OXYGEN THERAPY (synonym oxygenotherapy) — use of oxygen with the medical purpose, To. t. the hl is applied. obr. for treatment of a hypoxia at various forms acute and hron, respiratory insufficiency, is more rare for fight against a wound mephitic gangrene, for improvement of reparative processes and a trophicity of fabrics, for deworming and nonspecific physical therapy.
The thought about to lay down. use oxygen (see) in 1775 the English scientist J. Priestley for the first time stated. In 1780 the fr. doctor F. Chaussier recommended to apply oxygen by means of a mask and a special bag to revival of the newborns who were born in asphyxia. Pneumatic in-t, based at the end of 18 century in England by Beddouz (T. Beddoes), played an important role in studying of an inhalation method of use of gases in medicine, including oxygen, and in development of the equipment and indications for To. t. Since the beginning of 19 century. To. t. it is applied to treatment not only asphyxia, but also other diseases, napr, stenocardias, epilepsies. A wide spread occurance To. t. received in the second half of 19 century with introduction to practice of cylinders with the compressed oxygen, however its greatest development belongs to the second half of 20 century when the possibility of serial production of devices of a special purpose (e.g., devices for artificial ventilation of the lungs) and creations of new techniques appeared To. t., including oxygenobarotherapies (see. Hyperbaric oxygenation ).
Fiziol, action To. t. multilaterally, but crucial importance In to lay down. effect has compensation of deficit of oxygen in fabrics at hypoxias. At patients with respiratory insufficiency under the influence of inhalations of oxygen its tension In an alveolar air and in a blood plasma increases, concentration of oxyhemoglobin increases in an arterial blood, the metabolic acidosis decreases (thanks to reduction of quantity of nedookislenny products in fabrics and to improvement of function of a liver and kidneys); the mode of ventilation in connection with decrease patol, impulsation with sinocarotid and other chemoceptors changes; the katekholaminemiya decreases that is followed by normalization of the ABP and a rhythm of cordial reductions. Topical administration of oxygen (hypodermic, intra joint, intrapleural, its intraperitoneal introduction, oxygen bathtubs, etc.) improves reparative processes, contributes to normalization of a trophicity of fabrics.
it is applied To. t. hl. obr. at the general and local hypoxia of various genesis, and also at a tension of compensatory reactions of an organism to decrease in pO 2 in a surrounding gaseous fluid (low barometric pressure in the conditions of highlands, decrease in pO 2 in the atmosphere of artificial environment of dwelling etc.). In a wedge, practice by the most frequent indications to use To. t. are respiratory insufficiency (see) at diseases of respiratory system and hypoxia (see), caused by disturbances of blood circulation at cardiovascular diseases (a circulator hypoxia). A wedge, the signs defining expediency of use inhalation To. t., cyanosis, a tachypnea, a metabolic acidosis, pO are 2 in blood it is lower than 70 mm of mercury., saturation of hemoglobin is less than 80%.
Efficiency To. t. it is not identical at various mechanisms of hypoxias. The best effect To. t. gives at the low oxygen content in the atmosphere (highlands) and at disturbances of alveolocapillary diffusion of oxygen in lungs. Is less effective To. t. gemichesky forms of a hypoxia. It is almost absolutely inefficient at a gistotoksichesky hypoxia, and also at the anoxemia and a hypoxia caused by veno-arterial shunting (some inborn heart diseases and vessels) y insufficient oxygenation of a venous blood in lungs due to increase in the relation of perfusions to ventilation (see. Gas exchange ).
To. t. it is often necessary for recovery of therapeutic action of a number of drugs, a cut it is not shown or it is reduced in the conditions of a hypoxia (cardiotonic effect of cardiac glycosides, diuretic effect of diuretics). It is applied also to strengthening of effect of cytostatic and radiation therapy of malignant new growths.
Indications to topical administration of oxygen, except a local hypoxia, are the wounds infected with anaerobic flora (see. Mephitic gangrene ), inertly current inflammatory processes, local trophic frustration. In ophthalmology use administration of oxygen subkonjyunktivalno, retrobulbarno and in an anterior chamber of an eye at vitreous hemorrhages and a retina, at a secondary cataract, destruction of a vitreous.
Efficiency To. t. at a hypoxia it can be raised by simultaneous use of means of pathogenetic therapy of respiratory or circulator insufficiency. Therefore at the anoxemia and a hypoxia caused by hypoventilation of air cells To. t. combine (depending on the nature of hypoventilation) using respiratory analeptics, bronchial spasmolytics, expectorants with artificial ventilation of the lungs. At a circulator hypoxia efficiency To. t. raises at simultaneous normalization of a hemodynamics since transport of blood, oxygen-bearing improves. At a fluid lungs inhalation of oxygen is made together with inhalation of vapors of alcohol or aerosols of special antifoam means (see. Fluid lungs ). To. t. hypoxias, especially long and developed at elderly persons, is more effective at simultaneous use of vitamins and coenzymes (polyneuramins 2 , In 6 , In 15 , cocarboxylase), improving use of oxygen fabrics.
Objective criteria of adequacy To. t. — disappearance of cyanosis, normalization of a hemodynamics, acid-base state and gas structure of an arterial blood.
Absolute contraindications to To. t. no, however the choice of a way and technology of its carrying out shall correspond to specific features of the patient (to age, character patol, process) ve avoidance of possible complications.
Types and ways of Oxygen therapy
Depending on a way of administration of oxygen ways K. t. divide into two main types: inhalation (pulmonary) and neingalyatsioiny. Inhalation To. t. includes all ways of administration of oxygen in lungs through respiratory tracts. Not inhalation To. t. combines all extra pulmonary ways of administration of oxygen — enteral, intravascular (including use of the membrane oxygenator), hypodermic, intracavitary, intra joint, subconjunctival, cutaneous (the general and local oxygen bathtubs).
Separate look To. t. the hyperbaric oxygenation combining features of inhalation and not inhalation ways and Being, in essence, an independent method of treatment is.
A part of not inhalation ways of administration of oxygen is used only for local To. t. At the same time most often oxygen from several milliliters less (vnutrisustavno, subkonjyunktivalno) to several liters (subcutaneously, intraperitoneally) is entered through a needle by means of the syringe, Bobrov's device or other similar devices after usual antiseptic processing of an injection site of a needle. Oxygen bathtubs are applied as for the purpose of local To. t., and for the general nonspecific impact on an organism (see. Bathtubs ).
Ways K have the greatest practical value. t., which can be applied to fight against the general hypoxia. Except hyperbaric oxygenation (see), inhalation of oxygen and oxygen mixes, enteral oxygenation, intravascular introduction of microemulsions of oxygen, oxygenation of blood by means of the membrane oxygenator belong to such ways.
Inhalation of oxygen and oxygen mixes — the most widespread method K, t., applied as at natural, and artificial ventilation of the lungs. Inhalation is performed by means of various oxygen and respiratory equipment (the SI.) through nasal and oral masks, nasal catheters, endotracheal and tracheostomy tubes. At children less often at adults use oxygen tents tents.
One of rare options inhalation To. t. — so-called apnoyny oxygenation, or «diffusion breath» — administration of oxygen in respiratory tracts through a catheter against the background of an apnoea. The method can be considered as option of artificial ventilation of the lungs and is applied at the states causing an immovability of pulmonary fabric (a bronkhoskopiya, an injury of lungs, etc.).
Depending on the nature of a disease, and also from conditions of carrying out and duration To. t. for inhalation use either pure oxygen, or the gas mixtures containing 20 — 80% of oxygen. Inhalation of pure oxygen or its 95% of mix with carbon dioxide gas (Carbogenum) is shown at poisonings with carbon monoxide.
During the use of oxygen cushions the best oxygenation is reached by inhalation of oxygen through a mouthpiece (or directly through a tube of a pillow) which the patient densely clasps with lips; at the same time at the time of the exhalation made in Nov, supply of oxygen from a pillow is interrupted (turn of the crane in a mouthpiece or it is better crossclamping of a tube fingers), and the breath of oxygen is made forcedly after slowed down, but a deep exhalation.
Usually for To. t. use oxygen from cylinders in which it is stored in the compressed state, or from system of the centralized supply of oxygen in hospital chambers. It allows to bring oxygen directly to respiratory devices by means of which podb dig gas mixtures, optimum on concentration of oxygen. To. t. it can be carried out it is long.
Inhalation of mixes with concentration of oxygen of 40 — 60% is safest and effective. In this regard many modern inhalers for To. t. have injection devices, podsasyvayushchy air, and the dosimeters allowing to apply the mix enriched with oxygen, but not pure oxygen. It is necessary to consider that the flow rate of oxygen established on the dosimeter of an inhaler (e.g., 8 l/min) does not mean that the patient receives so much pure oxygen. The true concentration of oxygen reached in alveolar space of lungs depends on type of the inhalation device, a way of its connection to the patient (nasal catheters, an oral or nasal mask, etc.), rate of volume flow of breath, time of shift of gases in lungs, recirculation of gases at an exhalation and other circumstances.
The way of inhalation of oxygen through nasal catheters is most widespread. For achievement of efficiency concentration of oxygen in alveoluses catheters enter into the nasal courses rather deeply (length of the entered end of a catheter shall be approximately equal to distance from a wing of a nose to a trestle of an auricle of the patient).
Inhalation of oxygen mixes is carried out continuously or sessions on 30 — 60 min. Continuous mode K. t. more preferably at obligatory warming and moistening of the inhaled mix and ensuring sufficient volume of ventilation.
Since normal drainage and protective functions of respiratory tracts are carried out only in the conditions of nearly 100% of humidity, providing such or close conditions to them makes one of important technical tasks at an inhalation way K. t. It is necessary to consider influence on humidity of change of temperature. In process of temperature increase of gas mixture the maximum saturation pressure grows at its water vapor in this connection relative humidity of mix falls. E.g., relative humidity of the room air sated at a temperature of 20 ° with water vapor (17,5 mm of mercury.), decreases from 100% to 39% during the heating of this air to body temperature (37 °). Therefore, use for inhalation of the cooled gas mixtures (body temperatures are lower) excludes a possibility of achievement of the maximum saturation pressure their water vapor in respiratory tracts where gas is warmed without additional evaporation of water in respiratory tract. Under such circumstances inhalations evaporation of water in respiratory tracts (for maintenance of high relative humidity) shall be that big, than temperature of gas mixture in comparison with body temperature is lower.
If inhalation of oxygen is carried out under a tent tent or through a nosorotovy mask, i.e. gas passes through a mouth, Nov and a nasopharynx, then it is adequately humidified in respiratory tracts and in its additional moistening there is no need. At long To. t., especially if oxygen moves through deeply entered nasal catheters, an endotracheal tube or a tracheostomy cannula, and also at dehydration of the patient, special moistening of the inhaled mix surely is required. At the same time consider that from cylinders dry oxygen arrives, saturation to-rogo water vapor at body temperature requires 44 mg of water on 1 l of gas, i.e. at a consumption of oxygen of 8 l/min for its moistening it is necessary to spend 21 g of water an hour, or apprx. 0,5 l of water a day.
There are three methods of moistening of the inhalated oxygen. The first method — a transmission of oxygen through a vessel with water — is insufficiently effective since large bubbles of oxygen do not manage to be sated with water vapor. Besides, in connection with evaporation temperature of a humidifier at a gas flow apprx. 12 l/min goes down by several degrees in comparison with surrounding owing to what saturation pressure falls. These defects are eliminated, using finely porous sprayers of oxygen and warming up a humidifier to t ° 50 — 55 °.
The second method of moistening of oxygen mixes — use of «an artificial nose» — the roll of a corrugated foil established on a face. The foil heats up breath of the patient approximately to t ° 30 ° and detains moisture at an exhalation, sating gas at a breath no more, however, than for 80%.
The third — the most effective method of moistening — use of the aerosol inhalers creating a suspension of small drops of water in gas mixture (the size apprx. 1 micron) which evaporation in respiratory tracts sates gas with water vapor to 100%.
Enteral oxygenation, i.e. administration of oxygen in a stomach with the subsequent its passage in intestines and absorption, it was applied to fight against asphyxia of newborns and respiratory insufficiency at adults in 19 century. However it is proved that quantity soaked up in went. - kish. a path of oxygen it is not enough for ensuring metabolism at considerable disturbance of lung respiration. According to M. N. Speransky (1940), oxygen is soaked up in a small intestine with a speed of 0,15 ml/cm 2 / hour and in thick — 0,11 ml/cm 2 / hour. Administration of oxygen in intestines via the probe was applied before to deworming. Bigger distribution was gained by tubeless enteral oxygenation by a method H. N. Sirotinina — a proglatyvaniye patients of oxygen in the form of foam or special mousse. This way is applied to fight against late toxicoses of pregnancy, obesity, hron, respiratory insufficiency, to prevention of a senilism etc. Enteral oxygenation has the greatest value for improvement of functions of a liver since the oxygen which is soaking up in a digestive tract oxygenates blood of the portal vein coming to a liver. In this regard the method of enteral oxygenation is shown in complex therapy of an acute liver failure. At administration of oxygen via the probe it is dosed exact dosimeters or quantity of vials of the oxygen passing through bank of the device of Bobrov in a minute.
Intravascular oxygenation it is developed still experimentally. If rate of administering of gaseous oxygen exceeds 2 — 3 ml/min., according to S. N. Efuni et al. (1974), inevitably there is a gas embolism. However, as established B, V. Petrovsky et al. (1969), use of the microemulsion of oxygen received by foaming of a hydrolyzate of casein allows to support sufficient oxygenation of fabrics at full asphyxia of animals within 30 min. The patient of environments can consider a kind of intravascular oxygenation various ways of artificial oxygenation transfuziruyemy — blood and blood substitutes. For this purpose in more standardly bottle force oxygen which sates transfuziruyemy drug.
Use of the membrane oxygenator. This method K. t. it is close to artificial circulation and it is developed for use at temporary inability of lungs to provide adequate gas exchange, napr, at a syndrome of a shock lung, a post-perfused pulmonary syndrome, a fatty embolism, total pneumonia, etc. Passes through the membrane oxygenator only a part of the circulating volume of blood that allows to use it within several days and even weeks without considerable injury of blood cells. Fundamental difference To. t. by means of the membrane oxygenator from a method of extracorporal artificial circulation consists that the membrane oxygenator with hesitation pumping of blood is used only to its oxygenation, but not to ensuring blood circulation (See. Oxygenators ).
Complications and their prevention
Inhalation of 100% of oxygen of less than a day or multidaily inhalation of 60% of oxygen mix does not cause sharp disturbances in an organism which would be more dangerous than the hypoxia. At use of high concentration of oxygen, and also at long To. t., especially at elderly persons, some can be observed patofiziol, the effects leading to complications.
Apnoea («an apnoea of sleepy bodies») or considerable decrease in volume of ventilation with a hypercapnia can occur at the beginning To. t. at patients with oppression of activity of a respiratory center when regulation of breath is carried out generally from chemoceptors of the carotid balls sensitive to an anoxemia. Increase in pO 2 plasmas owing to To. t. brings in such cases to elimination of irritation of chemoceptors and emergence of an apnoea.
For the prevention of this complication it is recommended at states with existence or threat of oppression of a respiratory center (a high hypercapnia, wet brain, disturbances of cerebral circulation with a respiratory arrhythmia, poisonings with drugs, heavy inf. intoxication, etc.) to begin To. t. 25% oxygen mix and gradually to increase concentration of oxygen in it to 60% against the background of use of means of pathogenetic therapy of the central disturbances of breath.
At the hypoventilation which is not eliminated pharmakol, means To. t. in order to avoid a giperkapnichesky anesthesia and an apnoea it is carried out only At combinations it with auxiliary artificial ventilation of the lungs (see. Artificial respiration ).
Occasionally Carbogenum is applied to Excitement of a respiratory center. Sovr, inhalation devices allow to increase change of a contour of recirculation of gases concentration of carbon dioxide gas without use of Carbogenum.
Oxygen intoxication can develop at long inhalation of mixes with high concentration of oxygen or pure oxygen. Excess oxygen breaks Linear chains biol, oxidations, interrupting them and leaving a large number of the free radicals rendering irritant action on fabrics.
The leading displays of oxygen intoxication are signs of defeat of a respiratory organs and c. N of page (see. Hyperoxia ). At the beginning of its patients note dryness in a mouth, dry cough, burning behind a breast, thorax pains. Also spasms of peripheral vessels, acroparesthesias are observed. In respiratory tracts the hyperoxia causes irritation and an inflammation of mucous membranes; the ciliate epithelium is damaged, drainage function of bronchial tubes is broken, their resistance to a gas stream grows. In lungs collapses surfactant (see), surface intention of alveoluses increases, macroatelectases, pneumonites develop micro, and then and. Vital capacity decreases and diffusion capacity of lungs decreases, irregularity of ventilation and a blood-groove increases.
Giperoksichesky defeat of c. the N of page is most often shown by a convulsive syndrome and leads also to disturbance of thermal control, mental disorders, sometimes coma.
Development of the disturbances connected with a hyperoxia is promoted by insufficient moistening of the inhalated mixes and effects of a denitrogenation — washing away of nitrogen from an organism. Denitrogenation leads to hypostasis and a plethora of mucous membranes in various cavities (frontal sinuses, etc.), to emergence of absorbing microatelectases in lungs.
Prevention of oxygen intoxication consists in use of well moistened mixes with low concentration of oxygen and in periodic transitions to inhalation of air at long To. t. Allows to reduce efficiency concentration of oxygen in mix (to 25%) use of mixes of oxygen with helium, light body to-porb reduces resistance to a gas stream in respiratory tracts, prevents development of atelectases and improves transport of oxygen to an alveolocapillary membrane. Preventions of a hyperoxia and the related atelektazirovaniye reach also artificial increase funkts, the residual capacity of lungs. Most often for this purpose establish the additional resistance to an exhalation by means of the devices used in devices to artificial ventilation of the lungs.
Hypercapnia with the high tension of carbon dioxide gas in fabrics — a frequent complication To. t. at use of the high-concentrated oxygen mixes. Significant amounts
of CO are normal2 are removed from fabrics with the recovered hemoglobin. At the raised pO 2 the recovered hemoglobin is not enough, and carbonic acid is late in fabrics (see. Hypercapnia ). It is promoted by so-called paradoxical hemodynamic reaction to a hyperoxia, regional spasm of arterioles with the falloff of a blood-groove reducing intake of oxygen to fabrics and withdrawal of CO from them 2 . The prevention of this complication matches measures of the prevention of a hyperoxia.
Oxygen therapy at children
Anatomo-fiziol. features of a respiratory organs at children cause at them easier, than at adults, emergence is hypoxias at disturbances of functions of external respiration. Mechanisms of compensation of an anoxemia at newborns are absent; they begin to develop only with 5 — 6-month age and complete the formation by 7 — 8 years. These features define the importance of use To. t. at children at acute and hron, the diseases which are followed by an anoxemia and a hypoxia. Therefore indications for carrying out To. t. at children are rather wide and include various diseases of a respiratory organs and blood circulation, a disease of c. N page, anemia, disbolism. Refer seldom found individual intolerance of the increased concentration of oxygen to contraindications.
Most widely apply inhalation To. t. For its carrying out use oxygen tents (DKP-1 and KP-1), couveuses, tents, masks. Direct administration of oxygen in respiratory tracts is possible by means of the catheter entered through the closing nasal stroke to a nasopharynx. Inhalations of oxygen by means of a funnel, a mouthpiece or a pacifier are less effective.
The inhalated oxygen shall be humidified; ways of moistening same, as at To. t. at adults. Optimum concentration of oxygen in the inhalated mix makes 40 — 60%; higher concentration can, as well as at adults, cause undesirable effects.
Duration of a session To. t. can be various and depends on a state and age of the child, concentration of oxygen in the inhaled mix and the applied way of its introduction. Bo avoidance of complications M. S. Maslov, Yu. F. Dombrovskaya, V. A. Erenkov and others recommend to carry out inhalations of oxygen of 15 — 20 min. to 1 — 2 hour During the day depending on a condition of the child sessions To. t. it is necessary to repeat from 2 to 12 times.
There are various ways of dosing of the inhalated oxygen. N. A. Shalkov and V. N. Vanstein recommend to calculate a minute consumption of oxygen on 1 kg of weight of the child depending on age of the child: 1 — 6 month — 400 ml; 6 — 12 months — 350 ml; 1 — 1,5 years — 300 ml; 1,5 years — 6 years — 250 ml; 7 — 10 years — 200 ml; 11 — 18 years-100 of ml.
During the definition of a dose of the entered oxygen it is necessary to be guided by the minute volume of breath.
At obstructive changes of a trachea and bronchial tubes at patients with an atelectasis of lungs, a bronchiolitis, pneumonia, bronchial asthma, hypostasis of subcopular space (stenoses of the II—III degree) the good effect gives use of kislorodnogeliyevy mixes in the ratio 1:4, 1: 3 and even 1:1. Carrying out an oxygenotherapy oxygen-helium mix under supertension in pressures chamber is in case of need possible.
Neingalyatsioiny extra pulmonary methods of an oxygenotherapy at children are almost not applied because of danger of a gas embolism. In pleural and belly cavities, and in cerebral cavities oxygen is entered into the spinal canal seldom. Into a stomach and a small intestine oxygen is entered at an ascaridosis, into a rectum at an enterobiosis, a trichuriasis, exudative and catarral diathesis, bed wetting, hron, prick. Thanks to change under the influence of oxygen of flora of intestines, to decrease in putrefactive and fermentative processes, reduction of intoxication and a sensitization of an organism there is a nek-swarm an improvement of oxidizing processes and improvement of a condition of the child.
In pediatric practice it is more and more widely applied To. t. under supertension (see. Hyperbaric oxygenation ), especially shown for the newborns who were born in asphyxia with signs of disturbance of cerebral circulation, and also with the phenomena of the respiratory insufficiency caused by an atelectasis of lungs, hyaline membranes and diffusion disturbances of other nature.
Methods of carrying out an oxygenobarotherapy are various. The basic is the room of the newborn in a pressure chamber with pure oxygen and gradual (within 10 — 15 min.) build-up of pressure in it to 1,5 — 3,0 atm with the subsequent decrease to 0,3 — 0,5 atm. All session of an oxygenobarotherapy continues 40 — 60 min.; in case of need duration of hyperbaric oxygenation can be continued till 2 — 3 o'clock. Thanks to short duration of holding this procedure, a by-effect from use of pure oxygen it is not observed.
At children of early age carrying out To. t. quite often causes negative reaction that is shown by concern of the child owing to irritation and dryness of respiratory tracts, the disturbances of cordial activity, a rhythm and respiration rate reflex arising. Quite often at long To. t. at children weakness, dizziness, sometimes a headache is noted. Generally complications are caused by long inhalations of high concentration of oxygen (higher than 60%). Treat them: retrolental fibroplasia (see), fibrosis of pulmonary fabric, oppression of external respiration, decrease in systolic pressure, disturbance of tissue respiration in view of blockade of some enzymes.
Prevention of complications requires strict observance of rules of carrying out To. t.
Bibliography: Dombrovskaya Yu. F. Clinic and a pathogeny of an anoxemia of the growing organism, M., 1961; E re V. A. Oksigenoterapiya's nok in pediatrics, Kiev, 1975, bibliogr.; E faugh S. N., Shalnev B. I. and Eyge A. M wood. Oxygen parameters of blood and fabrics at intravascular oxygenation of an organism, Eksperim. hir. and anesteziol., No. 5, page 71, 1974; Zhironkin A. G. Oxygen, Physiological and toxic action, L., 1972; Zilber A. P. Clinical physiology for the anesthesiologist, M., 1977; Maslov M. S. A pathogeny of respiratory insufficiency at pneumonia at children and se treatment, L., 1953, bibliogr.; Petrovsky B. V. and Yo f at N and S. N. Bases of hyperbaric oxygenation, M., 1976; Problems of children's anesthesiology, resuscitation and an intensive care, under the editorship of Yu. F. Isakov and W. A. Michelson, M., 1971; Sykes M. K., Mac Nicol M. U. and To e m p e of l of l E. D. M. Respiratory insufficiency, the lane with English, page 99, M., 1974; Shalkov N. A. and Weinstein 3. I. Rational methods of oxygen therapy at children, Vopr. ped. and okhr. mat. also it is put., t. 18, No. 4, page 28, 1950; Egan D. F. Fundamentals of inhalation therapy, p. 250, St Louis — L., 1969; Respiratory therapy, ed. by P. Safar, p. 139, Philadelphia, 1966; Zapol W. M, Snider M. T. a. Schneider R. C. Ext-racorporeal membrane oxygenation for acute respiratory failure, Anesthesiology, v. 46, p. 272, 1977.
A. P. Zilber; H. A. Tyurin (ped.)