A reader of Metric Views from the USA raises the issue of measurement units in medical practice generally, or ‘cultural metrication’ as he terms it.
An article in Metric Views in December 2009 discussed the LACORS survey on weighing scales in NHS hospitals, http://tinyurl.com/yao9kzb . This issue was also taken up on 25 February in Parliament by Lord Walton, http://tinyurl.com/y8m45z3.
Paul Trusten writes from the US:
At the risk of being called a meddling Yank, my answer to the question offered here – namely, should a totally metric culture be enforced by NHS – I say, emphatically and categorically YES!
The use of two different systems of measurement in healthcare must end. Only the SI metric system should be used in medical records and in verbal communications of a patient’s weight and height.
I say this not just out of my commitment to metrication on my side of the pond as the Public Relations Director of the U.S. Metric Association, but, much more importantly, as a practicing pharmacist for the past 33 years. I agree completely with the statement that the use of customary units alongside metric units for height and weight in a hospital is a dangerous practice that should be ended as soon as possible, on both sides of the Atlantic. The entire culture in hospitals must be metric, and conversion of any kind should be banned. Ideally, weigh patients on scales that read in kilograms only, and measure height in meters or centimeters only. I believe that the traditional romance of weighing babies in pounds and ounces must be exchanged for the peace of mind parents should enjoy from the enforcement a metric-only healthcare environment. From a safety standpoint, their precious bundle’s weight in kilograms should be music to their ears.
My commitment to the goal of U.S. metrication began in 1974 when I was in pharmacy school. When I was studying pharmaceutical calculations, I was horrified to learn that two, even three systems of measurement (apothecary, avoirdupois, and metric) were involved. (Editor: It became illegal in the UK from 3 March 1969 to use any system of weights and measures other than the metric system for dispensing prescriptions). Also, the decimal nature of the metric units made them so much simpler to manipulate mathematically. Anyone who has ever tried to add apothecary weights denominated in ounces, drams, scruples, and grains vs. just adding up figures in grams will understand. My quest for one system of measurement in healthcare was easily extended to the goal of metric measurement for all purposes. It just made sense.
Banish any thought that medication dosing is ever going to accommodate the old units by being stated in something like milligrams per pound. That is out of the question. Medications can only be handled in the decimal metric system. Period. In the preparation of compounded sterile injectable products (intravenous and other injectables), use of only the decimal metric system is possible. Decimal calculations are the only safe ones.
For certain age groups (usually pediatric patients), medications are dosed on a milligram per kilogram of body weight basis. The anticoagulant drug heparin is often dosed at the rate of units of heparin per kilogram per hour. Many drugs, especially anti-neoplastic agents (chemotherapy or anti-cancer drugs), some antibiotics, and other specialized drugs, are often dosed in micrograms or milligrams per square meter of body surface area (BSA), with BSA being calculated using the patient height and weight in metric units. If, in the dose calculation, the patient weight in pounds were to be accidentally substituted for the weight in kilograms, a disastrous overdose could occur. In this arena, well will not have metric martyrs. We will have customary ones.
U.S. healthcare safety officials made considerable progress in cultural metrication last year. The Institute for Safe Medication Practices (ISMP), a non-profit organization devoted entirely to medication error prevention and safe medication use, has recommended the total metrication of the medication delivery process, from prescribing to order entry to pharmacist counseling of the patient (see http://www.ismp.org/Newsletters/ambulatory/archives/200905_1.asp).
I want to suggest also that body temperature should be taken and recorded only in degrees Celsius, to allow for worldwide ease of communication.
Be totally safe – be totally metric! Let us all, UK and U.S., at long last, use only one system of measurement in healthcare.