Body surface area - Wikipedia, the free encyclopedia


** Body surface area **

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In physiology and medicine, the *body surface area* (BSA) is the measured
or calculated surface area of a human body. For many clinical purposes BSA
is a better indicator of metabolic mass than body weight because it is less
affected by abnormal adipose mass. Nevertheless, there have been several
important critiques of the use of BSA in determining the dosage of
medications with a narrow therapeutic index like many chemotherapy
medications. Typically there is a 4-10 fold variation in cytotoxic drug
clearance between individuals due to differing activity of drug elimination
processes related to genetic and environmental factors. This can lead to
significant overdosing and even more perniciously to underdosing (and
increased risk of cancer recurrence). It is also thought to be a distorting
factor in Phase I and II trials that may result in potentially helpful
medications being prematurely rejected.^[1]^[2] The trend to personalized
medicine is one approach to counter this weakness. Estimation of BSA is
simpler than many measures of volume.


· 1 Uses
· 2 Calculation
· 3 Average values
· 4 References
· 5 External links


Examples of uses of the BSA:

· Renal clearance is usually divided by the BSA to gain an appreciation of
the true required glomerular filtration rate (GFR);
· The Quetelet index uses a somewhat modified form of the BSA;
· The cardiac index is a measure of cardiac output divided by the BSA,
giving a better approximation of the required cardiac output;
· Chemotherapy is often dosed according to the patient's BSA.
· Glucocorticoid dosing is also expressed in terms of BSA for calculating
maintenance doses or to compare high dose use with maintenance


what is bsa

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