How accurate are your sphygmomanometers?

Accuracy is of prime importance in using a blood pressure monitor regularly.

In order to establish the type and accuracy of sphygmomanometers in current use, a cross-sectional observation study was done by University of Oxford in 38 Oxfordshire primary care practices.

The testing method is as follows.

Sphygmomanometers were evaluated between 50 and 250 mmHg, using pressure meters. Devices were inflated to 280 mmHg, then the pressure was released to 250, 200, 150, 100, and 50 mmHg in turn, and at each level the true pressure was read on the pressure tester’s digital display.

If the error between the sphygmomanometer and pressure tester is more than 10 mmHg, this unit is classified as red, if the error is in 4 to 9 mmHg, this unit is classified as amber.

Table 1. (Modified) Manufacturers of blood pressure devices in use in 38 general practices in Oxfordshire

Device Type Number of tests in study Number (percentage) of tested device type classified amber / red
Aneroid (Accoson, Welch-Allyn and other brands) 191 41 (22%)
Hybrid (A&D UM-101) 10 0 (0%)

Aneroid sphygmomanometers are commonly used as a replacement for mercury sphygmomanometers. However, poor measurement precision was detected in as many as 22% of aneroid devices. As you can imagine, in medical settings the device error causes inaccurate measurements by doctor. In the worst cases, a normal person maybe diagnosed with hypertension or a person with hypertension may go undiagnosed.

In this observational study, hybrid devices had no problem with error, reinforcing the accuracy and reliability of the devices such as A&D's UM-101.

A&D's UM-102 is the latest model and successor of the UM-101. UM-102 comes with the same accuracy as the UM-101 plus a 42% (than the UM-101) lighter easy-to-carry body. The UM-102 also is chemically resistant and easy-to-clean, with a multi-angle display and professional grade cuff.

As a reliable and daily-use mercury-free sphygmomanometer, the UM-102 is well worth considering.

Journal Details
Christine A'Court, Richard Stevens, Sarah Sanders, Alison Ward, Richard McManus and Carl Heneghan:British Journal of General Practice, September 2011e598-e603.Department of Primary Health Care, University of Oxford, Oxford.
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