aThe Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Irelandbdabl Ltd., Blackrock Co., Dublin, IrelandcHypertension Center, Third University Department of Medicine, Sotiria Hospital, Athens, GreecedIstituto Scientifico Ospedale San Luca, IRCCS, Instituto Auxologico Italiano, Milan, ItalyeSociété Française d'Hypertension Artérielle, Filiale de la Société Française de Cardiolgie, Paris, FrancefThe Department of Clinical Pharmacology and Therapeutics, Tohoku University Graduate School of Pharmaceutical Science and Medicine, Sendai, JapangCentre for Epidemiological Studies and Clinical Trials, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, ChinahUniversity Clinic Bonn, Department of Internal Medicine, Bonn, GermanyiGuy's and St Thomas' Hospitals, London, UK
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IntroductionMeasurement of blood pressure is the commonest measurement made in clinical practice, and the interpretation of the figure resulting from that measurement has far-reaching implications for the individual in whom the technique is performed. If the measurement is erroneously low, for example, the patient may be denied the most valuable drug treatment to prevent future stroke and heart attack, whereas if, on the other hand, the measurement is erroneously high, the individual may be commenced on lifelong blood pressure lowering drugs unnecessarily. It is imperative, therefore, that the device being used to measure blood pressure is accurate and, because blood pressure is a complex haemodynamic variable, it is accepted that all blood pressure measuring devices must be validated independently in the clinical setting.Validation of blood pressure measuring devices began in the 1980s with a series of ad hoc validation protocols on devices . From the 1990s onwards, device validation became more structured with the publication of standards and protocols from the Association for the Advancement of Medical Instrumentation (AAMI) and the British Hypertension Society (BHS) [2–7]. In 2002, the Working Group on Blood Pressure Monitoring of the European Society of Hypertension (ESH), which is composed of experts in blood pressure measurement, many of whom have considerable experience in validating blood pressure measuring devices, published the International Protocol, which simplified previous protocols and was based on evidence from a large number of validation studies . The International Protocol was drafted in such a way as to be applicable to the majority of blood pressure measuring devices on the market. The validation procedure was therefore confined to adults over the age of 30 years (who constitute the majority of subjects with hypertension), and it did not make recommendations for special groups, such as children, pregnant women and the elderly, or for special circumstances, such as during exercise, or for abnormal pathophysiological circumstances, such as atrial fibrillation, or arterial stiffness as may occur in the elderly. The protocol did not preclude investigators and manufacturers from applying the International Protocol to assessment and validation in these circumstances. For full background information on this revision, it is recommended that investigators familiarise themselves with the original protocol, which can be downloaded directly from www.dableducational.org.Initially, the results of validation studies were published in peer-reviewed journals and, every few years, ‘state-of-the-market’ papers summarising device accuracy were published in general and specialised journals . However, it became apparent that many of these publications were not accessible to many would-be purchasers of blood pressure measuring devices. To overcome this deficiency, the Working Group of the European Society of Hypertension launched the www.dableducational.org website in 2004. This now receives visits from over 5000 organisations in 100 countries in all continents.Since the International Protocol was published in 2002, 78 reported studies have been analysed and this analysis is the evidence base for the changes being incorporated in the first revision of the International Protocol [1,10].Because of the increasing ban on the use of mercury-containing sphygmomanometers, there is a need for an equivalent standard device that does not contain mercury.The following are the basic changes to the revised protocol:(1) Forms replace free-text results so that all data must be standardised.(2) The age restriction is reduced from 30 to 25 years to facilitate recruitment.(3) Phase 1 has been removed, as this is now considered redundant.(4) As a consequence of improvements in technology, pass levels have been tightened.