Ketamine Enhances Intranasal Dexmedetomidine-Induced Sedation in Children: A Randomized, Double-Blind Trial

PURPOSE: To compare the efficacy of intranasal dexmedetomidine and dexmedetomidine-ketamine premedication in preschool children undergoing tonsillectomy. PATIENTS AND METHODS: We enrolled 66 children with American Society of Anesthesiologists physical status I or II, aged 3–7 years undergoing tonsillectomy. Patients were randomly allocated to receive intranasal premedication with either dexmedetomidine 2 μg kg(−1) (Group D) or dexmedetomidine 2 μg kg(−1) and ketamine 2 mg kg(−1) (Group DK). The primary outcome was the sedation level assessed by the Modified Observer’s Assessment of Alertness/Sedation Scale (MOAA/S) 30 min after intervention. The minimal clinically relevant difference in the MOAA/S score was 0.5. Secondary outcomes included sedation onset time, parental separation anxiety, acceptance of mask induction, emergence time, emergence delirium, postoperative pain intensity, length of stay in the post-anesthesia care unit (PACU), and adverse effects. RESULTS: At 30 min after premedication, the MOAA/S score was lower in Group DK than in Group D patients (median: 1.0, interquartile range [IQR]: 1.0–2.0 vs median: 3.0, IQR: 2.0–3.0; P<0.001), with a median difference of 1.0 (95% confidence interval [CI]: 1.0–2.0, P<0.001). Patients in Group DK showed considerably faster onset of sedation (15 min, 95% CI: 14.2–15.8 min) than Group D (24 min, 95% CI: 23.2–24.8 min), with a median difference of 8.0 min (95% CI: 7.0–9.0 min, P<0.001). Both parental separation and facemask acceptance scores were lower in Group DK than in Group D patients (P=0.012 and P=0.001, respectively). There was no significant difference in emergence time, incidence of emergence delirium, postoperative pain scores, and length of stay in the PACU between the two groups. CONCLUSION: Intranasal premedication with a combination of dexmedetomidine and ketamine produced better sedation for pediatric tonsillectomy than dexmedetomidine alone.