FENTANYL ATTENUATES CARDIOVASCULAR-RESPONSES TO TRACHEAL EXTUBATION

We carried out a controlled, randomized, double-blind study to examine the effects of intravenous fentanyl (1 or 2 mu g kg(-1)) on hemodynam ic changes during tracheal extubation and emergence from anesthesia in 60 ASA physical status I or II patients undergoing elective gynecolog ical surgery. Anesthesia was maintained with 0.5%-1.5% isoflurane and 60% nitrous oxide (N2O) in oxygen. Muscle relaxation was achieved with vecuronium. The patients were randomly assigned to three group (each, n = 20), and fentanyl (1 or 2 mu g k(-1)), or saline (as a control) w as given at the time of peritoneal closure. Changes in heart rate (HR) and blood pressure (BP) were measured during. and after tracheal extu bation. Adverse effects, including postoperative sedation and respirat ory depression, were also assessed. The HR, systolic BP, and diastolic BP increased significantly during tracheal extubation in the control group (P<0.05). Fentanyl 2 mu g kg(-1) attenuated the increases in the se variables more effectively than fentanyl 1 mu g kg(-1). The time in terval from the study drug to extubation was similar in each roup. Pos toperative somnolence and respiratory depression were not observed in any patients in any of the three groups. We concluded that a bolus dos e of intravenous fentanyl 2 mu g kg(-1) given at the time of peritonea l closure was of value in attenuating the cardiovascular changes assoc iated with tracheal extubation and emergence from anesthesia, and that this treatment did not prolong the recovery. However, further studies are required to assess this technique in patients with cardiovascular or cerebrovascular diseases.