(41C) Body Surface Area (BSA)

[Gene]

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

[SlideRule]

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

[Dieter]

(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

[Dinamarco]

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

[Dieter]

(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

[Dinamarco]

thanks a lot!

Regards.