From Big Medical Encyclopedia

INHALATION ANAESTHESIA (Latin inhalare to breathe, inhale; grech, narcosis numbness, catalepsy) — a type of an anesthesia, at Krom narcotic substance in gazo-or a vaporous state comes to an organism through lungs. For And. N apply nitrous oxide, ether, cyclopropane, Ftorotanum, metoksifluran (Penthranum), etc. And. the N is possible at independent breath of the patient.

During the carrying out artificial ventilation of the lungs when anesthetic is blown into lungs by means of a respiratory bag or a respirator, the anesthesia is called insufflyatsionny.

For the first time inhalation etherization was applied in 1842 by W. Clark at an odontectomy at the patient. The same year G. W. Long removed a tumor of a neck under etherization. However U. Morton who made extraction of tooth under etherization only in 1846 got glory of an opener of etherization. The anesthesia nitrous oxide was for the first time carried out in 1844 by G. Colton. The first operations under radio And. N in Russia were carried out by F. I. Inozemtsev and N. I. Pirogov in 1847. N. I. Pirogov's merit is that it not only implemented a method of the general anesthesia in surgery, but also made systematic researches of different ways of administration of ether to an organism, and also carried out mass use of etherization in field conditions.

And. the N is shown to the wide contingent of patients at various interventions on bodies of belly and chest cavities, extremity operations etc. However during the definition of indications to And. the N needs to consider a number of factors: injury and duration of surgical intervention, general condition of the patient and nature of associated diseases, technical capabilities and experience of the anesthesiologist. In the conditions of the modern combined anesthesia use of inhalation anesthetics is possible even at extremely heavy patients, however in a specific case it is necessary to consider strictly pharmakol, properties of inhalation anesthetics.

Absolute contraindications to And. there is no N, however it can be undesirable at a burn of respiratory tracts, is rather contraindicated at deformation of a nose and mouth, is complicated at deformations of cervical department of a backbone, cicatricial changes of a neck after injuries or burns etc.

Narcotic substance at an inhalation or insufflyatsionny anesthesia comes to blood through an alveolocapillary membrane. Speed of development of the general anesthesia depends on mechanisms of absorption and distribution of anesthetics in an organism. Absorption intensity of narcotic substance is defined by concentration of anesthetic in an alveolar air and diffusion properties of the alveolar capillary membrane, a solubility coefficient of anesthetic in blood, the volume of a blood-groove by pulmonary capillaries and an alveolar and venous gradient of partial pressures of anesthetic.

The more concentration of anesthetic in an alveolar air, the more vigorously occurs its absorption. The solubility coefficient of anesthetic in blood is higher, the is longer there is an introduction to an anesthesia (induction) and escaping it.

Very low coefficient blood/gas (the relation of concentration of anesthetic in blood and gas with its identical partial pressure in these environments) characterizes gaseous general anesthetics (nitrous oxide, cyclopropane). In this regard the gas anesthesia comes quickly and also quickly stops after cutoff of anesthetic. Flying narcotic substances are characterized by high coefficients blood/gas: metoksifluran — 13,0, diethyl ether — 12,1, chloroform — 10,3, Ftorotanum — 2,3. In complex process of distribution of anesthetics in an organism the large role is played by also minute volume of ventilation of the lungs, size of a pulmonary blood-groove; with their increase the speed of saturation of blood narcotic substance increases. Further advance and distribution of anesthetic in an organism determine the volume of the circulating blood, speed of a blood-groove and coefficient fabric/blood.

For comparison purposes inhalation anesthetics apply the concept «minimum alveolar concentration» (IAC), i.e. that its concentration, at a cut in half of cases there is no pain reaction on a skin section. Values of IAC for various anesthetics very differ and defined their chemical - pharmakol, properties.

Classification of methods of an inhalation anesthesia

Fig. 1. Carrying out an inhalation anesthesia in the open way: the patient makes a breath from the atmosphere through a multilayer gauze napkin (or Esmarkh's mask) which is moistened with inhalation anesthetic from a bottle (the breath and an exhalation in the atmosphere is made at preservation of independent breath).
Fig. 2. The diagrammatic representation of a half-open way of an inhalation anesthesia (the patient makes a breath from the narcotic device, exhaled in the atmosphere): 1 — a breath, the message with free air it is blocked by the special valve; 2 — the exhalation in the atmosphere, the valve is open; the arrow specified the valve.

On a way of supply of gas-narcotic mix to the patient distinguish the following types And. N: mask, nasopharyngeal and endotracheal.

At mask And. N put a rubber or plastic mask on a face of the patient, edges connects respiratory tracts of the patient to the narcotic device or the atmosphere (see. Anesthetic inhaler ).

At nasopharyngeal And. N enter two tubes of the corresponding diameter in Nov so that the internal ends of tubes were located at an entrance to a trachea, and outside — united to the narcotic device.

Endotracheal (intratracheal) And. N carry out after an intubation of a trachea, previously causing an anesthesia otherwise (is more often intravenous), or after local anesthesia of a throat (see. Intubation ). The endotracheal tube is connected to the narcotic device by means of special adapters.

And. the N can be carried out on the open, half-open way (an irreversive contour) closed and a half-closed way (a reverse contour). The last contour assumes a possibility of breath according to circulator and pendular schemes.

During the carrying out And. the N in the open way (fig. 1) narcotic substance at a breath of the patient arrives together with free air, the exhalation of the patient makes in the atmosphere (an anesthesia Esmarkh's mask).

Half-open (fig. 2) is called the way, at Krom during a breath gas-narcotic mix comes from the narcotic device to lungs of the patient, and the exhalation is made in the atmosphere.

Fig. 3. The scheme of the movement of gas-narcotic mix at the closed way of an inhalation anesthesia (the patient makes a breath and an exhalation in the narcotic device): 1 — a cylinder with oxygen; 2 — the dosimeter for gases; 3 — the evaporator; 4 — a rubber bag tank; 5 — an absorber of carbon dioxide gas; 6 — the valve of a breath; 7 — the valve of an exhalation; 8 — a connecting tube for administration of gas-narcotic mix to the patient.
Fig. 4. The scheme of the movement of gas-narcotic mix at a half-closed way of an inhalation anesthesia (the patient makes a breath from the narcotic device, exhaled in the narcotic device and partially in the atmosphere): 1 — a cylinder with oxygen; 2 — the dosimeter for gases; 3 — the evaporator; 4 — a rubber bag tank; 5 — an absorber of carbon dioxide gas; 6 — the valve of a breath; 7 — the valve of partial dumping (exhalation) into the atmosphere; 8 — the valve of an exhalation; 9 — a connecting tube for administration of gas-narcotic mix to the patient.
Fig. 5. Set for carrying out an inhalation anesthesia according to the pendular scheme: 1 — the hose for input of gas-narcotic mix in system connected to a tee; 2 — adsorbers of various capacity; 3 — an endotracheal tube (according to indications instead of it the mask — 4 can be used); 5 — a respiratory bag tank. On the right the system is above shown during an anesthesia.

Closed (fig. 3) is called the way, at Krom the exhalation of the patient is carried out only via the narcotic device. This way assumes obligatory use of an absorber of carbon dioxide gas, otherwise arises hypercapnia (see).

At a half-closed way (fig. 4) a part of gases at an exhalation is returned to the narcotic device, surplus is dumped in the atmosphere. At And. the N according to the pendular scheme a part of gases arrives to the patient from cylinders, another — from a bag of the narcotic device, as if making the pendulum movement, being on the way cleared in an adsorber of carbon dioxide gas; set for carrying out And. N according to the pendular scheme — fig. 5.

A technique and the equipment

the Mask anesthesia

Introduction to an anesthesia shall be made in the mask way slowly, smoothly, that the patient gradually adapted to a smell of the general anesthetic even in cases when drug has no sharp or off-flavor (nitrous oxide, cyclopropane). Before carrying out an anesthesia delete a natural part of nitrogen from blood of the patient and replace it with oxygen by inhalation of oxygen within 10 — 15 min. (denitrogenation). During an anesthesia constant overseeing by preservation of passability of respiratory tracts is necessary. Usually it is reached by introduction to a mouth of a special air duct or support of a mandible.

The mask anesthesia can be carried out on any way of breath, however the open way is practically not applied. As a rule, the mask anesthesia with preservation of spontaneous breath is carried out on a half-closed way. At the same time it is frequent for introduction anesthesia (see) use high-speed drugs of a barbituric row (see. Barbiturates )), Propanididum (see) and means for neyroleptanalgeziya (see).

Fear of an anesthesia, specific smell of the general anesthetics, duration of induction — here those shortcomings which limit use of a mask method of introduction to an anesthesia for adults. The mask introduction anesthesia cyclopropane any other drug often happens by method of the choice for children of early age to the subsequent transition to maintenance of an anesthesia. Intravenous administration of drugs for induction at children is possible if children after premedication are quiet and it gives the chance to make a venipuncture without risk of developing of tachycardia and hypertensia. Sometimes the anesthesia to children is carried out in chamber by Ketaminum intramusculary.

And. the N is applied in the drop way by Esmarkh's mask with dosing of narcotic substance extremely seldom. Speaking about a mask anesthesia, mean an anesthesia by means of the narcotic device and precisely calibrated evaporator, and the mask is only coupling between the sick and narcotic device.

And. the N can be carried out in the mask way by any flying or gaseous narcotic substance. For this purpose the patient shall inhale gas-narcotic mix from the device for an anesthesia. A narcotic mask, densely adjoining to a face of the patient, isolates his respiratory system from the atmosphere. Narcotic substance moves to the patient in mix with oxygen in strictly dosed ratios. Dosimeters for gas drugs (nitrous oxide, cyclopropane) are located out of a circulating system and allow to define an exact proportion of anesthetic gas and oxygen. However anyway it is necessary to consider possible recirculation of the exhaled gases and to give not less than 30 — 40% of oxygen in the inhaled mix. It is especially important to consider it at an anesthesia nitrous oxide (see); cyclopropane causes the general anesthesia at contents it in gas-narcotic mix from 20 to 30 about. %. During the carrying out a mask anesthesia with use of flying general anesthetics (ether, Ftorotanum, Penthranum etc.) this problem is not of so great importance, as at an anesthesia nitrous oxide since the general anesthesia is reached by the concentration never exceeding 20 about. % for ether, 3 — 4 about. % For Ftorotanum and 1,5 about. % for a metoksifluran.

During the use of a mask anesthesia with the kept spontaneous breath and a tone of cross-striped muscles maintenance of a necessary anesthetic plane requires bigger amount of the general anesthetic since the superficial anesthesia does not prevent response of an organism to a surgical injury and does not provide relaxation of muscles.

Mask anesthesia ethyl ether (see) is followed by feeling of suffocation, excitement and therefore it is applied seldom. For an introduction anesthesia intravenously enter barbiturates, Propanididum (Epontolum) or fentanyl with Propanididum, and then by means of a mask sate the patient with ether and support an anesthesia by this drug. At impossibility of carrying out an intravenous introduction anesthesia other drug and need of carrying out an anesthesia begins to give it ether in the increasing concentration so that not to cause cough, laringo-and a bronkhiolospazma. Usually introduction to an anesthesia ether takes 10 — 20 min.; at the same time the stage of excitement then there comes the surgical grade of anesthesia is often observed. If etherization is carried out by Esmarkh's mask (see. Anesthetic inhaler ), that dosing is carried out in the drop way. At the beginning of an anesthesia it is necessary to finish number of drops to 20 — 30 in 1 min., at maintenance of an anesthesia — reduce to 10 — 15 in 1 min. During the carrying out an anesthesia the device ether is given via the evaporator located in a circle of circulation. Apply to introduction to an anesthesia to 20 about. % of ether, for maintenance of an anesthesia — 5 — 10 about. %. Having a number of negative properties, ether remains the safest drug for Nominative.

Mask anesthesia Ftorotanum (see) it is applied only via the special Ftorotek evaporators located out of a circle of circulation. For achievement of an anesthesia but to a half-closed way it is enough 2 — 4 about. % of Ftorotanum, for maintenance — 0,5 — 2 about. %. The Ftorotanovy anesthesia is followed by decrease in the ABP, urezheniy numbers of cordial reductions.

The mask anesthesia constant boiling mixture has a number of advantages before an anesthesia Ftorotanum. Constant boiling mixture represents the liquid consisting of two volume parts of Ftorotanum and one volume part of ether. At an anesthesia constant boiling mixture the vagotropic reactions characteristic of Ftorotanum are leveled by ether, and negative properties of etherization are eliminated with Ftorotanum. The general anesthesia constant boiling mixture proceeds more favorably, than an anesthesia Ftorotanum or ether. The equipment of an anesthesia does not differ from the equipment of an anesthesia in Ftorotanum: the evaporator is located out of a circle of circulation, for an introduction anesthesia it is required to 4 about. % of constant boiling mixture on escaping of the evaporator, and apply to maintenance of an anesthesia 1,5 — 2,5 about. %.

Mask anesthesia chloroform (see) was not widely adopted because of toxic effect of drug on a liver and heart though it is proved that it is shown most often at the accompanying hypoxia. Complications meet rather seldom at an exact dosage of chloroform in a big flow of oxygen. The evaporator have out of a circle of circulation. For introduction to an anesthesia use to 2 — 4 about. % of chloroform, for maintenance — 0,75 — 1 about. %.

Mask anesthesia trichloroethylene (see) apply generally to obtaining effect of an analgesia in connection with its weak narcotic action. Drug should be used only on a half-open way since in the presence of natroncalc of an adsorber trichloroethylene forms toxic dichloracetylene (phosgene). The introduction anesthesia is possible only in combination with barbiturates or nitrous oxide, at the same time the maximum concentration of trichloroethylene in gas-narcotic mix 1,5 about. %. The evaporator is located out of a circle of circulation. Concentration 0,5 is sufficient for maintenance of an analgesia about. %.

Metoksifluran (see) as well as trichloroethylene, possesses good analgetic, but weak narcotic action therefore the introduction mask anesthesia is complicated by this drug. Introduction to an anesthesia can be caused at inhalation 1,5 about. % of a metoksifluran within 5 — 7 min. Maintenance of an anesthesia is provided with concentration of drug on escaping of the evaporator within 0,5 — 0,7 about. %. An anesthesia metoksiflurany at a stage of an analgesia (at inhalation 0,3 — 0,5 about. % of drug) use at operations under local anesthesia and in out-patient practice. The evaporator have out of a circle of circulation. During the carrying out an autoanalgeziya the patient inhales anesthetic from the special small-size evaporator moving from 0,25 to 0,8 about. % of a metoksifluran in mix with air.

Mask anesthesia cyclopropane (see) it is applied to short-term manipulations at the weakened patients and children, and also to an introduction anesthesia. Apply to induction 20 — 40 about. % of cyclopropane in mix with oxygen. The loss of consciousness comes in 1 — 2 min. For maintenance of the general anesthesia it is required from 10 to 15 about. % of anesthetic. Bigger distribution was gained by maintenance of the general anesthesia Shane's mix — Ashmana, the nitrous oxide consisting of 11,7% of cyclopropane, 29,4% and 58,9% of oxygen. At the same time in 1 min. 1 l of nitrous oxide, 2 l of oxygen and 0,4 l of cyclopropane is spent (therefore other name of the mix «1 — 2 — 4»). In certain cases the amount of cyclopropane can be reduced to 0.2 l in 1 min. («1 — 2 — 2»).

The mask anesthesia is applied by nitrous oxide to a thicket in stomatology and obstetrics only to an analgesia.

The nasopharyngeal anesthesia

the Nasopharyngeal anesthesia differs from mask in the fact that the breath comes as from the narcotic device through the catheters inserted in Nov, and through a mouth. The exhalation is almost completely carried out in the atmosphere through a mouth since the way of gas-current is directed towards smaller resistance, and resistance to an exhalation in the atmosphere is always less to exhalation in the narcotic device. Thus, carrying out an anesthesia is carried out in the nasopharyngeal way on a half-open way with impurity of free air in the inhaled gas-narcotic mix.

The endotracheal anesthesia

the Endotracheal anesthesia is carried out by means of the endotracheal tube entered into a trachea.

Conditions for an intubation of a trachea come in 60 — 120 sec. after introduction of Dithylinum (see. Muscle relaxants ). Action of a relaxant is slowed down in all cases of diseases when time of blood circulation is extended. Most clearly it is shown at patients with a mitral stenosis. During the use tubocurarine (see) a relaxation comes not earlier than in 4 — 6 min.

The introduction anesthesia is carried out by drugs of a barbituric row or other means for induction. Saturation of the patient with ether is carried out at 8 — 10 about. %, and maintenance of an anesthesia — at 4 — 6 about. % against the background of relaxation of muscles and constant artificial ventilation of the lungs.

The endotracheal anesthesia by Ftorotanum is carried out in combination with muscle relaxation and artificial ventilation of the lungs. For saturation of the patient (after an intravenous introduction anesthesia) it is required no more than 2 — 3 about. % of Ftorotanum on escaping of the evaporator. Apply to maintenance of the general anesthesia 0,5 — 2 about. % (the grade of anesthesia is not deeper than III 1 ). The evaporator is always located out of a circle of circulation.

The endotracheal anesthesia is more managed constant boiling mixture and consequently, and is safer, than an anesthesia Ftorotanum. Technology of its carrying out differs in nothing from the equipment of a ftorotanovy anesthesia except that a little big concentration on escaping of the evaporator for saturation and maintenance of the general anesthesia are required.

The endotracheal anesthesia chloroform did not find broad application in connection with toxicity of drug. Toxic effect of chloroform decreases by an organism at an exact dosage, an arrangement of the evaporator out of a circle of circulation and at a big flow of oxygen.

The endotracheal anesthesia is practically not applied by trichloroethylene since its use is connected with need to add more powerful anesthetics. The half-open way of breath which is obligatory at an anesthesia with trichloroethylene is extremely unprofitable.

The endotracheal anesthesia metoksiflurany is widespread in practice thanks to ability of drug to stabilize a hemodynamics and not to influence a rhythm of cordial activity. Saturation is carried out at concentration 1 — 1,5 about. %. The evaporator is located out of a circle of circulation. Apply to maintenance 0,3 — 0,5 about. % of a metoksifluran against the background of a relaxation. The combination of drug to nitrous oxide (to 70%) with Ftorotanum is possible. At induction usually apply intravenous anesthetics as saturation metoksiflurany happens slowly (up to 15 min.). Escaping of an anesthesia is also tightened that forces to disconnect anesthetic in 15 — 20 min. until the end of an operative measure. Drug causes a long postoperative analgesia.

The endotracheal anesthesia widely is not applied by cyclopropane because of a possibility of cordial complications and potential of explosion. Cyclopropane can be used in Shane's mix — Ashmana.

The endotracheal anesthesia in pure form is not applied by nitrous oxide due to the lack of narcotic action of safe concentrations.

Features of the equipment of an inhalation anesthesia at children

Because of weakness of respiratory muscles children overcome respiratory resistance created during the general anesthesia by the narcotic device both in an inspiratory phase, and in an expiratory phase more difficultly. Therefore at children use more often such ways of circulation of gases

which cause the minimum respiratory resistance. At a mask anesthesia apply a half-open way due to use of the valve on the adapter of the narcotic device. At an endotracheal anesthesia with the artificial ventilation of the lungs (AVL) the half-open way is provided with the automatic irreversive valve. The principle of its work is based that during inflation of gases in lungs the valve separates system the device — the patient from the atmosphere. During an exhalation the valve separates system of the patient — the atmosphere from the narcotic device. For this reason the breath comes from the device, and exhaled — in the atmosphere.

Fig. 6. Use of the T-shaped tube during the carrying out an endotracheal anesthesia on Eyre's system: and — the breath, oxygen-narcotic mix (the direction of the movement is specified by an arrow) from the device through a branch pipe (1) arrives to the patient by means of the branch pipe (2) connected to an endotracheal tube (3), at the same time through a branch pipe (4) air podsasyvatsya, diluting oxygen-narcotic mix; — the exhalation, expired air freely through a branch pipe (4) goes to the atmosphere (it is specified by an arrow).

During the carrying out the general anesthesia at children up to 3 years, and in particular till 1 year, use valveless systems of ventilation. Eyre and Reece's systems concern to them. Carrying out an anesthesia on Eyre's system is possible both by a mask method, and endotracheal. At IVL the main place in Eyre's system is taken by the T-shaped tube connected by one end to a mask (or an endotracheal tube), to others — with the narcotic device (a source of gas), the third end of a tube is open in the atmosphere (fig. 6). At And. the N a breath is carried out from the device provided that in the open end of a tube a certain amount of air podsasyvatsya. It depends on diameter of the T-shaped tube and size of a gas flow from the narcotic device, but usually does not exceed 20 — 30%. The exhalation occurs in the atmosphere through the open end of a tube.

Rees's system is modification of system of Eyre and is applied during the carrying out IVL. Put on a respiratory bag with a capacity not less than 400 cm the free end of the T-shaped tube 3 . The bottom of a bag connects to the atmosphere by means of a rubber tube to dia. 0,8 — 1,0 cm. At a breath this tube is pressed, at an exhalation — opens.

Advantage of the described systems of ventilation at children consists in the minimum respiratory resistance. The shortcoming them is connected with big losses of moisture and heat by children therefore systems with reversion of gases at children are especially shown at long general anesthesia or IVL. Apply the pendular scheme more often, the cut is modification Madzhill's system — Meyplesona excluding use of an adsorber. For this purpose use the minute volume of ventilation twice exceeding settlement (necessary for this patient) minute volume.

Complications of an inhalation anesthesia and their prevention

It is necessary to distinguish the complications connected with method of an anesthesia and the complications caused by properties of the used anesthetic. The most frequent complications of a mask anesthesia — vomiting and regurgitation with aspiration of gastric contents — arise at inadequate anesthesia, a hypoxia and a hypercapnia during an anesthesia. Vomiting and regurgitation are possible complications during the carrying out the emergency general anesthesia at patients with a «full» stomach. For the prevention of these complications it is necessary to evacuate contents of a stomach before an anesthesia, to block an entrance to a stomach special probes obturators. Retraction of a mandible is eliminated with its support or introduction of an air duct through a mouth or Nov. Earlier often being found complications And. N in the form of disturbance of breath, a cardiac standstill, motive excitement, a bronkhiolospazm are observed seldom thanks to improvement of the equipment of the general anesthesia.

During the carrying out an introduction anesthesia (especially drugs of a barbituric row) in induction period and an intubation the cardiac standstill (a vago-vagal reflex), post-intubation hypertensia, tachycardia or sharp hypotonia is possible. Muscle relaxants of the depolarizing type of action often cause muscular pains in the postoperative period, and during an anesthesia can cause sharp bradycardia up to an asystolia.

To one of measures of prevention of the complications connected with an introduction anesthesia serves use of new techniques of an introduction anesthesia with restriction of use of barbiturates (use of fentanyl, Propanididum, Ketaminum etc.). For the prevention of a cardiac standstill during an intubation of a trachea it is important to avoid a hypoxia, to block vagal reflexes (atropinization), to use local anesthesia of a mucous membrane of a throat, trachea and to carry out an intubation atraumatic. Post-intubation hypertensia and tachycardia are a consequence of insufficiently deep anesthesia. The complications connected using the depolarizing relaxants are eliminated with preliminary introduction of 5 mg of tubocurarine, slow introduction of the depolarizing muscle relaxants with preliminary atropinization.

At modern And. N the specific complications connected with use of this or that drug arise seldom since the anesthesia is carried out by several drugs and in the concentration providing the first level of a surgical stage (III 1 ). The complications connected with pharmakol characteristics of drugs, arise during the carrying out a monoanaesthesia more often (i.e. an anesthesia one drug). E.g., Ftorotanum oppresses function of a myocardium, is toxic for a liver, metoksifluran — is toxic for kidneys etc.

Devices for an inhalation anesthesia

Schematically devices for And. N represent the gas-carrying-out system with the measuring, dosing and valve devices in which proceed hydraulic and physical. - chemical processes. The part of the gas-carrying-out system of the device intended for connection with respiratory tracts of the patient is called a rebreathing system. Other part of the gas-carrying-out system for transfer of respiratory mix from its sources in a rebreathing system is called as the line of supply of respiratory mix. The movement of gas mixture in the line of supply of respiratory mix can be continuous or discontinuous depending on design features of the device. In this regard there are two types of devices for And. N: devices of a continuous stream and devices of a discontinuous flow. In devices of the first look (e.g., «Polynarcon») fresh respiratory mix moves through giving and comes to a rebreathing system continuously. In devices of the second look (e.g., NAPP-2, «Avtonarkon-C1») this process happens periodically, in process of consumption of gas by the patient.

There are two main types of rebreathing systems of devices for And. N: reverse and irreversive. In a reverse rebreathing system the exhaled mix is returned for repeated inhalation; in irreversive — mix is not returned for repeated inhalation.

Devices for And. N can be classified as devices of an open contour (e.g., Narkon), a semiopen circuit (e.g., «Narkon-2», NAPP-2) or the half-closed (closed) contour (e.g., «Polynarcon»). However such classification is conditional; it is possible to speak only about preferential purpose of this or that device for work on a certain contour as the majority of the released devices gives the chance to conduct an anesthesia more than on one rebreathing system.

The main nodes of devices

Cylinders serve as capacity for the compressed or liquefied gases — oxygen (color of a cylinder blue, the capacity 1, 2, 10, 40 l, pressure of gas 150 of an ata), nitrous oxides (color of a cylinder gray, the volume of 10 l, pressure of gas 50 of an ata), cyclopropane (color of a cylinder orange, the volume of 2 l, pressure of gas 6 of an ata), reducers are intended for decrease in high pressure and maintenance of constant predetermined pressure of gas (3 — 4 at) on escaping of a reducer. Dosimeters of gaseous anesthetics happen two types — rotametrichesky and dyuzny. The first are a kind of float-operated dosimeters in which the volume flow of gas in l/min is determined by height of raising of a float in a rotametrichesky tube. Dyuzny dosimeters create gas mixture with in advance set concentration of its components and irrespective of character of a gas stream by means of specially calibrated openings (nozzles). Dosimeters of liquid anesthetics (evaporators) are intended for transformation of anesthetics from liquid state in vaporous and dosing of the received vapors. On the device distinguish flowing evaporators in which the gas flow is enriched with vapors of anesthetic at contact with its surface; bubbling evaporators in which gas is enriched with vapors of anesthetic, passing through it; drop evaporators in which gas is enriched with vapors of anesthetic at introduction of its drops to a gas flow. Any of the above-stated types can be arranged as the stabilized evaporator i.e. providing constancy of the established concentration of vapors of anesthetics irrespective of external factors — ambient temperature and anesthetic, a gas rate via the evaporator, counter-pressures (in the set limits), e.g. the Anesthetist-1 evaporator.

Fig. 7 and 8. The scheme of the movement of gases at various arrangement of the evaporator for drugs (fig. 7 — the evaporator in a circle of circulation of gases; fig. 8 — the evaporator out of a circle): 1 — a cylinder with oxygen; 2 — the dosimeter for gases; 3 — a rubber bag tank; 4 — the evaporator for drugs; 5 — an absorber of carbon dioxide gas; 6 — the valve of a breath; 7 — the valve of an exhalation; 8 — the connecting tube going to the patient; shooters specified the direction of the movement of a flow of gases.

In devices for And. N with a reverse rebreathing system evaporators can be located both in a rebreathing system, and out of it (in the line of supply of breathing gas). The arrangement of the evaporator with other things being equal significantly influences the inhaled concentration of vapors of anesthetic. If the evaporator is located in a circle of circulation (fig. 7), then through it the air exhaled by the patient comes and, being enriched with vapors of anesthetic, again comes to lungs. At such system the exact dosage since via the evaporator, except the exhaled gas, the gas going through reducers arrives is impossible. If the evaporator is located out of a circle of circulation (fig. 8), then through it there does not pass the gas (or mix of gases) exhaled by the patient. At such system the exact dosage of vapors of anesthetic is possible.

During the carrying out And. N are used evaporators with an exact dosage of vapors of anesthetics. From foreign evaporators the greatest distribution was gained created in England the evaporator for a flyuotan (Ftorotanum) — Flyuotek and for a metoksifluran — Pentek. The most perfect is the Soviet Anesthetist-1 evaporator allowing to apply almost all most widespread flying anesthetics — Ftorotanum, metoksifluran, ether, chloroform, trichloroethylene.

The adsorber is intended for absorption of the exhaled carbon dioxide gas in a reverse rebreathing system. It represents the capacity filled with a chemical absorber of carbonic acid. Depending on the nature of passing of gas through an absorber distinguish adsorbers direct-flow and with back and forth motion of gas. There are several types of valve devices. The directing valves create the unilateral direction of a gas stream, safety — dump surplus of pressure of gas, exhaling — delete all in the atmosphere or a part of the exhaled gas, the irreversive valve divides flows of the inhaled and exhaled gas both at IVL, and at spontaneous breath. Respiratory bag (fur) — the elastic gas collector allowing to create a discontinuous flow in a rebreathing system. The respiratory hose — the flexible gas pipeline, on Krom breathing gas arrives to the patient and back. A respiratory mask (see. Anesthetic inhaler ) — the device for connection of respiratory hoses with a mouth and a nose of the patient. Connecting elements (tees, adapters, connectors, etc.) are intended for connection of respiratory hoses with a respiratory mask or an endotracheal tube.

Fig. 9. The universal device for an inhalation anesthesia «Polynarcon-2»: 1 — the dosimeter of gaseous anesthetics; 2 — a respiratory prefix; 3 — an adsorber for absorption of the exhaled carbon dioxide gas; 4 — respiratory hoses.

Main models of devices. The universal device — «Polynarcon-2» (fig. 9) provides maintaining an anesthesia on the half-open, half-closed and closed way with any gaseous or liquid anesthetics. In the device the universal stabilized Anesthetist-1 evaporator is used. Limits of the received concentration of vapors (about. %): ether — 1 — 20, Ftorotanum — 0,4 — 5, chloroform — 0,3 — 5, trichloroethylene — 0,15 — 2, a metoksiflurana — 0,3 — 2. The dosed consumption of gases (l/min): oxygen — 0,2 — 2 and 2 — 10, nitrous oxides — 1 — 10. Unitized construction, the main nodes are connected among themselves and to the case of the device by means of easily demountable connections. Thanks to it the rebreathing system can be easily sorted for cleaning and disinfection. For IVL there is a respiratory prefix — the device IVL RD-4.

Fig. 10. The figurative device for an inhalation anesthesia of «Narkon-2»: 1 — the dosimeter of gaseous anesthetics; 2 — the evaporator with liquid anesthetic; 3 — a respiratory hose; 4 — a respiratory mask.

The device for And. N figurative — «Narkon-2» (fig. 10) — the small-size device intended both for stationary and for field conditions. Provides maintaining an anesthesia generally on open and half-open ways, and at inclusion of a direct-flow adsorber — as well according to the pendular scheme. The basis of the device — the universal evaporator of low resistance — «Anesthetist-2» provides dosing of vapors of ether (to 20 about. %), Ftorotanum (to 5 about. %), chloroform (to 4 about. %), trichloroethylene (to 1,5 about. %), a metoksiflurana (to 2 about. %). The dosed consumption of gases (l/min): oxygen — 10, nitrous oxides — 1 — 10.

For carrying out IVL turn on the device ADR-2 or «Pnevmat-1».

Fig. 11. The device for an inhalation anesthesia of a discontinuous flow of NAPP-2: 1 — evaporators with liquid anesthetic; 2 — a respiratory mask; 3 — respiratory hoses.

Devices of a discontinuous flow of NAPP-2 (fig. 11) and «Avtonarkon-C1» are intended for carrying out (including and the patient) anesthesia by nitrous oxide, trichloroethylene, Ftorotanum on a half-open way. They are applied at obstetric aid, stomatol, and maxillofacial surgical interventions, for postoperative and to lay down. an anesthesia also allow to carry out also inhalation procedures oxygen or its mix with air. Devices have the dyuzny dosimeters providing the following concentration: 75% of N 2 O + 25% of O 2  ; 65% of N 2 O + 35% of O 2  ; 50% of N 2 O + 50% of O 2  ; 40% of air + + 60% of O 2 . The flowing evaporator provides concentration of vapors of Ftorotanum to 3 — 4 about. %, trichloroethylene — to 1,5 about. %.

The device AH-8 for ambulance is intended for short-term anesthesia by nitrous oxide with oxygen and IVL on a half-open way during the rendering ambulance. Malogabariten, weight with two cylinders — 12 kg.

Fig. 12. The device for an analgesia of AP-1 of Tringal (below — in unassembled form): 1 — the stopper closing a bottom of the evaporator through which the breath from the atmosphere is carried out; 2 — a cord for deduction of the evaporator on a wrist; 3 — a mouthpiece for inhalation of inhalation anesthetic; 4 — the valve of an exhalation; 5 — the case of the evaporator containing the match (6) impregnated with anesthetic.

The device for an analgesia of AP-1 (Tringal — fig. 12) represents a narcotic inhaler. It is intended for an autoanalgeziya by vapors of trichloroethylene or a metoksifluran in mix with air. The greatest concentration of vapors of the specified anesthetics maintained within 60 min. at ventilation of 8 l/min and temperature 18 — 22 ° makes for trichloroethylene 1 ± 0,3 about. %, for a metoksifluran 0,8 ± 0,3 about. %. The weight of the device — 30 kg. It is applied to anesthesia during short-term operations, and also in field conditions and during the transportation of patients and victims.

Methods of disinfection of devices and their separate nodes. Disinfecting of the device begins with careful power tool cleaning warm running water with soap right after use of the device.

Connecting elements (tees, connectors, adapters, etc.) made of metal or heat-resistant plastic after washing subject disinfection by boiling at t ° 100 ° within 45 min. Elements from rubber or not heat-resistant plastic disinfect immersion in 3% solution of hydrogen peroxide or 10% solution of formaldehyde within 1 hour with the subsequent rinsing sterile a dist, water.

The way of disinfecting of endotracheal tubes, front masks, air ducts, mouthpieces, respiratory hoses and bags consists in the following: after careful washing with soap under running water they are placed in a basin with solution at the rate on 1 l of water (t ° 40 °) by 30 ml of 30% pergidrolya, 1 table. l. powder «News». In such solution of a product are mechanically processed within 20 min. After rinsing they are immersed in 3% solution of hydrogen peroxide or 10% solution of formaldehyde for 1 hour. Then rinse sterile a dist, water or solution of sodium chloride, dry up on a sterile sheet and stack in sterile steam sterilizers.

At disinfection of all device after washing of its rubber details and connecting elements attach capacity from 10% to the tee going to the patient solution of formaldehyde, to-ruyu put on the heating device. Solution is brought to boiling, and vapors of formaldehyde continuously come to the device. Hashing and hypodispersion of vapors in the device make or manually by means of a respiratory bag, or by means of the connected device IVL. Exposure of disinfecting of 60 min. At infection with bacteria of tuberculosis exposure increases up to 90 min. Neutralization of vapors of formaldehyde is made, connecting to the device in the same way capacity from 10% solution of ammonia for 30 min. Then the device is blown air or oxygen (10 — 15 l/min) within 30 min.

Rubber details and connecting elements shall be exposed surely to disinfection after each anesthesia. For other parts of the device disinfection once a week in the absence of special indications to its more frequent carrying out is admissible.

See also Artificial respiration (artificial ventilation of the lungs) , Anaesthesia , Drugs .

Bibliography: Bunyatyan A. A., etc. Anesthesiology and resuscitation, M., 1377; Damir E. A., etc. Clinical assessment of the narcotic devices «Polynarcon-2» and «Narkon-2», It is new. medical technicians, century 2, page 23, 1974; Manevich A. 3. and Altshuller R. A. Ftorotanovy (flyuotanovy) anesthesia, M., 1966, bibliogr.; The guide to anesthesiology, under the editorship of T. M. Darbinyan, M., 1973; The Guide to clinical resuscitation, under the editorship of T. M. Darbinyan, M., 1974; Yurevich V. M. and Perelmutr A. S. Anesthesia and narcotic devices, M., 1973, bibliogr.; Anaesthesiology, Proc. 5-th World congr. anaesthesiol., N. Y., 1973; Richardson R. G. Surgery, old and new frontiers, N. Y., 1968, bibliogr.

T. M. Darbinyan; V. M. Yurevich (tekhn.).