Sub-dissociative-dose intranasal ketamine for moderate to severe pain in adult emergency department patients

Abstract

Background: There are currently no studies assessing effectiveness of sub-dissociative intranasal (IN) ketamine as the initial analgesic for adult patients in the ED. Objective: The study aims to examine the effectiveness of sub-dissociative IN ketamine as a primary analgesic agent for adult patients in the ED. Method: This is a prospective, observational study of adult ED patients presenting with severe pain (=6 on 11-point scale at triage). IN ketamine dose was 0.7mg/kg, with secondary dose of 0.5mg/kg at 15min if pain did not improve. After 6 months, initial dose was increased to 1.0mg/kg with the same optional secondary dose. Primary outcomes: The primary outcomes are change in VAS rating at 30min; percentage of patients reporting clinically significant reduction in VAS (=20mm) at 30min; dose resulting in clinically significant pain reduction. Results: Of the 72 patients available for analysis, median age was 34.5 years and 64% were men. Median initial VAS rating was 76mm (interquartile range [IQR]: 65-82). Median total dose of IN ketamine for all patients was 0.98mg/kg (IQR: 0.75-1.15, range: 0.59-1.57). Median reduction in VAS rating at 30min was 24mm (IQR: 2-45). Forty (56%, 95% CI: 44.0-66.7) reported VAS reduction =20mm, these patients having had a total median ketamine dose of 0.94mg/kg (IQR: 0.72-1.04). Conclusion: IN ketamine, at a dose of about 1mg/kg, was an effective analgesic agent in 56% of study patients. The place of IN ketamine in analgesic guidelines for adults requires further investigation.