Major Concern in a Pedestrian Hit by Car with Bilateral Femur Fractures and Hypotension
Hemorrhage is the Major Concern
The major concern in a pedestrian hit by a car with bilateral femur fractures and hypotension is hemorrhage. Bilateral femur fractures represent a significant source of blood loss that can lead to hemorrhagic shock, which requires immediate intervention 1.
Pathophysiology and Blood Loss
- Each femur fracture can result in 1-2 liters of blood loss into the thigh compartment
- Bilateral femur fractures can cause up to 3-4 liters of blood loss (60-80% of total blood volume)
- The hypotension in this scenario is most likely due to hypovolemia from hemorrhage
- Open fractures (if present) significantly increase the risk of uncontrolled bleeding 2
Evidence-Based Management Priorities
1. Control Bleeding and Restore Volume
- Immediate hemorrhage control takes precedence over transfer or other interventions 1
- Correction of hypovolemia is essential before considering transport 1
- Bilateral femur fractures with hypotension indicate severe systemic injury requiring aggressive management 3
2. Fluid Resuscitation Strategy
- Initial crystalloid bolus of 10-20 mL/kg (maximum 1,000 mL) 4
- Target MAP ≥65 mmHg to ensure adequate organ perfusion 4
- Avoid permissive hypotension in this scenario as it is contraindicated in patients with femur fractures 1
3. Blood Product Administration
- Early administration of blood products is crucial
- Consider activation of massive transfusion protocol if hypotension persists despite initial fluid resuscitation
- Monitor for development of coagulopathy, which is associated with higher mortality 5
Why Hemorrhage is the Primary Concern
Direct Evidence: The European guideline on management of major bleeding following trauma explicitly states: "In the context of trauma and brain injury, hypotension should be assumed to be due to haemorrhage and the bleeding should be controlled before transfer" 1
Severity Indicator: Bilateral femur fractures with hypotension indicate severe force trauma with significant blood loss 3
Mortality Risk: Uncontrolled hemorrhage is the leading cause of preventable death in trauma patients 1
Why Not the Other Options
- Hypotension is a clinical sign/symptom rather than the underlying concern; it's the result of hemorrhage
- Myoglobinuria is a secondary concern that develops later due to muscle damage (rhabdomyolysis) from the crush injury, but hemorrhage is the immediate life-threatening issue
Key Clinical Pearls
- Patients with bilateral femur fractures rarely present with shock unless the fractures are open or there are other sources of bleeding 2
- Open femur fractures are present in over 70% of isolated femur fracture patients who develop shock 2
- Always assess for other sources of bleeding beyond the obvious fractures
- Early surgical stabilization of femur fractures helps reduce ongoing blood loss
- Monitor for development of fat embolism syndrome, which can occur with bilateral femur fractures 6
Immediate hemorrhage control, adequate fluid resuscitation, and early surgical intervention are the cornerstones of management for this patient with bilateral femur fractures and hypotension.