EVALUATION OF AWAKENING AND RECOVERY CHARACTERISTICS FOLLOWING ANESTHESIA WITH NITROUS-OXIDE AND HALOTHANE FENTANYL OR BOTH FOR BRIEF OUTPATIENT PROCEDURES IN INFANTS

This study compared recovery characteristics and postoperative ventila tory function when halothane, fentanyl or combination of halothane and fentanyl in addition to N2O were used for intraoperative anaesthesia in term infants undergoing hernia repair as outpatients. Sixty-six ful l term ASA PS I infants ages 1-12 months were studied. All received in halation induction with N2O, O-2 and halothane, followed by intravenou s atropine and atracurium, tracheal intubation, and controlled ventila tion. For anaesthesia maintenance, patients were randomized into one o f three groups. Group I received 70% N2O, 30% O-2 and halothane. Group II received 70% N2O, 30% O-2, halothane and 2 mu g.kg(-1) fentanyl. G roup III received 70% N2O, 30% O-2 and 10 mu g.kg(-1) fentanyl. Awaken ing times were similar in all three groups, however, Group I patients had significantly shorter recovery and discharge times than those of G roup II and III. None of the patients experienced postoperative apnoea or periodic breathing. One patient in Group III experienced two brief episodes of bradycardia not associated with apnoea or arterial desatu ration (SpO(2) >90% for greater than 30 s). Decreased SpO(2) occurred less frequently in Group I (5.9%) compared to Group II (22.7%) and Gro up III (19.0%) patients, however, the group differences were not signi ficant. Transcutaneous CO2 (TcCO2) values were not statistically diffe rent among the three groups. Pain scores were initially lower in Group s IT and III, but at 120 min the differences were not significant. Pos toperative apnoea was not observed in this study. SpO(2) <90% and TcCO 2 >9 kPa (70 mmHg) was more common in infants receiving 2 and 10 mu g. kg(-1) fentanyl than in infants receiving halothane and nitrous oxide anaesthesia. Infants <3 months old did not have a higher incidence of SpO(2) <90% or significantly higher TcCO2 values when compared to infa nts >3 months old. Fentanyl in doses used in this study did not prolon g awakening time but did prolong recovery and discharge times in outpa tient infants.