(41C) Body Surface Area (BSA)
03-03-2019, 06:48 PM (This post was last modified: 03-05-2019 10:56 PM by Gene.)
Post: #1
 Gene Moderator Posts: 1,290 Joined: Dec 2013
(41C) Body Surface Area (BSA)
From Dinamarco

Input height in cm and weight in Kg

Code:
01 LBL "BSA" 02 FIX 1 03 BEEP 04 "HEIGHT CM:" 05 PROMPT 06 STO 01 07 "WEIGHT KG:" 08 PROMPT 09 STO 02 10 RCL 01 11 0.725 12 YˆX 13 RCL 02 14 0.425 15 YˆX 16 * 17 139.2 18 / 19 "BSA:" 20 ARCL X 21 AVIEW 22 END
03-03-2019, 08:17 PM
Post: #2
 SlideRule Senior Member Posts: 1,325 Joined: Dec 2013
RE: (41C) Surface Body Area (BSA)
a modest contribution, from the HP 33S Applications in Medicine:
Application 2: Body Surface Area (BSA)
There are two primary methods used to estimate body surface area, the Dubois method and the Boyd Method. Each method uses inputs of a patient’s height and weight in metric units and estimates the patient’s BSA.
Dubois’ formula is shown below in Figure 6 and requires input of the height in centimeters and the weight in kilograms.

BSA(m²) = Ht⁰·⁷²⁵ x Wt⁰·⁴²⁵ x 0.007184 Figure 6

Note that Dubois’ formula is undefined for children with a BSA less than 0.6 m2. Boyd’s formula should be used in these situations.

BEST!
SlideRule
03-04-2019, 10:15 AM (This post was last modified: 03-04-2019 11:11 AM by Dieter.)
Post: #3
 Dieter Senior Member Posts: 2,397 Joined: Dec 2013
RE: (41C) Surface Body Area (BSA)
(03-03-2019 06:48 PM)Gene Wrote:
Code:
01 LBL "BSA" 02 FIX 1 03 BEEP ...

Gene and Dinamarco, I hope you don't mind two comments:

– Please remove that BEEP. An audio signal may make sense after a long calculation to alert the user when input is required, but here it is only annoying. For me at least. You should also do so in the cholesterol program which even has two BEEPs at input and output. Or add "CF 26" as the second line. ;-)

– The program does not require any data registers:

Code:
01 LBL "BSA" 02 "HEIGHT CM ?" 03 PROMPT 04 .725 05 YˆX 06 "WEIGHT KG ?" 07 PROMPT 08 .425 09 YˆX 10 * 11 139.2 12 / 13 FIX 2 14 "BSA=" 15 ARCL X 16 AVIEW 17 END

(03-03-2019 08:17 PM)SlideRule Wrote:  Note that Dubois’ formula is undefined for children with a BSA less than 0.6 m2. Boyd’s formula should be used in these situations.

Here is a version with Boyd's formula.

Code:
01 LBL "BSAB" 02 "HEIGHT CM ?" 03 PROMPT 04 .3 05 YˆX 06 "WEIGHT KG ?" 07 PROMPT 08 ENTER 09 LOG 10 -.0188 11 * 12 .6157 13 + 14 Y^X 15 * 16 .0333 17 * 18 FIX 2 19 "BSA=" 20 ARCL X 21 AVIEW 22 END

Example:
height = 183 cm, weight = 90 kg
Dubois: 2,12 m²
Boyd: 2,15 m²

Dieter
03-05-2019, 03:05 AM
Post: #4
 Dinamarco Junior Member Posts: 21 Joined: Feb 2019
RE: (41C) Surface Body Area (BSA)
Thanks for your comment.

Currently, in medical calculations, the Dubois & Dubois Formula is being used. Boyd's Formula has fallen into disuse for adult patients with whom it actually works. That's why I wrote the program. In addition, the International System of Units, is recommending the use in the related units that are part of this system. I hope I justified myself.
Soon I will be posting more formulas.
Best Regards

Nelson Dinamarco
03-05-2019, 07:13 PM
Post: #5
 Dieter Senior Member Posts: 2,397 Joined: Dec 2013
RE: (41C) Surface Body Area (BSA)
(03-05-2019 03:05 AM)Dinamarco Wrote:  In addition, the International System of Units, is recommending the use in the related units that are part of this system. I hope I justified myself.

No justifications required. ;-)

Re. SI units: both the Dubois and the Boyd formula use (centi)meters and kilograms, i.e. regular SI-units. Which also applies to all other BSA formulas I have found (but what do I know about this subject).

Which - for me - leads to the question if there are any relevant medical applications where something else (e.g. imperial units) is used. I would expect SI to be the common worldwide standard, if only for safety reasons.

But the above program of course can be adjusted for "feet/inches" and "pounds". I'll gladly provide an "imperial" version. ;-)

BTW, Gene: maybe you can change the thread title from "Surface Body Area" to "Body Surface Area". Thank you.

Dieter
03-05-2019, 09:02 PM
Post: #6
 Dinamarco Junior Member Posts: 21 Joined: Feb 2019
RE: (41C) Surface Body Area (BSA)
thanks a lot!

Regards.

Nelson Dinamarco
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