Use of a dynamic bubble trap in the arterial line reduces microbubbles during cardiopulmonary bypass and microembolic signals in the middle cerebral artery

Abstract

Neurological complications remain an important cause of morbidity and mortality of patients following cardiopulmonary bypass (CPB). Microemboli, as well as cerebral hypoperfusion, are the main postulated mechanisms. This study demonstrates that the insertion of a dynamic bubble trap (DBT) into the curcuit reduces microbubbles in the arterial line and microembolic signals (MES) in the middle cerebral arteries (MCAs). We investigated 12 patients during coronary artery bypass grafting (CABG). The DBT was inserted between the arterial filter and the arterial cannula. For detection of microemboli before and after the DBT, a special ultrasound Doppler device was used. MES were detected by transcranial Doppler monitoring in both MCAs of the patients. Microbubbles and MES were counted during bypass. These data were compared to 12 patients who were operated in a previous period without the use of a DBT. There were no significant differences in both groups with respect to gender, age, crossclamp and bypass time and number of anastomoses. In the group without a DBT in the circuit, a mean of 6311 microbubbles per operation could be observed distal to the arterial filter, corresponding to 282 MES. After inclusion of a DBT, we could register, in the second group, 8496 microemboli proximal and 2915 distal of the DBT, corresponding to 89 MES per operation. The reduction rate of microbubbles in the tubing was 65.7%, corresponding to a reduction in MES of about 86.2%. We conclude that the insertion of a DBT in the arterial line of CPB circuit protects the cerebrovascular system from microembolic events, as demonstrated by lower MES counts.