Ketamine as an Analgesic Adjuvant in Adult Trauma Intensive Care Unit Patients With Rib Fracture

BACKGROUND: Rib fracture associated pain is difficult to control. There are no published studies that use ketamine as a therapeutic modality to reduce the amount of opioid to control rib fracture pain. OBJECTIVE: To examine the analgesic effects of adjuvant ketamine on pain scale scores in trauma intensive care unit (ICU) rib fracture. METHODS: This retrospective, case-control cohort chart review evaluated ICU adult patients with a diagnosis of ≥1 rib fracture and an Injury Severity Score >15 during 2016. Patients received standard-of-care pain management with the physician's choice analgesics with or without ketamine as a continuous, fixed, intravenous infusion at 0.1 mg/kg/h. RESULTS: A total of 15 ketamine treatment patients were matched with 15 control standard-of-care patients. Efficacy was measured via Numeric Pain Scale (NPS)/Behavioral Pain Scale (BPS) scores, opioid use, and ICU and hospital length of stay. Safety of ketamine was measured by changes in vital signs, adverse effects, and mortality. Average NPS/BPS, severest NPS/BPS, and opioid use were lower in the ketamine group than in controls (NPS: 4.1 vs 5.8, P < 0.001; severest NPS: 7.0 vs 8.9, P = 0.004; opioid use: 2.5 vs 3.5 mg morphine equivalents/h/d, P = 0.015). No difference was found between the cohort's length of stay or mortality. Average diastolic blood pressure was higher in the treatment group versus the control group (75.3 vs 64.6 mm Hg, P = 0.014). CONCLUSION: Low-dose ketamine appears to be a safe and effective adjuvant option to reduce pain and decrease opioid use in rib fracture.