ABSTRACT
Forty-eight patients between 20 and 40 years and 48 patients between 60 and 80 years, none of whom had received premedication were subdivided at random for induction of anaesthesia with propofol (Diprivan) in four doses with or without prior administration of fentanyl. ED95 (effective dosage for 95%) for the young patients was 3.4 mg/kg and, for the elderly patients, 2.4 mg/kg. When 4 micrograms/kg fentanyl was administered five minutes prior to induction of anaesthesia, ED95 was reduced by 10% in the young patients and 20% in the elderly patients. In both the young patients and the elderly patients, the mean arterial blood pressure (MAP) three minutes after induction was found to be reduced by 2-26%. No further reduction was observed. The pulse did not alter significantly from the original value. When 4 micrograms/kg of fentanyl was administered five minutes prior to induction of anaesthesia, a significantly more pronounced decrease in MAP was found in young and also elderly patients during the entire period. This decrease in MAP was dependent on the dosage in the group of elderly patients. During the period of investigation, the pulse decreased 5-35%, except in the group of the young patients who received the smallest doses of propofol, where an increase of 15-20% was observed. It is concluded that induction of anaesthesia with propofol preceded by administration of fentanyl, may be followed by a considerable reduction in MAP.
