The effects of hypothermic cardiopulmonary bypass on Doppler cerebral blood flow during the first 24 postoperative hours

摘要

To provide understanding of influence of cardiopulmonary bypass (CPB) on cerebral blood flow (CBF), we investigated the effect of CPB on patients' cerebral haemodynamic parameters. Twenty-three patients were prospectively enrolled. CBF was estimated by transcranial Doppler (TCD) to measure blood velocity in the middle cerebral artery (MVMCA), preoperatively (T_0) and at four postoperative times (T_1, T_2, T_3, T_4). At times T_2, T_3 and T_4, MVMCA remained at higher levels than T_0 (P < 0.0.5). In the multivariate analysis PaCO_2 was independently associated to MVMCA at times T_`1 and T_2 (P = 0.03, P = 0.01, respectively) and temperature was independently associated with MVMCA at time T! (P = 0,02). Thus, the present study showed an increase in CBF after CPB, that was correlated with raised temperature but not with decrease in haematocrit.