Ketamine infusion for pain control in elderly patients with multiple rib fractures: Results of a randomized controlled trial

BACKGROUND Rib fractures are associated with increased mortality, particularly in the elderly. While opiate-based pain regimens remain the cornerstone of rib fracture management, issues related to opioids have driven research into alternative analgesics. Adjunctive ketamine use in lieu of opioids continues to increase but little evidence exists to support its efficacy or safety within the elderly trauma population. METHODS A prospective, randomized, double-blind placebo-controlled trial of elderly patients (age, >= 65 years) with three or more rib fractures admitted to a Level I trauma center was conducted. Exclusion criteria included Glasgow Coma Scale score less than 14, and chronic opiate use. Groups were randomized to either low-dose ketamine (LDK) at 2 mu g center dot kg(-1)center dot min(-1) or an equivalent rate of 0.9% normal saline. The primary outcome was reduction in numeric pain scores (NPS). Secondary outcomes included oral morphine equivalent (OME) utilization, epidural rates, pulmonary complications, and adverse events. RESULTS Thirty (50.8%) of 59 were randomized to the experimental arm. Groups were similar in makeup. Low-dose ketamine failed to reduce 24-hour NPS or OME totals. Subgroup analysis of 24 patients with Injury Severity Score greater than 15 demonstrated that LDK was associated with a reduction in OME utilization the first 24-hours (25.6 mg vs. 42.6 mg, p = 0.04) but at no other time points. No difference in other secondary outcomes or adverse events was noted. CONCLUSION Low-dose ketamine failed to affect NPS or OME within the overall cohort, but a decrease in OME was observed in those with an Injury Severity Score greater than 15. Additional studies are necessary to confirm whether LDK benefits severely injured elderly patients.