What is the prehospital treatment for low hemoglobin (Hb) and hematocrit (Hct)?

Prehospital Treatment of Low Hemoglobin and Hematocrit

In the prehospital setting, crystalloid fluid therapy should be initiated for patients with low hemoglobin and hematocrit, using a restricted volume replacement strategy with balanced crystalloids while avoiding excessive fluid administration. 1

Assessment of Bleeding Severity

The first step in managing low hemoglobin and hematocrit in the prehospital setting is to accurately assess the severity of blood loss:

• Use shock index (heart rate divided by systolic blood pressure) and/or narrow pulse pressure to evaluate the degree of hypovolaemic shock 1
• Assess using a combination of:
  • Patient physiology (vital signs)
  • Anatomical injury pattern
  • Mechanism of injury
  • Response to initial resuscitation 1
• Monitor for early signs of inadequate circulation:
  • Relative tachycardia
  • Relative hypotension
  • Altered mental status 1

Initial Fluid Resuscitation

Crystalloid Administration

• Initial approach: Begin with balanced crystalloid solutions (0.9% NaCl) 1
• Volume strategy: Use a restricted volume replacement strategy with target systolic blood pressure of 80-90 mmHg (MAP 50-60 mmHg) until major bleeding is controlled 1
• Caution: Avoid aggressive crystalloid resuscitation as it increases risk of:
  • Coagulopathy (observed in >40% of patients with >2,000 ml fluid administered) 1
  • Secondary abdominal compartment syndrome 1
  • Increased mortality (OR 1.11,95% CI 1.05 to 1.17) 1

Special Considerations

• Traumatic brain injury: Permissive hypotension is contraindicated in TBI; maintain MAP ≥80 mmHg 1
• Elderly patients: Restricted volume strategy may be contraindicated in patients with chronic arterial hypertension 1
• Hypotonic solutions: Avoid Ringer's lactate in patients with severe head trauma 1

Blood Product Administration

Current evidence regarding prehospital blood product administration is conflicting:

• No clear recommendation can be provided for routine use of prehospital blood products at this time 1
• The most recent evidence from the RePHILL trial showed no difference in the composite endpoint of mortality and/or lactate clearance between prehospital blood products and crystalloid 1
• However, some evidence suggests potential benefits:
  • Combined prehospital packed red blood cells (pRBC) and plasma may provide greatest survival benefit at 30 days compared to crystalloid only 2
  • Meta-analysis showed reduced 24-hour mortality with pre-hospital plasma but no effect on 1-month mortality 1
  • NAEMSP recommends blood components over crystalloids for patients with traumatic life-threatening bleeding 3

Monitoring

• Repeatedly measure hemoglobin and/or hematocrit to detect ongoing bleeding 1
• Monitor blood lactate to estimate and monitor the extent of bleeding and tissue hypoperfusion 1
• If lactate unavailable, base deficit may be used as an alternative 1

Common Pitfalls to Avoid

1. Excessive fluid administration: Large-volume crystalloid resuscitation is associated with increased mortality, particularly in patients with:

   • Penetrating mechanisms of injury (OR 1.25)
   • Hypotension (OR 1.44)
   • Severe head injury (OR 1.34)
   • Patients requiring immediate surgery (OR 1.35) 1

2. Hyperventilation: Excessive positive pressure ventilation in hypovolemic patients may further compromise venous return, producing hypotension and cardiovascular collapse 1

3. Delayed transport: Prioritize rapid transport to definitive care while initiating appropriate fluid resuscitation

4. One-size-fits-all approach: Failure to adjust resuscitation strategy based on injury pattern (especially with TBI) and patient characteristics (age, comorbidities)

The prehospital management of low hemoglobin and hematocrit requires a balanced approach that provides adequate tissue perfusion while avoiding the complications of excessive fluid administration, with the primary goal of rapid transport to definitive care.