BLOODLETTING

From Big Medical Encyclopedia

BLOODLETTING (missio sanguinis; synonym krovoizvlecheniye, depletio sanguinis) — removal with the medical purpose of a certain amount of blood from circulatory system by method of a venipuncture or a venosektion, sometimes by method of a puncture of an artery.

To. it is known from an extreme antiquity and, though it is limited, the wedge, medicine is applied in modern. Views of efficiency and the mechanism to lay down. actions To. over time changed. In 18 century there was a steady opinion that To. promotes removal from an organism of the «poisonous» substances causing a disease. In 19 century there was a critical relation to To. as to a method empirical, with fiziol, the points of view a little reasonable, and from practical — doubtful. This point of view was divided by N. I. Pirogov. Interest to To. increased at the beginning of 20 century when action To. it became wide to be studied in an experiment and indications to its use received a nek-swarm scientific justification.

It is established that influence To. on an organism it is diverse. Artificial removal from circulatory system within a short period of time a significant amount of blood equivalently acute to blood loss (see). Massive To. reduces amount of the circulating blood and the nek-eye is followed by decrease in arterial, intra capillary and especially venous pressure that can have positive value at venous hypertensia in connection with right ventricular heart failure.

Recovery of normal volume of the circulating blood happens soon later To. for the account hydremias (see) — the increased water content in blood (is up to 15% higher than initial). Emergence of a hydremia is connected with inclusion neurohumoral the mechanism regulating a volemia as one of components of a homeostasis. As a result To. in some cases viscosity of blood goes down and time of its coagulation is extended, but these changes in system of a blood coagulation have phase character and depend also on features of a basic disease (e.g., at patients with an erythremia coagulant ability of blood later To. increases). Medical To. is rather strong irritant of nonspecific defense reactions of an organism. Besides, caused To. redistribution in an organism of water, electrolytes and uniform elements of blood is followed by increase in activity of mechanisms of regulation of the general and regional hemodynamics (see) that can contribute to normalization of the broken blood circulation. It, perhaps, speaks and observed in some cases later To. patients have a subjective improvement of a state, disappearance of head or retrosternal pains and paresthesias.

Indications and contraindications

Indications to To. can be: 1) right ventricular heart failure (see), proceeding with high venous pressure; 2) acute left ventricular heart failure with a fluid lungs (in the absence of shock or a collapse); 3) an eclampsia at acute nephrite and pregnancy (see. Eclampsia ); 4) poisoning with poisons, is long late in blood or communicating blood; 5) polycythemia (see).

Absolute contraindication to To. the states which are followed patol, arterial hypotension are (see. Hypotension arterial ) and a hypovolemia (see. Oligemiya ). Relative contraindications for To. — cerebral atherosclerosis, anemias of various genesis and tendency to a thrombogenesis.

Complications

Complications To. there can be hl. obr. owing to falling of the ABP, and also in connection with decrease in concentration of hemoglobin and quantity of erythrocytes in peripheral blood. To. at hypertensive crises at patients with the expressed cerebral atherosclerosis can promote development of ischemic circulatory disturbances in a brain. At such complications make completion of volume of the circulating blood introduction plasma substitutes or recovery of concentration of hemoglobin a hemotransfusion. Other complications To. are most often connected with errors in the equipment K. (injury of a vein or nearby artery, development of a hematoma). In similar cases it is necessary to take a needle and to apply a compressing bandage to the place of a hematoma. At the weakened faces, and also at too bystry extraction of blood the syncope is possible. At the same time recommend inhalation of spirit of ammonia, if necessary enter a phenylephine hydrochloride.


B. V. Konyaev, V. E. Salishchev.

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