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.