FACTORS INFLUENCING VALIDATION OF AMBULATORY BLOOD-PRESSURE MEASURINGDEVICES

With the introduction of 24 h ambulatory blood pressure monitoring int o clinical practice a vast market for ambulatory blood pressure monito ring devices has been created. To satisfy this market manufacturers ar e producing an array of ambulatory blood pressure monitoring devices. There is no obligation on manufacturers to have such devices validated independently, even though two national protocols, one from the Briti sh Hypertension Society (BHS) and the other from the Association for t he Advancement of Medical Instrumentation (AAMI), call for independent validation and state the means of doing so. However, many factors can influence the validation procedure. They include compliance to the pr otocol being employed; the accuracy of the standard; establishing prec isely the model being validated; the influences of blood pressure leve l, age and exercise on device accuracy; the provisions necessary for s pecial populations, such as pregnant women, the elderly and children; the influence of oscillometric versus Korotkoff sound detection and el ectrocardiographic gating on comparative measurements; the assessment of performance as distinct from accuracy; and the relevance of general factors, such as the algorithm being employed and computer compatibil ity. Forty-three ambulatory blood pressure monitoring devices have bee n marketed for ambulatory blood pressure measurement and of those only 18 have been validated according to either the BHS or the AAMI protoc ol. The influence of the factors listed above on the validation studie s of those devices will be considered and the relevance of validation procedures to the clinical use of ambulatory blood pressure monitoring devices will be discussed.