A 35-year-old woman is admitted to the burn unit 4 hours after sustaining a 40% TBSA deep partial-thickness burn from a house fire. She weighs 60 kg. Fluid resuscitation was initiated with Ringer's lactate using the Parkland formula. Her current vital signs are: heart rate 128/min, blood pressure 92/58 mmHg, respiratory rate 26/min, urine output 0.3 mL/kg/hr. What is the most appropriate next step in fluid management?

Explanation

## Fluid Resuscitation Endpoints in Burn Management **Key Point:** Urine output is the most reliable real-time indicator of adequate tissue perfusion in burn patients. Target endpoints vary by age and burn depth. ### Resuscitation Endpoints by Patient Type | Parameter | Target | | --- | --- | | **Adult (non-electrical burn)** | 0.5 mL/kg/hr | | **Child (<30 kg)** | 1 mL/kg/hr | | **Electrical burn** | 1 mL/kg/hr (risk of myoglobinuria) | | **Heart rate** | <120/min (not reliable alone) | | **Systolic BP** | >90 mmHg (not reliable alone) | | **Sensorium** | Alert and oriented | **High-Yield:** Urine output is superior to vital signs for guiding resuscitation because: 1. Tachycardia and hypotension persist despite adequate perfusion in the acute burn phase (due to catecholamine surge). 2. Urine output directly reflects glomerular filtration and renal perfusion. 3. Oliguria (<0.5 mL/kg/hr in adults) indicates under-resuscitation and risk of acute kidney injury. ### Analysis of This Patient - Current urine output: 0.3 mL/kg/hr (60 kg × 0.3 = 18 mL/hr) - **Target:** 0.5 mL/kg/hr (60 kg × 0.5 = 30 mL/hr) - **Deficit:** 12 mL/hr below target - Heart rate 128 and BP 92/58 are consistent with ongoing hypovolemia despite appearing "borderline acceptable." **Clinical Pearl:** "Fluid creep" (excessive resuscitation) is a recognized complication causing abdominal compartment syndrome, pulmonary edema, and increased mortality. However, under-resuscitation is immediately life-threatening. The solution is titration to urine output, not fixed-rate infusion. **Mnemonic: BURP** — **B**urn fluid **U**rine output **R**ate **P**erfusion - Monitor urine output hourly - Adjust IV rate to achieve target - Reassess every 1–2 hours - Prevent both under- and over-resuscitation ## Parkland Formula Calculation (Reference) - 4 mL × 60 kg × 40% TBSA = 9,600 mL over 24 hours - First 8 hours: 4,800 mL (600 mL/hr) - Next 16 hours: 4,800 mL (300 mL/hr) - Current rate should be adjusted upward to achieve 30 mL/hr urine output.