Anesthesia: everything you need to know about it. Induction of anesthesia and intubation (After sleep onset) Administration of anesthesia

Induction of anesthesia is a very important procedure, during which the patient is transferred from a state of wakefulness to a state of medicated sleep. The purpose of induction of anesthesia, or induction, is also to provide an effective level of anesthesia for laryngoscopy and tracheal intubation.

The last manipulation (intubation) under conditions of inadequate anesthesia can lead to the development of bradycardia and hypertension.

After administration of relaxants and a short period of hyperventilation, tracheal intubation is performed. The average size of the isubation tube is: 8.0 - for adult men, 7.0 - for adult women. It is believed that the diameter of the nail phalanx thumb hands corresponds to the diameter glottis. Laryngoscopy and tracheal intubation should not take more than 45-60 seconds, in patients with coronary artery disease and in cardiac anesthesiology - 30 seconds.

Currently, in adult patients, induction is usually carried out using the IV administration of drugs. Modern induction regimens include the use of propofol (diprivan) or barbiturates (thiopengal, brietal):

1. Barbituric (hexenal, Na thiopental, brietal). The pharmacology and pharmacodynamics of barbiturates allow induction of anesthesia quickly, efficiently and with minimal impact on the circulatory and respiratory systems.

Induction anesthesia scheme - sequentially, the following is administered intravenously:

Tracrium - 10 mg;

Brietal at a dose of 2-3 mg/kg in the form of a prepared ex tempera 1% solution;

Fentanyl at a dose of 5 mcg/kg;

Listenone at a dose of 2 mg/kg;

Tracheal intubation.

2. Introductory anesthesia with propofol (diprivan). Relative contraindication, due to the possible development of hypotension (reduction in blood pressure by 25-40% of initial values), - uncorrected hypovolemia.

Anesthesia regimen:

Tracrium - 10 mg;

Atropine 0.1% solution - 0.5 ml to reduce salivation and prevent vagal reflexes during tracheal intubation;

Diprivan at a dose of 1.5-2.5 mg/kg;

Fentanyl at a dose of 5 mcg/kg;

Listenone at a dose of 2 mg/kg;

Tracheal intubation.

Criteria for the effectiveness of induction anesthesia:

The patient is sleeping;

The pupils are constricted and fixed in the center eyeball, there is no reaction of the pupil to light;

The muscles are relaxed, the jaw opens easily;

The ciliary reflex is absent or significantly suppressed.

The patient can breathe on his own, but may also require

assisted ventilation through a mask. In any case, relaxants are administered only when there is complete confidence in the patency of the respiratory tract.

In children younger age induction anesthesia is carried out in the ward, for which ketamine is administered intramuscularly at a dose of 5-7 mg/kg. The presence of a doctor is required at all stages (induction, transportation).

An alternative to this technique is mask anesthesia with halothane: the mask is tightly fixed on the patient’s face and after a short period of oxygen inhalation necessary for adaptation to breathing through the mask, the concentration of halothane in the inhaled mixture begins to gradually increase.

To prevent nausea, vomiting, and severe agitation, it is unacceptable to sharply increase the concentration of anesthetic in the breathing circuit.

The clinic of general anesthesia was first described by Guedel (1937) for inhalation anesthesia with ether while maintaining spontaneous breathing. He identified four stages of anesthesia (Table 15.1).

Currently, the general anesthesia clinic described by Guedel can only be observed during mononarcosis with vapor-forming anesthetics, which is used extremely rarely in practice. Adequacy assessment modern methods combined general anesthesia (efficacy) will be described in the corresponding chapter.

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): majority narcotic substances Lipotropic, as a result of which they block the membranes of neurons, disrupting their metabolism.

3). Surface tension theory(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 on different stages operations of various narcotic substances; 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 evaporating, 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 discharging excess narcotic substances into the external environment) and non-reversible valve (for separating the flows 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 decline muscle tone, the root of the tongue may sink and block the airway. 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 at 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 patient, injury).
• 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

used more often than others, mainly for 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. Carry out an inspection: if 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.

IN Lately 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 apply:

• 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. Still 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 pathological changes on an 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 introduction medicines 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. Are used sleeping pills(phenobarbital) and tranquilizers (diazepan, phenazepam).

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

3). Prevention allergic reactions. Are used antihistamines(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 intravenous administration 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 cardiovascular system, therefore 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:

oppression respiratory center, decreased peristalsis and gastrointestinal secretion, nausea and vomiting. Addiction quickly sets in. To reduce side effects combined 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 drugs can lead to respiratory depression, which often forces 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.

Also used combination drug, containing both substances (thalamonal).

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.

Induction of anesthesia is a very important procedure, during which the patient is transferred from a state of wakefulness to a state of medicated sleep. The purpose of induction of anesthesia, or induction, is also to provide an effective level of anesthesia for laryngoscopy and tracheal intubation.

The last manipulation (intubation) under conditions of inadequate anesthesia can lead to the development of bradycardia and hypertension.

After administration of relaxants and a short period of hyperventilation, tracheal intubation is performed. The average size of the isubation tube is: 8.0 - for adult men, 7.0 - for adult women. It is believed that the diameter of the nail phalanx of the thumb corresponds to the diameter of the glottis. Laryngoscopy and tracheal intubation should not take more than 45-60 seconds, in patients with coronary artery disease and in cardiac anesthesiology - 30 seconds.

Currently, in adult patients, induction is usually carried out using the IV administration of drugs. Modern induction regimens include the use of propofol (diprivan) or barbiturates (thiopengal, brietal):

1. Barbituric (hexenal, Na thiopental, brietal). The pharmacology and pharmacodynamics of barbiturates allow induction of anesthesia quickly, efficiently and with minimal impact on the circulatory and respiratory systems.

Induction anesthesia scheme - sequentially, the following is administered intravenously:

Tracrium - 10 mg;

Brietal at a dose of 2-3 mg/kg in the form of a prepared ex tempera 1% solution;

Fentanyl at a dose of 5 mcg/kg;

Listenone at a dose of 2 mg/kg;

Tracheal intubation.

2. Introductory anesthesia with propofol (diprivan). A relative contraindication, due to the possible development of hypotension (a decrease in blood pressure by 25-40% of initial values), is uncorrected hypovolemia.

Anesthesia regimen:

Tracrium - 10 mg;

Atropine 0.1% solution - 0.5 ml to reduce salivation and prevent vagal reflexes during tracheal intubation;

Diprivan at a dose of 1.5-2.5 mg/kg;

Fentanyl at a dose of 5 mcg/kg;

Listenone at a dose of 2 mg/kg;

Tracheal intubation.

Criteria for the effectiveness of induction anesthesia:

The patient is sleeping;

The pupils are constricted and fixed in the center of the eyeball, there is no reaction of the pupil to light;

The muscles are relaxed, the jaw opens easily;

The ciliary reflex is absent or significantly suppressed.

The patient can breathe on his own, but may also require

assisted ventilation through a mask. In any case, relaxants are administered only when there is complete confidence in the patency of the airway.

In young children, induction anesthesia is carried out in the ward, for which ketamine is administered intramuscularly at a dose of 5-7 mg/kg. The presence of a doctor is required at all stages (induction, transportation).

An alternative to this technique is mask anesthesia with halothane: the mask is tightly fixed on the patient’s face and after a short period of oxygen inhalation necessary for adaptation to breathing through the mask, the concentration of halothane in the inhaled mixture begins to gradually increase.

To prevent nausea, vomiting, and severe agitation, it is unacceptable to sharply increase the concentration of anesthetic in the breathing circuit.

The clinic of general anesthesia was first described by Guedel (1937) for inhalation anesthesia with ether while maintaining spontaneous breathing. He identified four stages of anesthesia (Table 15.1).

Currently, the general anesthesia clinic described by Guedel can only be observed during mononarcosis with vapor-forming anesthetics, which is used extremely rarely in practice. An assessment of the adequacy of modern methods of combined general anesthesia (efficacy) will be presented in the corresponding chapter.

Health

Nowadays, many people in different periods have ended up on the operating table in their lives. Just 150 years ago it would have been impossible to imagine so that operations are performed in the same quantity as happens in modern world . One of the main reasons why in those days it was impossible to decide even on such relatively simple operations, which are now done at every step, is quite understandable. Surgeons of those days would have to cut patients who could not be put to sleep, due to the lack of any way to do this. This means that the operation was an unbearably painful process that could cause death due to severe painful shock. For this reason, there were often cases when they simply tried to “knock out” a patient with blows to the head in order to perform an operation. In the modern world, operations, for the most part, are absolutely painless thanks to such a medical invention as anesthesia.

The word "anesthesia" literally means "without feeling" in Greek. This procedure is mandatory for anyone who needs surgery or any other painful therapy. It is anesthesia that allows you to deprive your body of sensitivity to such an extent that you completely stop perceiving any information about the world around you and what is currently happening with your body. Anesthesia gave people the ability to cheat pain and death.

As you know, the part of the body that controls our consciousness and is responsible for our feelings, including motor ability and pain, is called the nervous system. The process of anesthesia involves the introduction of a chemical substance into the body, called an anesthetic, which leads to blocking the functionality of the part of the nervous system that needs to be desensitized. If certain anesthetic drugs are injected directly into the bloodstream, when they reach the brain, they block a major part of the central nervous system, causing complete loss of sensation throughout the body.

Exist various ways administration of anesthesia, including spinal cord, which is achieved by performing a spinal or epidural injection. This process results in loss of sensation in the lower body. Epidural anesthesia is a type of so-called local anesthesia when it is necessary to cause loss of sensitivity in a specific area of ​​the body. It is clear that the more complex the type of anesthesia, the more great risk For human body it is associated despite the general tendency of all types of anesthesia to become even safer.

HOW SAFE IS ANESTHESIA?

Anesthesia in conditions modern medicine has become a relatively safe procedure; It’s much more dangerous than, say, driving your own car every day! But, unfortunately, it has not yet been possible to completely eliminate the risk, which means that there is some probability that something may not go as planned by doctors. This means only one thing - any surgical intervention must be caused by conditions of extreme necessity (while the vast majority of cosmetic operations are clearly not caused by such conditions!).

Why is the anesthesia procedure considered more and more safe every year?

-- Every year humanity learns more and more about human body, improving anesthesia methods, which cannot but affect the general level of training of anesthesiologists.

-- Every year more and more advanced medical supplies, which contribute to the rapid and safe removal of anesthetic substances from the body after surgery.

-- Every year more and more advanced medical equipment, which allows surgeons and other medical personnel to obtain more information about the state of your body at the time of the operation, and therefore better control it.

Why is the risk of anesthesia still not completely eliminated?

-- It is not possible to completely eliminate the risk when using anesthetics, since these drugs are a foreign substance that has a paralytic effect on nervous system person.

-- Anesthetic drugs can also affect other human organs, including, for example, the heart.

Considering the fact that anesthetics can affect various human organs, as well as the fact that not every person is able to normally tolerate certain components that make up anesthetics, doctors are not always able to easily resolve the issue of prescribing one or another type anesthesia.

TYPES OF ANESTHESIA

When the need for surgical intervention in the body becomes inevitable, Doctors are faced with the task of choosing one or another type of anesthesia and anesthetic substance, which will enable surgeons to carry out this operation without problems or hitches. Obviously, when it comes to operations performed on the superficial part of our body, then it is quite possible to get by with local anesthesia. If we are talking about the need to penetrate inside any part of the human body in order to perform an operation (say, you need to make a deep cut on some limb), then there is a need for blocking nerve endings this part of the body.

If we go even further, we should mention such complex operations as replacing knee joint, for what only possible option is spinal (epidural) anesthesia, which carries a slightly greater risk. Much less dangerous form Anesthesia is the so-called local infiltration anesthesia, after which you do not lose consciousness. This type of anesthesia can be used for a variety of simple operations, such as dental or plastic surgery.

Finally, one of the most complex species anesthesia, when none of the listed options for local reduction of body sensitivity is suitable, is the so-called general anesthesia, or general anesthesia. It falls to the anesthesiologist and surgeon to decide which type of anesthesia is most optimal for performing a particular operation.

LOCAL ANESTHESIA

As you already understand, one of the most simple shapes anesthesia is local anesthesia. A local anesthetic is injected into the area of ​​the body where the nerve endings are located. the sensitivity of which must be neutralized for subsequent surgery in this area. When it comes to local anesthesia, the injection of an anesthetic is carried out by simply injecting the drug under the skin in the area of ​​​​the body where the nerve endings are located.

There are many nerve endings in the human body, and there are also many types of local anesthesia designed to temporarily block the sensation of these nerves. Because the local anesthesia requires a fairly small amount of anesthetic drug, injected not into the blood, but under the skin, the patient’s heart and brain are not exposed to the anesthetic. That is why local anesthesia is considered the most in a safe way anesthesia.

GENERAL ANESTHESIA

It would seem that it could be simpler than general anesthesia - you are simply injected with the appropriate drug into your blood, and your consciousness turns off, that is, you fall asleep. However this type of anesthesia requires the most careful preparation, during which doctors need to do many relevant tests that would demonstrate the possibility (or lack of possibility) of performing the operation under general anesthesia. Besides, During the operation itself, doctors are required to have all their attention and knowledge in order to monitor the slightest changes in the state of the body, and be ready, if something happens, to take the necessary measures.

As mentioned above, general anesthesia, as a rule, is prescribed only when none of the local anesthesia options are suitable for the operation. Examples of such cases include surgery performed internally. abdominal cavity, sternum or head. In fact, when they talk about general anesthesia, they mean the effect on the body of three components - anesthesia, an analgesic (pain reliever) and a muscle relaxant. Anesthesia renders the patient unconscious, turning off his consciousness. An anesthetic is necessary in order to completely dull the patient’s pain, which, although somewhat reduced through the administration of anesthesia, is still strong enough and can awaken a person from sleep. Finally, muscle relaxants are used to immobilize the patient's muscles so that so that the surgeon can safely make the necessary incisions, which will allow him to reach the necessary part of the body.

Administration of anesthesia and its maintenance

There are two ways to administer anesthesia and keep the patient asleep during surgery (meaning general anesthesia). The process of falling asleep should be as painless as possible and do not cause stress to the patient, as this may reduce the effectiveness of the anesthetic drug. The most common method of administering an anesthetic is intravenous injection appropriate drug, which is called an induction agent. Then, in order to maintain the human body in a sleeping state, drugs are used in the form of gas, which are administered through inhalation through a special mask worn on the face.

The induction anesthetic agent, which is pre-injected into a person’s vein, quickly reaches the brain thanks to blood circulation. Literally in one or two minutes the patient, who was just sober, plunges into a deep state of unconsciousness. The most commonly used drugs for induction of anesthesia include sodium thiopental (which has been successfully used for more than 60 years), propofol and etomidate.

Sodium thiopental is called a drug for non-inhalation general anesthesia of ultra-short action. A drug such as propofol can be used for continuous intravenous administration into a patient's vein while he is under general anesthesia. This method is one of the options for maintaining general anesthesia. In this case, an overdose can lead to very dangerous consequences for the patient's body, therefore, this method of maintaining anesthesia is used in the presence of modern operating equipment. Such equipment allows you to calculate and program the required portions of the drug, which will be administered using a so-called electronic syringe.

Another type of drugs that can be used as anesthesia are the so-called drugs for inhalation anesthesia. These drugs are injected into the patient's body in the form of gas vapor using a so-called anesthetic machine. This method is usually used to maintain anesthesia, but it can also be used for the initial administration of anesthesia. This technique of immersion in unconsciousness is not used very often., as it may seem. Inhaling such a gas through a special mask (like oxygen) can cause a lot of unpleasant emotions in the patient, which may be a factor preventing the patient from falling into deep sleep. On the other hand, as for children, this method of administering general anesthesia may look more suitable, since, often, not only the injection, but even the type of syringe itself is more unpleasant for children.

Painkillers (narcotic analgesics)

Although the patient may be under the influence of an anesthetic drug, he may experience some pain or pain. This pain, of course, is not capable of causing the same emotional response as in the waking state., but can cause a certain reaction in the body that will interfere with the operation. In order to prevent such occurrences pain, anesthesiologists use quite potent drugs, one of the common side effects may be difficulty breathing. This means that one of the tasks of the anesthesiologist is the need to carefully monitor any changes in the patient’s breathing in order to, if anything happens, take all necessary measures to facilitate the breathing process of the patient being operated on.

Muscle relaxants

A third type of medication regularly used by anesthesiologists to prepare patients for surgery is called a muscle relaxant. Once upon a time similar chemical substances used by the indigenous people South America - they processed the tips of their spears and arrows with them. Now these drugs are widely produced for the needs of modern medicine. Muscle relaxants, although they paralyze the patient's muscles, do not have any effect on his brain. That is why these drugs are given to the patient only after anesthesia has been administered.

Since muscle relaxants do not affect just one muscle group, but all the muscles of the body at once, including the respiratory muscle, an immobilized patient loses the ability to breathe during surgery. That is why during operations performed under general anesthesia, a device for artificial ventilation of the lungs is used.

Stage I - introduction to anesthesia. Introductory anesthesia can be carried out with any narcotic substance, against the background of which a sufficiently deep anesthetic sleep occurs without a stage of excitement. Barbiturates are mainly used. fentanyl in combination with sombrevin, promolol with sombrevin. Sodium thiopental is also often used. The drugs are used in the form of a 1% solution, administered intravenously at a dose of 400-500 mg. During induction of anesthesia, muscle relaxants are administered and tracheal intubation is performed.

Stage II - maintenance of anesthesia. To maintain general anesthesia, you can use any narcotic that can protect the body from surgical trauma (fluorotane, cyclopropane, nitrous oxide with oxygen), as well as neuroleptanalgesia. Anesthesia is maintained at the first and second level of the surgical stage, and to eliminate muscle tension, muscle relaxants are administered, which cause myoplegia of all groups of skeletal muscles, including respiratory ones. Therefore, the main condition of the modern combined method of pain relief is mechanical ventilation, which is carried out by rhythmically compressing the bag or fur or using an artificial respiration apparatus.

Recently, neuroleptanalgesia has become most widespread. With this method, nitrous oxide and oxygen are used for anesthesia. fentanyl, droperidol. muscle relaxants. Intravenous induction anesthesia. Anesthesia is maintained by inhalation of nitrous oxide with oxygen in a ratio of 2: 1, fractional intravenous administration of fentanyl and droperidol, 1-2 ml every 15-20 minutes. If the pulse increases, fentanyl is administered. when increasing blood pressure- droperidol. This type of anesthesia is safer for the patient. fentanyl enhances pain relief, droperidol suppresses autonomic reactions.

Stage III - recovery from anesthesia. Towards the end of the operation, the anesthesiologist gradually stops administering narcotics and muscle relaxants. The patient regains consciousness, spontaneous breathing and muscle tone are restored. The criterion for assessing the adequacy of spontaneous breathing is the indicators PO2, PCO2, pH. After awakening, restoration of spontaneous breathing and skeletal muscle tone, the anesthesiologist can extubate the patient and transport him for further observation to the recovery room.

Methods for monitoring the administration of anesthesia. During general anesthesia, the main hemodynamic parameters are constantly determined and assessed. Blood pressure and pulse rate are measured every 10-15 minutes. In persons with heart and vascular diseases, as well as during thoracic operations, it is especially important to carry out constant monitoring of cardiac activity.

Electroencephalographic observation can be used to determine the level of anesthesia. To monitor ventilation and metabolic changes during anesthesia and surgery, it is necessary to study the acid-base state (PO2, PCO2, pH, BE).

During anesthesia nurse maintains an anesthesiological record of the patient, in which he necessarily records the main indicators of homeostasis: pulse rate, blood pressure, central venous pressure, respiratory rate, mechanical ventilation parameters. This card reflects all stages of anesthesia and surgery, and indicates the doses of narcotic substances and muscle relaxants. All drugs used during anesthesia, including transfusion media, are noted. The time of all stages of the operation and administration of drugs is recorded. At the end of the operation, the total amount of all drugs used is determined, which is also noted in the anesthesia card. A record is made of all complications during anesthesia and surgery. The anesthesia card is included in the medical history.