Evaluation of factors affecting the formation of thrombi in hemoperfusion columns

Abstract The formation of thrombi in the haemoperfusion column is undesirable as it deprives the patient of blood elements and reduces the eliminating capacity of the haemoperfusion column. This applies in particular to patients with acute intoxications treated by haemoperfusion. In experimental haemoperfusions in animals the authors provided evidence of a close correlation between thrombus formation in the haemoperfusion column and the number of stops of the blood flow in the course of individual experimental haemoperfusions. The period of stops was always 1.5 min. A further even closer correlation was found only between the formation of thrombi in the haemoperfusion column and the products of the number of stops of the blood flow (and the total period of arrests of the blood flow resp.) and the pressure gradient on the blood pump (difference of actual pressure readings before and beyond the blood pump). This gradient differed in every haemoperfusion but was constant during operation. It was induced and maintained by means of mechanical keys on the tube of the suction set. The objective of the work was to evaluate the influence of blood pressures in the area of the blood pump on the process of blood clotting in the haemoperfusion column. The blood flow, another factor influencing the intensity of blood clotting in the haemoperfusion column, was therefore the same in all experiments and constant in the course of their implementation. The extent of thrombus formation was evaluated after completed haemoperfusion and destruction of the cover of the haemoperfusion column by quantitative assessment of protein nitrogen referred to the weight of the adsorbent. The authors maintain that poor suction of blood, which precedes in clinical practice forced arrest of the circulation promotes the process of thrombus formation in the haemoperfusion column.