Abstract
We assessed usefulness of simultaneous monitoring of bloot flow velocity of middle cerebral aretry(MCA-V) measured by TCD and short latency SEP during cardiopulmonary bypass (CPB). MCA-V promptly responded to a temporal decrease in systemic perfusion rate or cerebral blood flow during CPB. MCA-V during CPB did not differ from that of pre-CPB period, it significantly increased after CPB, possibly reflecting hyperdynamic state due to hemodilution and administered inotropic agents immediately after CPB. Latency of each wave component of SSEP prolonged during hypothermic CPB, but P2 and CCT completely recovered to the pre-CPB value. On the other hand, P1, N1 and N2 remained prolonged after CPB, although no neurologic disorder was observed in all patient. Positive correlation was observed between postoperative P1 latency and MCA-V and negative correlation between CCT and MCA-V, suggesting that there may be some relationship between cerebral blood flow and electroencephalic response. It is difficult to conclude from this study because there was no patients with neurologic complication, however, simultaneous monitoring of TCD and SSEP is expected to be a reliable combination of the modality warning of reversible cerebral ischemia during CPB.
