(925) Ketamine as an Adjunct for Acute Pain in Burn Patients

Introduction: Pain management in patients with cutaneous burn injuries is challenging. Procedural pain and development of opioid tolerance often leads to suboptimal analgesia. Ketamine is commonly used as an adjunct for procedural pain, but data specific to the burn population is sparse. The purpose of this study was to evaluate the efficacy of a continuous ketamine infusion as an opioid sparing adjunct. It was hypothesized that addition of ketamine would yield a reduction in morphine milligram equivalent (MME) requirement.

Methods: This was a retrospective, single center analysis of patients receiving a ketamine infusion as an adjunct for pain management in cutaneous burn injury. Patients were included if they received intravenous ketamine continuously for at least 24 hours and had at least 24 hours of pain management prior to ketamine initiation for comparison. The primary outcome of mean 24-hour MME and secondary outcome of mean pain scores were assessed during matched pre- and post-ketamine time periods. Patients were excluded from the pain score analysis if lacking at least one score documented in each period via the same testing method. Ketamine safety/tolerability was also examined. Statistics included a paired t-test for comparison of MME and a Wilcoxon Signed Rank test for assessment of pain scores.

Results: Twenty-five and 22 patients met inclusion for MME and pain score analyses, respectively. Severity of burn injury varied greatly, with a mean of 42.8% (SD 27.6) total body surface area. Duration of matched assessment periods also varied widely, ranging from 24 to 384 hours. No significant difference was observed in MME (mean ± SD) pre- and post-intervention (195 ± 151 mg vs 204 ± 174 mg, p=0.683). Thirteen patients demonstrated a reduction in MME and 12 had an increase. There was also no significant difference in pain scores (3.98 ± 2.84 vs 3.59 ± 2.75, p=0.260). Ketamine infusions were well tolerated overall.

Conclusions: Addition of a ketamine continuous infusion was not associated with a reduction in MME or more effective pain control. However, analysis of outcomes was limited by small sample size. Prospective, controlled trials are needed to better elucidate the potential benefits of ketamine in this setting.