Wallace Rule of Nines

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Equation / Last modified by pro on 2017/12/07 16:06
`BSA % = `
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The Wallace Rule of Nines calculator computes the percent of a Body Surface Area that is burned based on the Wallace Rule of Nines.513_Degree_of_burns.jpg Burn Percentage 

INSTRUCTIONS:  Enter the following estimated percentages:

  • (H)  % of the head burned.
  • (LA)  % of the left arm burned.
  • (RA)  % of the right arm burned.
  • (C)  % of the chest burned.
  • (A)  % of the abdomen burned.
  • (B)  % of the back burned.
  • (G)  % of the groin burned.
  • (LL)  % of the left leg burned.
  • (RL)  % of the right leg burned.

Percent BSA (%BSA):  The calculator returns the percent of the burned Body Surface Area.

Related Calculators:

  • To compute the Replacement Fluid Requirement for a burn victim using the Parkland Formula, CLICK HERE.
  • Compute the Body Surface Area using the following methods:

Burn Surface Area

The Wallace Rule of Nines can be used to approximate the percent of a patient that is burned.   It applies a percent of Body Surface Area, often a multiple of 9, for different body parts as follows:

  • (9%) Entire head
  • (9%) Complete left arm
  • (9%) Complete right arm
  • (9%) Entire chest
  • (9%) Entire abdomen
  • (18%) Complete back
  • (1%) Groin
  • (18%) Complete left leg
  • (18%) Complete right leg

If you compute the body surface area of a person using one of the standard body surface area methods  (e.g. Takahira Body Surface Area) and get a BSA of 2 square meters, and then note that the patient’s skin issue (e.g. burn) is on half (50%) of his chest and all (100%) of an arm, you can use the Wallace Rule of Nine as follows:

  • Burn Area on Chest = 50% * 9% * 2 square meters = 0.09 square meters
  • Burn Area on Arm = 100% * 9% * 2 square meters = 0.18 square meters
  • Total Burn Area = 0.09 + 0.18 = 0.27 square meters of skin

This Wallace Rule of Nines Calculator makes the process simpler.   In this example, you would enter 50% for the chest and 100% for the arm.  The calculator would return 13.5%.  That's the total estimate of the body surface area that is burned.  You then multiply 13.5% times 2 square meters to get 0.27 square meters of burned skin.

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