Brain emboli distribution and differentiation during cardiopulmonary bypass

Abstract

Objective: Cardiopulmonary bypass (CPB) is a lifesaving practice in cardiac surgery, but its use frequently is associated with cerebral injury and neurocognitive dysfunctions. Despite the involvement of numerous factors, microembolism occurring during CPB seems to be one of the main mechanisms leading to such alterations. The aim of the present study was to characterize the occurrence of cerebral microembolism with reference to microembolic amount, nature, and distribution in different combinations of cardiac procedures and CPB on the microembolic load.

Design: A retrospective observational clinical study.

Setting: A single-center regional hospital.

Participants: Fifty-five patients undergoing elective cardiac surgery with CPB.

Interventions: Bilateral detection of the patients' middle cerebral arteries using a multifrequency transcranial Doppler.

Measurements and main results: Patients were divided into 3 groups depending on the CPB circuit used (open, open with vacuum, or closed). There was a significant difference between the number of solid and gaseous microemboli (p<0.001), with the solid lower than the gaseous ones. The number of solid microemboli was affected by group (p< 0.05), CPB phase (p<0.001), and laterality (p<0.01). The number of gaseous microemboli was affected only by group (p<0.05) and CPB phase (p<0.001). Generally, the length of CPB phase did not affect the number of microemboli.

Conclusions: Surgical procedures combined with CPB circuits, but not the CPB phase length, affected the occurrence, nature, and laterality of microemboli.

Keywords: cardiac surgery; cardiopulmonary bypass; cerebral microembolism; transcranial Doppler.