Body Surface Area

Body surface area (BSA) is the total surface area of the human body. In simple terms, body surface area is the area covered by one's skin - the largest organ of the body. The body surface area is used in the calculation of drug dosages and the amount of fluids to be administered intravenously.

Body surface area is a better indicator of metabolic mass than body weight since it is less affected by abnormal body fat.

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Different formulas are used to calculate BSA; however the most commonly used formula now is that of Mosteller, published in 1987 in The New England Journal of Medicine.

According to Mosteller's "simplified calculation of body-surface area in metric terms" the body surface area = the square root of product of the weight in kg times the height in cm divided by 3600.

Apart from height and weight BSA depends on other factors like age and gender of the individual.

Find the body surface area for given height and weight.

Where is Body Surface Area Used

• Total body surface area (TBSA) is an assessment of injury (burns) or skin disease (psoriasis).
• Renal function is measured by glomerular filtration rate (GFR) which is calculated based on BSA
• Cardiac index - A measure of cardiac output divided by BSA. The cardiac index helps measure the amount of blood that the heart pumps each minute.
• Chemotherapy is dosed according to patient’s BSA
• Steroids dosing is expressed in terms of BSA

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