Abstract
Cerebral blood flow during mild hypothermic cardiopulmonary bypass (CPB) was investigated by measuring the blood flow velocity of the medial cerebral artery (MCAV), ophthalmic artery (OAV), and common carotid artery (CAV), and the regional cerebral oxygen saturation (rSO2), in 5 adult patients who underwent cardiac surgery. Maximal blood flow velocity in the medial cerebral artery (MCAVmax), ophthalmic artery (OAVmax), and common carotid artery (CAVmax) were measured with Doppler ultrasonography. MCAVmax, OAVmax, and CAVmax before CPB were 25.9±3.6cm/s, 28.3±14.5cm/s, 62.5±28.8cm/s, respectively. When CPB pump flow was varied 2.4 to 2.0l/min/m2, the parameters during and after CPB changed as follows: MCAVmax, 93.2%, 83.8%, 131%; OAVmax, 47.6%, 46.7%, 161%; and CAVmax, 69.3%, 70.7%, 213%. rSO 2 was 72.4±3.7% before CPB, 70.4% and 68.5% during CPB, and 71.8% after CPB. Because MCAVmax was maintained during CPB and less increased after CPB compared with OAVmax and CAVmax, autoregulation was thought to be preserved during mild hypothermic cardiopulmonary bypass. It was determined that 2.0l/min/m 2 of CPB pump flow in mild hypothermic cardiopulmonary bypass was adequate, based on changes in rSO 2.
