The case for eliminating mercury sphygmomanometers starts with a simple fact: Mercury and its by-product methylmercury are toxic. They especially present a risk to young children, and are known to cause a variety of neurologic disorders and even death. Furthermore, mercury sphygmomanometers are no longer needed: There are now effective alternatives for measuring blood pressure.
Mercury control measures are being put in place in many countries, including the United States. In 1998, the American Hospital Association and the Environmental Protection Agency signed a memorandum of understanding to virtually eliminate mercury from hospitals' waste stream by 2005. The large, for-profit hospital chain, HCA Inc., recently pledged to immediately stop buying mercury sphygmomanometers.
Each mercury sphygmomanometer contains about 135 g of mercury When broken or refurbished, these instruments need to be handled by hazardous waste management rules. Breaks result in hefty cleanup costs: They result in a cost of about $10,000 per spill in a carpeted room at the Mayo Clinic.
What are our alternatives to mercury sphygmomanometers? Aneroid devices provide a high degree of accuracy when supported by a regular maintenance program. In my experience at Mayo, aneroid manometers that are repeatedly used need to be calibrated at least twice a year with a Digimano nonmercury standard. Other institutions have had a similar experience with a different nonmercury standard, the Universal Biometer DPM-III.
New devices use diodes and other current technology to supplant the century-old standard mercury and aneroid sphygmomanometers, while retaining the auscultatory technique.