How To Burn Fluid Calculation

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Burn Fluid Resuscitation: Complete Guide

Step 1 - Estimate Burn Size (%TBSA)

Only second- and third-degree burns are counted. First-degree burns (simple redness/sunburn) are excluded.

Rule of Nines (Adults)

Body Region	% TBSA
Head & Neck	9%
Each Upper Limb	9% (×2 = 18%)
Anterior Trunk	18%
Posterior Trunk	18%
Each Lower Limb	18% (×2 = 36%)
Genitalia/Perineum	1%
Total	100%

In children, the head is proportionally larger (up to 18% in toddlers) and the legs smaller - use the Lund-Browder chart for accuracy.

Palm method: The patient's palm (including fingers) = approximately 1% TBSA - useful for small or irregular burns.

Step 2 - Choose the Formula

The Parkland (Baxter) Formula - Most Widely Used

Total fluid in first 24 hours = 4 mL × body weight (kg) × %TBSA

Fluid: Lactated Ringer's (LR) solution only

Timing:

First 8 hours from time of burn: give ½ of total volume
Next 16 hours (hours 9-24): give remaining ½

Important: The 24-hour clock starts at time of burn, not time of arrival to hospital. If the patient arrives 2 hours after injury, the first 8-hour half must be infused over only 6 hours.

ABLS (Advanced Burn Life Support) Modified Formula

The 2011 ABLS Manual notes that the classic 4 mL Parkland formula frequently causes over-resuscitation ("fluid creep"). It recommends:

Patient	Formula
Adults	2 mL LR × kg × %TBSA (24 hours)
Children ≤14 yrs / <40 kg	3 mL LR × kg × %TBSA + add maintenance fluids (use dextrose-containing maintenance in infants)
High-voltage electrical burns (with deep tissue injury or pigmenturia)	4 mL LR × kg × %TBSA

Consensus / Baxter Formula (Mulholland)

2-4 mL × %TBSA × weight (kg) in first 24 hours

Half in first 8 hours, half over next 16 hours - same timing as Parkland.

Worked example: 70 kg patient with 20% TBSA burn at 10:00 AM, presenting at 12:00 PM (2 hrs later):

Total fluid = 4 mL × 70 kg × 20% = 5,600 mL
First 8-hr half = 2,800 mL - but only 6 hours remain to the 8-hr mark
Rate = 2,800 mL ÷ 6 hours = ~467 mL/hr for first 6 hrs
Then 2,800 mL over next 16 hrs = 175 mL/hr

Step 3 - The Rule of 10 (US Army / Prehospital Simplified Formula)

A simpler bedside estimate for adult patients weighing 40-80 kg:

%TBSA × 10 = initial fluid rate in mL/hr

For every 10 kg above 80 kg, add 100 mL/hr

(Round %TBSA to the nearest 10 for quick calculation)

Step 4 - Monitor and Titrate

Formulas are starting points only - titrate hourly based on urine output:

Patient	Target Urine Output
Adults	0.5 mL/kg/hr
Children (<40 kg)	1.0 mL/kg/hr
Adults with electrical/pigment injury	1.0 mL/kg/hr (to clear myoglobin)

Insert a Foley catheter in all major burns for accurate hourly measurement.

Additional monitoring parameters:

Lactate (trend for perfusion)
Heart rate & blood pressure (note: burn patients are often tachycardic regardless)
Urine color (clear vs. dark/pigmented)
Intra-abdominal pressure (risk of compartment syndrome with >300 mL/kg in 24 hrs)

Step 5 - Second 24 Hours

Continue LR to maintain urine output and perfusion parameters
Begin tapering fluids after 24-36 hrs (reduce by ~⅓ if urine output adequate)
Colloid (5% albumin at 0.3-0.5 mL/kg per %TBSA over 24 hrs) can be added after initial crystalloid resuscitation
Consider albumin if patient requires >1.5× the calculated Parkland volume (reduces abdominal compartment syndrome risk)
Pediatric patients under 1 year: use D5-LR for maintenance to prevent hypoglycemia

Key Clinical Points

Fluid of choice: Lactated Ringer's - preferred over normal saline (avoids hyperchloremic acidosis) and over colloids in the first 24 hours
"Fluid creep" (over-resuscitation) causes pulmonary edema, fasciotomy-requiring compartment syndrome, raised intraocular pressure, and conversion of superficial to deep burns
IV fluid is indicated for burns >20% TBSA in adults and >10% TBSA in children
Electrical burns: fluid requirements are often greater than predicted by surface burns because of deep tissue destruction; start with 4 mL/kg/%TBSA and titrate up
Inhalation injury, delayed resuscitation, or concomitant trauma all increase fluid requirements beyond formula predictions

Sources:

Roberts and Hedges' Clinical Procedures in Emergency Medicine, Box 38.2-38.3
Mulholland and Greenfield's Surgery, p. 735-736 (Consensus Formula)
Miller's Anesthesia 10e, Box 43.1 (Parkland Formula)
Tintinalli's Emergency Medicine, Table 219-4

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