The haemodynamic effects of propofol and ketamine were studied in two groups of eight randomly allocated elderly patients (mean age 85.8 years) anaesthetised for hip replacement. Group 1 patients patients received propofol 1 mg/kg by intravenous bolus for induction and 0.1 mg/kg/minute by continuous infusion for maintenance. Group 2 patients received ketamine 1.5 mg/kg by intravenous bolus as induction dose and 50 micrograms/kg/minute by continuous infusion for maintenance. All patients breathed spontaneously via a facemask at FIO2 1.0. Haemodynamic status was established before induction and at 1, 3, 5, 10 and 15 minutes after induction. Arterial pressure and cardiac output decreased slightly in group 1 but heart rate, right atrial pressure and pulmonary arterial pressure remained unchanged. Myocardial oxygen consumption showed a significant decrease of 27%. There was a significant increase in blood pressure and pulmonary capillary wedge pressure (by 97%) in group 2. Cardiac output and systemic vascular resistance remained unchanged whereas myocardial oxygen consumption showed a very significant increase of 100%.