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The Accuracy of Alternatives to Mercury Sphygmomanometers
Authors: Susan Buchanan, MD, MPH
October 2009. 22 pages.
Summary
The mercury sphygmomanometer was first introduced over 100 years ago and has not changed much since then. Due to the move towards removal of mercury from health care settings, alternatives to the mercury sphygmomanometer are in common use in many hospitals and clinics.
Concern has been voiced regarding the accuracy of these alternative devices. This monograph comprises a review of the medical literature that evaluates the accuracy of mercury, aneroid, and oscillometric blood pressure devices. Articles published between 1995 and 2009 were included. Seventeen articles met the inclusion criteria.
Mercury sphygmomanometers were not as unfailingly accurate as often expected. Failure rates using various validation, calibration and inspection protocols ranged from 1% to 28%. Aneroid sphygmomanometer accuracy also varied widely, failing calibration tests between 4 and 61% of the time in this literature. Both the mercury and aneroid sphygmomanometers evaluated in the studies had not undergone the recommended regular maintenance and calibration. As to potential substitution of aneroid for mercury devices, recent articles reported that when aneroid devices were calibrated and maintained appropriately, they performed equally or better than mercury devices.
Although most professional organizations still require mercury for validation protocols, electronic pressure gauges offer superior accuracy and should be substituted for mercury manometers for calibration and validation. Organizations that publish validation and calibration protocols should immediately re-evaluate their recommendations regarding the use of mercury devices.
