The total body surface area (TBSA) of a burn can be calculated with a Lund and Browder Chart, Wallace Rule-of-Nines or the palmar method. An accurate estimation of a burn guides acute management, fluid resuscitation, nutrition supplementation and prognosis.
In this Article
Lund and Browder vs Rule-of-9s vs Palmar
The total body surface area of a burn and burn depth are two key aspects of a burn assessment. These factors influence the volume of fluid resuscitation.
The Lund-and-Browder Chart, Wallace Rule-of-Nines, and the palmar method are different ways to calculate and estimate the total body surface area (TBSA) of a burn. This table compares the different formulas:
|Lund & Browder||Rule of 9s||Palmar|
|Theory||Standardised age-based assessment||Body is divided in 9% areas.||Patients palm is 1%|
|Pro’s||“Gold-standard” accuracy||Efficient||Minor Burn Estimation|
According to the National Burn Repository, the mean burn size is 13.4% of the total body surface area1. These estimations are heavily user dependent which may result in over-estimation and significant inter-rater variability2. This is, however, an issue for all traditional burn estimation techniques.
Assessment of burn size should not include erythematous/red areas. This is discussed more in the burn depth article.
Lund and Browder Chart
The Lund and Browder Chart is considered the gold standard in burn surface area calculations. Since its first publication in 1944, this formula has established accuracy. Its limitation is in relation to clinical inefficiency.
What is the Lund and Browder Chart?
The Lund and Browder (LB) chart, which was developed in 19443, is the most broadly used tool worldwide to calculate the total body surface area of a burn.
Lund and Browder's chart is the most accurate graphical record of the extent of the burn4. Unlike other burn surface area formulas, it accounts for variation in body shape with age. It also requires knowledge of the burn depth. This means it can be used in adults and children. For example, the area of the head makes up a relatively large portion of the total skin area in infants as compared with adults. This proportion is counterbalanced in infants by the smaller area of the thighs and legs. The Lund and Browder chart takes these factors into consideration for full thickness and partial thickness burns.
It does not include superficial burns in the calculation.
The main benefit of using the Lund and Browder Chart is its accuracy. Studies have compared different burn calculation methods. Lund and Browder chart, on average, provides a 3% more accurate calculation of total body surface area burnt with less variability that using Wallace’s Rule of Nines4.
Weaknesses with the Lund and Browder chart are:
- Difficulties in assessing lateral burns
- Lack of anatomical landmarks for reference
- Inability to accurately represent obese
- Less efficient than Wallace Rule-of-Nines or the 1% palmar method.
- Requires knowledge and experience in triaging the burn depth.
The Wallace Rule of Nines is a clinically efficient and accurate method to calculate the total body surface area of a burn. It is calculated by dividing the body into percentages of 9. Limitations are noted in the paediatric and obese population.
What is the Wallace Rule-of-Nines?
The Rule of Nines can be used as an alternative to the Lund and Browder Chart for calculating the total body surface area (TBSA) involved in burn patients. It was first described by E.J. Palaski and C.W. Tennison in 1947 and later published by Wallace in 19515. It is commonly used in healthcare practice because of its clinical efficiency and proven accuracy6,7
The Rule of Nines is calculated by assigning percentages to different areas of the body. It is for full-thickness and partial thickness burns. This is described in the table below:
|Head||9%||Anterior Head = 4.5%|
Posterior Head = 4.5%
|Torso||18%||Chest = 9%|
Abdomen = 9%
|Each Arm||9%||Anterior Arm = 4.5%|
Posterior Arm = 4.5%
|Each Leg||18%||Anterior Leg = 9%|
Posterior Leg = 9%
Rule of Nines Online Calculator
For some, it is easier to visualise the Rules-of-9 when calculating the total body surface area of a burn. This is illustrated in the image and be downloaded as a PDF below.
It does not include superficial burns in the calculation.
The main benefit of using the Wallace Rule of nines is the clinical efficiency. It is simple to use and easy to remember. It is also infrequent to underestimate a burn using this technique.
The Rule of Nines can often over-estimate the total body surface area percentage of a burn4 which can result in over-fluid resuscitation.
There is a concern among clinicians of the accuracy of the Rule of Nines pertaining to the obese and pediatric populations. The Rule of Nines can be best used in patients greater than 10 kilograms and less than 80 kilograms if defined by BMI as less than obese8.
Infants have proportionately larger heads which alters the surface area contribution of other major body segments. A “Rule of Eights” better approximates infants weighing less than 10 kg.” This rule dictates approximately 32% TBSA for the patient’s trunk, 20% TBSA for the head, 16% TBSA for each leg, and 8% TBSA for each arm8.
The Palmar Method is the simplest calculator of a burn’s skin percentage. By utilising the patients palm, this technique is ideal for small and scattered burns. It is limited by user and patient variability.
What is the Palmar Method?
The palmar method is the simplest way to calculate the total body surface area of a burn. To simplify calculations, the palmar method is often described as representing 1% of the patient's total body surface area. A recent literature review has concluded that palm and digits are 0.8% and the palm without digits is 0.5% of the patient’s body surface area.
NICE guidelines for Burns and Scalds recommend the palm including digits in the estimation of smaller or scattered burns.
The technique raised controversy as to whether the palm including digits or palm excluding digits should be used. Confusion amongst healthcare professionals has been noted in the literature9. In larger burns, there is a reported 10-20% burn estimation when using the palmar method10.
For deeper burns, consider reading our scar managementarticle and increasing fluid requirements.
How do you calculate the total body surface area (TBSA) of a burn?
There are 3 common methods to estimate the total body surface area of a burn: Lund and Browder Chart, Wallace Rule-of-Nines, Palmar Method. These 3 calculations have an established role in the primary assessment of burns
How do you calculate the Rule of Nines?
The rule of nines is an efficient method to quickly determine the surface area of a burn. It is based on the principle that the body is made up of individual 9% areas, which total to 100%.
What percentage of burns is fatal?
There is no exact percentage that can predict mortality of burns. There are 3 major risk factors of a fatal burn. These are: an age of more than 60 years, burn size of more than 40 percent of body-surface area, and inhalation injury. This is further explored in a landmark publication in the NEJM.
For further reading, consider search “Total Body Surface Area” in Google Scholar or PubMed.
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- 2. Chan QE, Barzi F, Cheney L, Harvey JG, Holland AJ. Burn size estimation in children: Still a problem. Emergency Medicine Australasia. November 2011:181-186. doi:10.1111/j.1742-6723.2011.01511.x
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- 7. Cheah A, Kangkorn T, Tan E, Loo M, Chong S. The validation study on a three-dimensional burn estimation smart-phone application: accurate, free and fast? Burns Trauma. 2018;6:7. doi:10.1186/s41038-018-0109-0
- 8. Moore R, Waheed A, Burns B. statpearls. February 2020. http://www.ncbi.nlm.nih.gov/books/NBK513287/.
- 9. Jose RM, Roy DK, Vidyadharan R, Erdmann M. Burns area estimation—an error perpetuated. Burns. August 2004:481-482. doi:10.1016/j.burns.2004.01.019
- 10. Kamolz L, Lumenta D, Parvizi D, et al. Smartphones and burn size estimation: “Rapid Burn Assessor”. Ann Burns Fire Disasters. 2014;27(2):101-104. https://www.ncbi.nlm.nih.gov/pubmed/26170784.