Effect of early ultrasound-guided femoral nerve block on preoperative opioid consumption in emergency patients with hip fracture: a randomized trial.

Background and importance: Ultrasound-guided femoral nerve block (FNB) could be used as part of a multimodal preoperative pain management for patients with hip fracture. Evidence of the effects of its early implementation in the emergency room as an immediate alternative to intravenous morphine titration is sparse.

Objective: To investigate the effect of an early ultrasound-guided FNB performed by emergency physicians on preoperative opioid consumption, compared to standard pain management.

Design, setting, and participants: This open randomized controlled trial was conducted in the Emergency Department of a French hospital with patients with neck or trochanteric femoral fracture who had a pain score ≥7 out of 10 points at triage.

Intervention: Patients were randomized to receive an initial analgesia with an early ultrasound-guided FNB or with standard pain management. The continuation of pain treatment followed standardized pain control guidelines until hospital discharge in both groups.

Outcome measure and analysis: The primary outcome was preoperative opioid consumption truncated 48h after triage time, and converted in morphine milligram intravenous equivalents (MME). Secondary outcomes were time to pain relief, time for regaining walk, opioid consumption and occurrence of opioid and FNB adverse effects during the hospital stay. Exploratory outcomes included ease and duration of the procedure.

Main results: We randomized 35 patients: 17 to standard pain management and 18 to ultrasound-guided FNB, among whom 30 patients completed the protocol. The median of preoperative opioid consumption was reduced by 60% in the ultrasound-guided FNB group compared to standard group [6 MME (3-9) vs. 15 MME (11-18)], with a consumption difference of 9 MME (95% CI: 3-14, P  < 0.001). Throughout hospital stay, opioid consumption was reduced by 56% in the ultrasound-guided FNB group compared to standard group, with a consumption difference of 11.5 MME (95% CI: 0.5-22).Times to pain relief and for regaining walk did not differ between groups. Opioid adverse events occurrence were reduced by 40% (95% CI: 5.1-74.9) in the ultrasound-guided FNB group compared to standard group. No adverse effects of FNB have been detected.

Conclusion: Early ultrasound-guided FNB resulted in reducing preoperative opioid consumption, without delaying time to pain relief.