Freeware for the Palm Operating System

Journal of Family Practice, Sept, 2001 by Gary N. Fox

Medical Calculators and Clinical Decision Rules

MedCalc and MedMath are medical calculators. MedCalc contains more than 50 formulas compared with approximately 25 for MedMath. Both have equations for estimated creatinine clearance, body mass index (BMI), ideal body weight, and basal energy expenditure. Also, MedCalc includes a pregnancy calculator, predicted peak flow rates for adults, and pediatric maintenance intravenous fluid rates. Both allow for visualizing the equations used. MedCalc also has an advantage on some little things. For example, when calculating energy requirements, MedCalc allows an extra step that lets users adjust for increased metabolic demands (eg, 1.5 or 1.8 times basal requirements) if they wish. MedMath appears to be superfluous.

One small but useful calculator, DietCalc, is admittedly redundant with these others. It requires English units (pounds, inches), and offers 4 related calculations--resting metabolic rate, ideal body weight, BMI, and an estimate of calories used each day based on the patient's activity level--from single entry of the patient's age, height, and weight. Many of us still use English units, at least to communicate with our patients. These calculations help physicians answer the clinical questions: How much should I weigh? How many calories should I eat to lose weight? and Am I a candidate for weight-loss medication? MedCalc and MedMath require 3 separate entries to obtain these answers.

Unfortunately, MedCalc and MedMed lack some useful calculations, specifically preoperative cardiac risking scores and Gaff breast cancer risking.[2] Two programs, MedRules and InfoRules, present a variety of clinical decision rules. Both are somewhat slower than the previously mentioned software, because they are written using NSBasic (an interpreted language) rather than C . Although these 2 programs include many of the same rules, InfoRules provides more background information on each rule and focuses on rules that have been prospectively validated.

STAT Cardiac Risk is another specialized calculator for which the input is cardiac risk factors (eg, age, sex, cholesterol) and the output is the expected 10-year coronary heart disease (CHD) risk based on Framingham data. As the user changes any parameter, the 10-year risk estimate changes simultaneously. In practice, I suspect physicians will use this program to illustrate to patients how changes in their risk factors (from adherence to therapy) will reduce their chance of developing CHD. Unfortunately, Framingham data are not developed from interventional trials, and there are some tenuous assumptions in using these results in this manner.

STAT Growth Charts calculates children's growth percentiles based on their ages, weights, heights, and depending on age, head circumferences or BMI, according to the new growth charts from the Centers for Disease Control and Prevention. For both. STAT products, the price is some advertising at the bottom of the screen.

Almost any text-based, information accessed from a desktop computer can be reformatted through free software (eg, MakeDocW, available at www.pierce.de/makedocw.html) to Palm format, transported to a Palm device, and read on the Palm with a free document reader (eg, CspotRun, available at www.32768.com/bill/palmos/ cspotrun). However, these free programs lack features found in programs available for purchase. Users can generate their own information or download information others have generated (eg, documents available at pda.tucows.com/ palm/docs_medical.html).