Entropy monitoring decreases isoflurane concentration and recovery time in pediatric day care surgery -a randomized controlled trial

Aim: To assess if titrating anesthesia with entropy would result in faster awakening in children undergoing day care surgery. Background: Entropy, an EEG-based anesthesia depth monitor, has been used in children; however, only one other study has evaluated the effectiveness of entropy monitoring in decreasing awakening time and for titrating anesthetic agents in children undergoing short procedures under anesthesia. Methods: In a randomized prospective single-blind parallel group trial, 50 ASA grade I-II children, aged 2-12 years, scheduled for lower abdominal or urological surgeries were studied after ethics committee approval and parental consent. The children were randomized to the entropy or control group. Following laryngeal mask airway insertion and caudal analgesia, anesthesia was maintained with nitrous oxide, oxygen, isoflurane. In the control group, anesthesia was titrated according to the hemodynamic parameters and the simultaneously monitored entropy values obscured from the anesthesiologist. In the entropy group, the entropy values (between 45 and 65) were used to titrate the anesthesia. Results: Time to awakening from anesthesia was 7 (3-18) min in the entropy group when compared to 10 (5-21) min in the control group. (P < 0.05) The difference in the mean time to awakening was 2.72 min 95% CI (0.34, 5.1). The end tidal isoflurane concentrations were lower in the entropy group when compared to the control group 15 s following airway insertion (0.78 ± 0.14 vs 1.24 ± 0.19), 15 s post caudal and skin incision (0.68 ± 0.40 vs 0.84 ± 0.05, 0.68 ± 0.03 vs 0.77 ± 0.32, respectively) as well as 5 min after skin incision 0.67 ± 0.04 vs 0.79 ± 0.02), (P ≤ 0.05). Conclusion: In pediatric day care surgery, entropy monitoring resulted in statistically though not clinically significant faster awakening and significantly lower end - tidal isoflurane concentrations.