Abstract
The purpose of this study was to investigate wakefulness during induction of anesthesia with high dose fentanyl by using the isolated forearm technique. Thirty six patients scheduled for elective cardiac surgery were divided into five groups according to the methods of premedication or induction of anesthesia. The patients in group I-III were premedicated with morphine (0.15mg/kg) and scoplamine (0.4-0.5mg) intramuscularly one hour before the operation, while those in group IV and V were premedicated with hydroxyzine (50-100mg) and scoplamine, and pethidine (17.5-35mg) was added to group V. Anesthesia was induced with intravenous drip injection of fentanyl (100μg/kg) over a 15 minute period in all patients. Following 10μg/kg of fentanyl, diazepam (0.1mg/kg IV) was added to group II and 50% N2O in oxygen administrated to group III.
In group I, 7 out of 11 patients responded to verbal commands after 100μg/kg of fentanyl. One out of 5 patients in group II and 2 out of 7 patients in group III responded to verbal commands after 75μg/kg and 50μg/kg of fentanyl, respectively.
In group IV and V, none of the responses was detected after 25μg/kg of fentanyl. Most or patients in group IV, V were sedated adequately or were sufficiently sleepy before the operation. There were some complications such as tachycardia, rigidity and hypotension in proup I-III.
We conclude that patients undergoing high dose fentanyl anesthesia should be well sedated before the operation in order to obtain smooth induction and to prevent wakefulness during anesthesia.
