Current concepts: Ambulatory blood-pressure monitoring

In the past 30 years, the techniques for measuring blood pressure to determine whether a patient has hypertension have undergone a substantial change. The bulk of our knowledge about the risks of hypertension and the benefits of treating it is based on the traditional method of taking a small number of readings with the auscultatory technique in a medical setting. However, such measurements, which are of enormous value on a population basis, often provide a poor estimate of risk in an individual patient for reasons such as poor technique of the observer, the "white-coat" effect (the transient but variable elevation of blood pressure in a medical setting), 1 and the inherent variability of blood pressure.2 Any clinical measurement of blood pressure may be regarded as a surrogate measure for the "true" blood pressure of the patient, which may be defined as the mean level over prolonged periods. Two techniques have been developed to improve the estimate of true blood pressure - ambulatory monitoring and home monitoring (or self-monitoring). We discuss only ambulatory monitoring in this review. Copyright © 2006 Massachusetts Medical Society.