Air embolism – obstruction of the blood course the vials of air which got to a blood-groove from the external environment. Clinical manifestations depend on type and size of the struck vessel. The obturation of coronary and pulmonary arteries, systems of blood supply of a brain is most dangerous. At defeat of LA there are symptoms of sharp respiratory and heart failure. The cerebral form of a disease proceeds with development of symptomatology of an ischemic stroke. The diagnosis is established on the basis of a clinical picture, data of dopplerography, a kapnogramma, measurement of TsVD. Specific treatment – aspiration of gas through a catheter, restoration of integrity of the vascular course.
The Air Embolism (AE) – the sharp pathological state arising at hit in a blood vessel of air from the outside. The amount of in one stage entered gas has to make not less than 10-20 ml, otherwise it will be dissolved in blood, without doing harm. Pathology is considered rather rare, no more than 2% of all possible types of vascular occlusion fall to its share. Decides on identical frequency at men and women, has no binding to age. Mortality at timely diagnostics and rendering the qualified help fluctuates from 10 to 40%. Lack of a medical grant at an embolization of pulmonary and cerebral vessels leads to death of the patient in 90% of cases.
Reasons of an air embolism
Spontaneous hit of air in blood system of the healthy person is almost excluded. Pressure in the majority of vessels is superfluous in relation to the atmosphere therefore suction of gases at damage of a vascular wall is not observed. An exception – an internal jugular vein in pressure at which breath is lower than atmospheric. Otherwise the situation with the dehydrated patients looks. Due to reduction of OTsK pressure in the central vessels becomes negative, violation of integrity of a wall of a vessel can lead to hit in gases from the environment. Treat common causes of air occlusion:
- Travmatization. Atmospheric gases get into blood at a barotrauma of lungs (sharp emersion from depth, incorrectly picked up device IVL mode), the injuries of a thorax which are followed by a rupture of blood vessels. VE also comes to light against the background of injuries of other anatomic zones in the absence of a timely stop of profuzny bleeding.
- Childbirth. Penetration of gases becomes possible at a rupture of placentary venous sine. Air in the damaged vessels is forced under pressure during uterine reductions. The disease develops irrespective of the size of the central venous pressure. The symptomatology can arise not only directly in labor, but also 1-2 days later.
- Medical procedures. With high risk of formation of VE refer operations on vessels, bodies of a thorax, a brain to manipulations if during intervention opening of a venous sine is made. Besides, air system of blood supply can get at leaky connection of infusional system with the central venous catheter or in the course of infusional therapy. Similar occurs at negative TsVD.
Large bubbles in the blood course can lead to occlusion of any vessels. Pulmonary veins, the heart vessels, arterial trunks feeding a brain are most often blocked. At damage of a pulmonary artery regional intra vascular hypertensia, an overload of PZh and sharp right ventricular insufficiency is noted. Further the left ventricle is involved in process, warm emission decreases, peripheral blood circulation is broken, shock develops. The air embolism of LA is followed by emergence of a bronchospasm, ventilating an imbalance, a heart attack of a lung and respiratory insufficiency.
At violation of a blood-groove in brain vessels formation of pathology happens as an ischemic stroke. On a certain site of a brain blood supply is broken, neurofabric experiences oxygen starvation and dies off. The site of a necrosis is formed, there are multiple small hemorrhages in brain fabric. The further course of disease depends on localization of an affected area. Paresis, paralyzes, violation of cognitive functions, failures in activity of internals can be found.
There are several criteria of systematization of VE. The air embolism is classified by character of a current (lightning, sharp and subsharp), ways of penetration of air to a blood-groove (yatrogenny, traumatic), to the direction of the movement of an embol (ortogradny, retrograde, paradoxical). In clinical practice use the division of forms of a disease by the form the struck vessel including the following options of pathology:
- Arterial. Obstruction of large arterial trunks is observed (coronary, pulmonary, cerebral). Meets in 30-35% of cases, develops immediately, proceeds hard, with the expressed clinical symptomatology. The patient perishes within several hours, sometimes – minutes. Formation of AVE requires more than 40-50 cm3 of the gas which in one stage got to a blood-groove.
- Venous. It is found in 65-70% of cases. Leads to violation of venous outflow. The symptomatology progresses rather slowly, zhizneugrozhayushchy states come to light seldom. It is inclined to a subsharp current. At obstruction of small veins also faded can proceed asymptomatically, the blood-groove at the same time is provided at the expense of system kollateraly. An exception – air occlusion of pulmonary veins on which the oxygenated blood arrives from lungs to heart.
Symptoms of an air embolism
The clinical picture differs depending on a look and the size of the struck vessel. At violation of outflow of blood on large peripheral veins there are typical symptoms of thrombosis. The affected area swells, increases in sizes. When squeezing strong morbidity is defined. Skin in a zone of pathology of a tsianotichn, takes place a local hyperthermia. System reaction is the moderate tachycardia caused by deposition of a certain volume of liquid and reduction of OTsK.
The air embolism of small branches of a pulmonary artery causes cough, a blood spitting, episodes , short wind more than 20 breaths, tachycardia within 100-120 beats per minute. Violations of haemo dynamics are absent. At obstruction of large trunks the picture of sharp pulmonary heart develops. At the patient sharp hypotonia, swelling of cervical veins, increase in the sizes of a liver, growth of TsVD, psychomotor excitement, strengthening of a warm push comes to light. Skin is pale, cold, it is covered sticky then.
Damage of coronary arteries leads to developing of a sharp myocardial infarction. Typical pains behind a breast of the squeezing character are noted. Use of nitrates does not give the expected effect. HELL decreases up to shock figures. Hypostasis of lungs of a warm origin is possible. Typical picture OIM is observed not always. In 40% of cases the disease proceeds in atypical option, is shown by belly-aches, a throat, the left hand etc.
Embolization of structures of blood supply of a brain becomes the stroke reason. In tissues of a brain the center of a necrosis on which localization the clinical symptomatology depends is formed. Carry paresis and paralyzes, local decrease in a muscular tone, paresteziya, speech disturbance, a sight illegibility, dizziness, a headache, violations of stability, the drop-attack, easing of skin sensitivity to the most widespread symptoms of an ischemic stroke.
At an embolization of peripheral arteries trophic ulcers are formed, there are necrosis zones. Violation of venous outflow in extremities leads to hypostases. Changes from system of blood supply of internals become the reason of easing or complete cessation of their activity. The sharp renal or liver failure, intestines paresis, insufficiency of function of heart and lungs can develop. Defeat of cerebral blood structures provokes irreversible violations in work of an organism. Paralyzes, violations in the psychoemotional sphere, changes in work of the internals innervated by the damaged site of a brain are observed.
Diagnostics of VE is performed by the intensivist in a tandem with the direct attending physician of the patient. Data of clinical inspection in combination with information obtained when using hardware diagnostic techniques usually do not leave doubts in the diagnosis. Difficulties arise when determining a type of an embolism. It is necessary to differentiate the occlusion of vessels caused by the air, vials of gas which are formed it is endogenous at sharp change of pressure of the environment (a lacunar disease, a gas embolism), blood clot, a tumor, a foreign matter, a conglomerate of bacterial cages. Are among diagnostic actions:
- Fizikalnye. Are carried out in intensive care unit or in the location of the patient. During survey reveal indirect symptoms of thrombosis and make the preliminary diagnosis. It is necessary to consider that the disease not always proceeds with a totality of symptoms, the frequency of occurrence of some of them does not exceed 50-60%.
- Laboratory. At the initial stages of development of VE laboratory inspection not too informatively. Changes of composition of gases of blood, acid-base balance, balance of electrolytes are noted. At damage of internals and development of polyorgan insufficiency there is an increase in activity of hepatic enzymes, growth of concentration of creatinine and urea in blood. Destructive processes in muscular tissue become the reason of increase in level of a myoglobin.
- Tool. When carrying out prekardialny, transezofagalny or transkranialny doppler sonography it is possible to establish the fact of availability of air in vessels. The research is qualitative, it is impossible to determine gas volume with its help. Kapnogramma demonstrates increase in concentration of carbon dioxide at the end of an exhalation, at measurement of TsVD the inadequate growth of indicators comes to light. On the ECG ventricular ekstrasistola, changes of a tooth P, ST segment depression are found.
Treatment of an air embolism
Elimination of consequences of hit of air in vessels is made with use of medicamentous and hardware ways of treatment. The volume of the necessary help depends on a condition of the patient, expressiveness of violation of the vital functions, existence in clinic of the necessary equipment. Usually the scheme of recovery actions includes the following methods of influence:
- Nonspecific medicamentous. Treatment is directed to minimization of clinical symptoms of a disease and prevention of complications. To the patient appoint steroid hormones, cardiotonics, loopback diuretics, vasodilating means, antioxidants. At a stage of restoration use polyvitaminic complexes, nootropic medicines. At the expressed respiratory insufficiency of the patient transfer to IVL in the mode of compulsory ventilation.
- Equipment rooms. The air embolism is treated by means of hyperbaric oxygenation and the operated hypothermia. GBO is carried out under pressure of 2-3 atmospheres, the number of sessions varies from 5 to 12. Duration of each of them – 45 minutes. When using a hypothermia the body of the patient is cooled to 34 °C. Both the barolecheniye, and cold promote increase in solubility of gases in blood that allows to destroy the blood clot inaccessible for removal in the operational way.
- Quick. An optimum method of extraction of an embol at intracardial VE is its aspiration through a subclavial catheter. At the same time there is a removal of several hundred milliliters of blood that can demand performing massive infusional therapy or a hemotransfusion. At exact definition of localization of an embol opening of a vessel or a venous sine is possible.
Forecast and prevention
Outcome favorable when air manages to be removed by means of low-traumatic subclavial access. At intra cranial or pulmonary localization of an embol the forecast worsens as it is almost impossible to take it by surgical methods. Application of GBO and hypothermia does not allow to normalize quickly a blood-groove, therefore, the probability of irreversible consequences increases. At damage of peripheral veins and arteries the threat for life usually is absent, but restoration of the struck fabrics proceeds is long, full regeneration manages to be achieved not always.
The air embolization most often arises during medical manipulations therefore actions for its prevention completely lay down on the staff of medical institution. At interventions on the top hollow vein of the patient has to be in the provision of Trandelenburga, the kateterization of a subclavial vein at the moment when the needle remains with an open end face (a syringe detachment, extraction of the conductor), is carried out on a deep exhalation of the patient. At low TsVD it is necessary to block in due time terminated infusional systems.