ANAESTHESIA

Evidences, which reached us, prove that attempts of fighting with pain (anaesthesia) were made in the far past too. So, in ІV–ІІІ centuries AD in Egypt and later in Greece and Rome, China and India, the extracts of mandragora, belladonna, etc. were applied. During the Renaissance and later during the process of illness mechanism investigation, the operative methods of treatment began to use more often. Nevertheless, the more surgeons were managed with tissue dissection, the more complications arose, and frequently operations resulted in the patient’s death. Now we know that the cause of these deaths consists in pain shock. In those times at the operational room of one of the London hospitals a bell was sounded to try to muffle the cries of the patients being operated on.

Lev Tolstoi in his novel “The war and peace” describes an operation at that time:

”In the ward there were three tables. Two were occupied, and prince Andrey was put on the third. On the nearest table a Tatar, probably a Cossack juging by his uniform, was sitting. Four soldiers held him. The doctor in glasses was cutting something on his brown, brawny back.

Ah, Ah, Ah! — as the Tatar grunted and suddenly lifting up his black, snub-nosed face, grinned with white teeth, started tear away, twitch and shrill. On the other table where people crowded, a big, stout person was lying on his back with his head thrown back. Some medical assistants pushed hard on the chest and held him down. The white, big, stout leg quickly and frequently, not ceasing, twitched with feverish trembling. This person convulsively sobbed and choked…

The doctor in glasses, wiping off his hands, approached prince Andrey… bent down over the wound, palpated it and sighed. And then he gave someone a sign. And unbearable pain in the stomach forced prince Andrey to lose consciousness. When he regained consciousness, the broken bones of the hip had been taken out, torn skin was cut off and the wound was sutured up. His face was sprinkled with water”. Anestesia was not used.

The attempts to struggle with pain were undertaken by Avicenna, Larrey, A. Pare. Sometimes there were severe methods: bloodletting, cross-damping of the carotids, cooling the place of operation. The recommendations to use opium, hemp and decoctions of other herbals for the removal of pain were offered in the handwritten manuscripts of ХV–ХVІ centuries in the Kiev Russia.

There was a paradoxical situation — knowing that the patient could recover after surgical treatment, the surgeons started being afraid to carry out operations with high death rates.

Together with the development of anatomy, biochemistry, chemistry, medical biology the application of surgical methods of treatment were forced to develop.Achievements in engeneering and science assisted surgeons to adjust to situation.

In the XІ century the operational anaesthesia appears. Using Cordus’s supervision of the role of ether, doctors made attempts to use it for narcosis.

In 1844 Wells used nitrogen oxide, which was being investigated by Kolton for its demonstration of a sleepy effect during an operation. But after the first operation the failures occured. Wells was made fun of and his attempts were rejected. Unrecognized Wells committed suicide. The true date of birth of anesthesiology — the science of fighting against pain — is considered October, 16, 1846. On this day, Warren removed a tumour from the submaxillar area under ether narcosis in a Boston hospital. Then the avalanche of discovering substances which have anesthetic effect rolled. The drugs began to be used in the clinic. In 1847 Simpson suggested chloroform, in 1879 Anrep — cocaine, in 1902 Kravtsov — gedonal. In 1899 Bir suggested to inject the anesthetic into the spinal channel. In 1905 Einhorn suggested to use novocain; in 1942 Griffit — myorelaxants.

Certainly, every anesthetic has positive and negative properties. Cocain  was very toxic, chloroform narcosis caused a lot complications. Clinical physicians studied each substance, course of the disease and in time eventually it was determined that special doctors should perform anaesthesia. In 1937 in England Makintosh created a school for new specialists — anaesthesiologists.

Depending upon the anesthetic, the ways of its introduction, depth of pain sensitivity removal, modern anesthesiology distinguishes general and local anaesthesia.

General anaesthesia (narcosis) is a condition when reactions to operational traumas are absent or reduced with a loss of consciousness.

Under narcosis the function of the brain cortex is turned off, areflexia, and absence of sensitivity are observed. During this period the function of the oblong brain is not disturbed, spontaneous breathing and the work of the heart are kept. Narcosis is divided into inhalation (anesthetic is given through the respiratory tract) and non-inhalation — anesthetic is given beyond the respiratory ways.

If narcosis is achieved with one preparation, it is called mononarcosis, if with several ones, it is called mixed narcosis. If narcosis is performed by anesthetics given with several ways, it is called combined narcosis.

The mechanism of narcosis development has some explanations which show the concept of the narcosis theory. These theories change, supplemented during studying the course of narcosis. Today there are the following theories of narcosis:

the lipoid theory — suggested by Overton, consists in an ability an anesthetic to dissolve in fats. Penetrating into the cells of the brain, where there is a lot of lecithine and cholesterol, they cause sleep;

the adsorption theory — suggested by Traube, explains the adsorption of narcotic substances on the surface of cells, which results in delay of enzyme processes and produces sleep;

the Veber’s permeability theory is based on an ability of anesthetics to penetrate through the membrane of a cell and to change its colloid-osmotic properties;

the Varburg’s asphyxia theory — anesthetics disturb the oxidation processes in the brain cells. Cells lose an ability to intake oxygen, cellular dyspnoe occurs;

the Miller’s water crystal theory — crystallohydrates are formed in the cell under the influence of anesthetics — the resistance of the cellular membrane changes and a block is formed from carrying through synapses, which produces anaesthesia;

20 modern theories have appeared today thanks to works of chemists and biophysics, which come to a change in the oxidation processes in brain cells, infringements of calcium ions concentration. The assumption that anesthetics strengthen the emission of morphine-like substances — endorphine, has appeared;

neuroreflector theory — based on the work of Sechenov, Pav-lov, Ukhtomsky and Vvedensky on the activity of the central nervous system, Batrak suggested a theory based on the changes in the inhibitory and stimulating processes, and the changes in the function of the reflex arch. This theory does not eliminate all the previous ones but explains the clinical course of narcosis more completely.

Inhalation Narcosis

Different substances which are entered into an organism through the respiratory ways are applied in this kind of narcosis.

Liquid anesthetics:

ether for narcosis — a liquid which quickly evaporates, has a wide range of therapeutic action. It is kept in orange glass bottles because under the action of solar beams it can decompose;

halothane — 4 times more active in comparison with ether. It should be dosed out precisely and it requires oxygen;

methoxyflurane (penthran) — less toxic, does not decompose under the action of light, intensively accumulates in fatty tissue, capable of strengthening the action of relaxants;

enflurane (entran) — have significant relaxant action, but when a patient is coming out of narcosis he may faint, have a fever, headaches;

isoflurane (foran) — stronger than other inhalation anesthetics, depresses breathing, weakens muscles and strengthens the action of relaxants. While coming out of narcosis, excitation can be observed;

chlorethyl — the range of therapeutic action is narrow, overdosage is frequently observed. It can be applied for short-term narcosis;

trichlorethylene is not used as narcosis for long operations; it has many side effects (oppression of heart function, liver).

Gaseous narcotic substances:

а) nitrous oxide — inert, colorless gas. It causes superficial anaesthesia, therefore it is combined with ether or halothane. It is always combined with oxygen. Sleep comes in 2–3 min;

b) cyclopropane — colorless gas with a typical odour. Because in a mixture with oxygen and air it is explosive, a precise doze ratio is necessary. It is applied seldom.

Equipment and Methods of Carrying out

Inhalation Narcosis

Anesthetics are given through the respiratory ways, applying an equipment which works by the follow methods:

Open method — the patient inhales the anesthetic from a device and exhales it into the surrounding atmosphere of the operational room.

Semi-open method — the anesthetic is inhaled from a device isolated from the environment and exhaled into the surrounding atmosphere.

Closed method — the anesthetic is inhaled from a device and is either partially exhaled into the surrounding atmosphere or only into a device where there is a carbonic gas absorber — soda lime.

Today either mask or endotracheal intubation narcosis are used. Narcotic apparatuses are of different forms and modifications: Ро-1; Ро-2; Ро-6, etc. They have an inhalation anesthetic vaporizer, respiratory bag, connecting tubes, and masks. Modern devices are equipped with system for artificial lung ventilation. At the operating room there is a narcosis table with a set of medicines, intubation tubes, defibrillator, etc.

Stages of narcosis

There are 4 stages of the course of inhalation narcosis:

І stage (analgesia) — occurs 3–5 min after the beginning of narcosis, pain sensitivity decreases and consciousness is depressed up to dissappearence. In this stage it is possible to perform small surgical operations, as a rule, such as opening of abscesses or processing superficial wounds.

ІІ stage (excitation) — occurs 6–8 min after the beginning of narcosis, accelerated breath, ABP increases, hyperemia of the skin, pupils are dilated, but react to light, motoric and speach excitation are observed, consciousness is absent.

ІІІ stage — excitation is replaced with gradual sleep. Consciousness is lost, muscles relaxed, breath is leveled, pulse is stabilized and the patient does not react to pain and touch.

According to the deapth of the sleep, including the removal of pain sensitivity, the ІІІ stage is divided into 4 levels.

ІV stage — awakening or overdosage.

Control over the course is conducted by the following parameters: pulse, ABP, breath, pupil reaction and also eye reflexes.

Endotracheal Narcosis

In 1847 under experimental conditions M. I. Pyrogov applied the anesthetics through the trachea. Today, the technique of endotracheal narcosis is developed and on occasion endobroncheal intubation is performed.

Intubation narcosis has a number of advantages in comparison with mask narcosis.

It interferes the tongue swallowing, reduces the danger of aspiration and allows to apply relaxants and control the respiration. During intubation the artificial lung ventilation is carried out, which reduces the possiblity of pneumonia occurrence.

During the introduction of the intubation tube, it is necessary to follow some rules: determine length and diameter of the intubation tube, before intubation it is necessary to conduct an introductory intravenous narcosis. Artificial lung ventilation (ALV) is carried out with the help of respirators for artificial ventilation or a respiratory bag. Today the automatic narcosis devices are also used.

Muscle Relaxants

Modern narcosis is combined with the introduction of relaxants which relax the muscles. Their application considerably reduces the amount of anesthetics and creates conditions for artificial lung ventilation.

Relaxants are divided into 2 groups: depolarizing (make a stable depolarization of the synaptic membrane) and non-depolarizing (connects with the post-synaptic membrane structures and block the opportunity of their interaction with acetylcholine). Non-depolarizating relaxants are mostly used. Their action comes quickly, on the average in about 3–5 min and the duration of the action is from 20 up to 45 min.

Tubocurarine chloride, diplazin, arduan, anatruxoni and dioxonium belong to this group.

The action of the depolarizing relaxants (lysthenon, dithylin, myorelaxin) lasts for 4–5 min.

Complications of Inhalation Narcosis

Complications can occur in any anaesthesia. They can appear during narcosis or after it. During narcosis complications are observed in connection with side actions of the anesthetic, malfunction of the narcosis equipment, ignoring safety measures or underestimation of accompanying diseases.

During narcosis complications with the respiratory and cardiovascular systems can happen. Therefore, the anesthesiologist should determine the condition of these systems, choose the anesthetic and appoint its dose while considering the time and volume of operation before it. It is necessary to remember that M. I. Pyrogov said that there is one step from narcotic sleep to death.

The rhythm and conduction infringements, cardiac arrest, thrombembolia, lung oedema can be observed on the side of the cardiovascular system.

Ventricular fibrillation, mostly observed during narcosis, can be the reason of cardiac arrest. Arterial pressure falls or is not determined, pupils dilate and bleeding in the wounds ceases. Sometimes at the beginning of narcosis the rhythm failure in the cardiac activity is observed — specially in chloroformic and fluoroatan narcosis. The direct or indirect massage of the heart, intracardiac introduction of adrenaline, atropine, calcium chloride and sometimes electric defibrillation are conducted in case of cardiac arrest. Arrhythmia, which occurred, a drop in pressure can be connected with insufficient depth of narcosis or an extensive operational trauma. It is necessary to deepen narcosis, stop the operation for a while.

Pulmonary oedema can develop due to weakness of left ventricle activity. It is necessary to remove mucous from the lumens of the bronchial tubes, strengthen heart activity by the introduction of heart glycosides, corticosteroids and diuretics.

In respiratory infringement it is necessary to assume acute hypoxia. This complication arises because of faulty equipment, disruption between the ratio of entered anesthetics and oxygen, respiratory standstill. Cyanosis of the mucous, dark blood in the wound may be observed. There are a number of reasons which can result in hypoxia. The reflex reason is a reaction to the anesthetic, resulting in laryngo- or bronchospasm. The action of the anesthetic should be removed by using spasmolytics. Laryngo- and bronchospasms are severe complications, which are hardly removed and rather frequently can be the cause of death. Asphyxia can be caused by mechanical factors — most often vomitive masses, which gather into the lumens of the bronchial tubes. Sometimes during narcosis regurgitation is observed — gastric and intestinal contents get into the nasopharynx due to return peristalsis. That is why washing of the stomach should be done before the introduction of narcosis and a stomach probe should be entered for the period of narcosis.

The most severe type of hypoxia is toxic, which results from overdosage of anesthetics. It is sometimes difficult to estimate the condition of the patient during narcosis, because decrease in pressure, breathing, pupils and reflexes can change according to the severity of the disease, in particular, bacterial intoxication.

Sometimes, if respiratory volume is not taken into account, a significant amount of carbonic gas can accumulate in the blood, causing hypercapnia.

While awakening (coming out of narcosis) motoric excitation, vomiting can occur, which can lead to traumas, asphyxia, etc. The postoperative period is always accompanied by changes in metabolism. The depth of these changes depends  not only on the time of narcosis but also the extent of the operation, the presence of infection or pathology of the main organs and systems. The patient needs a certain period for metabolism restoration, that is why this period is called postoperative disease. It has several phases:

The phase of adrenergic and cortical activity increase. It lastsfor 1–3 days. During this phase the amount of daily diuresis and quantity of water in the organism decreases. Deficiency of potassium is observed both on account of aldosteronum, and due to the reduction of protein. In its turn, the potassium deficiency results in atony of the GIT and a decrease of muscle tone and the respiratory functions. Acidosis is observed. Respiration is accelerated. With vomiting the potassium deficiency and hyperventilation can result in alkalosis.

Correction of alkalosis is conducted by the Astrup formula.

Phase of adrenergic and cortical activity decrease is observedon the 4th–8th day. Thus diuresis amplifies, sodium is excreted with urine, the excretion of potassium decreases.

Phase of anabolism occurs on the 8th–14th day and during thisphase there is levelling in the nitrogenous balance, improvement in metabolism (carbohydrate, proteins, mineral).

The phase of fat accumulation usually occurs after the 14thday and manifests in the body weight increase.

NON-INHALATION NARCOSIS

It is possible to achieve anaesthesia not only by respiratory introduction. There are intravenous, intramuscular, subcutaneusly, intraperitoneal, per rectum methods.

Intravenous narcosis is applied most often. This way of introduction has been investigated for a long time, even Pyrogov tried to give ether. In 1902 M. P. Kravtsov discovered hedonal and this narcosis received the name “Russian narcosis”. Today there are many preparations for intravenous narcosis. They are subdivided into several groups:

Derivatives of barbituric acids — hexenalum, thiopentalumnatrium; distributed in ampoules and powder; before application they should by diluted.

It’s necessary to note that while using these preparations there is no phase of excitation, patients quickly calm down. But it is necessary to remember that these substances are strong drugs, nevertheless their analgesic action is of little significance. They depress the respiratory center; therefore they cannot be applied without devices which control respiration.

Steroid anesthetics are altezinum, viadrilum. They have notoxic action on the liver, easily endured by patients, can be used with all inhalation and non-inhalation anesthetics, but they have a weak analgesic action.

Propanididum (or sombrevinum) — propyl ether from phenylacid. Sleep comes quickly, but anaesthesia lasts for 3–5 min. It is necessary to carefully use it for patients who suffer from allergies because it can become a cause of anaphylactic shock.

Ketamin (ketalor, kalipsol) — derivative of cyclohexane: narcosis quickly comes and lasts for 30–40 min. Narcosis occurs on the first level of the ІІІ stage of narcosis. Sometimes it can provoke spasms, therefore it is impossible to give to patients who suffer from epilepsy and psychomotor excitation.

Ethomidat (radennarcon) — narcosis comes quickly and lastsfor 10 min., sometimes it serves as the reason for convulsive twitching in certain muscles. It shows a good effect in combination with other anesthetics.

Sodium hydroxybutyrate or GABA. It has a weak analgesicaction; narcosis comes 10–15 min after introduction and lasts for 2– 4 h. It cannot be applied during myasthenia.

Neuroleptanalgesia is a modern non-inhalation narcosis offered by de Castro in 1959. The essence of it consists in the association of actions of neuroleptics and analgesia.

The following preparations are applied in this narcosis:

а) droperidolum — possible to enter intravenously and intramuscularly, duration of effect is 3–7 h. It has a smoothing, relaxing action;

fentanyl is narcotic analgesic. It is 100 times stronger than morphine in analgesic action. I/v introduction. The effect comes in 2–3 min, but lasts almost 1.5 h;

thalamonal is a combination of droperidol and fentanyl in one bottle.

Ataralgesia is narcosis which combines sedative, tranquilizing and analgesic means. Palfium, dipidolor, fentanyl, pentosacinum are mostly used as analgesic means; sibazon (diazepam), relanium, etc. — as sedative means.

There are standard techniques for ataralgesia:

а) combination of sibazonum, dipidolor and muscle relaxants and nitrogen oxide with oxygen;

combination of seduxen and palfium and nitrogen oxide with oxygen;

combination of seduxenum and fentanyl.

Central analgesia is a variant of multicomponent anaesthesia, which is achieved due to the introduction of large doses of analgesics, which influence the CNS with a change in the conducting pain signals. Morphine or fentanyl are applied as anesthetics.

After the loss of consciousness with the help of ketalar and seduxen with the inhalation of nitrogen oxide with oxygen, morphine is given with the calculation of 3 mg per 1 kg or fentanyl — 3–6 mg per 1 kg. Analgesia is kept for 4–6 h. Sometimes morphine and fentanyl are combined with promedol, dipidolor.

Anaesthesia like that is used for extensive operations on organs of the thorax, traumatic shock, as well as operations with the application of artificial blood circulation.

Controlled Hypotension

Attempts to operate on patients under the conditions of decreased arterial pressure have been known for a long time. In old treatises, it is described that patients with hypotension tolerate the surgical intervention easier. If earlier people resorted to bloodlettings, today there is a number of medicines which block ganglia of the VNS: pentamin, bensohexonium, harphonad, sodium nitroprussid. Their introduction provokes hypotension, which is especially important in neurosurgical and vascular operations. These preparations can be applied in other operations as well, if there is arterial hypertension. Contraindications to controlled hypotension are acute coronary insufficiency, blood loss, glaucoma, insult.

Artificial Hypothermia

Decrease in the body temperature as a whole or on a local site has been used since ancient times. J. D. Lorray and M. I. Pyrogov marked a decrease in pain sensitivity during hypothermia. Bigelou widely introduced this method into clinic. First, the local hypothermia was applied, and in due time the general one.

Cooling the patient begins after his introduction into deep narcosis by the application of neuroleptics and muscular relaxants. The patient is immersed into a cold bath or is edged with ice blisters. Last years, special hydrosuits are used or cooled liquids are passed through the stomach of the patient. During operations on the cardiovascular system the application of cooling blood in a system is widely used (so-called extra-corporal hypothermia). As a rule, the body temperature is reduced to 30–33°С (superficial hypothermia) or 20– 25°С (deep hypothermia).

Surgical treatment concludes with bringing the patient out of hypothermia with the help of active warming (hot-water bottle, mattress) or massive thermal wrappings.

Such a method is allowable only with the presence of good equipment and individual patient care.

Artificial Hybernation

Any operation demands corresponding reaction of an organism, increase in metabolism. In nature some animals fall into a winter sleep, and their vital activity being supported against a background of significant decrease in metabolism. It appears that a condition of anabiosis is possible in clinic, which allows the introduction of a number of lytic mixtures, which consist of neuroleptics, ganglioblockers. Most often it is a combination of aminazine, isopromethazine, and lidol. The body temperature decreases to 2–7°С. Supplementing narcosis with this method, a more adequate response of an organism to operational trauma is achieved.

Local Anaesthesia

Fight against pain can occur not only with the help of the abovestated methods, which come to the loss of consciousness. It can be combined with the loss of pain sensitivity at the operation site. Even Anrep, and then Einhorn, suggested the use of cocain  and novocain for entering into nervous trunks or plexus. Since then different ways of introduction of different preparations and their toxic action have been studied; the technique of introduction and clinical efficiency were developed.

Today a number of preparations for local anaesthesia are known:

а) novocain — a preparation which is applied as 0.25%, 0.5%, 1%, 2%, 5% solutions. The solutions are prepared from Novocain powder and in sterile vials or ampoules are delivered to the hospitals. Tolerability of this preparation is high; however it is necessary to carry out tests for sensitivity because sometimes it can be the reason of allergic reactions. The doses of different preparations are different depending upon the concentration — from 500 ml of a

0.25% solution up to 5 ml of a 2% solution;

b) adhering to certain doses and ways of introduction, sovacaine, cocaine, lidocaine, trimecaine, celnovocain  are used. As a rule, they are given as solutions hypodermically, intramuscularly, periand endoneurally.

Depending upon the way of introduction the following kinds of local anaesthesia are distinguished:

— surface (contact), or greasing anaesthesia. Mostly, it is action on mucous membranes. This kind of anaesthesia is mostly used in the ear-nose-throat clinic, ophthalmology and in different endoscope examinations. A 1–3% solution of cocaine, or 0.25–3% solution of dicaine, or 2–5% solution of novocain or lidocain  are most often applied;

— infiltration anaesthesia is the method of infiltration of tissues with anesthetics. At the site of the expected operation, a solution of novocain (formation of “citric crust”) is given intradermally and further by layers they infiltrate tissue according to their incision. The anesthetic is given linearly according to the course of opening or rhomboidally.

O. V. Vishnevsky developed infiltrative anaesthesia, techniques of performance and effectiveness. As an anesthetic agent for anaesthesia, a 0.25–0.5% solution of novocain is applied, or sometimes it is given together with adrenaline or lidocain  — this strengthens the effect of anaesthesia;

— block (regional) anaesthesia — with this anaesthesia the flow of pain pulses is disrupted by the introduction of the anesthetic into a nerve (endoneural) or around it (perineural) or into the neural plexus. Thus sensitivity below the place of introduction is switched off. As a rule, with this purpose a 1–2% solution of novocain or lidocain  is applied. Block anaesthesia is used during operative interventions (extremities, thorax) and in stomatology;

— intraosseous anaesthesia is applied during operations on extremities. The extremity is lifted up and a tourniquet is applied, then in the spongiform substance of the bone, a needle is stuck and through it a 0.25% solution of novocain with an amount from 50 up to 150 ml is entered. This is a type of internal anaesthesia. In modern practice it is applied seldom.

Spinal, Peridural and Sacral Anaesthesia

This kind of anaesthesia is connected with the introduction of anesthetic into the subarachnoidal, peridural or sacral cavity. Solutions of sovocain, novocain, lidocain with concentration of 1–2% are used. The techniques of its conduction demand practice because introduction of anesthetic can cause complications, which should be avoided.

During spinal anaesthesia the patient usually sits on the operational table. The patient inclines forward; spine as much as possible is bent. The spinal canal is punctured between the ІІІ and ІV lumbar vertebra. Some liquid is deleted, mixing it in a syringe with the anesthetic, and then the mixture is entered into the spinal canal. Then, the patient is put on the operational table with the head lifted. During peridural anaesthesia the dura mater is not punctured, and the anesthetic is given into the peridural cavity.

During sacral anaesthesia, the anesthetic is entered into the sacral canal. Depending upon the way of introduction the removal of pain sensitivity occurs on different levels (a certain segment of the spine is switched off). During this anaesthesia, it is possible to operate on the lower extremities, organs of the pelvis and abdominal cavity. It is necessary to remember that with different kinds of local anaesthesia there are different kinds of complications. First of all, there may be damage to the nerves and the occurrence of paresis and paralyses. With the violation of technique and sterility hematomas can appear, tissue can be infected. During spinal anaesthesia hypotension or respiratory standstill, if the anesthetic numbs the top segments of the spinal cord, can be observed. Sometimes during this anaesthesia, weakness in the lower extremities, elements of muscular atrophy can be observed for a long time. Nevertheless, greatest disadvantage of local anaesthesia is the preservation of consciousness, that is why it is not applied during operations on children and people with hyperexcitability of the nervous system. The mentioned circumstances make local anaesthesia the method of choice today.