Mercury sphygmomanometer replacement validated
MedWire News: Researchers report that a hybrid mercury-free blood pressure (BP) monitor is a valid alternative to the mercury sphygmomanometer for professional use and as a standard for future validation studies.
Due to concerns about the toxicity of mercury, the European Commission Scientific Committee on Emerging and Newly Identified Health Risks recommended in 2009 that mercury sphygmomanometers should only be used in clinical validation studies until an alternative standard is developed and recognized.
George Stergiou and team from Sotiria Hospital in Athens, Greece, therefore validated the accuracy of a hybrid mercury-free auscultatory device (Nissen DM3000, Japan Precision Instruments) on the basis of the European Society of Hypertension International Protocol (ESH-IP) 2010, but using more stringent criteria.
This allowed simultaneous, rather than sequential, auscultatory BP measurements performed with the Nissen DM3000 and with two standard mercury sphygmomanometers, write editorialists Gianfranco Parati and J Ochoa, both from the Istituto Auxologico Italiano in Milan, Italy, in an accompanying commentary.
The revised ESH-IP 2010 criteria requires five BP measurements to be obtained by two observers using two mercury sphygmomanometers alternating with four measurements taken by the supervisor using the test device.
Part one of the criteria deals with the accuracy of the individual BP measurements (BP differences within 5, 10, and 15 mmHg among 99 comparisons) and part two with the accuracy per subject (subjects with two of their three and none of their three BP comparisons having a difference within 5 mmHg).
If the achieved results met the requirements in both part one and two for systolic and diastolic BP, the study result is a "Pass."
The mean difference between the observers (n=99) was 0.2 mmHg for systolic and 0.1 mmHg for diastolic BP.
Almost all systolic (97 of 99) and diastolic (98 of 99) device-observer BP differences fell within 5 mmHg; therefore "the test device comfortably passed all the validation criteria of part 1 and 2," say the authors.
Further analysis showed that the mean of the device-observer BP differences was almost identical to the differences between observers, both in terms of mean and absolute BP differences. In addition, the number of BP measurements with absolute device-observer BP differences within 2 and 4 mmHg were similar to those of the between-observer differences.
"This device appears to be a reliable alternative to the mercury sphygmomanometers for professional use in the office and also as a standard for future validation studies of new BP monitors," write the authors in the Journal of Human Hypertension.
Parati and Ocho add: "This paper also offers an example for future validation studies in this specific field, indicating which key research questions are to be addressed in order to provide physicians with useful information in their daily practice."
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By Piriya Mahendra