How to manage high hemoglobin (Hb) levels secondary to burns?

Management of High Hemoglobin Secondary to Burns

High hemoglobin in burn patients is a marker of hemoconcentration from inadequate fluid resuscitation, not true polycythemia, and should be managed by optimizing fluid administration to achieve target urine output of 0.5-1 mL/kg/hour while avoiding over-resuscitation. 1, 2

Understanding the Pathophysiology

• Elevated hemoglobin in acute burn injury reflects plasma volume loss and hemoconcentration from capillary leak, not increased red blood cell production 3
• The screening hematologic profile at admission in burn patients is typically normal, with hemoglobin levels remaining stable around 10 g/dL after the first week despite massive fluid resuscitation 4
• Hematocrit changes between admission and 8-24 hours post-burn correlate weakly with fluid volumes administered (r²=0.13), making it an unreliable marker for detecting over-resuscitation 3

Immediate Management Algorithm

Step 1: Assess Fluid Resuscitation Adequacy

• Target urine output of 0.5-1 mL/kg/hour as the primary parameter to guide fluid administration 1, 2, 5
• Calculate 24-hour fluid requirements using the Parkland formula (2-4 mL/kg/%TBSA burned), administering half in the first 8 hours post-burn 2, 6
• Use balanced crystalloid solution (Ringer's Lactate preferred) as the initial resuscitation fluid 2, 6

Step 2: Monitor for Under-Resuscitation

• Check for signs of inadequate circulation: relative tachycardia, relative hypotension, oxygen extraction >50%, and mixed venous oxygen pressure <32 mmHg 1
• Persistent oliguria despite resuscitation warrants advanced hemodynamic monitoring with echocardiography or cardiac output monitoring 1, 5
• If hypotension persists despite appropriate fluid resuscitation, evaluate cardiac function before initiating vasopressors 1, 2

Step 3: Avoid Over-Resuscitation ("Fluid Creep")

• Resuscitation volumes exceeding 5.2 mL/kg/%TBSA are independently associated with excess mortality 3
• Over-resuscitation increases risk of abdominal compartment syndrome, acute kidney injury, and respiratory complications 1, 2
• Consider albumin administration after the first 6-8 hours in patients with TBSA >30% to reduce crystalloid volumes and prevent fluid creep 1, 2

Adjunctive Measures for Severe Burns (TBSA >30%)

• Administer 5% human albumin starting 8-12 hours post-burn to maintain serum albumin >30 g/L, which reduces crystalloid requirements and associated morbidity 2
• Typical albumin dosing is 1-2 g/kg/day, which has been shown to reduce organ failure incidence and mortality 2
• Use advanced hemodynamic monitoring (echocardiography, transpulmonary thermodilution) in patients with hemodynamic instability to guide fluid management 1, 5

Critical Pitfalls to Avoid

• Do not use elevated hemoglobin/hematocrit alone to guide fluid resuscitation, as these parameters correlate poorly with actual fluid status and resuscitation needs 3
• Never delay fluid resuscitation based on hemoglobin levels, as hemoconcentration indicates inadequate plasma volume replacement 4, 3
• Avoid normal saline (0.9% NaCl) as primary resuscitation fluid due to increased risk of hyperchloremic metabolic acidosis and acute kidney injury 2
• Do not transfuse red blood cells based solely on hemoglobin levels in the acute phase; transfusion is generally recommended only when hemoglobin falls below 7-9 g/dL with signs of inadequate oxygen delivery 1, 7

Monitoring Parameters Beyond Hemoglobin

• Arterial lactate concentration to assess tissue perfusion 1
• Base deficit as a predictor of tissue anoxia and mortality (odds ratio 2.23 for mortality prediction) 8
• Serial serum albumin levels, as hypoalbuminemia is an independent predictor of mortality (odds ratio 3.56) 8
• Hourly urine output remains the easiest and most reliable parameter for adjusting fluid rates 1, 2, 5

Special Considerations

• In children with burns ≥5% TBSA, higher fluid volumes (approximately 6 mL/kg/%TBSA) may be required due to higher surface area-to-weight ratio 2
• For electrical burns, expect deeper tissue damage than apparent on surface examination and anticipate higher fluid requirements 2, 6
• Monitor for compartment syndrome in circumferential third-degree burns, which may require escharotomy regardless of fluid status 2, 6