Ambulatory blood pressure monitoring

Non-invasive measurement of blood pressure in ambulatory humans began in the 1960s. Ambulatory devices have been modified over the years and are now pocket-sized, with almost noiseless pumps. Their accuracy must be validated by independent laboratories using a standardised protocol. Twenty-four-hour ambulatory monitoring offers considerable advantages over conventional measurement, including avoidance of error associated with conventional measurement, elimination of white-coat effect and the provision of a series of blood pressure readings over the time period rather than a one-off measurement. In clinical practice, 24-hr monitoring provides valuable assistance in both the diagnosis and treatment of hypertension, in particular, in the selection of drug and dosage regimen. In the research setting, 24-hr monitoring plays an important role in establishing dose-response relationships and the duration of action of new drugs. It also has a role in the design of antihypertensive trials by ensuring that those with white-coat hypertension are excluded and by reducing the number of subjects necessary for recruitment. Although 24-hr ambulatory blood pressure is a better predictor of target organ damage, definitive evidence as to whether it is a better predictor of prognosis in hypertension awaits the results of longitudinal studies, which are now underway.