HEMODYNAMIC STABILITY AND KETAMINE-ALFENTANIL ANESTHETIC INDUCTION

We have determined if alfentanil could obtund the haemodynamic instabi lity commonly seen at induction of anaesthesia with ketamine. Five gro ups of ASA I and II patients received ketamine 1 mg kg(-1) i.v., prece ded by saline (group 1) or alfentanil 10, 20, 30 or 40 mu g kg(-1) (gr oups 2-5, respectively). Heart rate (HR), mean arterial pressure (AP), postoperative patient complaints and dysphoria were noted. All groups showed increases (P<0.05) in both HR and AP after administration of k etamine, which were progressively smaller as the dose of alfentanil in creased. After tracheal intubation, all groups showed further increase s in HR and AP, with groups 3-5 (alfentanil 20-40 mu g kg(-1)) showing significant obtundation (P<0.05) of these increases compared with gro up 1. No patient in any group reported postoperative dysphoria or diss atisfaction with their anaesthetic. Ketamine 1 mg kg(-1) with alfentan il 20-40 mu g kg(-1) provided statistically significant obtundation of the haemodynamic instability that is com mon with ketamine alone.