Optimal Dexmedetomidine Dose to Prevent Emergence Agitation Under Sevoflurane and Remifentanil Anesthesia During Pediatric Tonsillectomy and Adenoidectomy.

Emergence agitation (EA) is a common pediatric complication after sevoflurane anesthesia that can be prevented with dexmedetomidine. However, an inappropriate dose of dexmedetomidine can cause prolonged sedation and cardiovascular complications. Thus, we evaluated the optimal dose (ED95) of dexmedetomidine for preventing EA with sevoflurane and remifentanil anesthesia after pediatric tonsillectomy and adenoidectomy. We enrolled American Society of Anesthesiologists (ASA) I and II children 3-7 years of age who underwent tonsillectomy with adenoidectomy. During induction, dexmedetomidine was infused for 10 min. Anesthesia was induced with sevoflurane and maintained with sevoflurane and remifentanil, resulting in a bispectral spectrum index (BIS) range from 40 to 60. Extubation time, surgical and anesthetic duration time, and duration time in the postanesthesia care unit (PACU) stay were recorded. EA [measured with Pediatric Anaesthesia Emergence Delirium (PAED) scores] and pain [measured with Face, Legs, Activity, Cry, Consolability (FLACC) scores] were assessed at extubation (E0), 15 min after extubation (E1), and 30 min after extubation (E2). If EA occurred, the next surgical procedure included increased dexmedetomidine by 0.1 μg/kg, and if not, the drug was reduced by 0.1 μg/kg. The 50% effective dose (ED50) of dexmedetomidine for preventing EA after sevoflurane and remifentanil anesthesia for tonsillectomy and adenoidectomy was 0.13 μg/kg, and its 95% confidence interval is 0.09-0.19 μg/kg; ED95 was 0.30 μg/kg, and its 95% confidence interval is 0.21-1.00 μg/kg. Intravenous dexmedetomidine infusion at ED50 (0.13 μg/kg) or ED95 (0.30 μg/kg) during induction for 10 min can prevent half or almost all EA after sevoflurane and remifentanil anesthesia during pediatric tonsillectomy and adenoidectomy.