Use of Math in the Medical Field

¶ … Math in the Medical Field

The use of math in medicine: Calculating patients' weights

Almost everyone has walked into a drug store and bought an over-the-counter medication and taken a dosage based upon the recommended dose on the label. While these generic guidelines may be acceptable for some types of medication, this is not true for all drugs. The dosage of many medications is dependent upon the weight of the patient. Doctors must use math to calculate appropriate dosages based upon the patient's needs. "Most medications have guidelines for dosage amounts in milligrams (mg) per kilogram (kg). Doctors need to figure out how many milligrams of medication each patient will need, depending on their [patient's] weight" (Glydon 2012). Because weight is often kept track of as pounds in the U.S., doctors must also be able to convert kilograms into pounds. And nurses must likewise understand such calculations to fulfill doctor's orders: "Such an order may be given as: 25 mcg/kg/min. If the patient weighs 52kg, how many milligrams should the patient receive in one hour? In order to do this, nurses must convert micrograms (mcg) to milligrams (mg)" (Glydon 2012).

Finally, as well as the weight ratio of the patient to the dosage required, the doctor must take into consideration other medical calculations, such as the half-life of the drug. If a patient takes a drug every morning, the dosage from the day before may still be lingering within his or her body, and the doctor must take that into consideration when writing the prescription. Of course, this is not a concern when administering singular drug treatments like anesthesia, although the amount of anesthesia given is very weight-dependent.

The need for a patient to maintain a healthy weight and body fat percentage is also a critical component of providing effective treatment. Excessive weight is linked to a variety of different ailments, including diabetes and heart disease. In years past, weight was often calculated purely in terms of pounds. But this fails to take into consideration the height of the patient, his or her age, body composition, and/or build. A small-boned 5'0 woman who is one hundred pounds may be a good weight for her size, but not a 5'8 woman who weighs the same amount. Doctors must be able to calculate BMI (Body Mass Index) to determine the patient's state of health. "Your BMI is equal to your weight in pounds, times 704.7, divided by the square of your height in inches" (Glydon 2012).

But even BMI should not be calculated in isolation as BMI "is not a direct measurement of body fat, it is quite possible for a person with a higher BMI to have a lower body fat content than another, less athletic person. Body mass index is one tool in the health and weight management toolbox and should not be considered the only indicator of a healthy body" (Smith 2007). A pound of muscle weights more than a pound of fat, so someone who is very muscular and athletic might have a BMI that is technically overweight, even though he or she has a much lower body fat percentage than someone who does not 'work out' and has the same calculated BMI.