Appropriate dose of dexmedetomidine for the prevention of emergence agitation after desflurane anesthesia for tonsillectomy or adenoidectomy in children: up and down sequential allocation

Background: Dexmedetomidine can be used for the prevention of emergence agitation (EA) in children. However, an inadequate dose of dexmedetomidine can induce prolonged sedation and cardiovascular complications. The aim of this study was to evaluate the effective dose of dexmedetomidine for the prevention of EA after desflurane anesthesia for patients undergoing a tonsillectomy or adenoidectomy. Methods: We enrolled 21 unpremedicated children, between 2 and 12 years, undergoing either a tonsillectomy or an adenoidectomy. General anesthesia was induced using sevoflurane and oxygen, and dexmedetomidine was administered before surgery. Anesthesia was maintained using desflurane resulting in a BIS range of 40-60. In the postanesthetic care unit (PACU), EA (agitation measured at level 4 or more at least once) was assessed on arrival in the PACU, 15 min later, and 30 min later. The dose of dexmedetomidine for consecutive patients was determined by the response of the previous patient, using an increment or decrement of 0.1 mu g/kg. Results: The 50% effective dose of dexmedetomidine for prevention of EA was 0.25 mu g/kg (95% confidence limits, 0.17-0.33 mu g/kg), and the 95% effective dose was 0.38 mu g/kg (95% confidence limits, 0.29-0.39 mu g/kg). Conclusions: For prevention of EA after desflurane anesthesia for 50% and 95% of children undergoing tonsillectomies or adenoidectomies, 0.25 mu g/kg or 0.38 mu g/kg of dexmedetomidine is suggested. Further study is needed to validate the suggested dose of dexmedetomidine to prevent the EA that was identified in the present study.