STUDY OBJECTIVE: We aimed to assess and compare the analgesic efficacies and adverse effects of ketamine administered through a breath-actuated nebulizer at 3 different dosing regimens for emergency department patients presenting with acute and chronic painful conditions.
METHODS: This was a prospective, randomized, double-blinded trial comparing 3 doses of nebulized ketamine (0.75 mg/kg, 1 mg/kg, and 1.5 mg/kg) administered through breath-actuated nebulizer in adult emergency department patients aged 18 years and older with moderate to severe acute and chronic pain. The primary outcome included the difference in pain scores on an 11-point numeric rating scale between all 3 groups at 30 minutes. Secondary outcomes included the need for rescue analgesia (additional doses of nebulized ketamine or intravenous morphine) and adverse events in each group at 30 and 60 minutes.
RESULTS: We enrolled 120 subjects (40 per group). The difference in mean pain scores at 30 minutes between the 0.75 mg/kg and 1 mg/kg groups was 0.25 (95% confidence interval [CI] 1.28 to 1.78); between the 1 mg/kg and 1.5 mg/kg groups was -0.225 (95% CI -1.76 to 1.31); and between the 0.75 mg/kg and 1.5 mg/kg groups was 0.025 (95% CI -1.51 to 1.56). No clinically concerning changes in vital signs occurred. No serious adverse events occurred in any of the groups.
CONCLUSION: We found no difference between all 3 doses of ketamine administered through breath-actuated nebulizer for short-term treatment of moderate to severe pain in the emergency department.
Studies of this sort have limited usefulness since the range of options, even for use of a single drug, is larger than the scope of the trial. The results, however, might justify starting in the lower dose range provided that close monitoring of response is possible.
This is an interesting study and I hope it will stimulate additional research in the area.