What is the recommended fluid resuscitation formula for burn patients using the Modified Parkland (MP) formula?

Modified Parkland Formula for Burn Resuscitation

The Modified Parkland formula calculates fluid requirements as 3-4 mL/kg/% TBSA over 24 hours, with half administered in the first 8 hours and the remainder over the next 16 hours, titrated to urine output of 0.5-1 mL/kg/hour. 1, 2, 3

Formula Components and Calculation

The Modified Parkland formula differs from the original Parkland (2-4 mL/kg/% TBSA) by using a higher volume range:

• Adults: 3-4 mL/kg/% TBSA over 24 hours 1, 2
• Children: 3-4 mL/kg/% TBSA PLUS maintenance fluids calculated by the 4-2-1 rule (Holliday-Segar) for burns >10% TBSA 4, 3
• Fluid type: Ringer's Lactate or Hartmann's solution (avoid 0.9% NaCl due to hyperchloremic acidosis risk) 1

Timing of Administration

• First 8 hours: Give 50% of calculated 24-hour volume 1, 2, 3
• Next 16 hours: Give remaining 50% 1, 2, 3
• Timing starts from time of burn injury, not time of presentation 2

Indications for Formal Resuscitation

• Adults: Burns ≥10% TBSA 2, 3
• Children: Burns ≥10% TBSA (some sources suggest ≥5% TBSA) 1, 3
• Initial bolus: 20 mL/kg balanced crystalloid in first hour regardless of burn size to address early hypovolemic shock 1, 2

Monitoring and Titration

Urine output is the primary endpoint for adjusting fluid rates:

• Target: 0.5-1 mL/kg/hour in adults and children 4, 1, 2, 3
• Electrical burns with myoglobinuria: Target higher output of 1-2 mL/kg/hour to prevent acute kidney injury 2

Additional Monitoring Parameters

Beyond urine output, consider:

• Arterial lactate concentration 4, 3
• Mean arterial pressure 4
• Advanced hemodynamic monitoring (echocardiography, cardiac output, central venous pressure) for persistent oliguria or hemodynamic instability 4, 3

Critical Pitfall: Fluid Creep

Over-resuscitation ("fluid creep") is a major complication, with studies showing 76% of patients receive more than the upper Parkland limit, averaging 6.3 mL/kg/%TBSA. 1

Consequences of fluid creep include:

• Abdominal compartment syndrome 4, 5, 6
• Pulmonary edema 1
• Intestinal edema 1
• Increased morbidity and hospital length of stay 4, 3

Strategies to avoid fluid creep:

• Strict adherence to urine output targets (avoid targeting >1 mL/kg/hour unless myoglobinuria present) 4, 6
• Consider colloid (5% albumin) for "rescue" when crystalloid requirements progressively increase beyond predicted amounts 5, 6
• Use computer-based decision support systems when available 4, 3

Special Populations Requiring Higher Volumes

Certain patients may require volumes at the higher end (4 mL/kg/% TBSA) or above:

• Inhalation injury: Consistently requires more fluid 4, 6
• Full-thickness burns: Higher risk of wound conversion, may need upper range 1
• Electrical burns: Deeper tissue damage than apparent, often requires more volume 2
• High blood alcohol level: Increases fluid requirements 7
• Delayed presentation: May need more aggressive initial resuscitation 2

Pediatric Considerations

Children have unique physiologic differences requiring modified approach:

• Higher surface area-to-weight ratio necessitates proportionally more fluid 2, 3
• Actual requirements: Retrospective data shows children need approximately 6 mL/kg/% TBSA over first 48 hours 4, 3
• Add maintenance fluids using 4-2-1 rule on top of Modified Parkland calculation for burns >10% TBSA 4, 3
• Exception: Children with 10-20% TBSA may benefit from reduced total fluid intake (shorter hospital stay, less grafting needed) 4

Albumin Administration

For burns >30% TBSA, administer human albumin after the first 6 hours of management. 4

Evidence supporting albumin use:

• Reduces mortality when given within first 24 hours (OR 0.34) after excluding high-bias studies 4
• Significantly reduces abdominal compartment syndrome from 15.4% to 2.8% 4
• Rapidly normalizes resuscitation ratios and ameliorates fluid creep when used as rescue therapy 5

Practical Implementation Algorithm

1. Calculate initial rate: (3-4 mL/kg × weight in kg × % TBSA) ÷ 2 ÷ 8 hours = mL/hour for first 8 hours 1, 2
2. Start infusion immediately with Ringer's Lactate 1
3. Monitor urine output hourly and adjust rate by 20-25% increments to maintain 0.5-1 mL/kg/hour 4, 3
4. If fluid requirements progressively increase beyond predicted (I/O ratio >1.0), consider adding 5% albumin 5
5. At 8 hours post-burn, reduce rate to deliver remaining 50% over next 16 hours 1, 2
6. If hypotension persists despite adequate urine output, evaluate cardiac function with echocardiography before adding vasopressors 4, 3