Body surface area
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2008-06-02T09:43:20Z
Jfdwolff
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Reverted edits by [[Special:Contributions/87.101.156.205|87.101.156.205]] ([[User talk:87.101.156.205|talk]]) to last version by Davidruben
In [[physiology]] and [[medicine]], the '''body surface area''' (BSA) is the measured or calculated surface 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. Estimation of BSA is simpler than many measures of volume.
==Uses==
Examples of uses of the BSA:
* [[Renal function]] is usually fractioned over 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 requirement.
==Calculation==
Various calculations have been published to arrive at the BSA without direct measurement, starting in [[1916]] with the Dubois & Dubois formula. A commonly used formula is the Mosteller formula, published in [[1987]]:
Metric (area in square metres from [[weight]] in [[kilogram]]s and [[height]] in [[centimetre]]s):
:<math>{x}= \sqrt\frac{\mbox{weight} \times \mbox{height} }{3600}</math>
half-[[English unit]]s (area in '''square metres''' from [[human weight|weight]] in [[pound (mass)|pounds]], height in [[inch]]es):
:<math>{x}= \sqrt\frac{\mbox{weight} \times \mbox{height} }{3131}</math>
Another is the Haycock formula (in children):
:<math>{x}=0.024265 \times {weight \mbox{ (kg)}}^{0.5378} \times {height \mbox{ (cm)}}^{0.3964}</math>
Du Bois & Du Bois, ''Arch Intern Med'' [[1916]];17:863:
:<math>{x}=(71.84 \times {weight \mbox{ (kg)}}^{0.425} \times {height \mbox{ (cm)}}^{0.725})\ / \ 10000</math>
Gehan EA, George SL, ''Cancer Chemother Rep'' 1970;54:225-235:
:<math>\mathrm{S} = 0.0235 \times height \mbox{ (cm)}^{0.42246} \times weight \mbox{ (kg)}^{0.51456}</math>
Boyd's Formula:
:<math>\mathrm{S} = 0.0003207
\times height \mbox{ (cm)}^{0.3} \times weight \mbox{ (g)}^{(0.7285 - 0.0188 \log_{10}{weight \mathrm{ (g)}})}</math>
National Cancer Institute {{Fact|date=February 2008}}
:<math>{x}=({weight \mbox{ (kg)}}^{0.425} \times {height \mbox{ (cm)}}^{0.725})\ / \ 139.315</math>
==Normal values==
"Normal" BSA is generally taken to be 1.7 m² for an adult.
:{|
! colspan="3" | Average BSA values
|-
| Neonate || 0.25 ||m²
|-
| Child 2 years || 0.5 || m²
|-
| Child 9 years || 1.07 || m²
|-
| Child 10 years || 1.14 || m²
|-
| Child 12-13 years || 1.33 || m²
|-
|For men || 1.9 || m²
|-
|For women || 1.6 || m²
|}
==References==
* Mosteller RD. ''Simplified calculation of body-surface area''. [[N Engl J Med]] 1987;317:1098. PMID 3657876.
* Haycock GB, Schwartz GJ, Wisotsky DH ''Geometric method for measuring body surface area: A height-weight formula validated in infants, children and adults'' ''J Pediatr'' 1978;93:62-66
==External links==
* [http://www.bccancer.bc.ca/HPI/drugdatabase/appendices/appendix9.htm BC Cancer network] BSA calculation guidelines.
* [http://www.cato.eu/body-surface-area.html Online Body Surface Area Calculator (Dubois Formula)]
* [http://www.cato.eu/body-surface-area-children-1.html Online Body Surface Area Calculator (Mosteller Formula)]
* [http://www.webcooltools.com/Medicine/BSA.html Web CoolTool to Calculate BSA using any of the five formulae]
[[Category:Pharmacology]]
[[de:Körperoberfläche]]
[[es:Área de superficie corporal]]
[[fr:Surface corporelle]]
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[[pl:Powierzchnia ciała]]