The Rule of Nines is a method used to calculate the total body surface area (TBSA) percentage that is burned in adult patients.
This calculation is crucial for assessing burn severity and determining treatment needs.
Part of a series focused on burns, highlighting the importance of TBSA in treatment.
Importance of the Rule of Nines
Criteria for Burn Unit Admission: Determines if a patient meets the criteria to be admitted to a burn unit.
Risk of Hypovolemic Shock: Severe burns increase capillary permeability, leading to fluid loss from the intravascular to interstitial tissues, risking shock and death.
Fluid Replacement: Helps calculate fluid replacement needs using the Parkland formula during the first 24 hours post-burn.
Common Solution Used: Lactated Ringers is often used for fluid replacement.
Calculating the Rule of Nines
It's essential to consider both anterior (front) and posterior (back) surfaces.
Each body part is assigned a percentage, generally a multiple of nine.
Body Part Percentages
Head and Neck:
Anterior: 4.5%
Posterior: 4.5%
Total: 9%
Trunk:
Anterior: 18%
Posterior: 18%
Total: 36%
Arms (Upper Extremities):
Each arm, anterior: 4.5%
Each arm, posterior: 4.5%
Total for both arms, all sides: 18%
Perineum:
Total: 1%
Legs (Lower Extremities):
Each leg, anterior: 9%
Each leg, posterior: 9%
Total for both legs, all sides: 36%
Total body surface area equals 100% when all segments are combined.
Practice Problem
Scenario: 35-year-old female with burns:
Front and back of both arms
Anterior trunk
Back of left leg
Anterior and posterior of right leg
Posterior head and neck
Perineum
Calculation:
Front and back of both arms: 18%
Anterior trunk: 18%
Back of left leg: 9%
Front and back of right leg: 18%
Posterior head and neck: 4.5%
Perineum: 1%
Total TBSA Burned: 68.5%
Conclusion
This method simplifies the assessment of burn surface area which is critical for immediate clinical decisions.
Encourages practice through quizzes and further study to ensure mastery of the calculation.