SIGNS OF BRAIN-CELL INJURY DURING OPEN-HEART OPERATIONS - PAST AND PRESENT

Signs of brain cell injury have been studied during the evolution of o pen heart surgery in the last quarter century. At the beginning of the period, it was possible to elucidate signs of brain injury with rathe r crude psychometric tests and clinical observations in seemingly norm al patients having routine operations. Over the next 5 years, a marked improvement in psychometric scores was observed. However, a biochemic al cerebral cell injury marker (adenylate kinase) showed increased lev els in the cerebrospinal fluid, a finding indicative of brain cell inj ury. There was a correlation between cerebrospinal fluid levels of ade nylate kinase and psychometric test results as well as between the mar ker levels and clinical signs. Because of the relative insensitivity o f the psychometric tests used and the increasing difficulty in receivi ng permission for spinal fluid taps, other methods were sought. Refine d psychometric memory tests were used and showed that even in the 1990 s, there are subtle signs of brain cell injury during open heart opera tions. This finding was corroborated by using a highly brain-specific and brain-sensitive biochemical cell injury marker (S-100 beta) that i ncreased during extracorporeal circulation and showed a correlation wi th clinical cerebral complications.