What is the recommended formula for calculating fluid requirements in burn patients, specifically using the Modified Parkland formula (Total Body Surface Area %TBSA)?

Modified Parkland Formula for Burn Resuscitation

The Formula

The Modified Parkland formula calculates fluid requirements as 3-4 mL/kg/% TBSA over 24 hours, with half administered in the first 8 hours from time of burn (not time of presentation) and the remaining half over the next 16 hours. 1, 2

Calculation Steps

• Total 24-hour volume = 3-4 mL/kg × % TBSA burned 1, 2
• First 8 hours (from time of burn): Give 50% of calculated volume 1, 2
• Next 16 hours: Give remaining 50% of calculated volume 1, 2
• Use Ringer's Lactate or Hartmann's solution as the resuscitation fluid 1, 3

Key Differences from Original Parkland

The Modified Parkland uses 3-4 mL/kg/% TBSA compared to the original Parkland's 2-4 mL/kg/% TBSA range, reflecting higher volume requirements observed in clinical practice 2. However, the original 2-4 mL/kg range has never been rigorously validated, and no formula has been formally proven superior to others 4.

Indications for Formal Resuscitation

• Adults: Burns ≥10% TBSA 1, 2
• Children: Burns ≥10% TBSA 1, 2, 3
• All burn patients should receive an initial 20 mL/kg balanced crystalloid bolus within the first hour, regardless of burn size 1, 3

Pediatric Modifications

Children require additional maintenance fluids on top of the Modified Parkland calculation. 2, 3

• Calculate burn resuscitation: 3-4 mL/kg/% TBSA over 24 hours 1, 3
• Add maintenance fluids using the 4-2-1 rule (Holliday-Segar): 4, 2, 3
  • 4 mL/kg/hr for first 10 kg body weight
  • 2 mL/kg/hr for next 10 kg body weight
  • 1 mL/kg/hr for each kg above 20 kg
• Children typically require approximately 6 mL/kg/% TBSA total over the first 48 hours 4, 1, 2

Titration and Monitoring

The formula provides only a starting point—actual infusion rates must be adjusted based on urine output, which is the primary endpoint. 4, 1, 5

Target Urine Output

• Adults and children: 0.5-1 mL/kg/hour 4, 1, 2, 3
• Electrical burns with myoglobinuria: 1-2 mL/kg/hour 2

Titration Algorithm

• Adjust fluid rate by 10-20% per hour based on urine output 6
• If oliguria persists for 2 hours despite adequate fluid rates, consider additional interventions 6
• Monitor arterial lactate, mean arterial pressure, and consider advanced hemodynamic monitoring in unstable patients 4

Critical Pitfall: Fluid Creep (Over-Resuscitation)

Over-resuscitation is extremely common and dangerous—76% of burn resuscitations exceed the upper Parkland limit, averaging 6.3 mL/kg/% TBSA. 1, 2, 3

Complications of Over-Resuscitation

• Compartment syndrome 1, 3
• Pulmonary edema 1, 3
• Intestinal edema 1, 3
• Acute kidney injury 1
• Abdominal compartment syndrome 2

Prevention Strategy

• Do not rigidly adhere to calculated volumes—titrate to urine output 1, 5
• Once adequate urine output is achieved, reduce fluid rates rather than continuing excessive administration 1
• Consider computer-based decision support systems to limit over-resuscitation risk 4

Situations Requiring Higher Volumes (4 mL/kg/% TBSA)

Certain patient populations require volumes at the higher end of the range or above: 1, 2

• Inhalation injury 1, 2
• Full-thickness burns 1, 3
• Electrical burns 1, 2
• Delayed presentation (>2 hours from injury) 2

Albumin Supplementation

For burns >30% TBSA, administer human albumin starting at 8-12 hours post-burn in patients requiring fluid rates above expected targets. 1, 2

• Target serum albumin level >30 g/L 1
• Albumin reduces abdominal compartment syndrome from 15.4% to 2.8% 2
• Hydroxyethyl starches (HES) are contraindicated 1

Common Calculation Errors to Avoid

• Do not use the Rule of Nines for TBSA calculation—it overestimates TBSA in 70-94% of cases 1
• Use the Lund-Browder chart as the gold standard for TBSA assessment 1
• Time zero is the time of burn injury, not time of hospital arrival 1, 2
• Do not delay the initial 20 mL/kg bolus while calculating precise TBSA 1
• Reassess TBSA during initial management to prevent overtriage and undertriage 1

Evidence Quality Note

The Modified Parkland formula has never been rigorously validated in prospective trials, and no burn resuscitation formula has been formally proven superior to others. 4 Real-world data consistently shows that actual fluid requirements exceed calculated volumes, with studies reporting mean administration of 5.58-6.1 mL/kg/% TBSA in adequately resuscitated patients 7, 5. Recent evidence suggests even more restrictive approaches (2 mL/kg/% TBSA with early plasma) may improve outcomes, though this requires further validation 6.