Aneroid Gauges versus Mercury Manometers for Blood Pressure Measurements
FAQ [Health Devices Apr-May 1998;27(4-5):176-7]
Should we replace our old mercury blood
pressure manometers with aneroid blood pressure gauges?
Yes—switching to aneroid blood pressure
gauges is a good idea, primarily because these gauges do not contain mercury.
Mercury is a highly toxic heavy metal that is volatile at room temperature; it
therefore poses a significant inhalation and skin-contact hazard. Acute exposure
to mercury can result in local skin and mucous membrane irritation, interstitial
pneumonitis, bronchitis, and bronchiolitis. Chronic exposure, which is more
common, produces symptoms that include inflammation of the gums, excessive
salivation, muscular tremors, and mental disorders.
The principal concern with mercury manometers is that spills can occur during calibration of the unit or filtering of the mercury—which are required periodically—or that the manometer might break while being used in a patient's room. Even a small amount of unrecovered mercury can volatilize to toxic levels. It is therefore essential that hospitals have policies and procedures in place to handle mercury spills.
Although current aneroid gauges are generally accurate and reliable, users need to remember that the effective function of these instruments depends greatly on periodic inspection. Aneroid gauges register pressure by the deflection of a diaphragm within the meter. Overpressurization, mechanical vibration, and shock received during normal use can all cause these gauges to register erroneously. Clinical personnel should be advised to have the units checked following any abuse (e.g., an accidental drop) that might have caused damage. This will reduce the risk of inaccurate readings.
Replacing mercury blood pressure manometers on a high-priority basis is probably not cost-effective or justified if the facility has adequate procedures in place for handling mercury. However, we do recommend the planned elimination of mercury blood pressure manometers to reduce the risk of mercury exposure.
- Sphygmomanometers, Aneroid [16-156]
- Sphygmomanometers, Mercury