[Experimental study of the decrease in leukocytes and changes in leukotriene B4 caused by ECMO].

Abstract

Extracorporeal membrane oxygenation (ECMO) was performed in 27 mongrel adult dogs employing a V-V bypass between the proximal region of the inferior vena cava, used as a blood outlet, and the external jugular vein, used as a blood inlet, in order to investigate the decrease in leukocytes and the change in leukotriene B4 (LTB4) caused by ECMO. AA-861, an inhibitor of LTB4 activity, was given to 10 of the animals (AA-861 group), and the results obtained from this group were compared with those of a control group not given AA-861. Pulmonary arterial blood and pulmonary venous blood, for which femoral arterial blood was substituted, were sampled before ECMO, 5, 15, 30, 60, and 90 minutes after the beginning of ECMO, and 30 and 60 minutes after the termination of ECMO; measurements of various parameters, including WBC count, were carried out. The WBC count was seen to markedly drop immediately after the beginning of ECMO in both the control and AA-861 groups, and was significantly decreased in the femoral arterial blood than in the pulmonary arterial blood in the early phase of ECMO in both groups, revealing that the number of leukocytes differed between regions proximal and distal to the vital lung. This leukosequestration in the vital lung, pulmonary leukocyte sequestration in other words, was markedly inhibited in the AA-861 group than in the control group. Provided that leukosequestration is a phenomenon of leukocyte entrapment in the vital lung, a rate of entrapment could be calculated in the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)