Ketamine with pancuronium for induction of anaesthesia

Abstract

KETAMINE AND PANCURONIU1V[ are relatively new agents each of which has been described as valuable for anaesthesia in poor-risk patients. The fact that one of them is a general anaesthetic and the other a muscle relaxant suitable for intubation suggests that the sequential or combined use of these drugs might be considered as a technique for induction of anaesthesia. This possibility was examined during routine clinical anaesthesia in the following inanner:One group consisting of ten healthy adult patients was premedicated with morphine 10 mg and hyoscine 0.4 mg. Anaesthesia was induced either with pancuronium 0.1 mg/kg followed by thiopentone 5 mg/kg over a period of 60 seconds, or with pancuronium 0.1 mg/kg followed by ketamine 2 mg/kg again over 60 seconds. The lungs of these patients were al~ificially ventilated with nitrous oxide and oxygen during the succeeding two minutes and the trachea was then intubated. The blood pressure was measured by sphygmomanometry and written records of the electrocardiograph were made. The findings are shown in Table I. The increase in pulse rate was similar in both groups. The patient who had received ketamine had an increase in both systolic and diastolic pressure. Those who had received thiopentone showed a decrease in systolic pressure. There were no cardiac irregularities in either group.The next group of patients was dealt with in a similar manner except that the ketamine or the thiopentone preceded the pancuronium. The findings appear in Table II and are similar to the previous group.Commercial preparations of ketamine and pancuronium are miscible and consequently in yet another group of ten healthy adult patients ketamine 2 mg/kg and pancuronium 0.1 mg/kg were mixed in the same syringe, the total volume of solution varying from 20 to 25 ml and the whole was iniected intravenously over a period of 60 seconds. The changes produced were similar to those observed when the drugs were given sequentially.Finally in Table III are shown the results of iniecting a mixture of ketamine 2 mg/kg and pancuronium 0.1 mg/kg over 60 .seconds or pancuronium 0.1 mg/kg followed by thiopentone 3 mg/kg over the same sixty-second period into patients about to undergo coronary artery bypass procedures. Systemic blood pressures were recorded from intra-arterial catheters. A slight increase was seen in the pulse rate of those patients who had received ketamine and there was an increase in systemic blood pressure. No cardiac arrhythmias occurred; however, there was a marked response to tracheal intubation in both groups. This same drug combination was administered to two patients for mitral valve replacement. The results