Significant reduction of air microbubbles with the dynamic bubble trap during cardiopulmonary bypass

Abstract

Air microbubbles mostly occur unnoticed during cardiopulmonary bypass and are predominantly responsible for serious postoperative psycho- neurological dysfunction. A dynamic bubble trap (DBT), which removes air microbubbles from the arterial blood, was tested in a clinical study. The aim was to evaluate the efficiency of microbubble removal under clinical conditions. As blood passes through the DBT, which is placed in the arterial line between the arterial filter and arterial cannula, it is converted into a rotating stream. The bubbles are directed to the centre of the blood flow and are collected in the distal end of the DBT, from where they are returned to the cardiotomy reservoir. Doppler ultrasonography was used to detect the microbubbles before and after the DBT, and also the number of high- intensity transient signals (HITS) in the right and left middle cerebral artery during extracorporeal circulation. A significant reduction of microbubbles in the arterial line (3990 before DBT, 537 after, p < 0.001) and HITS in the brain (51 in the DBT group, 77 in the placebo group, p = 0.04) was measured.