INDUCTION, RECOVERY, AND SAFETY CHARACTERISTICS OF SEVOFLURANE IN CHILDREN UNDERGOING AMBULATORY SURGERY - A COMPARISON WITH HALOTHANE

Background: Sevoflurane is an inhalational anesthetic with characteris tics suited for use in children. To determine whether the induction, r ecovery, and safety characteristics of sevoflurane differ from those o f halothane, the following open-labeled, multicenter, randomized, cont rolled, phase III study in children undergoing ambulatory surgery was designed. Methods: Three hundred seventy-five children, ASA physical s tatus 1 or 2, were randomly assigned in a 2:1 ratio to receive either sevoflurane or halothane, both in 60% N2O and 40% O-2. Anesthesia was induced using a mask with an Ayre's t piece or Bain circuit in four of the centers and a mask with a circle circuit in the fifth center. Max imum inspired concentrations during induction of anesthesia were 7% se voflurane and 4.3% halothane. Anesthesia was maintained by spontaneous ventilation, without tracheal intubation. End tidal concentrations of both inhalational anesthetics were adjusted to 1.0 MAC for at least 1 0 min before the end of surgery. Induction and recovery characteristic s and all side effects were recorded. The plasma concentration of inor ganic fluoride was measured at induction of and 1 h after anesthesia. Results: During induction of anesthesia, the time to loss of the eyela sh reflex with sevoflurane was 0.3 min faster than with halothane (P < 0.001), The incidence of airway reflex responses was similar, albeit Infrequent with both anesthetics. The total MAC h exposure to sevoflur ane was 11% less than the exposure to halothane (P < 0.013), although the end-tidal MAC multiple during the final 10 min of anesthesia was s imilar for both groups. Early recovery as evidenced by the time to res ponse to commands after sevoflurane was 33% more rapid than it was aft er halothane (P < 0.001), although the time to discharge from hospital was similar for both anesthetics. The mean (+/- SD) plasma concentrat ion of inorganic fluoride 1 h after discontinuation of sevoflurane was 10.3 +/- 3.5 mu M. The overall incidence of adverse events attributab le to sevoflurane was similar to that of halothane, although the incid ence of agitation attributable to sevoflurane was almost threefold gre ater than that attributable to halothane (P < 0.004). Conclusions: Sev oflurane compared favorably with halothane. Early recovery after sevof lurane was predictably more rapid than after halothane, although this was not reflected in a more rapid discharge from the hospital. The inc idence of adverse events was similar for both anesthetics. Clinically, the induction, recovery, and safety characteristics of sevoflurane an d halothane are similar, Sevoflurane is a suitable alternative to halo thane for use in children undergoing minor ambulatory surgery.