ABC of hypertension: Blood pressure measurement

Abstract

Automated devices: an automated alternative to mercury Automated devices, by providing timed printouts of blood pressure, remove many of the sources of error associated with the conventional auscultatory technique, and thereby improve the overall accuracy of measurement, provided, of course, that they themselves are accurate. Although the mercury sphygmomanometer is disappearing from use, unfortunately there are not many alternative devices available to replace it. The automated devices on the market have been designed for self measurement of blood pressure, and although automated devices are being developed specifically for clinical use, the automated devices presently being used in clinical practice have been adapted for a use for which they were not designed. Details of ABPM device manufacturers Additional information about manufacturers can be found on the BMJ 's website: http://www.bmj.com/cgi/content/short/322/7285/531/DC1#2. See also O'Brien et al. BMJ 2001;322:531-6 The advent of accurate automated devices, however welcome, is not without problems. Firstly, automated devices have been notorious for their inaccuracy, although accurate devices are now appearing on the market. Secondly, the available automated devices were designed for self measurement of blood pressure, and it should not be assumed that they will be suitable for clinical use, or that they will remain accurate with use, although some are being used successfully in hospital practice and a number of major hypertension studies. Thirdly, oscillometric techniques cannot measure blood pressure in all situations, particularly in patients with arrhythmias, such as rapid atrial fibrillation, and there are also individuals in whom these devices cannot measure blood pressure for reasons that are not always apparent. Fourthly, doctors are uneasy about trusting algorithmic methods, zealously guarded by manufacturers. To ensure that new devices conform with recommended validation protocols the mercury sphygmomanometer will have to be retained as a gold standard in designated laboratories.11