O1023: Pediatric Lower Extremity Ultrasound Guided Nerve Block (PLEXUS): A multicenter comparative study for femur fracture analgesia

Background: Femur fractures are a common injury requiring hospitalization in children. The fascia iliaca compartment nerve block (FICNB) and femoral nerve block (FNB) target nerves responsible for sensation and motor function in the thigh and groin and are used to treat pain from hip and femur fractures. Although nerve blocks are increasingly performed, data for the safety and effectiveness in children is limited in the pediatric emergency department (PED). We are conducting a multicenter, prospective, comparative, observational study comparing children who received ultrasound-guided nerve block to those who received no nerve block for treatment of femur fracture pain.

Methods: This is an interim analysis of a multicenter, prospective, comparative, observational study using a convenience sample of eligible children aged 4-17 years with isolated, acute, unilateral femur fractures. Exclusion criteria include neurovascular compromise, pregnancy, and known allergy to local anesthetic agents. Sites include PEDs across Australia and North America. All pain management is at the discretion of the treating physician and individual sites/physicians may or may not offer multimodal analgesia including nerve block. The FICNB or FNB (together referred to as “nerve block”) is offered when appropriately-trained clinical staff are available using site-specific protocols. Primary study outcome is patient pain score 60 minutes after enrollment, measured using the Faces Pain Scale-Revised (FPS-R). Secondary study outcomes include oral morphine equivalents (OME) administered, patient pain score 240 minutes after enrollment or when the patient was dispositioned from the PED, whichever came first, and adverse events. Each site’s Institutional Review Board approved the protocol. Between-group comparisons were made using Fisher’s exact, Chi-squared, or T-tests as appropriate using SAS statistical software. Multivariable linear regressions were used to control for demographic and patient-level factors.

Results: Seventy children were eligible from 8 sites, with 39 subjects receiving a nerve block. There were no significant differences in gender, age, weight, or initial pain score between groups. Patient reported pain score at 60 minutes was significantly lower in the nerve block group as compared to the no nerve block group (1.6 vs 5.2, p< 0.001), and these patients received significantly less opioids (0.37 vs 1.12 OME, p=0.019), both of which remained significant when controlling for initial pain score and age. There were four adverse events reported in the ED for children receiving no nerve block and one adverse event in the group receiving nerve block after discharge from the ED (nausea/vomiting).

Conclusion: Ultrasound-guided nerve block resulted in significantly reduced pain compared with participants who received no nerve block at 60 minutes in children with acute femur fractures. Patients that received a nerve block required less overall opioid doses and no serious adverse events were reported. Ultrasound-guided nerve blocks should be implemented as routine pain management for patients with femur fracture in the PED.