Innovar has been compared with meperidine and a placebo in a blind study on 150 surgical patients. Both subjective and objective data were recorded, tabulated, and analysed statistically after it had been ascertained that the three groups were comparable from the point of view of sex distribution, mean age, mean weight, physical status, and baseline vital signs. It was found that more patients were drowsy after Innovar than after meperidine and that the same applied to meperidine when compared with the placebo. From the anaesthetist's point of view, Innovar and meperidine were better sedatives than the placebo, and this was also the impression of most patients. As far as objective parameters were concerned, there was a fall in both systolic and diastolic blood pressure after Innovar and in systolic blood pressure after meperidine. However, in the case of Innovar this response started with 10 minutes of the intramuscular injection with the effect progressing for approximately 30 to 40 minutes, after which time it stabilized. After meperidine no major changes were seen for 60 minutes, but then the systolic blood pressure declined below that recorded after Innovar. There was a sustained decrease in mean pulse pressure throughout the period of observation after both Innovar and meperidine. The mean pulse rate after Innovar tended to fall throughout the period of observation whereas that following meperidine remained essentially unchanged for the first 50 minutes and then fell rapidly to levels similar to those seen with Innovar. With the exception of the diastolic blood pressure after meperidine, all changes were found to be statistically significant, but no significant changes occurred after placebo in any parameter. © 1969 Canadian Anesthesiologists.
