The clinical significance of changes in cerebral perfusion pressure during open-heart surgery.

In 34 high-risk patients, the intracranial epidural pressure (EDP) and the cerebral perfusion pressure (CPP) were monitored in connection with open-heart surgery. The findings were clinically evaluated, with special attention to affection of the central nervous system. Reduction of EDP to 10-30 mmHg for periods up to 10 min at the start of extracorporeal circulation and transient rise of EDP in the early postoperative period were relatively well tolerated. Late postoperative EDP rise, on the other hand, denoted an unfavourable trend, associated with permanent cerebral damage. Mannitol and/or barbiturates are indicated when an early rise in postoperative EDP persists or a late rise occurs. Covariation of EDP and arterial blood pressure (BP) should be regarded as a warning sign, especially if it is pronounced or appears during the postoperative course. In such conditions it seems important to stabilize the CPP by reducing a high EDP and by careful management of BP variations, i.e. with use of vasopressors. Postoperative epileptiform seizures seem to be prognostically unfavourable.