Burn Percentage Calculation Using the Rule of Nines
The total body surface area (TBSA) burned for the right upper extremity, anterior trunk, and right lower extremity is 45.5% using the Rule of Nines in adults.
Breakdown by Body Region
Using the Rule of Nines method for adults 1:
- Right upper extremity: 9% TBSA 1
- Anterior trunk: 18% TBSA (anterior chest 9% + anterior abdomen 9%) 1
- Right lower extremity: 18% TBSA 1
- Total: 45% TBSA
Important Clinical Context
This represents a very extensive burn requiring immediate specialized care. Patients with TBSA >40% have significantly increased mortality risk and require immediate transfer to a burn center 2, 3.
Immediate Management Priorities
- Fluid resuscitation is critical: Administer 20 mL/kg of balanced crystalloid solution (preferably Ringer's Lactate) within the first hour 2, 4
- Establish IV access immediately in unburned areas; consider intraosseous access if IV cannot be rapidly obtained 2, 4
- Consider early intubation: Burns with TBSA ≥40% are an indication for intubation, especially if combined with facial/neck involvement or signs of airway obstruction 2
- Transfer to burn center immediately: This patient meets multiple criteria for burn center referral (TBSA >20%, extensive burns) 4, 3
Critical Measurement Caveats
TBSA is overestimated in 70-94% of cases, which leads to excessive fluid administration 4, 5. However, given the extensive nature of these burns, even conservative estimates would exceed critical thresholds for specialized care 6.
The Lund-Browder chart is the most accurate method and should be used for definitive TBSA calculation when available, as it accounts for age-related variations in body proportions 4, 5. The Rule of Nines provides a reasonable field estimate but may be less precise 7.
Expected Complications with This Burn Extent
- Hypovolemic shock from capillary leak syndrome requiring aggressive fluid resuscitation 2, 3
- Compartment syndrome risk in the right extremities may require escharotomy within 48 hours 2
- 50% mortality risk at approximately 78% TBSA in historical data, though this patient's 45% TBSA carries substantial but lower mortality 8
- Increased risk with age >60 years or presence of inhalation injury 3