Change in heart rate, mean arterial pressure, PaO2 and PaCO2 Caused by enflurane and halothane anesthesia were investigated in patients premedicated with diazepam and glycop-yrrolate. Enflurane caused a slightly(10.1%) increase in heart rate and not change in mean arter-ial pressure(0.1%), Halothane depressed heart slightly(10.16%) and arterial pressure was also (12.2%). The authors conclude that enflurane possesses a positive chronotropic effect.