[Effects of speed of injection on anesthesia induction with propofol and fentanyl]

We examined the effects of injection rate of propofol on injection pain and postinduction hypotension and bradycardia when fentanyl was administrated before propofol. Fifty-five patients premedicated with midazolam and atropine were randomly allocated to two groups. Three minutes after administration of fentanyl 100 micrograms, propofol 1.5 mg.kg-1 was injected to a forearm vein at a rate of 800 ml.hr-1 in Group FS or 1 ml.s-1 in Group FR. Anesthesia was maintained with 67% nitrous oxide in oxygen and supplemental propofol infusion. The incidence and severity of pain on injection were not influenced with injection speed. The rapid rate of injection significantly shortened the induction time. The decrease in systolic and diastolic blood pressures and heart rate after induction were not affected by injection speed. In conclusion, rapid injection of propofol after fentanyl was effective to shorten the induction time without increasing the postinduction hypotension and bradycardia.