What role do tourniquets have in managing crush injuries?

Tourniquets in Crush Injury: A Specialized Application

In crush injuries, tourniquets serve a unique and potentially life-saving role by delaying reperfusion injury when applied immediately before extrication, though this represents a specialized use distinct from their primary indication for controlling active hemorrhage. 1

Primary Role: Hemorrhage Control

Tourniquets are fundamentally designed for severe, life-threatening extremity bleeding that cannot be controlled with direct manual pressure. 2 The 2024 American Heart Association guidelines confirm that tourniquet application is appropriate for extremity hemorrhage when direct pressure is ineffective. 2

For crush injuries with active bleeding, apply a tourniquet proximal to the injury site if direct pressure fails to control hemorrhage. 2

Specialized Application: Preventing Reperfusion Syndrome

The unique aspect of tourniquets in crush injury management involves their prophylactic application before releasing the crushing force:

When to Consider Pre-Extrication Tourniquet Application

• Apply the tourniquet to the crushed extremity BEFORE removing the crushing object or extricating the patient if prolonged crush time (typically >4-6 hours) has occurred. 1
• This delays the sudden release of toxic metabolites (potassium, myoglobin, acidic compounds) into the systemic circulation that occurs with reperfusion. 1
• Case evidence demonstrates this approach can reduce morbidity and achieve complete limb salvage. 1

Critical Timing Considerations

Early prehospital tourniquet placement is associated with reduced mortality compared to delayed hospital application (3.0% vs 14% hemorrhagic death, P=0.01). 2 This time-sensitive effectiveness applies to both hemorrhage control and crush injury scenarios.

Application Technique for Crush Injuries

• Position the tourniquet proximal to the crushed segment before extrication begins. 2, 3
• Tighten sufficiently to abolish distal pulses. 3
• Document the application time clearly and communicate this to all receiving providers. 3
• Use manufactured tourniquets when available, as they demonstrate superior effectiveness (85-100% pulse cessation) compared to improvised devices (10-75%). 2

Critical Management After Application

Avoid Iterative Release

Never perform intermittent tourniquet release cycles in crush injuries—this worsens both local muscle injury and systemic rhabdomyolysis. 3, 4 The 2010 consensus explicitly identified this as harmful practice. 3

Repeated ischemia-reperfusion cycles trigger enhanced neutrophil migration and progressive muscle damage. 3

Definitive Management Priorities

• Maintain the tourniquet until surgical control or medical stabilization is achieved. 3
• Keep application time as short as possible while ensuring adequate resuscitation. 3
• Consider local hypothermia of the extremity during prolonged application to reduce ischemic injury. 3
• If tourniquet removal becomes necessary, apply a second tourniquet distal to the first before loosening the proximal one. 3

Monitoring and Reassessment

• Re-evaluate tourniquet effectiveness, location, and necessity as soon as feasible after application. 3
• Monitor for resumption of bleeding if gradual loosening is attempted. 3
• Assess for compartment syndrome development, which may require fasciotomy. 5

Evidence Quality and Limitations

The evidence supporting tourniquet use for hemorrhage control is weak (very low-certainty evidence), though guidelines consistently recommend their use based on observational data and simulation studies. 2 A 2025 meta-analysis found no statistically significant mortality reduction with prehospital tourniquet use (RR 0.70,95% CI 0.46-1.07), though this analysis did not specifically address crush injuries. 6

For crush injury-specific applications, evidence is limited to case reports and theoretical considerations, but the potential to prevent fatal reperfusion syndrome justifies consideration in appropriate scenarios. 1

Common Pitfalls to Avoid

• Do not delay tourniquet application in active hemorrhage while attempting prolonged direct pressure—early application improves outcomes. 2
• Do not remove and reapply tourniquets in crush injuries to "reduce ischemia"—this increases systemic toxicity. 3, 4
• Do not apply tourniquets to proximal extremity wounds or areas where anatomic constraints prevent effective application. 2
• Do not use tourniquets as a substitute for direct pressure when direct pressure alone can control bleeding. 2

Pediatric Considerations

Commercial windlass-type tourniquets (C-A-T GEN 7) successfully occlude pulses in children as young as 2 years with limb circumferences ≥13 cm. 2 The same principles apply to pediatric crush injuries, though smaller limb sizes may limit tourniquet effectiveness in very young children. 2