EMBOLISM

From Big Medical Encyclopedia

EMBOLISM (Greek embole an insert, invasion) — the pathological process caused by transfer by a blood flow of various substrates (emboluses) which are not found normal and capable to cause acute occlusion of a vessel with disturbance of blood supply of fabric or body.

Meets more often thromboembolism (see). Besides, can be observed bacterial, air, gas, fatty, fabric (cellular) E., and also embolism foreign bodys.

Bacterial E. represents a heavy complication of purulent inflammatory process practically of any localization. Occlusion of vessels the agglutinated microorganisms or is more often fragments of the blood clot which underwent septic fusion, leads to development of a septicopyemia and formation of metastatic suppurative focuses in various bodies (see. Sepsis ).

Air E. (aeroembolism) develops as a result of hit in a blood stream of air traps at wound of jugular or subclavial veins, an open injury of sine of a firm brain obodochka, injury of a lung under the influence of an explosive shock vodna (see. Barotrauma ), the nek-ry neurosurgical operations performed in position of the patient sitting, operative measures on lungs, at heart and aorta operations with use of the cardiopulmonary bypass (see), carrying out a hemodialysis (see), imposing of a diagnostic or medical pneumoperitoneum (see) or pheumothorax (see. Pheumothorax artificial ). Close on character to air gas E. is a rare complication of gas gangrene (see. Mephitic gangrene ) or a major factor of development of a compressed-air disease (see).

Fatty E.— obturation of small vessels of internals drops of neutral fat — meets hl. obr. at the closed fractures of long tubular bones, multiple fractures of edges and pelvic bones, heavy burns, an electric trauma and extensive damages of soft tissues with crush of hypodermic cellulose. At expressed osteoporosis (see) even the insignificant injury of a musculoskeletal system can become the reason of a fatty embolism. It is described fatty E. at osteomyelitis, acute pancreatitis, a heavy current of a diabetes mellitus, fatty dystrophy of a liver, a convulsive syndrome of various genesis, heavy intoxications, and also at a number of orthopedic operations (first of all an intramedullary metalosteosynthesis), an anesthesia ether, chloroform or Ftorotanum, the closed cardiac massage, treatment by oil solutions of pharmaceuticals or in cases of non-compliance with rules of introduction of the fatty emulsions applied to parenteral food.

Fabric (cellular) E. it is noted at severe injuries with crush of fabric or body, malignant tumors, disturbance of a technique of carrying out a transdermal puncture biopsy of internals, non-compliance with rules of a puncture and catheterization of subclavial or jugular veins. Pieces of the damaged tissue of a brain or a liver, marrowy cells, scraps of a derma and cross-striped muscle fibers become emboluses in such cases. The embolism cells of a malignant tumor is the cornerstone of its hematogenous dissimination (see. Innidiation ). Carry to peculiar fabric embolisms amniotic E., caused by hit of amniotic waters (see) in a circulatory bed of the woman in labor (see. Childbirth , shock and an embolism in labor), and also the trophoblastic embolism arising in isolated cases at the broken pipe pregnancy or a scraping of a cavity of the uterus concerning a vesical drift (see).

AA. foreign bodys (fraction, a bullet, a splinter of a shell, scraps of clothes at gunshot wounds) meets extremely seldom. In resuscitation practice, it is preferential at the patients who are in a condition of psychomotor excitement E is occasionally observed. a fragment of the catheter entered into a large vein (see. Resuscitation pathology ). E belongs to the same type of complications. the calcinated fragments of atherosclerotic plaques getting to a blood stream at operations on calciphied valves of heart or at an ulceration of atherosclerotic plaques.

At a nezarashchenny oval opening, existence of defect of an interatrial or interventricular partition with dumping of blood from right to left (see. Heart diseases inborn ) it can be observed paradoxical E. It is characterized by transfer of emboluses from veins of a big circle of blood circulation (having passed lungs) and obturation of branches of aortas or other arteries.

Retrograde E.— transfer of an embolus against a blood flow from a venous vessel, proximal in distal department. It can be observed when the embolus (as a rule, the foreign body, is more rare the blood clot having high specific density) moves by gravity, usually at the slowed-down blood-groove in a vessel.

Depending on the size of an embolus it is possible to allocate E. large vessels and microcirculator E.

Mechanical obturation of an artery an embolus is followed by the regional vasoconstriction accepting sometimes more or less diffusion character. As a result of it the gleam of an artery is reduced and pressure of blood distalny places of occlusion decreases. In the conditions of the termination of a blood-groove in this site of a vascular bed the continued blood clot forms (see. Thrombosis ) capable to block all gleam of a vessel with development at first of ischemia (see), and then a necrosis of fabric or body (see. Necrosis ). Emboluses also formation of the blood clot extending in the proximal direction turns out to be inevitable consequence of acute blockade of a microcirculator bed.

Any E. causes frustration fiziol. balances between processes of coagulation and a fibrinolysis. Than heavier the basic disease proceeds, E appears a complication to-rogo., than the content in the circulating blood of potential emboluses (e.g., fatty drops) and more their diameter is higher, than disturbances in system of microcirculation, especially quickly are more extensive and deeper and it is expressed transition of a gaperkoagulyation to a phase of consumption of factors of coagulation with the subsequent emergence of hemorrhagic manifestations up to fibrinolitic bleeding is carried out. Not accidentally, e.g., the fatty embolism is defined quite often as a traumatic coagulopathy. Thus, any kind E. can act as the allowing factor of development of the disseminated intravascular coagulation (see. Hemorrhagic diathesis , Trombogemorragichesky syndrome ).

The first barrier on the way of microemboluses always is the microcirculator bed of lungs. At a large diameter of microemboluses there is a blockade of pulmonary capillaries and pulmonary vascular pressure increases. Further rise in pulmonary arterial pressure in the conditions of the broken blood-groove is promoted by a giperkatekholaminemiya and hypercoagulation as nonspecific reactions of an organism to a stress, change of rheological properties of blood and release of substances at aggregation of thrombocytes on emboluses and a vascular wall. At an amniotic embolism pulmonary arterial hypertension is caused by pressor influence of F2a prostaglandin which is contained in amniotic waters. Under influence of the listed factors filtrational pressure in capillaries of lungs and resistance of intersticial liquid in lungs increases. Due to the mobilization of lipids and increase in activity of a serumal lipase concentration free fat grows to - t in blood (especially at a fatty embolism), to-rye strengthen aggregation of thrombocytes and, getting into alveoluses, bring to inaktivatsiin surfactant (see) that comes to the end with formation of an atelectasis. Natural result of all these processes is the arterial anoxemia aggravating vascular disorders and promoting progressing of the disseminated intravascular coagulation.

At all types E. the pathoanatomical changes inherent to the disseminated intravascular coagulation are noted. These changes are especially expressed at bacterial, fatty and amniotic E. Tak, at septic shock of fibrinferments of capillaries of a spleen and glomerular capillaries of kidneys, capillaries of a liver, lungs, fatty and megalotsitarny E. the last are combined with multiple hemorrhages in a spleen and adrenal glands, to skin and a mucous membrane went. - kish. a path (see. Sepsis ).

Wedge. manifestations at a thromboembolism of pulmonary arteries (see) and other types pulmonary E. are in essence identical. Syndromes of an acute pulmonary heart (see), acute arterial hypotension (see), acute coronary insufficiency are observed (see), fluid lungs (see), acute respiratory insufficiency (see), and also the abdominal syndrome connected with irradiation of pain in upper parts of a stomach owing to pleurisy or stretching of a fibrous cover of a liver at acute stagnation and swelling of a liver (see. Pseudoabdominal syndrome ), and the cerebral frustration caused by preferential arterial anoxemia and falloff of a brain blood-groove (see. Cerebral circulation ).

At air E. at the patient at auscultation of heart the special, «gurgling» noise, so-called noise of a mill wheel can come to light. Focal disturbance of sensitivity of language, development of visual, vestibular and other disturbances is sometimes noted. During operation with use of the cardiopulmonary bypass air E. it can be revealed on the basis of emergence in blood or cardial cavities of vials of gas (see. Artificial circulation, complications). Bacterial and different types fabric E. are followed by clinical and biochemical signs of a syndrome of the disseminated intravascular coagulation quite often in combination with hemorrhagic complications (see. Hemorrhagic diathesis) and an acute renal failure (see). Wedge. picture fatty E. it is characterized by a resistant hyperthermia with a hyperhidrosis, a petekhialny enanthesis most often at the basis of a neck, in axillary poles, on a conjunctiva of a lower eyelid and a mucous membrane of a mouth; the progressing decrease in level of hemoglobin, number of erythrocytes and thrombocytes expressed by a leukocytosis with a deviation to the left and increase of ROE; increase in coagulating activity of blood and activity of a serumal lipase; a hamaturia and increase in content of creatinine in blood by 1,5 — 2 times in comparison with norm.

Diagnosis pulmonary E. establish on the basis of careful studying of the anamnesis of a disease, a wedge. pictures of the arisen complication and results of special researches. As well as at a thromboembolism of pulmonary arteries, an important role is played by dynamic definition of gas structure and an acid-base condition of an arterial blood, these gemostaziogramma, polyposition perfused scanning of lungs, a X-ray analysis of bodies of a chest cavity and an angiopulmonografiya.

Special value at fatty E. have existence of a so-called light interval on average during 8 — 16 hours after an injury, identification of fatty emboluses in the form of white spots in vessels of a retina at Ophthalmolum. a research, definition of particles of neutral fat (frequent diameter there is twice more erythrocyte) and its content in blood and urine by means of fluorescent microscopy.

At E. vessels of a big circle of blood circulation this wedge. researches demonstrate sudden dysfunction and development of ischemia or heart attack of a kidney (see), spleens (see), a liver (see). Extremely heavy pain syndrome meets at E. the main arteries of extremities (see. Gangrene , Blood vessels ), coronary arteries (see the Myocardial infarction, Coronary insufficiency), arteries of a mesentery (see. Belly toad , Intestines ). AA. vessels of a brain the hl is characterized. obr. a clinical picture of an ischemic stroke (see). Manifestations air and fatty E. vessels of a brain are extremely various: from a somnolention or an oglushennost before sharp psychomotor excitement, development of a delirious or convulsive syndrome, focal nevrol. disturbances and hemiparesis. It is characteristic that a cerebral form fatty E. arises most often against the background of pulmonary. In addition to detailed clinical, radionuclide and laboratory researches, an important role in timely recognition arterial E. belongs angiography (see).

Acute current patol. process E is peculiar. branchings of an aorta or pulmonary trunk; at E. arteries of smaller caliber both the acute, and subacute current is noted. The acute or subacute type of a current with a frequent lethal outcome is characteristic of an air and fabric embolism. Cellular E. it can clinically not be shown. At bacterial E., as well as at a thromboembolism. perhaps acute, subacute and recurrent current. At fatty E. allocate the following options of a current: immediate (apoplektiformny), if between an injury and AA. there pass several minutes; early, if injury and beginning E. divide several hours; late when the «light» interval is extended up to several days; delayed (erased, or subclinical) when the symptomatology is not clear, and the correct diagnosis is established seldom. Acute occlusion only a microcirculator-nogo of a bed of lungs is characteristic of the first two options of a current; wedge. the picture masks in these cases symptoms of traumatic shock (see). At the late and delayed options of a current obturation by neutral fat of microvessels of both a small, and big circle of blood circulation is noted.

Rational therapy at E. it is directed to treatment of a basic disease, and also is defined by a type of an embolism, caliber of an obturirovanny vessel and extensiveness of defeat of a microcirculator bed. Conservative pathogenetic therapy at a thromboembolism consists in use of trombolitik, anticoagulants and antiagregant. These drugs use at development of the disseminated intravascular coagulation in patients bacterial, amniotic, trophoblastic or fatty E. The major action at air E. aspiration of air from a right ventricle (by means of its puncture) or the right auricle (through the catheter entered into a vein) in the conditions of artificial ventilation of the lungs with positive pressure on an exhalation is (see. Artificial respiration ). At all types of an air embolism and a heavy current fatty E. hyperbaric oxygenation (see), use of the drugs improving fabric exchange is shown.

Acute arterial impassability in connection with a thromboembolism, fabric E. or an embolism a foreign body demands operational treatment. Operational treatment — embolectomy — consists from a gleam of a vessel of an embolus at a distance. Most often the embolectomy is made from vessels of a big circle of blood circulation — bifurcation of an aorta, the main arteries of extremities, an upper mesenteric artery and renal arteries. The absolute indication to an embolectomy is the embolism of arteries of extremities and bifurcation of an aorta. Operation is inexpedient only in the preagonal condition of the patient incompatible with any operative measure. The embolectomy is carried out under local infiltration or peridural anesthesia. The anesthesia is applied seldom, e.g. at a direct embolectomy from bifurcation of an aorta.

On a way of performance the embolectomy can be direct and indirect. For carrying out a direct embolectomy the vessel is bared directly in the place of its obstruction, open its gleam and after removal of an embolus imposed vascular seam (see). The indirect embolectomy is made by an exposure of a vessel in the most available anatomic area below or places of obstruction are higher. The embolus is deleted in this case by means of special flexible tools, e.g. a balloon catheter (see. Fogarti catheter ).

At an embolectomy from a femoral artery apply access in an upper third of a hip according to a projection of the main vessels. After an exposure of a femoral artery in the place of an otkhozhdeniye of a deep artery of a hip it is pressed tourniquets above and lower by places of occlusion. Make an arteriotomy and delete an embolus. Emergence of a pulse jet of blood from a proximal piece of a vessel, and also a good retrograde blood-groove from the periphery testifies to efficiency of an embolectomy (after weakening of tourniquets). Operation is completed an angiorrhaphy on a wall of a femoral artery.

The embolectomy from an outside ileal artery is carried out by means of a balloon catheter, to-ry out through a femoral artery in the proximal direction above an embolus. After that the cylinder of a catheter is filled with liquid and the return traction of the tool take an embolus through an opening in a wall of a femoral artery. Approximately also carry out an embolectomy from bifurcation of an aorta, using bilateral femoral access. The embolectomy from a popliteal artery can be a straight line (from a medial section in an upper third of a shin) and indirect — by means of the balloon catheter entered through a femoral artery. The embolectomy from humeral, axillary and subclavial arteries is made access through area of an elbow pole (an elbow bend).

The embolectomy from an upper mesenteric artery can be carried out as independent intervention (in early terms after an embolism when yet the heart attack of intestines did not develop) or to be combined with a resection of impractical sites of intestines. Operation is made abdominal access under anesthetic or peridural anesthesia. In recent years at E. an upper mesenteric artery began to apply a technique of an indirect X-ray endovascular embolectomy. For this purpose use special balloon catheters, with the help to-rykh under rentgenol. control make an embolectomy (see. X-ray endovascular surgery).

The embolectomy from a pulmonary trunk or pulmonary arteries is shown at sharply expressed disturbances of perfusion (switching off from blood circulation of 60% of a pulmonary and arterial bed) and heavy frustration of a gemodinamnka (persistent arterial hypotension with the level of system pressure below 100 mm of mercury. or considerable pulmonary hypertensia is higher than 60 mm of mercury.). The embolectomy can be executed from a pulmonary trunk and pulmonary arteries in various ways. In a crust. time apply an embolectomy through one of leading branchs of a pulmonary artery and an embolectomy in the conditions of temporary occlusion of venas cava or in the conditions of artificial circulation more often.

At the isolated defeat of one of pulmonary arteries the embolectomy is made by a side thoracotomy (see) in the IV mezhreberye (at the left and on the right). After imposing on a pulmonary artery of two tourniquets between them carry out an arteriotomy and delete an embolus. This option of intervention differs rather small travmatichnostyo, but it is applicable only in those exceptional cases when there is hemilesion of a pulmonary arterial bed.

In the conditions of temporary occlusion of venas cava it is possible to make intervention on pulmonary arteries on both sides. After a longitudinal sternotomy and opening of a pericardium impose tourniquets on venas cava and seams handles on a front wall of a pulmonary trunk, to-ry pristenochno wring out and over a clip make a longitudinal arteriotomy. Press venas cava, remove a clip from a pulmonary trunk and delete an embolus. No more than 3 min. then again impose a pristenochny clip shall be spent for this stage of operation and release venas cava. Additional audit of a pulmonary arterial bed in 10 — 15 min. can be made for removal of the remained emboluses. Operation comes to the end with sewing up of a wall of a pulmonary trunk.

An optimal variant of operation at a thromboembolism of a pulmonary artery — an embolectomy in the conditions of artificial circulation. At the first stage of operation under local anesthesia make venous and arterial auxiliary perfusion, edges allows to support satisfactory indicators of a hemodynamics and facilitates an introduction anesthesia. After a thoracotomy the embolectomy is carried out in the conditions of full artificial circulation. Any option of an embolectomy from a pulmonary trunk and pulmonary arteries shall be combined with implantation in the lower vena cava of the special filter for prevention of a recurrence of a thromboembolism.

In recent years the method of X-ray endovascular treatment of a thromboembolism of pulmonary arteries with use of long introduction to a pulmonary artery of Streptoliasum is developed (see). After carrying out topical diagnosis by means of an angiopulmonografiya through a median vein (an intermediate vein, T.) forearms enter the managed cordial catheter, to-ry advance in the right auricle, a ventricle and in a pulmonary trunk. Then a catheter rekanalizirut an embolus and make fragmentation of trombotichesky masses. On a catheter, the end to-rogo is established in close proximity to the mass of a tromboembol, kapelno during 6 — 7 hours enter a strentoliaza.

Results of an embolectomy depend on duration and degree of ischemia of fabrics and bodies, localization of an embolus, timeliness both the intervention, and adequate use of anticoagulants and trombolitik in the preoperative and postoperative periods.

Embolism in the medicolegal relation. In court. - medical practice meet air, fatty and fabric E more often. Expert diagnosis E. also the lab is based on studying of circumstances of death, results of necropsy. researches.

At suspicion on air E. necropsy is begun with midsection from the handle of a breast, then saw her body at the level of II mezhreberye and deleted. Edges of the opened pericardium raise in hold tweezers or clips. In a pericardiac cavity pour water so that it covered heart. Through a sheet of water puncture a front wall of a right ventricle of heart with a post-mortem knife or a scalpel. Vykhozhdeniye of air traps with a characteristic sound serves as the proof air E. Before performance of test on air E. do not make other cuts and do not open the volost of a skull. The negative take of this test does not exclude a possibility of approach of death from air E. cerebral vessels therefore before extraction of a brain it is necessary to tie up internal carotid and vertebral arteries. After opening of cerebral cavities tie up and investigate vascular textures under a stereomicroscope, in to-rykh air traps can be found. Air E. it is necessary to differentiate from the postmortem changes which are followed by formation of putrefactive gases usually days later in more after approach of death. For this purpose during the conducting the test described above also under water puncture also a wall of a left ventricle of heart. Allocation of air traps not only from right, but also from a left ventricle makes the diagnosis air E. under doubt. A certain value for differential diagnosis has, besides, existence of the putrefactive changes which are coming to light at a research of a corpse.

For fatty E. multiple petekhialny hemorrhages on skin in the field of a shoulder girdle and in a conjunctiva are characteristic. Existence fatty E. in lungs establish at a research of the contact preparations of pulmonary fabric painted on fat by Sudan (see). At microscopic examination of the pulmonary fabric taken from various departments of lungs it is possible to find fatty emboluses in capillaries. At Fatty E. vessels of a brain in bark and white matter multiple small and larger hemorrhages (a brain purpura) are observed. Along with it numerous fatty emboluses are defined in capillaries of a liver and balls of kidneys. At fabric E. in gleams of vessels or in cardial cavities find fragments of fabrics or cellular elements of the damaged bodies.

In case of amniotic E. at microscopic examination of a tsentrifugat of the blood taken in time of opening from the lower vena cava and the right departments of heart epidermal cells of a fruit, a particle of syrovidny lubricant, meconium come to light. The same elements can be found also in capillaries of a lung.


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V. D. Topolyanoky; G. A. Nashinyan (court.), E. G. Yablokov (hir.).

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