinder is contained in liquid form, the readings of the pressure gauge on the cylinder do not depend on its content. * To determine the amount of nitrous oxide in the cylinder, it must be weighed

CHAPTER 1. ANESTHESIA

Dosimeters are included in the inhalation circuit of the anesthesia machine. The gaseous substance, through the systems)" of hoses and reducers, arrives in a dosimeter, which allows a given volume of narcotic gas to be supplied to the patient. Usually, float dosimeters are used, designed for a flow of uiu or 1 to 10 liters per minute) (for nitrous oxide and oxygen). Dosed according to -1 ECT1 of liquid narcotic substances is carried out using evaporators, in which these substances evaporate and are inhaled in the form of vapors by the patient. The simplest evaporators allow the drug to be supplied (usually h)>ir) only in an approximate concentration. The actual concentration depends on the air temperature, drop in the temperature of the evaporating drug, the amount of drug poured, the amount of gas flow and other parameters. Temperature-compensated evaporators, along with dosing taps, have thermal water tanks or automatic devices that monitor the influence of external conditions on the concentration of the anesthetic in the mixture. These evaporators are used for such powerful narcotic substances , like fgorotan.

The breathing circuit includes corrugated hoses, valves, a breathing bag (fur) and a mask or incubation tube. There are four methods (circuits) of inhalation anesthesia: open, semi-open, semi-closed and closed.

At open method the patient inhales the anesthetic along with the air and exhales it into the surrounding atmosphere. The simplest method of anesthesia according to the open guru is ether anesthesia using an Es-Marha mask. Closed circuit anesthesia is used in the absence of oxygen cylinders (Fig. 1)

At semi-open method the patient inhales the anesthetic from the machine, the isonarcotic mixture is isolated from the surrounding air, and the exhaled substance is completely released into the surrounding atmosphere “Fig. 2)

Semi-closed method provides that the patient inhales a narcotic mixture from a closed space, and the exhaled air with the narcotic drug is partially released into the atmosphere and partially reused when inhaling. This allows you to significantly reduce the amount of drug and oxygen used. Another advantage is the minimal loss of heat and moisture by the patient (Fig. 3).

Closed source involves both inhalation and exhalation in a closed system; this method requires the most careful control of the gas composition of the inhaled mixture. What makes it attractive is its cost-effectiveness (Figure 4).

When carrying out anesthesia using the gas reversal method (semi-closed or closed circuits), an adsorbent is included in the breathing circuit - an accelerator.

CHAPTER XI. PAIN RELIEF

------ -^

Rice. 1. Schematic diagram of an open system: / - mask; 2 - exhalation valve; 3 shtnt; 4 - inhalation valve; 5 - evaporator

trinity to absorb excess CO 2 . Soda lime is used as a chemical absorbent (Fig. 5).

Modern domestic anesthesiologists use devices for inhalation anesthesia of the third (“Polinarcon-2”, “Polinarcon-2P”) and fourth (“Polinar-

con-4" and "Polinarkon-5") poko-, v at

Lenin (Fig. 6). In addition to inhalation, *rt

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mask anesthesia, they make it possible to perform mechanical ventilation manually (with fur or a breathing bag) or automatically by connecting a domestic or foreign ventilator. There are also: a portable apparatus for administering anesthesia and performing mechanical ventilation with a breathing bag in any medical institutions, in military field conditions and in emergency rooms - p > 1C 2. Schematic diagram of the semi-open “Narkon-2”; intermittent system devices/dosimeter; 2- evaporator; 01 oh flow applied in 3 safety clips; dentistry and gynecology valve, - inhalation; 5- hose; b valve.sh gydokha, / ma-PAPP-2, NLPP-4; portagivska; L" breathing bag

CHAPTER XI. ANESTHESIA

ilj_a_No

now a self-powered device - AN-2; anesthesia inhalers for spontaneous breathing - “Tringal” and “Trilan”.

Breathing equipment. A modern breathing apparatus has:

Compressor for ventilation.

Injection vacuum suction.

Rotameter-gas doser. Respiratory capabilities

monitoring: pressure in the breathing circuit, oxygen content in the inhaled air and carbon dioxide in the exhaled air, real tidal volume and minute breathing volume. Additionally, you can perform pulse oximetry (determining the partial pressure of oxygen in the blood) and monitoring the concentration of anesthetic during inspiration.

Old RO type respirators had a fur pneumatic system. In second generation pneumatic systems, the gas flow is interrupted in accordance with the specified parameters (of the “Phase” type). Modern equipment has a third-generation pneumatic system, in which stepper electric motors are installed and the mixture is supplied under a given pressure.

The built-in microprocessor allows you to regulate the distribution of the gas mixture in the lungs, determining the compliance of the lungs (“complasgaps”) and the resistance of the sneeze tract (“resns-eps”). The lower class includes Р^pirptors from the companies "Drster", "Kgsgrem", "Benket", "Khprapa".

1*1 N**-b&

Rice. 6. Device for carrying out the park “I 1olpnGfKoi-4”

CHAPTER XI. ANESTHESIA

Incubation method of anesthesia. The method is based on the introduction of an anesthetic substance, depending on the design of the tubation tube, directly into the trachea (endotracheal) or bronchi (endobronchal).

The tubation method of anesthesia has a number of advantages over other methods of inhalation anesthesia. It ensures patency of the airways, preventing the tongue from retracting, prevents the entry and aspiration of gastric contents and blood into the trachea, and allows the contents to be suctioned from the trachea and bronchi; creates optimal conditions for mechanical ventilation, reduces the volume of anatomical “dead space” (airways where gas exchange does not occur between atmospheric air and blood); opens up the possibility of using muscle relaxants, reduces the amount of anesthetic used, and anesthesia can be carried out at a more superficial and safer level, makes anesthesia more manageable in terms of control over the vital functions of the body (respiration, blood circulation, homeostasis).

Indications for the intubation method of anesthesia are: 1) operations in which there is a high probability of airway obstruction - maxillofacial surgery; 2) operations requiring the use of muscle relaxants - abdominal surgery, traumatology; 3) operations on the open chest - cardiopulmonary surgery; 4) the expected high traumatic nature of the operation and its duration. Tracheal intubation allows for mechanical ventilation in the postoperative period (extended mechanical ventilation); 5) old age of patients, severe concomitant pathology, i.e. those situations where careful monitoring of vital functions is necessary.

There are no absolute contraindications to intubation anesthesia. Relative contraindications include significant difficulties during tracheal intubation associated with the anatomical characteristics of the patient: stiffness of the cervical spine, narrowing of the trachea and larynx

Endotracheal anesthesia, as a rule, is combined.

Tracheal intubation technique. Tracheal intubation is carried out under induction anesthesia or, much less frequently, under local anesthesia - after irrigating the pharynx, epiglottis and area vocal cords a local anesthetic such as lidocaine or dicaipe

To carry out intubation, you need: a laryngoscope with a set of blades - straight and curved (Fig. 7), tubing tubes (usually with an inflatable cuff) of different diameters, a rigid conductor for dividing

Modern surgery cannot be imagined without adequate pain relief. The painlessness of surgical operations is currently ensured by an entire branch of medical science called anesthesiology. This science deals not only with methods of pain relief, but also with methods of managing body functions in a critical condition, which is modern anesthesia. In the arsenal of a modern anesthesiologist who comes to the aid of a surgeon, there are a large number of techniques - from relatively simple ones (local anesthesia) to the most complex methods of controlling body functions (hypothermia, controlled hypotension, artificial circulation).

But it was not always so. For several centuries, stupefying tinctures were offered as a means of combating pain; patients were stunned or even strangled, and nerve trunks were tied with tourniquets. Another way was to reduce the duration of surgery (for example, N.I. Pirogov removed stones from the bladder in less than 2 minutes). But before the discovery of anesthesia, abdominal operations were not available to surgeons.

The era of modern surgery began in 1846, when chemist C. T. Jackson and dentist W. T. G. Morton discovered the anesthetic properties of ether vapor and performed the first tooth extraction under general anesthesia. Somewhat later, surgeon M. Warren performed the world's first operation (removal of a neck tumor) under inhalation anesthesia using ether. In Russia, the introduction of anesthesia techniques was facilitated by the work of F. I. Inozemtsev and N. I. Pirogov. The works of the latter (he performed about 10 thousand anesthesia during the Crimean War) played an extremely important role. Since that time, the technique of anesthesia has become many times more complex and improved, opening the surgeon up to unusually complex interventions. But the question still remains open about what anesthesia sleep is and what are the mechanisms of its occurrence.

A large number of theories have been put forward to explain the phenomenon of anesthesia, many of which have not stood the test of time and are of purely historical interest. These are, for example:

1) Bernard's coagulation theory(according to his ideas, the drugs used to induce anesthesia caused coagulation of the protoplasm of neurons and a change in their metabolism);

2) lipoid theory(according to her ideas, narcotics dissolve the lipid substances of the membranes of nerve cells and, penetrating inside, cause a change in their metabolism);

3) protein theory(drugs bind to enzyme proteins of nerve cells and cause disruption of oxidative processes in them);

4) adsorption theory(in the light of this theory, drug molecules are adsorbed on the surface of cells and cause a change in the properties of membranes and, consequently, the physiology of nervous tissue);

5) theory of noble gases;

6) neurophysiological theory(most fully answers all the questions of researchers, explains the development of anesthesia sleep under the influence of certain drugs by phasic changes in the activity of the reticular formation, which leads to inhibition of the central nervous system).

In parallel, research was conducted to improve methods of local anesthesia. The founder and main promoter of this method of pain relief was A.V. Vishnevsky, whose fundamental works on this issue still remain unsurpassed.

2. Anesthesia. Its components and types

Anesthesia- This is an artificially induced deep sleep with switching off consciousness, analgesia, suppression of reflexes and muscle relaxation. It becomes clear that modern anesthesia for surgical intervention, or anesthesia, is a complex multicomponent procedure, which includes:

1) narcotic sleep (caused by anesthetic drugs). Includes:

a) switching off consciousness - complete retrograde amnesia (events that happened to the patient during anesthesia are recorded in memory);

b) decreased sensitivity (paresthesia, hypoesthesia, anesthesia);

c) analgesia itself;

2) neurovegetative blockade. It is necessary to stabilize the reactions of the autonomic nervous system to surgery, since autonomic activity is not largely controlled by the central nervous system and is not regulated by narcotic drugs. Therefore, this component of anesthesia is carried out through the use of peripheral effectors of the autonomic nervous system - anticholinergics, adrenergic blockers, ganglion blockers;

3) muscle relaxation. Its use is applicable only for endotracheal anesthesia with controlled breathing, but is necessary for operations on the gastrointestinal tract and major traumatic interventions;

4) maintaining an adequate state of vital functions: gas exchange (achieved by precise calculation of the ratio of the gas mixture inhaled by the patient), blood circulation, normal systemic and organ blood flow. You can monitor the state of blood flow by blood pressure, as well as (indirectly) by the amount of urine excreted per hour (urine flow-hour). It should not be below 50 ml/h. Maintaining blood flow at an adequate level is achieved by diluting the blood - hemodilution - through constant intravenous infusion of saline solutions under the control of central venous pressure (normal value is 60 mm H2O);

5) maintaining metabolic processes at the proper level. It is necessary to take into account how much heat the patient loses during surgery and provide adequate warming or, conversely, cooling of the patient.

Indications for surgical intervention under anesthesia determined by the severity of the planned intervention and the patient’s condition. The more severe the patient’s condition and the more extensive the intervention, the more indications for anesthesia. Minor interventions in relatively satisfactory condition of the patient are carried out under local anesthesia.

Classification of anesthesia along the route of introduction of the narcotic substance into the body.

1. Inhalation (a narcotic substance in vapor form is supplied to the patient’s respiratory system and diffuses through the alveoli into the blood):

1) mask;

2) edotracheal.

2. Intravenous.

3. Combined (as a rule, induction anesthesia with an intravenous drug followed by inhalation anesthesia).

3. Stages of ether anesthesia

First stage

Analgesia (hypnotic phase, Rausch anesthesia). Clinically, this stage is manifested by a gradual depression of the patient’s consciousness, which, however, does not completely disappear during this phase. The patient's speech gradually becomes incoherent. The patient's skin turns red. Pulse and breathing increase slightly. The pupils are the same size as before the operation and react to light. The most important change at this stage concerns pain sensitivity, which practically disappears. Other types of sensitivity are preserved. At this stage, surgical interventions are usually not performed, but small superficial incisions and reduction of dislocations can be made.

Second stage

Excitement stage. At this stage, the patient loses consciousness, but there is an increase in motor and autonomic activity. The patient does not give an account of his actions. His behavior can be compared to the behavior of a person who is heavily intoxicated. The patient's face turns red, all muscles tense, and the veins of the neck swell. On the part of the respiratory system, there is a sharp increase in breathing, and there may be a short-term stop due to hyperventilation. The secretion of the salivary and bronchial glands increases. Blood pressure and pulse rate increase. Due to the strengthening of the gag reflex, vomiting may occur.

Patients often experience involuntary urination. The pupils dilate at this stage, their reaction to light is preserved. The duration of this stage during ether anesthesia can reach 12 minutes, with the most pronounced excitement in patients who have been abusing alcohol for a long time and drug addicts. These categories of patients require fixation. In children and women, this stage is practically not expressed. As anesthesia deepens, the patient gradually calms down, and the next stage of anesthesia begins.

Third stage

Stage of anesthesia sleep (surgical). It is at this stage that all surgical interventions are carried out. Depending on the depth of anesthesia, several levels of anesthesia sleep are distinguished. In all of them there is a complete absence of consciousness, but the systemic reactions of the body differ. Due to the special importance of this stage of anesthesia for surgery, it is advisable to know all its levels.

Signs first level, or the stage of intact reflexes.

1. Only superficial reflexes are absent, the laryngeal and corneal reflexes are preserved.

2. Breathing is calm.

4. The pupils are somewhat constricted, the reaction to light is lively.

5. Eyeballs move smoothly.

6. Skeletal muscles are in good shape, therefore, in the absence of muscle relaxants, operations in the abdominal cavity at this level are not performed.

Second level characterized by the following manifestations.

1. Reflexes (laryngo-pharyngeal and corneal) weaken and then completely disappear.

2. Breathing is calm.

3. Pulse and blood pressure at pre-anesthesia levels.

4. The pupils gradually dilate, and in parallel with this, their reaction to light weakens.

5. There is no movement of the eyeballs, the pupils are set centrally.

6. Relaxation of skeletal muscles begins.

Third level has the following clinical signs.

1. There are no reflexes.

2. Breathing is carried out only through movements of the diaphragm, therefore shallow and rapid.

3. Blood pressure decreases, pulse rate increases.

4. The pupils dilate, and their reaction to a common light stimulus is practically absent.

5. Skeletal muscles (including intercostal muscles) are completely relaxed. As a result, the jaw often sagging, the tongue may retract and breathing may stop, so the anesthesiologist always moves the jaw forward during this period.

6. The patient’s transition to this level of anesthesia is dangerous for his life, therefore, if such a situation arises, it is necessary to adjust the dose of the anesthesia.

Fourth level previously called agonal, since the state of the body at this level is essentially critical. Death can occur at any time due to respiratory paralysis or cessation of blood circulation. The patient requires a complex of resuscitation measures. Increasing anesthesia at this stage is an indicator of the low qualifications of the anesthesiologist.

1. All reflexes are absent, there is no reaction of the pupil to light.

2. The pupils are maximally dilated.

3. Breathing is shallow, sharply rapid.

4. Tachycardia, thread-like pulse, blood pressure is significantly reduced, may not be detected.

5. There is no muscle tone.

Fourth stage

Occurs after stopping the supply of the narcotic. The clinical manifestations of this stage correspond to the reverse development of those during immersion in anesthesia. But they, as a rule, occur more quickly and are not so pronounced.

4. Certain types of anesthesia

Mask anesthesia. With this type of anesthesia, an anesthetic in a gaseous state is supplied to the patient's respiratory tract through a specially designed mask. The patient can breathe on his own, or the gas mixture is supplied under pressure. When performing inhalation mask anesthesia, it is necessary to take care of the constant patency of the airways. There are several techniques for this.

2. Bringing the lower jaw forward (prevents tongue retraction).

3. Installation of an oropharyngeal or nasopharyngeal airway.

Mask anesthesia is quite difficult for patients to tolerate, so it is not used so often - for minor surgical interventions that do not require muscle relaxation.

Advantages endotracheal anesthesia. This is to ensure constant stable ventilation of the lungs and prevent blockage of the airways with aspirate. The disadvantage is the higher complexity of performing this procedure (if there is an experienced anesthesiologist, this factor is not particularly important).

These qualities of endotracheal anesthesia determine the scope of its application.

1. Operations with an increased risk of aspiration.

2. Operations using muscle relaxants, especially thoracic ones, in which there may often be a need for separate ventilation of the lungs, which is achieved by using double-lumen endotracheal tubes.

3. Surgeries on the head and neck.

4. Operations with turning the body on its side or stomach (urological, etc.), during which independent breathing becomes very difficult.

5. Long-term surgical interventions.

In modern surgery it is difficult to do without the use of muscle relaxants.

These drugs are used for anesthesia during intubated trachea, abdominal operations, especially during surgical interventions on the lungs (intubation of the trachea with a double-lumen tube allows ventilation of only one lung). They have the property of potentiating the effect of other components of anesthesia, therefore, when used together, the concentration of the anesthetic can be reduced. In addition to anesthesia, they are used in the treatment of tetanus and emergency treatment of laryngospasm.

To perform combined anesthesia, several drugs are used simultaneously. This is either several drugs for inhalation anesthesia, or a combination of intravenous and inhalation anesthesia, or the use of an anesthetic and a muscle relaxant (for the reduction of dislocations).

In combination with anesthesia, special methods of influencing the body are used - controlled hypotension and controlled hypothermia. With the help of controlled hypotension, tissue perfusion is reduced, including in the surgical area, which leads to minimization of blood loss. Controlled hypothermia or a decrease in temperature of either the entire body or part of it leads to a decrease in tissue oxygen demand, which makes it possible to carry out long-term interventions with restriction or shutdown of blood supply.

5. Complications of anesthesia. Special forms of pain relief

Special forms of pain relief are neuroleptanalgesia– the use of a combination of a neuroleptic (droperidol) and an anesthetic drug (fentanyl) for pain relief – and ataralgesia – the use of a tranquilizer and an anesthetic drug for pain relief. These methods can be used for minor interventions.

Electroanalgesia– special effect on the cerebral cortex electric shock, which leads to synchronization of the electrical activity of the cortex in ? -rhythm, which is also formed during anesthesia.

Carrying out anesthesia requires the presence of a specialist anesthesiologist. This is a complex procedure and a very serious interference in the functioning of the body. Correctly performed anesthesia, as a rule, is not accompanied by complications, but they still occur even with experienced anesthesiologists.

Quantity complications of anesthesia extremely large.

1. Laryngitis, tracheobronchitis.

2. Obstruction of the respiratory tract - retraction of the tongue, entry of teeth and dentures into the respiratory tract.

3. Atelectasis of the lung.

4. Pneumonia.

5. Disturbances in the activity of the cardiovascular system: collapse, tachycardia, other heart rhythm disturbances up to fibrillation and circulatory arrest.

6. Traumatic complications during intubation (injuries of the larynx, pharynx, trachea).

7. Disorders of motor activity of the gastrointestinal tract: nausea, vomiting, regurgitation, aspiration, intestinal paresis.

8. Urinary retention.

9. Hypothermia.