Systemic Opioid-Sparing Efficacy of Emergency Department-Initiated Regional Nerve Blocks in Acute Multiple-Extremity Trauma: A Rapid Systematic Review and Meta-analysis of Resuscitation-Bay Outcomes

Abstract

Background: Severe pain from acute extremity trauma is commonly treated with intravenous opioids during emergency resuscitation, yet repeated dosing can complicate neurological assessment, ventilation, hemodynamic monitoring, and delirium prevention. Regional nerve blocks may interrupt nociception without the same systemic exposure, but evidence directly involving multiple-extremity trauma is sparse. Objective: To estimate the opioid-sparing association of emergency department (ED)-initiated regional nerve blocks and to determine how confidently isolated-extremity evidence can be transferred to resuscitation-bay polytrauma. Methods: A structured rapid review of PubMed-indexed studies, open full texts, guideline repositories, and backward citations was updated through 21 July 2026. Controlled ED or prehospital studies of acute traumatic extremity pain were synthesized narratively. A random-effects DerSimonian-Laird meta-analysis pooled trials reporting whether a patient received any rescue/systemic opioid after block allocation. Results: Twelve controlled or comparative studies informed the qualitative synthesis; four studies (n=459) provided compatible binary rescue-opioid data. Regional blockade reduced the probability of receiving systemic/rescue opioid compared with systemic analgesia or sham (risk ratio 0.50, 95% confidence interval 0.33-0.75), with substantial heterogeneity (I²=80.9%; tau²=0.123). Leave-one-out estimates remained below unity (RR range 0.44-0.55). Individual studies also reported faster pain relief, lower morphine-equivalent exposure, fewer opioid-related adverse effects, or less procedural sedation, although neutral trials occurred when background opioid treatment was already established or when sham-controlled opioid demand was low. No included randomized trial specifically enrolled hemodynamically unstable patients with simultaneous injuries to multiple extremities. Conclusions: ED-initiated regional nerve blocks produce a credible opioid-sparing signal in acute extremity trauma, especially hip and femur fractures. The pooled effect should not be presented as definitive proof for complex polytrauma; rather, it supports protocolized use after resuscitation priorities, neurological documentation, cumulative local-anesthetic dosing, and compartment-syndrome surveillance are secured.