Preemptive nebulized ketamine for pain control after tonsillectomy in children: randomized controlled trial

OBJECTIVES: The administration of ketamine as nebulized inhalation is relatively new and studies on nebulized ketamine are scarce. We aimed to investigate the analgesic efficacy of nebulized ketamine (1 and 2 mg.kg(−1)) administered 30 min before general anesthesia in children undergoing elective tonsillectomy in comparison with intravenous ketamine (0.5 mg.kg(−1)) and saline placebo. METHODS: One hundred children aged (7–12) years were randomly allocated in four groups (n = 25) receive; Saline Placebo (Group C), Intravenous Ketamine 0.5 mg.kg(−1) (Group K-IV), Nebulized Ketamine 1 mg.kg(−1) (Group K-N1) or 2 mg.kg(−1) (Group K-N2). The primary endpoint was the total consumption of rescue analgesics in the first 24 h postoperative. RESULTS: The mean time to first request for rescue analgesics was prolonged in K-N1 (400.9 ± 60.5 min, 95% CI 375.9–425.87) and K-N2 (455.5 ± 44.6 min, 95% CI 437.1–473.9) groups compared with Group K-IV (318.5 ± 86.1 min, 95% CI 282.9–354.1) and Group C (68.3 ± 21.9 min, 95% CI 59.5–77.1; p < 0.001), with a significant difference between K-N1 and K-N2 Groups (p < 0.001). The total consumption of IV paracetamol in the first 24 h postoperative was reduced in Group K-IV (672.6 ± 272.8 mg, 95% CI 559.9–785.2), Group K-N1 (715.6 ± 103.2 mg, 95% CI 590.4–840.8) and Group K-N2 (696.6 ± 133.3 mg, 95% CI 558.8–834.4) compared with Control Group (1153.8 ± 312.4 mg, 95% CI 1024.8–1282.8; p < 0.001). With no difference between intravenous and Nebulized Ketamine Groups (p = 0.312). Patients in intravenous and Nebulized Ketamine Groups showed lower postoperative VRS scores compared with Group C (p < 0.001), no differences between K-IV, K-N1 or K-N2 group and without significant adverse effects. CONCLUSION: Preemptive nebulized ketamine was effective for post-tonsillectomy pain relief. It can be considered as an effective alternative route to IV ketamine.