Urine Output is the Most Reliable Indicator of Adequate Burn Resuscitation
The answer is C: Urine output of 0.6 ml/kg/hr is the most reliable indicator that adequate resuscitation has been achieved in this burn patient. This value falls within the target range of 0.5-1 mL/kg/hour recommended by current burn resuscitation guidelines 1.
Why Urine Output is the Primary Resuscitation Target
Urine output is explicitly identified as "the easiest and fastest way to adjust fluid resuscitation rates" in burn patients 1. The guidelines emphasize that while resuscitation formulae (like Parkland) provide initial estimates, actual fluid rates must be titrated to clinical response, with hourly urine output serving as the key parameter 1.
The Target Range
- Adults with thermal burns should maintain urine output of 0.5-1 mL/kg/hour 1, 2
- The patient's urine output of 0.6 mL/kg/hr falls perfectly within this therapeutic window 1
- This target has been consistently used across major burn centers despite lack of formal validation 1, 3
Why Other Options Are Less Reliable
Heart Rate and Blood Pressure (Options A & B)
Vital signs alone are inadequate for detecting malperfusion in burn patients 4. Recent studies demonstrate that:
- Blood pressure and heart rate may appear normal despite ongoing hypovolemia 5
- Patients with different urine outputs showed no differences in heart rate or mean arterial pressure, yet had different perfusion states 5
- Noninvasive parameters like vital signs have been questioned as insufficient endpoints for burn resuscitation 4
Central Venous Pressure (Option D)
CVP is reserved for complex cases, not routine monitoring 1. The guidelines specify that:
- Advanced hemodynamic monitoring (including CVP, echocardiography, cardiac output monitoring) should be used "particularly in patients with haemodynamic instability and/or persistent oliguria despite resuscitation" 1
- The impact of targeting specific hemodynamic parameters on outcome is unclear 1
- CVP is not part of first-line resuscitation monitoring 2
Critical Pitfalls to Avoid
Over-Resuscitation ("Fluid Creep")
- Both insufficient and excessive fluid administration are associated with increased morbidity 1, 6
- Urine output monitoring helps prevent over-resuscitation, which can lead to compartment syndrome, prolonged ventilation, and longer hospital stays 1, 7
Under-Resuscitation
- Inadequate fluid resuscitation increases mortality significantly (44% vs 11% in adequately resuscitated patients) 8
- Early fluid resuscitation (within 2 hours) reduces morbidity and mortality 1
Clinical Application
For this patient with 20% TBSA burns:
- Continue monitoring hourly urine output as the primary resuscitation endpoint 1, 2
- Adjust fluid rates to maintain 0.5-1 mL/kg/hour 1, 6
- Consider advanced hemodynamic monitoring only if oliguria persists despite adequate fluid administration or if hemodynamic instability develops 1, 2
- Supplement urine output monitoring with lactate levels if available, as lactate normalization indicates adequate tissue perfusion 5
The urine output of 0.6 mL/kg/hr demonstrates that this patient is receiving adequate resuscitation to maintain end-organ perfusion while avoiding the complications of fluid overload 1, 2, 3.