HEART-SURGERY - WHAT ARE THE NEUROPSYCHOLOGICAL CONSEQUENCES

The effects of cardiopulmonary bypass (CPB) on neuropsychological func tioning were investigated. Sixty-one patients were included in the stu dy; 42 underwent coronary artery bypass grafting (CABG) and 19 valve r eplacement or a double procedure of valve replacement and CABG (VR). A single standardised CPB protocol was used for all patients. Patients received one of two standard anaesthetics: propofol-fentanyl or isoflu rane-fentanyl. A battery of standard neuropsychological tests assessin g memory, information processing and visuospatial skills were administ ered one day pre-operation and 7 days post-operation (day 7). Change i n performance from pre-operation to day 7 and whether there were any d ifferences according to operation or anaesthetic administered was inve stigated. A repeated measures ANOVA was used. There were no significan t differences in the effects of the two drugs. There was no strong evi dence at a group level of deterioration in neuropsychological function ing at day 7. There were presurgical differences between the two opera tive groups in visuospatial abilities and speed of performance. The VR group performed more poorly than the CABG group and this persisted at day 7. Despite the preoperative differences, the neuropsychological c onsequences of CPB did not differ for the two groups. To allow compara bility with other studies, the number of subjects deteriorating more t han one standard deviation from the preoperative mean was calculated. This indicated that when analysis moved from the group to the individu al, there was evidence of deficit. Peri-operative variables were found to be poor predictors of post-operative cognitive functioning in comp arison to psychological variables.