Advertising on the portal

Components of general anesthesia, their characteristics and clinical significance. Special anesthesia components

1503 0

Terminologically, anesthesia for surgical interventions is divided into general, conduction and local.

The main requirement for anesthesia in both adults and children is its adequacy. The adequacy of anesthesia means:

  • compliance of its effectiveness with the nature, severity and duration of the surgical injury;
  • taking into account the requirements for it in accordance with the patient’s age, concomitant pathology, severity of the initial condition, characteristics of the neurovegetative status, etc.
Adequacy of anesthesia is ensured through the management of various components of the anesthetic management. The main components of modern general anesthesia realize the following effects: 1) inhibition of mental perception (hypnosis, deep sedation); 2) blockade of pain (afferent) impulses (analgesia); 3) inhibition of autonomic reactions (hyporeflexia); 4) turning off motor activity (myorelaxation or myoplegia).

In this regard, the concept of the so-called ideal anesthetic has been put forward, which determines the main directions and trends in the development of pharmacology.

Anesthesiologists working in pediatrics take into account the characteristics of the child’s body that affect the pharmacodynamics and pharmacokinetics of anesthesia components. Of these, the most important:

  • decreased protein binding capacity;
  • increased volume of distribution;
  • reduction in the proportion of fat and muscle mass.
In this regard, initial dosages and intervals between repeated administrations in children often differ significantly from those in adult patients.

Inhalation anesthesia agents

Inhalation (in English literature - volatile, "volatile") anesthetic from the evaporator of the anesthesia machine during ventilation enters the alveoli and from them into the bloodstream. From the blood, the anesthetic spreads to all tissues, mainly concentrating in the brain, liver, kidneys and heart. In muscles and especially in adipose tissue, the concentration of anesthetic increases very slowly and significantly lags behind its increase in the lungs.

For most inhalational anesthetics, the role of metabolic transformation is small (20% for halothane), therefore, there is a certain relationship between the inhaled concentration and the concentration in tissues (directly proportional to nitrous oxide anesthesia).

The depth of anesthesia mainly depends on the tension of the anesthetic in the brain, which is directly related to its tension in the blood. The latter depends on the volume of alveolar ventilation and the magnitude of cardiac output (for example, a decrease in alveolar ventilation and an increase in cardiac output increase the duration of the induction period). Of particular importance is the solubility of the anesthetic in the blood. Diethyl ether, methoxyflurane, chloroform and trichlorethylene, which are currently little used, have high solubility; low - modern anesthetics (isoflurane, sevoflurane, etc.).

The anesthetic can be delivered through a mask or endotracheal tube. Inhalational anesthetics can be used in the form of non-reversible (exhalation into the atmosphere) and reverse (exhalation partly into the anesthesia machine, partly into the atmosphere) circuits. The reversible circuit has a system for absorbing exhaled carbon dioxide.

In pediatric anesthesiology, a non-reversible circuit is more often used, which has a number of disadvantages, in particular, loss of heat to the patient, pollution of the operating room atmosphere, and high consumption of anesthetic gases. In recent years, due to the advent of a new generation of anesthesia-respiratory equipment and monitoring, the reverse circuit method of low flow anesthesia has begun to be increasingly used. The total gas flow is less than 1 l/min.

General anesthesia with inhalational anesthetics is used much more often in children than in adult patients. This is primarily due to the widespread use of mask anesthesia in children. The most popular anesthetic in Russia is halothane (fluorothane), which is usually used in combination with nitrous oxide.

Children require a higher concentration of inhalational anesthetic (about 30%) than adults, which is likely due to the rapid increase in alveolar anesthetic concentration due to the high ratio between alveolar ventilation and functional residual capacity. A high cardiac index and its relatively high proportion in the cerebral blood flow are also important. This leads to the fact that in children, the introduction and recovery from anesthesia, all other things being equal, occurs faster than in adults. At the same time, a very rapid development of a cardiodepressive effect is possible, especially in newborns.

Halothane (fluorothane, narcotane, fluotane)- the most common inhalational anesthetic in Russia today. In children, it causes a gradual loss of consciousness (within 1-2 minutes); the drug does not irritate the mucous membranes of the respiratory tract. With further exposure and an increase in inhaled concentration to 2.4-4 vol.%, a complete loss of consciousness occurs within 3-4 minutes from the start of inhalation. Halothane has relatively low analgesic properties, so it is usually combined with nitrous oxide or narcotic analgesics.

Halothane has a bronchodilator effect, and therefore is indicated for anesthesia in children with bronchial asthma. The negative properties of halothane include increased sensitivity to catecholamines (their administration during anesthesia with halothane is contraindicated). It has a cardiodepressive effect (inhibits the inotropic ability of the myocardium, especially in high concentrations), reduces peripheral vascular resistance and blood pressure. Halothane significantly increases cerebral blood flow, and therefore its use is not recommended for children with increased intracranial pressure. It is also not indicated for liver pathology.

Enflurane (ethrane) has a slightly lower blood/gas solubility than halothane, so induction and recovery from anesthesia are somewhat faster. Unlike halothane, enflurane has analgesic properties. The depressive effect on respiration and cardiac muscle is pronounced, but sensitivity to catecholamines is significantly lower than that of halothane. Causes tachycardia, increased cerebral blood flow and intracranial pressure, toxic effects on the liver and kidneys. There is evidence of epileptiform activity of enflurane.

Isoflurane (foran) even less soluble than enflurane. The extremely low metabolism (about 0.2%) makes anesthesia more manageable and induction and recovery faster than with halothane. Has an analgesic effect. Unlike halothane and enflurane, isoflurane does not have a significant effect on the myocardium in average concentrations. Isoflurane reduces blood pressure due to vasodilation, due to which it slightly increases the heart rate, and does not sensitize the myocardium to catecholamines. Less effect on brain perfusion and intracranial pressure than halothane and enflurane. The disadvantages of isoflurane include an increase in induction of secretion of the respiratory tract, cough and quite frequent (more than 20%) cases of laryngospasm in children.

Sevoflurane and desflurane- inhalation anesthetics of the latest generation, which have not yet found widespread use in Russia.

Nitrous oxide- a colorless gas heavier than air, with a characteristic odor and sweetish taste, not explosive, although it supports combustion. Supplied in liquid form in cylinders (1 kg of liquid nitrous oxide produces 500 liters of gas). Does not metabolize in the body. It has good analgesic properties, but is a very weak anesthetic, therefore it is used as a component of inhalation or intravenous anesthesia. Used in concentrations of no more than 3:1 in relation to oxygen (higher concentrations are fraught with the development of hypoxemia). Cardiac and respiratory depression and effects on cerebral blood flow are minimal. Long-term use of nitrous oxide can lead to the development of myelodepression and agranulocytosis.

Components of intravenous anesthesia

They are subject to the following requirements: 1) speed of onset of effect; 2) easy intravenous administration (low viscosity) and painless injection; 3) minimal cardiorespiratory depression; 4) absence of side effects; 5) the possibility of carrying out a titration regime; 6) rapid and complete recovery of the patient after anesthesia.

These agents are used both in combination with inhalation agents and without them - the latter method is called total intravenous anesthesia (TIA). It is with this method of anesthesia that it is possible to completely avoid the negative effects on the body of operating room personnel.

Hypnotics ensure that the patient's consciousness is turned off. They tend to be highly soluble in lipids, quickly passing through the blood-brain barrier.

Barbiturates, ketamine, benzodiazepines and propofol are widely used in pediatric anesthesiology. All of these drugs have different effects on respiration, intracranial pressure and hemodynamics.

Barbiturates

The most widely used barbiturates for general anesthesia are sodium thiopental and hexenal, which are mostly used for induction in adult patients and much less frequently in children.

Sodium thiopental in children is used mainly for induction intravenously at a dose of 5-6 mg/kg, at the age of up to 1 year 5-8 mg/kg, in newborns 3-4 mg/kg. Loss of consciousness occurs after 20-30 seconds and lasts 3-5 minutes. To maintain the effect, doses of 0.5-2 mg/kg are required. For children, a 1% solution is used, and for older people - 2%. Like most other hypnotics, sodium thiopental has no analgesic properties, although it does reduce the pain threshold.

Children metabolize thiopental 2 times faster than adults. The half-life of the drug is 10-12 hours, which mainly depends on liver function, since very small amounts are excreted in the urine. It has a moderate ability to bind to proteins, especially albumins (the free fraction is 15-25%). The drug is toxic when administered subcutaneously or intraarterially, has a histamine effect, and causes respiratory depression, including apnea. It has a weak vasodilating effect and causes myocardial depression and activates the parasympathetic (vagal) system. Negative hemodynamic effects are especially pronounced during hypovolemia. Thiopental increases pharyngeal reflexes and can cause coughing, hiccups, laryngo- and bronchospasm. Some patients have tolerance to thiopental, and it occurs less frequently in children than in adults. Premedication with promedol in children allows you to reduce the induction dose by approximately 1/3.

Hexenal in its properties differs little from thiopental. The drug is easily soluble in water, and such a solution can be stored for no more than an hour. In children it is administered intravenously in the form of a 1% solution (in adults 2-5%) in doses similar to thiopental. The half-life of hexenal is about 5 hours, the effect on respiration and hemodynamics is similar to thiopental, although the vagal effect is less pronounced. Cases of laryngo- and bronchospasm are reported less frequently, so it is more often used for induction.

The dose of thiopental and hexenal for induction in older children (as in adults) is 4-5 mg/kg when administered intravenously. Unlike thiopental, hexenal can be administered intramuscularly (IM) and rectally. When administered intramuscularly, the dose of hexenal is 8-10 mg/kg (with the induction of narcotic sleep occurring within 10-15 minutes). For rectal administration, hexenal is used in a dosage of 20-30 mg/kg. Sleep occurs within 15-20 minutes and lasts at least 40-60 minutes (followed by prolonged depression of consciousness, requiring control). Nowadays, this method is rarely resorted to and only in cases where it is not possible to use more modern techniques.

Ketamine- phencyclidine derivative. When administered, the laryngeal, pharyngeal and cough reflexes are preserved. In children it is used widely for both induction and maintenance of anesthesia. It is very convenient for induction in the form of intramuscular injections: the dose for children under 1 year of age is 10-13 mg/kg, for children under 6 years of age - 8-10 mg/kg, for older children - 6-8 mg/kg. After intramuscular administration, the effect occurs within 4-5 minutes and lasts 16-20 minutes. Doses for intravenous administration are 2 mg/kg; the effect develops within 30-40 s and lasts about 5 minutes. To maintain anesthesia, it is used mainly as a continuous infusion at a rate of 0.5-3 mg/kg per hour.

The administration of ketamine is accompanied by an increase in blood pressure and heart rate by 20-30%, which is determined by its adrenergic activity. The latter provides a bronchodilator effect. Only 2% of the ketamine solution is excreted unchanged in the urine, the remaining (overwhelming) part is metabolized. Ketamine has high lipid solubility (5-10 times higher than thiopental), which ensures its rapid penetration into the central nervous system. As a result of rapid redistribution from the brain to other tissues, ketamine provides a fairly rapid awakening.

If administered rapidly, it can cause respiratory depression, spontaneous movements, increased muscle tone, intracranial and intraocular pressure.

In adults and older children, administration of the drug (usually intravenous) without prior protection benzodiazepines (BD) derivatives (diazepam, midazolam) can cause unpleasant dreams and hallucinations. To relieve side effects, not only BD is used, but also piracetam. 1/3 of children experience vomiting during the postoperative period.

Unlike adults, children tolerate ketamine much better, and therefore the indications for its use in pediatric anesthesiology are quite wide.

In self-anesthesia, ketamine is widely used for painful procedures, central vein catheterization and dressings, and minor surgical interventions. As a component of anesthesia, it is indicated for induction and for maintenance as part of combined anesthesia.

Contraindications

Contraindications for the administration of ketamine are pathology of the central nervous system associated with intracranial hypertension, arterial hypertension, epilepsy, mental illness, and hyperfunction of the thyroid gland.

Sodium hydroxybutyrate is used in children to induce and maintain anesthesia. For induction, it is prescribed intravenously at a dose of about 100 mg/kg (the effect develops after 10-15 minutes), orally in a 5% glucose solution at a dose of 150 mg/kg or intramuscularly (120-130 mg/kg) - in In these cases, the effect appears after 30 minutes and lasts about 1.5-2 hours. For induction, hydroxybutyrate is usually used in combination with other drugs, in particular with benzodiazepines, promedol or barbiturates, and to maintain anesthesia - with inhalational anesthetics. Cardiodepressive effect is practically absent.

Sodium hydroxybutyrate is easily included in metabolism, and after breakdown it is excreted from the body in the form of carbon dioxide. Small amounts (3-5%) are excreted in the urine. After intravenous administration, the maximum concentration in the blood is reached after 15 minutes; when taken orally, this period is extended to almost 1.5 hours.

May cause spontaneous movements, a significant increase in peripheral vascular resistance and a slight increase in blood pressure. Respiratory depression, vomiting (especially when taken orally), motor and speech agitation at the end of the action are sometimes observed, and with prolonged administration - hypokalemia.

Benzodiazepines (BD) widely used in anesthesiology. Their action is mediated by increasing the inhibitory effect of gamma-aminobutyric acid on neuronal transmission. Biotransformation occurs in the liver.

The most widely used in anesthesiological practice is diazepam. It has a calming, sedative, hypnotic, anticonvulsant and muscle relaxant effect, enhances the effect of narcotic, analgesic, and neuroleptic drugs. In children, unlike adults, it does not cause mental depression. Used in pediatric anesthesiology for premedication (usually IM at a dose of 0.2-0.4 mg/kg), as well as intravenously as a component of anesthesia for induction (0.2-0.3 mg/kg) and maintenance of anesthesia in the form boluses or continuous infusion.

When taken orally, it is well absorbed from the intestines (peak plasma concentrations are reached after 60 minutes). About 98% binds to plasma proteins. It is a slowly released drug from the body (half-life ranges from 21 to 37 hours) and is therefore considered a difficult drug to administer.

When administered parenterally in adult patients with hypovolemia, diazepam can cause moderate arterial hypotension. In children, a decrease in blood pressure is observed much less frequently - when taken in combination with thiopental, fentanyl or propofol. Impaired respiratory function may be associated with muscular hypotension of central origin, especially when combined with opioids. With intravenous administration, pain may be observed along the vein, which is relieved by preliminary administration of lidocaine.

Midazolam is much more manageable than diazepam, and therefore is increasingly used in anesthesiology. In addition to hypnotic, sedative, anticonvulsant and relaxing effects, it causes anterograde amnesia.

Used for premedication in children: 1) by mouth (in our country they use the ampoule form, although special sweet syrups are produced) at a dose of 0.75 mg/kg for children from 1 year to 6 years and 0.4 mg/kg from 6 to 12 years, its effect is manifested after 10-15 minutes; 2) intramuscularly at a dose of 0.2-0.3 mg/kg; 3) per rectum into the ampoule of the rectum at a dose of 0.5-0.7 mg/kg (the effect occurs after 7-8 minutes); 4) intranasally in drops for children under 5 years of age at a dose of 0.2 mg/kg (in this case, the effect occurs within 5 minutes, approaching intravenous). After premedication with midazolam, the child can be easily separated from the parents. Widely used as a component of anesthesia for induction (IV 0.15-0.3 mg/kg) and maintenance of anesthesia in the form of a continuous infusion in a titration mode at a rate of 0.1 to 0.6 mg/kg per hour and its cessation 15 minutes before the end of the operation.

The half-life of midazolam (1.5-4 hours) is 20 times shorter than that of diazepam. When taken orally, about 50% of midazolam undergoes hepatic metabolism. When administered intranasally, due to the absence of primary hepatic metabolism, the effect approaches intravenous administration, and therefore the dose must be reduced.

Midazolam has a slight effect on hemodynamics; respiratory depression is possible with rapid administration of the drug. Allergic reactions are extremely rare. In recent years, in foreign literature one can find indications of hiccups after the use of midazolam.

Midazolam combines well with various drugs (droperidol, opioids, ketamine). Its specific antagonist flumazenil (Anexat) is administered to adults at a loading dose of 0.2 mg/kg and then 0.1 mg every minute until awakening.

Propofol (diprivan)- 2,6-diisopropylphenol, a short-acting hypnotic with a very rapid action. Available as a 1% solution in a 10% soybean oil emulsion (Intralipid). It has been used in children since 1985. Propofol causes a rapid (within 30-40 s) loss of consciousness (in adults at a dose of 2 mg/kg, duration is about 4 minutes) followed by rapid recovery. When inducing anesthesia in children, its dosage is significantly higher than in adults: the recommended dose for adults is 2-2.5 mg/kg, for young children - 4-5 mg/kg.

To maintain anesthesia, a continuous infusion is recommended with an initial rate of approximately 15 mg/kg per hour in children. Then there are different infusion regimens. A distinctive feature of propofol is a very rapid recovery after the end of its administration with rapid activation of motor functions compared to barbiturates. Combines well with opiates, ketamine, midazolam and other drugs.

Propofol suppresses laryngeal-pharyngeal reflexes, which makes it possible to successfully use the introduction of a laryngeal mask, reduces intracranial pressure and cerebrospinal fluid pressure, has an antiemetic effect, and has virtually no histamine effect.

Side effects of propofol include pain at the injection site, which can be prevented by the simultaneous administration of lignocaine (1 mg per 1 ml of propofol). Propofol causes respiratory depression in most children. When administered, dose-dependent arterial hypotension is observed due to a decrease in vascular resistance, an increase in vagal tone and bradycardia. Excitement and spontaneous motor reactions may be observed.

Droperidol, a butyrophenone-type antipsychotic, is widely used in total intravenous and balanced anesthesia regimens. Droperidol has a pronounced sedative effect. Combines well with analgesics, ketamine and benzodiazepine derivatives. It has a pronounced antiemetic effect, has an α-adrenolytic effect (this may be beneficial for preventing spasm in the microcirculation system during surgical interventions), prevents the effect of catecholamines (anti-stress and anti-shock effects), and has local analgesic and antiarrhythmic effects.

Used in children for premedication intramuscularly 30-40 minutes before surgery at a dose of 1-5 mg/kg; for induction, it is used intravenously at a dose of 0.2-0.5 mg/kg, usually together with fentanyl (so-called neuroleptanalgesia, NLA); the effect appears after 2-3 minutes. If necessary, re-introduce to maintain anesthesia in doses of 0.05-0.07 mg/kg.

Side effects - extrapyramidal disorders, severe hypotension in patients with hypovolemia.

Narcotic analgesics include opium alkaloids (opiates) and synthetic compounds with opiate-like properties (opioids). In the body, narcotic analgesics bind to opioid receptors, which are structurally and functionally divided into mu, delta, kappa and sigma. The most active and effective painkillers are m-receptor agonists. These include morphine, fentanyl, promedol, new synthetic opioids - alfentanil, sufentanil and remifentanil (not yet registered in Russia). In addition to high antinociceptive activity, these drugs cause a number of side effects, including euphoria, depression of the respiratory center, emesis (nausea, vomiting) and other symptoms of inhibition of gastrointestinal tract activity, mental and physical dependence with their long-term use.

Based on their effect on opiate receptors, modern narcotic analgesics are divided into 4 groups: full agonists (they cause the maximum possible analgesia), partial agonists (weakly activate receptors), antagonists (bind to receptors, but do not activate them) and agonists/antagonists (activate one group and block the other).

Narcotic analgesics are used for premedication, induction and maintenance of anesthesia, and postoperative analgesia. However, if agonists are used for all these purposes, partial agonists are used mainly for postoperative analgesia, and antagonists are used as antidotes for agonist overdose.

Morphine- a classic narcotic analgesic. Its analgesic potency is taken as unity. Approved for use in children of all age groups. Doses for induction in children are 0.05-0.2 mg/kg intravenously, for maintenance - 0.05-0.2 mg/kg intravenously every 3-4 hours. It is also used epidurally. Destroyed in the liver; With kidney pathology, morphine metabolites may accumulate. Among the numerous side effects of morphine, special mention should be made of respiratory depression, increased intracranial pressure, sphincter spasm, nausea and vomiting, and the possibility of histamine release when administered intravenously. Increased sensitivity to morphine has been noted in newborns.

Trimeperidine (Promedol)- a synthetic opioid that is widely used in pediatric anesthesiology and for premedication (0.1 mg/year of life intramuscularly), and as an analgesic component of general anesthesia during operations (0.2-0.4 mg/kg after 40-50 minutes intravenously) , and for the purpose of postoperative analgesia (in doses of 1 mg/year of life, but not more than 10 mg intramuscularly). After intravenous administration, the half-life of promedol is 3-4 hours. Compared with morphine, promedol has less analgesic power and less pronounced side effects.

Fentanyl- a synthetic narcotic analgesic widely used in pediatrics. Its analgesic activity is 100 times greater than that of morphine. Slightly changes blood pressure and does not cause histamine release. Used in children: for premedication - intramuscularly 30-40 minutes before surgery 0.002 mg/kg, for induction - intravenously 0.002-0.01 mg/kg. After intravenous administration (at a rate of 1 ml/min), the effect reaches its maximum after 2-3 minutes. To maintain analgesia during surgery, 0.001-0.004 mg/kg is administered every 20 minutes as a bolus or infusion. It is used in combination with droperidol (neuroleptanalgesia) and benzodiazepines (ataralgesia), and in these cases the duration of effective analgesia increases (up to 40 minutes).

Due to its high fat solubility, fentanyl accumulates in fat depots, and therefore its half-life from the body can reach 3-4 hours. If rational dosages are exceeded, this may affect the timely restoration of spontaneous breathing after surgery (for respiratory depression, opioid receptor antagonists nalorphine or naloxone; in recent years, agonists-antagonists have been used for this purpose - nalbuphine, butorphanol tartrate, etc.).

In addition to central respiratory depression, side effects of fentanyl include severe muscle and chest rigidity (especially after rapid intravenous administration), bradycardia, increased ICP, miosis, sphincter spasm, and cough with rapid intravenous administration.

Piritramide (dipidolor) is similar in activity to morphine. The dose for induction in children is 0.2-0.3 mg/kg intravenously, for maintenance - 0.1-0.2 mg/kg every 60 minutes. For postoperative pain relief, it is administered at a dose of 0.05-0.2 mg/kg every 4-6 hours. It has a moderate sedative effect. Has virtually no effect on hemodynamics. When administered intramuscularly, the half-life is 4-10 hours. Metabolizes in the liver. Side effects manifest themselves in the form of nausea and vomiting, sphincter spasm, and increased intracranial pressure. Respiratory depression is possible when large doses are used.

Among the drugs from the group of opioid receptor agonists-antagonists, buprenorphine (morphine, Temgesic), nalbuphine (Nubain), butorphanol (Moradol, Stadol, Beforal) and pen-tazocine (Fortral, Lexir) are used in Russia. The analgesic potency of these drugs is not sufficient for their use as a primary analgesic, so they are mainly used for postoperative pain relief. Due to their antagonistic effect on m-receptors, these drugs are used to reverse the side effects of opiates and, above all, to relieve respiratory depression. They allow you to relieve side effects, but maintain pain relief.

However, pentazocine can be used in both adults and children at the end of fentanyl anesthesia, when it allows for rapid relief of respiratory depression and retains the analgesic component. In children, it is administered intravenously at a dose of 0.5-1.0 mg/kg.

Muscle relaxants

Muscle relaxants (MP) are an integral component of modern combined anesthesia, providing relaxation of striated muscles. They are used to intubate the trachea, prevent reflex muscle activity and facilitate mechanical ventilation.

According to the duration of action, muscle relaxants are divided into ultra-short-acting drugs - less than 5-7 minutes, short-acting - less than 20 minutes, medium-acting - less than 40 minutes and long-acting - more than 40 minutes. Depending on the mechanism of action, MPs can be divided into two groups - depolarizing and non-depolarizing.

Depolarizing muscle relaxants have an ultra-short effect, mainly suxamethonium preparations (listenone, ditilin and myorelaxin). The neuromuscular block caused by these drugs has the following characteristic features.

Intravenous administration causes complete neuromuscular blockade within 30-40 s, and therefore these drugs remain indispensable for urgent tracheal intubation. The duration of neuromuscular blockade is usually 4-6 minutes, so they are used either only for endotracheal intubation with subsequent transition to non-depolarizing drugs, or during short procedures (for example, bronchoscopy under general anesthesia), when their fractional administration can be used to prolong myoplegia.

Side effects of depolarizing MPs include the appearance after their administration of muscle twitching (fibrillation), which, as a rule, lasts no more than 30-40 s. The consequences of this are post-anesthesia muscle pain. This happens more often in adults and children with developed muscles. At the time of muscle fibrillation, potassium is released into the blood, which can be unsafe for the functioning of the heart. To prevent this unfavorable effect, it is recommended to carry out precurarization - the introduction of small doses of non-depolarizing muscle relaxants (MP).

Depolarizing muscle relaxants increase intraocular pressure, so they should be used with caution in patients with glaucoma, and their use is not recommended in patients with penetrating ocular injuries. The administration of depolarizing MPs can cause bradycardia and provoke the onset of malignant hyperthermia syndrome.

Suxamethonium in its chemical structure can be considered as a double molecule acetylcholine (ACh). It is used in the form of a 1-2% solution at a rate of 1-2 mg/kg intravenously. Alternatively, the drug can be administered sublingually; in this case, the block develops after 60-75 s.

Non-depolarizing muscle relaxants

Non-depolarizing muscle relaxants include short-, medium- and long-acting drugs. Currently, drugs of the steroid and isoquinoline series are most often used.

Non-depolarizing MPs have the following features:

  • compared to depolarizing MPs, a slower onset of action (even with short-acting drugs) without the phenomena of muscle fibrillation;
  • the effect of depolarizing muscle relaxants ceases under the influence of anticholinesterase drugs;
  • the duration of elimination for most non-depolarizing MPs depends on the function of the kidneys and liver, although drug accumulation is possible with repeated administration of most MPs, even in patients with normal function of these organs;
  • most non-depolarizing muscle relaxants have a histamine effect;
  • block prolongation when using inhalational anesthetics varies depending on the type of drug: the use of halothane causes a block prolongation of 20%, isoflurane and enflurane - by 30%.
Tubocurarine chloride (tubocurarine, tubarin)- a derivative of isoquinolines, a natural alkaloid. This is the first muscle relaxant used in the clinic. The drug is long-acting (35-45 minutes), so repeat doses are reduced by 2-4 times compared to the initial ones, so that relaxation is extended by another 35-45 minutes.

Side effects include a pronounced histamine effect, which can lead to the development of laryngo- and bronchospasm, decreased blood pressure, and tachycardia. The drug has a pronounced ability to cumulate.

Pancuronium bromide (Pavulon), like pipecuronium bromide (Arduan), are steroidal compounds that do not have hormonal activity. They refer to neuromuscular blockers (NMB) long-acting; muscle relaxation lasts 40-50 minutes. When repeated administration, the dose is reduced by 3-4 times: with increasing dose and frequency of administration, the accumulation of the drug increases. The advantages of the drugs include a low probability of a histamine effect and a decrease in intraocular pressure. Side effects are more characteristic of pancuronium: a slight increase in blood pressure and heart rate (sometimes pronounced tachycardia is noted).

Vecuronium bromide (norcuron)- steroid compound, medium duration MP. At a dose of 0.08-0.1 mg/kg, it allows tracheal intubation within 2 minutes and causes a block lasting 20-35 minutes; with repeated administration - up to 60 minutes. It accumulates quite rarely, more often in patients with impaired liver and/or kidney function. It has a low histamine effect, although in rare cases it causes true anaphylactic reactions.

Atracurium bensilate (tracrium)- a muscle relaxant of medium duration of action from the group of isoquinoline derivatives. Intravenous administration of Tracrium in doses of 0.3-0.6 mg/kg allows tracheal intubation to be performed in 1.5-2 minutes. Duration of action is 20-35 minutes. With fractional administration, subsequent doses are reduced by 3-4 times, while repeated bolus doses prolong muscle relaxation by 15-35 minutes. Infusion of atracurium at a rate of 0.4-0.5 mg/kg per hour is advisable. The recovery period takes 35 minutes.

Does not have a negative effect on hemodynamics, does not accumulate. Due to the unique ability of spontaneous biodegradation (Hofmann elimination), atracurium has a predictable effect. The disadvantages of the drug include the histamine effect of one of its metabolites (laudonosine). Due to the possibility of spontaneous biodegradation, atracurium should only be stored in the refrigerator at a temperature of 2 to 8 ° C. Do not mix atracurium in the same syringe with thiopental and alkaline solutions.

Mivacurium chloride (mivacron)- the only short-acting non-depolarizing MP, a derivative of the isoquinoline series. At doses of 0.2-0.25 mg/kg, tracheal intubation is possible after 1.5-2 minutes. The duration of the block is 2-2.5 times longer than that of suxamethonium. May be administered as an infusion. In children, the initial infusion rate is 14 mg/kg per minute. Mivacurium has exceptional block recovery parameters (2.5 times shorter than vecuronium and 2 times shorter than atracurium); almost complete (95%) restoration of neuromuscular conduction occurs in children after 15 minutes.

The drug does not accumulate and has minimal effect on blood circulation parameters. The histamine effect is weak and manifests itself in the form of short-term redness of the skin of the face and chest. In patients with renal and hepatic impairment, the initial infusion rate should be reduced without significantly reducing the total dose. Mivacurium is the relaxant of choice for short procedures (in particular, endoscopic surgery), in one-day hospitals, for operations of unpredictable duration and when rapid restoration of the neuromuscular block is necessary.

Cisatracurium (nimbex)- non-depolarizing NMB, is one of ten stereoisomers of atracurium. The onset of action, duration and recovery of block are similar to atracurium. After administration of doses of 0.10 and 0.15 mg/kg, tracheal intubation can be performed in about 2 minutes, the duration of the block is about 45 minutes, and the recovery time is about 30 minutes. To maintain the block, the infusion rate is 1-2 mg/kg per minute. In children, when cisatracurium is administered, the onset, duration, and recovery of block are shorter compared to adults.

It should be noted that there are no changes in the circulatory system and (which is especially important) the absence of a histamine effect. Like atracurium, it undergoes organ-independent Hofmann elimination. Having all the positive qualities of atracurium (no accumulation, organ-independent elimination, absence of active metabolites), taking into account the absence of a histamine effect, cisatracurium is a safer neuromuscular blocker with an average duration of action, which can be widely used in various fields of anesthesiology and resuscitation.

L.A. Durnov, G.V. Goldobenko

JSC "Astana Medical University" Department of Anesthesiology and Reanimatology Completed by: Brown A.V. 6/114 group Checked by: Syzdykbaev M.K. Astana 2015

Slide 2

Anesthesia

1. Complete loss of sensitivity (in the narrow sense of the word). 2. A set of measures aimed at protecting the patient’s body from pain and adverse reactions that occur during surgery. General anesthesia is an artificially induced hyporeflexia with complete shutdown of consciousness, pain sensitivity and inhibition of a wide range of somatic and autonomic reflexes, achieved using pharmacological agents.

Slide 3

Classification of pain relief methods

Local anesthesia Regional anesthesia General anesthesia

Slide 4

General anesthesia

  • Slide 5

    Slide 6

    The main components of general anesthesia:

    1. Turning off consciousness. Inhalational anesthetics (halothane, isoflurane, sevoflurane, nitrous oxide), as well as non-inhalational anesthetics (propofol, midazolam, diazepam, sodium thiopental, ketamine) are used. 2. Pain relief. Narcotic analgesics (fentanyl, sufentanil, remifentanil), as well as regional anesthesia methods, are used. 3. Muscle relaxation. Muscle relaxants are used (ditilin, arduan, tracrium). There are also special components of anesthesia, for example, the use of a heart-lung machine during heart surgery, hypothermia, and others.

    Slide 7

    Slide 8

    Slide 9

    Periods (stages) of general anesthesia.

    1. Administration period (induction of anesthesia, induction). 2. The period of maintaining anesthesia (basic anesthesia). 3. Period of elimination (awakening).

    Slide 10

    Induction anesthesia.

    Anesthetics are administered by inhalation through a face mask (usually in children or with airway obstruction) using an anesthesia machine or intravenously through a peripheral venous catheter. The anesthesia (anesthesia-respiratory) apparatus is designed for ventilation of the lungs, as well as the administration of inhalational anesthetics. The dose of anesthetic is determined by body weight, age and state of the cardiovascular system. Intravenous drugs are administered slowly, with the exception of patients at risk of regurgitation (emergency surgery, pregnancy, obesity, etc.), when anesthetics are administered quickly.

    Slide 11

    During the period of maintaining anesthesia, intravenous, inhalational or combined administration of anesthetics continues. To maintain patency of the airway, an endotracheal tube or laryngeal mask is used. The procedure of inserting an endotracheal tube into the airway is called tracheal intubation. To carry it out, it is necessary to have endotracheal tubes of various sizes and a laryngoscope (an optical device designed to visualize the larynx; it consists of a handle and a blade).

    Slide 12

    During the period of recovery from anesthesia, the supply of anesthetics to the patient is stopped, after which a gradual restoration of consciousness occurs. After the patient awakens (determined by the ability to carry out simple commands, for example, opening the mouth), restoration of muscle tone (determined by the ability to raise the head) and the return of respiratory reflexes (determined by the presence of a reaction to the endotracheal tube, coughing), tracheal extubation is performed (removal of the endotracheal tube ). Before extubation, the gas mixture is replaced with 100% oxygen; if necessary, using a sanitation catheter, mucus is suctioned from the pharynx and tracheal tree (through an endotracheal tube). After extubation, it is imperative to ensure that the patient is able to maintain adequate breathing and, if necessary, use a triple maneuver, oropharyngeal airway, and assisted ventilation. Also, after extubation, the patient is given oxygen through a face mask.

    Slide 13

    Slide 14

    Slide 15

    Mask method

    Drip and hardware method of administration

    Slide 16

    Slide 17

    Non-inhalational anesthesia

  • Slide 18

    Drugs used:

    Ketamine Baryturates Propofol Sodium oxybutyrate Benzodiazepines

    Slide 19

    Combined methods of general anesthesia

  • Slide 20

    Slide 21

    Local anesthesia

    Can be caused by chemical and physical factors. Chemical factors include the use of local anesthetics. Depending on the method of administration of the local anesthetic drug, there are: 1. Superficial (terminal, application), 2. Infiltration 3. Regional anesthesia. stem, plexus, intraosseous, intravenous, intra-arterial, ganglion (zpidural and subarachnoid anesthesia). Physical factors include cooling the area of ​​the intended operation or damage with ice or chloroethyl.

    Slide 22

    Advantages of local anesthesia: a) safety; b) simplicity of the technique (no participation of other persons or complex equipment is required); c) cheap. Disadvantages: a) it is impossible to control body functions during extensive traumatic operations, especially on the organs of the thoracic cavity; b) it is difficult to perform an inspection during operations on the abdominal organs, since there is no relaxation of the muscles; c) it is not always possible to achieve complete pain relief (surgeries in the area of ​​scar tissue, etc.); d) in patients with unstable mental health, maintaining consciousness during surgery is undesirable.

    Slide 23

    In the clinical course of all types of local anesthesia, the following stages are distinguished: 1) administration of an anesthetic; 2) waiting (the effect of an anesthetic substance on the nerve elements of tissues); 3) complete pain relief; 4) restoration of sensitivity.

    Slide 24

    SUPERFICIAL ANESTHESIA Superficial, or terminal, anesthesia is possible only during operations and manipulations on the mucous membranes, which are lubricated or irrigated with an anesthetic solution. Therefore, this method is mainly used in ophthalmology, otolaryngology and urology. For anesthesia, 0.25-3% solutions of dicaine, 5% solution of xicaine, 10% solution of novocaine are used. For superficial anesthesia of the skin, the method of freezing with chlorethyl is used. In a surgical clinic, surface anesthesia is most often used for bronchological examinations (bronchoscopy, bronchography, bronchospirometry) and medical procedures (endotracheal infusions of drugs), as well as esophagoscopy, gastroscopy and duodenoscopy.

    Slide 25

    INFILTRATION ANESTHESIA The method of infiltration anesthesia according to A.V. Vishnevsky has become widespread. It is based on layer-by-layer tight infiltration of tissues, taking into account the spread of novocaine solution through the fascial sheaths - “tight creeping infiltration”. Weak solutions of novocaine are used - 0.25 and 0.5% solutions up to 1 or more liters per operation, and most of the solution flows out during the incision, which prevents intoxication. Infiltration anesthesia according to the method of A. V. Vishnevsky includes the following stages: intradermal anesthesia along the incision line using a thin needle with the formation of a “lemon peel”; tight infiltration of subcutaneous tissue; after incision of the skin and subcutaneous tissue, injection of novocaine under the aponeurosis; after dissection of the aponeurosis, muscle infiltration; after opening the abdominal cavity, infiltration of the parietal peritoneum. With anesthesia according to A.V. Vishnevsky, “the operation proceeds with a constant change of knife and syringe. Along with complete anesthesia, the tight creeping infiltrate also provides hydraulic tissue preparation.

    Slide 26

    Regional anesthesia

    Advantages of regional anesthesia methods 1. Reliable intraoperative anesthesia due to pharmacological control of pain at the spinal or peripheral level. 2. Effective autonomic blockade with minimal impact on homeostasis, endocrine-metabolic stability, prevention of pathological reflexes from the surgical field. 3. The ability to use controlled sedation of varying degrees, rather than turning off consciousness, which is mandatory when performing general anesthesia. 4. Reducing the recovery period after anesthesia, increasing the comfort of the postoperative period (no nausea, vomiting, reduced need for drugs, early restoration of mental function and motor activity). 5. Reduced incidence of postoperative pulmonary complications, faster recovery of gastrointestinal tract function compared to what occurs after combined general anesthesia. 6. Reducing the risk of deep vein thrombosis of the leg (DVT) and pulmonary embolism (PE). 7. Maintaining contact with the patient during surgery. 8. After orthopedic and traumatological interventions performed under regional anesthesia, conditions for immobilization of the damaged limb are optimized. 9. The advantage of regional anesthesia in obstetrics seems even more significant: the woman in labor is psychologically present during childbirth in conditions of complete analgesia, there is no fetal depression, early contact between mother and newborn is possible. 10. Regional anesthesia eliminates the risk of developing malignant hyperthermia, which is triggered by relaxants and inhalational anesthetics. 11. Regional anesthesia has a lower potential for inducing a systemic inflammatory response and an immunosuppressive effect compared to general anesthesia. 12. Environmental feasibility of using regional anesthesia - reducing “pollution” of operating rooms. 13. When using regional anesthesia, a statistically significant shortening of the length of stay of patients in the ICU and the duration of hospital treatment was noted. In general, it should be noted that the widespread use of regional anesthesia makes it possible to rationally limit the “all indications” of combined endotracheal anesthesia and thereby avoid the undesirable consequences of this method.

    Slide 27

    Basic methods of regional anesthesia

    Peripheral blockades: Conduction anesthesia Brainstem anesthesia Plexus anesthesia Intra-osseous* Region Intravenous * Central segmental blockades: Subarachnoidal (spinal, subdural) Epidural ( epidural) caudal; lumbar; thoracic *intraosseous and intravenous regional anesthesia are practically not used and are currently of only historical interest.

    Slide 28

    For regional anesthesia, the principle applies: the more proximal, the more effective, the more distal, the safer (Gileva V.M., 1995).

    Slide 29

    Local anesthetics used for regional anesthesia. Lidocaine (lignocaine, xylocaine) is a kind of standard with which other anesthetics are compared. Lidocaine has a relatively short-lived analgesic effect, moderate potency and toxicity. It is widely used for peripheral blocks and EA. Bupivacaine (marcaine, anecaine, carbostezin) is a powerful long-acting anesthetic. Bupivacaine is used for all types of regional anesthesia - peripheral and central segmental blocks. When performing SA, marcaine, used in the form of iso- and hyperbaric solutions, has minimal local toxicity and is currently the drug of choice. Ultracaine (articaine) is a drug with a short latent period, like lidocaine, and a fairly long action, comparable to bupivocaine. Like bupivocaine, ultracaine can be used for all types of regional anesthesia. Ropivacaine (naropin) is used for conduction (blockade of trunks and plexuses) and epidural anesthesia. The combination of high anesthetic activity, low systemic toxicity and the ability to cause differential blockade makes ropivacaine the drug of choice in obstetric practice and for prolonged epidural anesthesia in surgery.

    Slide 30

    Epidural anesthesia.

    Advantages: 1.Long duration of anesthesia. For example: a single-stage injection of 2% r-ralidocaine into the epidural space provides an average duration of anesthesia of 90 minutes. 2. Possibility of postoperative analgesia. Opioids and local anesthetics can be administered through the epidural catheter for postoperative analgesia. 3. Less severe hypotensive reaction. This advantage is more clearly evident if catheterization of the epidural space has been performed. Disadvantages: 1. Danger of intravascular injection. 2. Danger of subarachnoid injection. 3.Lengthening the time between induction and the start of surgery. 4.Technical difficulties. The lumen of the epidural space is approximately 5 mm and good manual skills are required to identify it. Puncture of the dura mater (occurs in 1–3% of cases) leads to severe post-puncture headaches. The frequency of inadequate anesthesia, according to various authors, is 3 – 17%. 5. Toxic effect of the anesthetic on the fetus. Relatively high doses of local anesthetic are used. Therefore, subtle physiological studies always reveal a certain degree of fetal depression, which worsens its adaptation. In fairness, it should be noted that with properly administered anesthesia, clinical signs of fetal depression are rarely detected.

    Slide 31

    Spinal anesthesia.

    Advantages. 1. During spinal anesthesia, manifestations of systemic toxicity of the drug are extremely rare. 2.Simpler implementation. The appearance of cerebrospinal fluid is an ideal reference for identifying the position of the needle. 3. Good quality of anesthesia. Spinal anesthesia, compared to epidural, provides a deeper motor and sensory blockade, which facilitates the surgeon’s work. 4. Quick onset. After administration of the anesthetic, the intervention can begin within 3 to 4 minutes. 5. When using standard dosages of anesthetic, spinal anesthesia, compared to epidural, has less individual variability in the extent of the anesthesia zone. 6. Spinal anesthesia is much cheaper than epidural and general anesthesia. Disadvantages: 1. Hypotension. Despite preventive measures, it is registered in 20–60% of cases. Eliminated by administration of ephedrine solution. Extended spinal anesthesia eliminates this disadvantage, but the high cost of the kit and the complexity of catheter installation make this technique inaccessible. Due to the higher frequency of neurological complications (compared to single-stage), the widespread use of prolonged spinal anesthesia in recent years has been suspended in a number of developed countries. 2. Limited duration. As already mentioned, the duration of anesthesia after a single injection of lidocaine is 60–70 minutes, which is sometimes really not enough and requires additional methods of pain relief. Bupivacaine lasts for more than 2 hours. This time is quite enough for intervention. 3. Post-puncture headache. When using small-diameter needles (from 22 gauge and above - 0.6 - 0.3 mm), the incidence of post-puncture headache is comparable to the frequency of a similar complication during epidural anesthesia, and is approximately 1 - 2%.

    Slide 32

    List of used literature

    Sumin S.A., Rudenko M.V., Borodinov I.M. Anesthesiology and resuscitation. 2009 Moscow. http://studentmedic.ru http://onarkoze.ru

    View all slides

    Under general anesthesia components should imply targeted measures of medicinal or instrumental influence aimed at preventing or weakening certain general pathophysiological reactions caused by surgical trauma or surgical disease. There are seven of these common components. The first of these is turning off consciousness, which is achieved with the help of one or another drug. It should be emphasized that to turn off consciousness, it is often enough to use superficial anesthesia. More often, the least harmless nitrous oxide or a combination of nitrous oxide with oxygen and 0.5-1% fluorothane by volume is used for this purpose. Superficial anesthesia, which turns off consciousness, simultaneously partially (depending on the type of general anesthetic) affects the following two components - analgesia and neurovegetative inhibition. Modern anesthesiology does not assign other tasks to a general anesthetic, since deep anesthesia itself is a unique form of aggression and causes pronounced changes in vital organs and systems.

    Second component - analgesia, as stated above, is partially achieved by a general anesthetic. However, it should be emphasized that here we can only talk about suppressing the psycho-emotional component of pain while maintaining neurovegetative and neuroendocrine reactions to painful stimuli. To eliminate these reactions, modern anesthesiology uses specific strong analgesics, preferably short-acting. If the operations were not accompanied by pronounced pathophysiological disorders, then local anesthesia would be the ideal remedy for eliminating pain. The latter is currently used quite widely for small outpatient operations. Various types of local anesthesia (conduction, perndural anesthesia) are used as an aalgesic component of general anesthesia in many medical institutions.

    Neurovegetative inhibition- the third component of modern anesthesia. As the name implies, we are talking here about preventing excessive reactions of the autonomic nervous system, i.e. about their inhibition, suppression, but not blockade. The first two components of anesthesia to a certain extent reduce neurovegetative reactions, and for small-scale surgical interventions this may be sufficient. However, during traumatic operations it is necessary to use special neuroleptic drugs (droperidol), which, by causing neurovegetative inhibition, help preserve the body's compensatory mechanisms and a smoother postoperative period.

    Fourth component- muscle relaxation and immobilization - allows you to create the necessary conditions for the operation. With mononarcosis, the necessary muscle relaxation was achieved by significantly deepening it, which in itself is unacceptable for modern anesthesia. In this regard, to achieve multiplegine, special drugs began to be used - muscle relaxants, which temporarily relax the striated muscles and thereby make it possible not to increase the concentration of the general anesthetic in the blood deeper than the surface level. However, the use of muscle relaxants, as a rule, requires the presence of a fifth component - maintaining adequate gas exchange with the help of artificial ventilation, since the respiratory muscles are exposed to the action of muscle relaxants. Maintaining adequate gas exchange is one of the main components of modern anesthesia. Actually, it was the absence of this component that for a long time hampered the development of thoracic surgery, because in the conditions of surgical pneumothorax the adequacy of gas exchange was out of the question. Rapidly developing hypoxia and hypercapnia negated the results of brilliantly performed operations. This one, it would seem. an insoluble problem that ceased to exist with the beginning of the era of muscle relaxants and artificial ventilation.

    For small operations, which do not require complete muscle relaxation and do not significantly affect the function of external respiration, instead of artificial ventilation, you can use the method of assisted ventilation. As the name implies, this method is used while the patient is still breathing independently. During assisted ventilation, the anesthesiologist synchronously with the patient’s spontaneous inhalation injects an additional volume of the gas-narcotic mixture into the lungs either manually or (if the anesthesia machine has a unit for assisted ventilation with a switch-off system) automatically.

    Maintaining adequate blood circulation- the sixth in a row, but one of the first most important components of modern anesthesia. During surgery, the circulating blood volume (CBV) undergoes the greatest changes; the pumping function of the heart and vascular tone are affected to a lesser extent. It should be emphasized that a decrease in blood volume can be associated not only, and sometimes not so much, with blood loss from the surgical wound, but with the deposition of blood in various organs, tissues and vascular venous collectors. The degree of deposition can sometimes reach such great magnitudes that the patient develops a typical picture of hemorrhagic shock during surgery without visible signs of external bleeding.

    From here it is obvious that anesthetist to assess BCC, one should be guided not so much by the measurement of external blood loss, but by special methods for determining BCC or (in their absence) clinical data. Today, all anesthesiologists are well aware of this, who, during any operation of even moderate complexity, make timely replenishment of the deficit of blood volume, or rather, try to prevent a significant decrease in blood volume. This is achieved by preliminary (even before blood loss!) administration of blood and blood substitutes or by using special methods aimed at reducing tissue bleeding (artificial hypotension, postural ischemia). It is thanks to this approach that the operational shock occurs. which was most often associated with a sharp decrease in BCC, i.e. which was essentially hemorrhagic shock, is beginning to disappear wherever there is a modern anesthesiological service.

    Important for adequate blood supply a large array of peripheral tissues (mainly muscles) has the condition of small arterial and venous vessels, i.e. vessels providing the so-called adequate microcirculation. As mentioned above, disruption of microcirculation is facilitated by excessive adrenergic reactions that accompany any traumatic operation. By providing neurovegetative and neuroendocrine inhibition with the special means indicated above, the anesthesiologist thereby prevents microcirculatory disorders and promotes adequate peripheral blood supply.

    More difficult to manage cardiac output. To regulate cardiac output, modern anesthesiology has a complex of cardiotonic agents that enhance myocardial contractility. Methods of mechanical and electrical influence are also used (conpulsation, electrical stimulation of the heart), and in some cases the transition to artificial blood circulation. With the introduction of membrane oxygenators into clinical practice, anesthesiologists were able to perform long-term artificial circulation and thereby control cardiac output not only during the operation itself, but also for 2-3 weeks.

    The main and main goal of anesthesia for surgical interventions is to adequately protect the child’s body from surgical stress. Modern anesthesia care, depending on the initial condition of the patient and the nature of the operation, includes the following components:

    Inhibition of mental perception or switching off consciousness. Suppression of the child’s emotional reactions before surgery is ensured by premedication or basic anesthesia. During surgery, consciousness is turned off by any inhalational or non-inhalational anesthetic, or a combination thereof. Turning off or suppressing the child’s consciousness during an operation or painful manipulation is mandatory!

    2. Providing central or peripheral analgesia (pain relief). Central analgesia is provided by blockade of the central nervous structures involved in the perception of pain. Analgesia can be achieved by administering narcotic analgesics; morphine, promedol, fentanyl; all general anesthetics also have a fairly pronounced analgesic effect. Peripheral analgesia means the shutdown of the reception and/or conduction of pain impulses along the axons of the nocisensory system by local anesthetics administered by any means. The combination of central and peripheral analgesia significantly improves the quality of general anesthesia.

    3. Neurovegetative blockade. To a certain extent, neurovegetative blockade is provided by anesthetics and analgesics. It is more reliably achieved by using ganglion blockers, neuroplegs, central and peripheral anticholinergic and adrenergic agents, using local anesthesia. Drugs of these groups reduce the patient’s excessive autonomic and hormonal reactions to stress factors that arise during surgery, especially if the operation is long and traumatic.

    4. Muscle relaxation. Moderate muscle relaxation is necessary to relax the child’s muscles during almost all operations, but when the nature of the surgical intervention requires mechanical ventilation or complete relaxation of the muscles in the operation area, muscle relaxation becomes a particularly important component. A certain level of relaxation is provided by general anesthetics. Muscle relaxation directly in the surgical area can be achieved using all methods of local anesthesia (except infiltration). Total myoplegia is a mandatory requirement in thoracic surgery and when performing a number of operations. To achieve this, muscle relaxants are used - drugs that block the conduction of impulses at neuromuscular synapses.

    5. Maintaining adequate gas exchange. Disturbances in gas exchange during anesthesia and surgery depend on various reasons: the nature of the underlying disease or surgical injury, the depth of anesthesia, the accumulation of sputum in the child’s respiratory tract, an increase in the concentration of carbon dioxide in the patient-device system, the patient’s position on the operating table, and others.

    Effective pulmonary ventilation is ensured if the following conditions are met: 1) correct choice of spontaneous or controlled breathing of the child during surgery; 2) maintaining free airway patency; 3) sizes of masks, endotracheal tubes, connectors, and breathing circuits selected according to age and anatomical characteristics.

    The above provisions must be taken into account not only for inhalation anesthesia, but also for all other types of anesthesia.

    6. Ensuring adequate blood circulation. Children are especially sensitive to blood loss and hypovolemic conditions, since the compensatory capabilities of the pumping function of the heart relative to the capacity of their vessels are reduced. In this regard, maintaining adequate blood circulation requires careful correction of water and electrolyte disturbances and anemia before surgery. Along with this, it is necessary to adequately maintain blood volume during the operation and in the postoperative period. The volume of blood loss during most surgical interventions in children is approximately known. Most anesthesiologists in their practical work use the gravimetric method for determining blood loss, weighing the “waste” surgical material and assuming that 55-58% of its total mass is blood. The method is very simple; but very approximate. Naturally, the functional state of blood circulation is one of the criteria for the adequacy of anesthesia. In order to maintain normal levels and correct emerging hemodynamic disorders, the anesthesiologist can use not only infusion media, but also drugs that have cardio- and vasoactive effects.

    7. Maintaining adequate metabolism is the provision of the necessary energy resources of the body, protein and carbohydrate metabolism, regulation of water and electrolyte balance, CBS, diuresis and body temperature during the intraoperative period. All these issues are covered in the relevant sections.

    The modern arsenal of means and methods of general and local anesthesia is quite large. In order to clearly navigate it and make the most of all its capabilities, you need a system. Based on historical experience and modern concepts about anesthetic protection of the body, we can present the following classification of types of anesthesia (Table 26.1.).

    Table 26.1. Classification of types of pain relief

    General anesthesia (anesthesia) Local anesthesia

    a) contact

    b) infiltration
    Simple

    (one-component) anesthesia

    		 Combined (multicomponent) anesthesia
    Inhalation Inhalation c) central conductor
    Non-inhalation Non-inhalation (spinal, epidural, caudal)
    a) intraosseous Non-inhalation +d) peripheral conductor
    b) intramuscular inhalation (case and nerve block
    c) intravenous Combined with trunks and plexuses)
    d) rectal muscle relaxants e) regional intravenous
    e)electronescosis Combined anesthesia e) regional intraosseous
    g)electroacupuncture

    This classification reflects all types of pain relief when one drug or method is used; different drugs are combined or fundamentally different methods of pain relief are combined.

    Single-component anesthesia. With this type of anesthesia, switching off consciousness, analgesia and relaxation are achieved with one anesthetic. Minor surgical interventions, painful procedures, examinations and dressings are performed under single-component inhalation or non-inhalation anesthesia. In pediatric practice, fluorotane, ketamine, and barbiturates are used more often than other anesthetics in this case. The relative advantage of this type of pain relief is the simplicity of the technique. The main disadvantage should be considered the need for a high concentration of the anesthetic, which leads to an increase in its negative effects; side effects on organs and systems.

    Inhalation anesthesia is the most common type of general anesthesia. It is based on the introduction of anesthetics in a gas-narcotic mixture into the patient’s respiratory tract, followed by their diffusion from the alveoli into the blood and saturation of the tissues. Consequently, the higher the concentration of anesthetic in the respiratory mixture and the greater the minute volume of ventilation, the faster the required depth of anesthesia is achieved, all other things being equal. In addition, the functional state of the cardiovascular system and the solubility of the anesthetic in blood and fats play an important role. The main advantage of inhalation anesthesia is its controllability and the ability to easily maintain the desired concentration of anesthetic in the blood. A relative disadvantage is the need for special equipment (anesthesia machines). Inhalation anesthesia can be carried out using a simple mask (not used in modern anesthesiology), hardware mask and endotracheal methods. A variation of the latter is the endobronchial method or one-pulmonary anesthesia, when inhalation of a gas-narcotic mixture occurs through an endotracheal tube inserted into one of the main bronchi.

    Non-inhalational anesthesia. With this type of anesthesia, anesthetics are introduced into the body by any possible route, except for inhalation through the respiratory tract. The most common drugs administered intravenously are: barbiturates, altesin, sodium hydroxybutyrate, ketamine, midazolam, diprivan, neuroleptanalgesia drugs. These drugs can also be administered intramuscularly; Ketamine is especially often administered this way. The remaining routes - rectal, oral, intraosseous - are rarely used for administering anesthetics. The advantage of non-inhalation mononarcosis is its simplicity: there is no need for anesthesia equipment. Non-inhalation anesthesia is very convenient on the day of induction (introductory anesthesia - the period from the onset of anesthesia to the onset of the surgical stage). Disadvantage: poor controllability. In pediatric practice, non-inhalation anesthesia is widely used for minor surgical interventions and manipulations, and is also often combined with any other types of anesthesia.

    Due to the general trend of more careful use of new medicinal substances and methods in pediatric practice, inhalation anesthesia is still used in the vast majority of cases for pain relief in children. This is mainly due to the fact that in children, especially young children, puncture of peripheral veins is difficult and children are afraid of this manipulation. However, such undoubted advantages of non-inhalation anesthesia as the possibility of intramuscular injections, ease of use, rapid action, low toxicity - make this type of anesthesia very promising in pediatric practice. In addition, it should be noted that the possibility of intramuscular administration of some non-inhalational anesthetics greatly facilitates general anesthesia in children, especially young children, as it allows one to begin anesthesia in the ward and then transport them to the operating room.

    Combined anesthesia. This is a broad concept that implies the sequential or simultaneous use of various anesthetics, as well as their combination with other drugs: analgesics, tranquilizers, relaxants, which provide or enhance individual components of anesthesia. In the desire to combine various drugs, the idea is to obtain from each drug only the effect that is best provided by this substance, to enhance the weak effects of one anesthetic at the expense of another while simultaneously reducing the concentration or dose of the drugs used. For example, during fluorotane anesthesia, nitrous oxide enhances the weak analgesic effect of fluorotane, and during ether anesthesia, nitrous oxide provides better induction, softening the stage of excitation.

    The discovery and introduction of muscle relaxants into anesthesiological practice has qualitatively changed the approach to combined pain relief. Muscle relaxation, which was achieved only with large (toxic) concentrations of anesthetics, is now provided by muscle relaxants. This makes it possible to achieve an adequate level of pain relief using relatively small doses of drugs with a decrease in their toxic effect. For example, consciousness can be turned off with propofol. relaxation should be provided with muscle relaxants, analgesia with the administration of fentanyl. In this case, adequate gas exchange is ensured by mechanical ventilation.

    Such a dream cannot be compared with ordinary daily sleep, when a person can be awakened by the slightest rustle. During medical sleep, a person essentially turns off for some time almost all vital systems, except the cardiovascular system.

    Premedication

    Before undergoing general anesthesia, the patient must undergo special training - premedication. Almost all people tend to experience anxiety or fear before surgery. Stress caused by anxiety can have an extremely negative impact on the course of surgery. At this moment, the patient experiences a huge event. This leads to malfunctions in the functioning of vital organs - the heart, kidneys, lungs, liver, which is fraught with complications during the operation and after its completion.

    For this reason, anesthesiologists consider it necessary to calm a person before surgery. For this purpose, he is prescribed sedative drugs - this is called premedication. For operations planned in advance, premedication is carried out the day before. As for emergency cases, it’s right on the operating table.

    Main stages, types and stages of general anesthesia

    General anesthesia is carried out in three stages:

    • Introductory anesthesia, or induction- carried out as soon as the patient is on the operating table. He is given medications to ensure deep sleep, complete relaxation and pain relief.
    • Maintenance anesthesia— the anesthesiologist must accurately calculate the amount of medications needed. During the operation, all functions of the patient’s body are constantly monitored: blood pressure is measured, pulse rate and breathing are monitored. An important indicator in this situation is the work of the heart and the amount of oxygen and carbon dioxide in the blood. The anesthesiologist must be aware of all stages of the operation and its duration, so that he can add or reduce the dose of drugs if necessary.
    • Awakening- recovery from anesthesia. The anesthesiologist accurately calculates the amount of drugs also with the aim of bringing the patient out of deep drug-induced sleep in time. At this stage, the medications should finish their effect, and the person gradually begins to awaken. All organs and systems are included. The anesthesiologist does not leave the patient until he regains full consciousness. The patient's breathing should become independent, blood pressure and pulse should stabilize, reflexes and muscle tone should completely return to normal.

    General anesthesia has the following stages:

    • Superficial anesthesia- disappears and is not felt, but reflexes of skeletal muscles and internal organs remain.
    • Light anesthesia- skeletal muscles relax, most reflexes disappear. Surgeons have the opportunity to perform light superficial operations.
    • Full anesthesia- relaxation of the skeletal muscles, almost all reflexes and systems are blocked, except the cardiovascular one. It becomes possible to carry out operations of any complexity.
    • Ultra-deep anesthesia- we can say that this is a state between life and death. Almost all reflexes are blocked, the muscles of both skeletal and smooth muscles are completely relaxed.

    Types of general anesthesia:

    • mask;
    • intravenous;
    • general.

    Adaptation period after general anesthesia

    After the patient recovers from general anesthesia, doctors monitor his condition. Complications of general anesthesia are extremely rare. After each operation there are indications. For example, if surgery was performed on the abdominal cavity, then you should not drink water for some time. In some cases it is allowed. The issue of patient movement after surgery is controversial today. Previously, it was believed that it was advisable for a person to stay in bed as long as possible. Today, it is recommended to get up and move independently within a fairly short period of time after the operation. This is believed to promote rapid recovery.

    Choosing a pain relief method

    An anesthesiologist is responsible for the anesthesia process. He, together with the surgeon and the patient, decides which type of anesthesia to give preference in a particular case. The choice of pain relief method is influenced by many factors:

    • The scope of the planned surgical intervention. For example, removing a mole does not require general anesthesia, but surgical intervention on the patient’s internal organs is a serious matter and requires deep and long medicated sleep.
    • The patient's condition. If the patient is in serious condition or any complications of the operation are expected, then local anesthesia is out of the question.
    • Experience and qualifications of the surgeon. The anesthesiologist approximately knows the course of the operation, especially in cases where this is not the first time he has worked with the surgeon.
    • But, of course, the anesthesiologist, given the opportunity to choose and in the absence of contraindications, will always choose the method of pain relief that is closest to him, and in this matter it is better to rely on him. Whether it is general or local anesthesia, the main thing is that the operation is successful.

    Reminder for the patient before surgery

    Before surgery there is always communication between the patient and the anesthesiologist. The doctor should ask about previous operations, what kind of anesthesia was used and how the patient tolerated it. On the part of the patient, it is very important to tell the doctor everything, without missing the slightest detail, since this can then play a role during the operation.

    Before the operation, the patient needs to remember the diseases that he had to endure throughout his entire life. This is especially true for chronic diseases. The patient should also tell the doctor about the medications he is currently taking. It is possible that the doctor may ask many more additional questions in addition to all of the above. He needs this information in order to eliminate the slightest mistake when choosing a method of pain relief. Serious complications of general anesthesia are extremely rare if all actions on the part of both the anesthesiologist and the patient were performed correctly.

    Local anesthesia

    Local anesthesia in most cases does not require the intervention of an anesthesiologist. Surgeons can independently perform this type of anesthesia. They simply inject the surgical site with a medical drug.

    With local anesthesia, there is always a risk that an insufficient amount of medication is administered and the pain threshold is not felt. In this case, there is no need to panic. You must ask your doctor to add the drug.

    Spinal anesthesia

    In spinal anesthesia, an injection is made directly into the spinal cord. The patient only feels the injection itself. After the administration of anesthesia, the entire lower part of the body becomes numb and loses all sensitivity.

    This type of anesthesia is successfully used for operations on the legs, urology and gynecology.

    Epidural anesthesia

    During epidural anesthesia, a catheter is inserted into the area between the spinal canal and the spinal cord through which

    Sometimes used for pain relief during childbirth and often during long-term operations in the field of gynecology and urology.

    Which is better, epidural anesthesia or general anesthesia? This is a very controversial issue today. Everyone has their own arguments about this.

    Mask anesthesia

    Mask anesthesia, or inhalation general anesthesia, is introduced into the body through the patient's respiratory tract. With this type of anesthesia, sleep is maintained thanks to a special gas that anesthesiologists supply through a mask applied to the patient's face. Used for light, short-term operations.

    If mask anesthesia is used, the main thing for the patient is to listen to the doctor: breathe as he asks, do what he says, answer the questions he asks. With mask anesthesia, it is easy to put the patient to sleep, and just as easy to wake him up.

    Intravenous anesthesia

    During intravenous anesthesia, drugs that induce medicinal sleep and relaxation are injected directly into a vein. This allows you to achieve quick effect and high-quality results.

    Intravenous anesthesia can be used for a wide variety of operations. It is the most common in classical surgery.

    Multicomponent general anesthesia with muscle relaxation

    This type of anesthesia is called multicomponent because it combines mask and intravenous anesthesia. That is, the components of general anesthesia are administered in the form of drugs intravenously, and in the form of gases through the respiratory system. This type of anesthesia allows you to achieve maximum results.

    Myorelaxation is the relaxation of all skeletal muscles. This is a very important point when performing surgery.

    General anesthesia. Contraindications

    There are some contraindications to the use of general anesthesia:

    • cardiovascular failure;
    • severe anemia;
    • myocardial infarction;
    • pneumonia;
    • acute kidney and liver diseases;
    • bronchial asthma;
    • epilepsy attacks;
    • treatment with anticoagulants;
    • such as thyrotoxicosis, decompensated diabetes, adrenal diseases;
    • full stomach;
    • severe alcohol intoxication;
    • lack of an anesthesiologist, necessary drugs and equipment.

    General and local anesthesia are very important elements in modern surgery. No operation takes place without pain relief. In this matter, medicine must be given its due, because not every person can endure a painful shock.