Changes in haemodynamic variables during transurethral resection of the prostate: comparison of general and spinal...

We have compared changes in haemodynamic variables before and during transurethral resection of the prostate in 22 patients under general or spinal anaesthesia. In the general anaesthetic group there was a significant decrease in cardiac output (mean 32% (SEM 5%)) and mean arterial pressure (14% (3%)) after induction of anaesthesia and a significant decrease (27% (3%)) in heart rate before the start of resection. Otherwise, variables remained close to baseline values. In the subarachnoid block group, mean arterial pressure decreased after induction (16% (2%)), but overall variables remained unchanged. We conclude that with both these anaesthetic techniques the greatest changes in haemodynamic variables occurred shortly after induction, and that these changes were greater during general than spinal anaesthesia. The resection period was not associated with significant haemodynamic changes.