A complete clinical guide to calculating fluid requirements in burn injuries — TBSA assessment, Rule of Nines, delivery timing, Modified Brooke, and common pitfalls.
Burns are among the most physiologically devastating injuries a human body can sustain. A large burn triggers a cascade of systemic responses — fluid pours out of blood vessels into surrounding tissues, blood pressure drops, organs fail. Without rapid and precisely calculated fluid resuscitation, a patient with a severe burn can die within hours from hypovolaemic shock — even if the burn itself does not seem immediately life-threatening.
The Parkland Formula is the most widely used calculation in burn resuscitation. It tells clinicians exactly how much intravenous fluid to give — and critically, when to give it — based on the patient's weight and the extent of the burn.
This guide covers everything you need to know: the formula itself, how to accurately estimate burn size, delivery timing, the Modified Brooke alternative, paediatric considerations, and common errors that can harm patients.
When the skin is burned, the barrier that normally keeps fluid inside the body is destroyed. Simultaneously, the burn triggers a massive inflammatory response: capillaries throughout the body — not just at the burn site — become "leaky," allowing plasma (the fluid component of blood) to pour into surrounding tissues.
This process, called capillary leak or burn oedema, is most intense in the first 8 hours after injury and continues for up to 48 hours. The result is a dramatic drop in circulating blood volume — called hypovolaemia — that can rapidly lead to shock, organ failure, and death if not corrected with IV fluids.
The goal of burn resuscitation is to replace this lost volume precisely — enough to maintain organ perfusion, but not so much that you cause dangerous fluid overload (a condition called oedema in unburned tissues, which can cause its own complications including abdominal compartment syndrome and pulmonary oedema).
Developed by Dr Charles Baxter at Parkland Memorial Hospital in Dallas in the 1960s, the Parkland Formula estimates the total volume of Ringer's Lactate (RL) solution required in the first 24 hours after a burn injury.
This total volume is not given all at once. It is divided into two halves and administered over specific time windows:
⚠️ Critical timing rule: The 8-hour clock starts from the time of the burn injury — not the time the patient arrives at hospital. If 3 hours have already passed by the time the patient reaches you, the first half must be delivered in the remaining 5 hours. This often requires a significantly higher initial infusion rate.
🔥 Use the RxMedCalc Parkland Formula Calculator to instantly calculate total fluid volume, 8-hour rate, and 16-hour rate by entering weight and % TBSA.
Patient: 40-year-old man, weight 70 kg, 35% TBSA burn (flame injury to trunk and both legs). Arrived at hospital 2 hours after injury.
Total fluid = 4 × 70 × 35 = 9,800 mL of Ringer's Lactate
First half (4,900 mL) to be given in the remaining 6 hours (8 hrs from burn − 2 hrs already elapsed) → Rate: 4,900 ÷ 6 = ~817 mL/hr
Second half (4,900 mL) over the next 16 hours → Rate: 4,900 ÷ 16 = ~306 mL/hr
These are starting rates. Adjust based on urine output (target 0.5–1 mL/kg/hr in adults) and clinical response — do not simply follow the calculated rate rigidly.
The Parkland Formula is only as accurate as your TBSA estimate. Overestimating TBSA leads to fluid overload; underestimating leads to inadequate resuscitation. Only partial thickness (second degree) and full thickness (third degree) burns are counted — superficial (first degree) burns are excluded.
The most widely used method for adults is the Rule of Nines:
⚠️ The Rule of Nines is inaccurate in children. A child's head is proportionally much larger (up to 19% in an infant) and legs are smaller than in adults. For children, always use the Lund and Browder Chart, which accounts for age-specific proportions.
When burns are patchy, irregular, or scattered across the body, the Rule of Nines becomes difficult to apply. In these cases, use the Palmar Method: the patient's own palm (including fingers) represents approximately 1% of their TBSA. Count how many "palms" the burn covers to estimate percentage.
| Depth | Old Term | Appearance | Sensation | Count in TBSA? |
|---|---|---|---|---|
| Superficial | First degree | Red, dry, no blisters (like sunburn) | Painful | No |
| Superficial partial thickness | Second degree (superficial) | Blisters, moist, red/pink base | Very painful | Yes |
| Deep partial thickness | Second degree (deep) | Pale, mottled, blisters may be absent | Reduced pain | Yes |
| Full thickness | Third degree | Leathery, white/brown/black, dry | Painless (nerves destroyed) | Yes |
| Fourth degree | — | Charred, involves muscle/bone | Painless | Yes |
The Modified Brooke Formula is an alternative to Parkland, preferred by some centres because it uses a lower fluid volume (reducing the risk of fluid overload) and incorporates colloid in the second 24 hours.
In the second 24 hours, Modified Brooke uses:
| Feature | Parkland | Modified Brooke |
|---|---|---|
| Volume multiplier | 4 mL/kg/%TBSA | 2 mL/kg/%TBSA |
| First 24h fluid | Ringer's Lactate only | Ringer's Lactate only |
| Colloid | Not in first 24h | Added in second 24h |
| Preferred in | Most centres worldwide | Centres concerned about fluid creep |
The Parkland formula gives you a starting point — not a rigid prescription. The primary endpoint for titrating fluid resuscitation is urine output, measured via a urinary catheter:
| Patient | Target Urine Output |
|---|---|
| Adults | 0.5 mL/kg/hr (approximately 30–50 mL/hr) |
| Children (< 30 kg) | 1 mL/kg/hr |
| Electrical burns / myoglobinuria | 1–1.5 mL/kg/hr (to flush myoglobin and prevent renal tubular damage) |
⚠️ "Fluid Creep" — giving significantly more fluid than the Parkland formula predicts — is a recognised and dangerous phenomenon in burn care. It is associated with abdominal compartment syndrome, pulmonary oedema, and limb compartment syndrome. Avoid aggressive over-resuscitation. Aim for the lower end of the urine output target range.
Children are not simply small adults when it comes to burn resuscitation. Key differences:
Not all burns can be managed at a general hospital. Transfer to a specialist burns centre is indicated for:
| Mistake | Consequence | Correction |
|---|---|---|
| Counting first-degree burns in TBSA | Overestimates volume needed → fluid overload | Count only second and third degree burns |
| Starting the 8-hour clock from hospital arrival | First half delivered too slowly → under-resuscitation early | Clock runs from time of burn injury, not ED arrival |
| Using colloid in first 24 hours (Parkland) | Leaks into tissues during capillary leak phase — ineffective | Ringer's Lactate only for first 24h in Parkland protocol |
| Not inserting a urinary catheter | Cannot titrate fluid to urine output | Catheterise all burns ≥ 20% TBSA immediately |
| Blind adherence to calculated rate | Under- or over-resuscitation as patient's needs change | Titrate hourly based on urine output and clinical status |
| Forgetting maintenance fluids in children | Under-resuscitation in paediatric patients | Add Holliday-Segar maintenance to Parkland total in children |
Inhalation injury — caused by breathing hot gases, steam, or toxic combustion products — significantly increases fluid requirements beyond what the Parkland formula predicts. Patients with confirmed or suspected inhalation injury may require 30–50% more fluid than calculated.
Suspect inhalation injury if the patient was in an enclosed space, has singed nasal hairs or eyebrows, carbonaceous (sooty) sputum, a hoarse voice, stridor, or facial burns. These patients should be intubated early — airway oedema can develop rapidly and make late intubation extremely difficult or impossible.
🔥 Calculate total fluid volume, 8-hour rate, and 16-hour infusion rate instantly using the RxMedCalc Parkland Formula Calculator.
This article is written for educational purposes and is based on internationally recognised burn care guidelines. It is not a substitute for professional medical advice or formal burn care training. Management of major burns requires specialist input. Always follow your institution's protocols and involve a burns specialist for severe injuries.
Built by an MBBS, AFIH Certified Physician in Punjab, India | RxMedCalc.com