8.3 Parkland Formula & Fluid Resuscitation Protocols for Burns
Key Takeaways
- The Parkland formula dictates 2–4 mL of Lactated Ringer's per kilogram of body weight per percentage TBSA of partial- and full-thickness burns, with 50% given in the first 8 hours post-injury.
- Fluid resuscitation timing starts at the exact time of burn injury onset, NOT the time of arrival at the emergency department or trauma center.
- Urine output is the primary physiological indicator of resuscitation adequacy, with targets of 0.5–1.0 mL/kg/hr in adults and 1.0–1.5 mL/kg/hr in pediatric patients under 30 kg.
- Lactated Ringer's is the preferred crystalloid because its electrolyte composition and lactate buffer minimize hyperchloremic metabolic acidosis caused by large-volume normal saline.
- Fluid creep describes over-resuscitation leading to systemic complications such as abdominal compartment syndrome, ocular compartment syndrome, and pulmonary edema.
Severe burn trauma involving greater than 20% Total Body Surface Area (%TBSA) triggers systemic inflammatory response syndrome (SIRS) and burn shock. Fluid resuscitation aims to restore effective intravascular volume, maintain end-organ tissue perfusion, and prevent ischemic conversion of marginal burn zones without inducing fluid overload complications.
Pathophysiology of Burn Shock & Vascular Permeability
Burn shock is a complex form of combined hypovolemic and cellular shock. Thermal injury releases systemic inflammatory mediators—including histamine, bradykinin, prostaglandins, thromboxane A2, leukotrienes, and interleukins—that disrupt microvascular endothelial tight junctions.
This systemic capillary leak permits massive movement of water, electrolytes, and plasma proteins (primarily albumin) from the intravascular space into the interstitial compartment. Peak systemic microvascular permeability occurs within the first 8 to 18 hours post-injury and gradually resolves between 24 and 36 hours as endothelial integrity is restored. Concurrently, cellular sodium-potassium ATPase pump dysfunction causes intracellular sodium accumulation and myocyte swelling, further exacerbating intravascular volume depletion.
Crystalloid Selection: Why Lactated Ringer’s?
Lactated Ringer’s (LR) is the isotonic crystalloid solution of choice for burn shock resuscitation. Its electrolyte composition closely mimics human extracellular fluid:
- Sodium: 130 mEq/L
- Chloride: 109 mEq/L
- Potassium: 4 mEq/L
- Calcium: 2.7 mEq/L
- Sodium Lactate: 28 mEq/L
Resuscitation with large volumes of 0.9% Normal Saline (154 mEq/L Na+ and 154 mEq/L Cl-) causes severe hyperchloremic metabolic acidosis, renal afferent arteriolar vasoconstriction, reduced glomerular filtration rate, and impaired intestinal perfusion. In contrast, the lactate component in LR is metabolized by the liver into bicarbonate, helping buffer burn-induced metabolic acidosis.
The Parkland & American Burn Association (ABA) Formulas
The Parkland formula dictates initial crystalloid volume calculations for partial- and full-thickness burns during the first 24 hours post-injury. The American Burn Association (ABA) Consensus guidelines specify adjusted constant multipliers based on burn etiology:
| Burn Etiology & Patient Category | Recommended 24-Hour Fluid Formula | Fluid Type |
|---|---|---|
| Adult Thermal & Chemical Burns | 2 mL x kg body weight x %TBSA | Lactated Ringer's |
| Pediatric Thermal Burns (<30 kg) | 3 mL x kg body weight x %TBSA | LR + Maintenance D5 0.45% NS |
| High-Voltage Electrical Burns (All Ages) | 4 mL x kg body weight x %TBSA | Lactated Ringer's |
Fluid Administration Schedule: The 8 / 16 Hour Rule
The calculated 24-hour total fluid volume is divided into two operational delivery windows:
- First 50% of Total Volume: Infused over the FIRST 8 HOURS post-injury.
- Remaining 50% of Total Volume: Infused over the SUBSEQUENT 16 HOURS.
CRITICAL TIMING PRINCIPLE: The resuscitation clock begins at the exact TIME OF BURN INJURY, NOT the time of emergency department arrival. If an adult patient arrives at the trauma center 2 hours after injury, the first 50% of the calculated fluid volume must be infused over the remaining 6 hours of that initial 8-hour window.
Clinical Calculation Example
An 80 kg adult sustains partial- and full-thickness thermal burns to 40% TBSA. Injury occurred at 10:00 AM, and arrival occurs at 12:00 PM (2 hours post-injury).
Using Parkland (4 mL constant):
- Total 24-Hour Volume = 4 mL x 80 kg x 40% = 12,800 mL LR.
- First 8-Hour Allocation (50%) = 6,400 mL.
- Elapsed Time = 2 hours; Remaining Time = 6 hours.
- Initial Infusion Rate = 6,400 mL / 6 hours = 1,067 mL/hr.
- Second 16-Hour Allocation (50%) = 6,400 mL.
- Subsequent Infusion Rate = 6,400 mL / 16 hours = 400 mL/hr.
Using ABA Consensus (2 mL constant):
- Total 24-Hour Volume = 2 mL x 80 kg x 40% = 6,400 mL LR.
- First 8-Hour Allocation (50%) = 3,200 mL / 6 hours = 533 mL/hr.
- Second 16-Hour Allocation (50%) = 3,200 mL / 16 hours = 200 mL/hr.
Titration Endpoints: Urine Output as the Gold Standard
Fluid formulas provide only a starting rate. Infusion rates must be titrated hourly up or down by 20% to 30% based on continuous physiological response. Hourly Urine Output (UO) is the primary clinical endpoint for guiding titration:
| Patient Category | Target Hourly Urine Output | Primary Goal |
|---|---|---|
| Adults (Thermal/Chemical) | 0.5–1.0 mL/kg/hr (~30–50 mL/hr) | Prevents acute tubular necrosis without fluid creep |
| Pediatric Patients (<30 kg) | 1.0–1.5 mL/kg/hr | Protects higher pediatric metabolic rate |
| High-Voltage Electrical / Myoglobinuria | 1.0–1.5 mL/kg/hr (200–300 mL/hr in severe cases) | Flushes myoglobin casts until urine clears |
Secondary resuscitation targets include Mean Arterial Pressure (MAP >65 mmHg), heart rate (<120 bpm), normalized base deficit (-2 to +2 mEq/L), and serum lactate (<2.0 mmol/L).
Fluid Creep & Over-Resuscitation Complications
"Fluid creep" refers to excessive volume administration significantly exceeding formula estimates. Driven by inappropriate titration for transient hypotension or oliguria, fluid creep results in severe edema complications:
- Abdominal Compartment Syndrome (ACS): Elevated intra-abdominal pressure (>20 mmHg) causing decreased renal perfusion, diaphragmatic elevation, and respiratory failure.
- Ocular Compartment Syndrome: Increased orbital tissue pressure compromising optic artery blood flow.
- Pulmonary Edema & ARDS: Hydrostatic fluid overload impairing pulmonary gas exchange.
A 70 kg adult patient sustains partial- and full-thickness flame burns to 50% TBSA. The burn occurred at 12:00 PM, and the patient arrives at the trauma center at 2:00 PM. Using the Parkland formula (4 mL/kg/%TBSA), at what hourly rate should Lactated Ringer's be infused for the remaining 6 hours of the first post-injury window?
Which physiological metric serves as the primary clinical indicator for hourly titration of IV crystalloid fluid rates during acute burn resuscitation?
An adult burn patient undergoing fluid resuscitation for a 60% TBSA burn develops progressive abdominal distension, peak airway pressures increasing from 28 to 48 cm H2O, oliguria (<15 mL/hr), and a bladder catheter pressure of 24 mmHg. What condition is this patient experiencing?