Implementing Automated Office Blood Pressure Measurement

Abstract

W hy is it we talk and write so much about blood pressure (BP) measurement? Why another debate about yet another BP measurement methodology? Of all the important risk factors for cardiovascular disease (CVD), it is only BP measurement that attracts so much discussion and debate. 1 The method-ological approaches for measuring other CVD risk factors such as glucose, glycated hemoglobin, low-density lipoprotein cholesterol , non-high-density lipoprotein cholesterol, body weight, height, body mass index, waist circumference, and smoking status are well-defined and widely agreed upon. What distinguishes BP from these more easily measured CVD risk factors? First, and perhaps the most difficult to address from a measurement perspective, is the moment-to-moment biologic variability in BP. While most other CVD risk factors are characterized by some level of biologic variability, BP is unique in its volatility. Physical activity (even mild), emotional stress, and many other factors can result in sudden changes to one's BP. Like other risk factors, BP changes over time (with age), especially in industrialized societies. 2 Second, all the convenient and clinically practical methods for measuring BP are indirect measurements. The reference standard for BP measurement is intraarterial measurement, a precise, but impractical method for most clinical settings. 3-5 Indirect measurement methods, on the contrary, generally depend on the use of a pressurized cuff to impede blood flow in an artery, usually the brachial artery. Precise determination of BP is essential. Clinicians rely on precise BP levels to predict and manage CVD risk, to accurately diagnose hypertension, to determine appropriate initial therapy for BP management in those with hypertension or elevated BP, and to assess patients' progress toward goal BP. 1 In recent years, the use of performance measures to evaluate quality in patient care has driven a new focus on assessment of all common CVD risk factors. BP control is a frequently used performance measure for these evaluations, further necessitating accurate methods for measuring and monitoring BP. Currently, office BP measurements are the most frequently used measure of control, with the last recorded office BP often cited as the performance measure. 6 Automated Office Blood Pressure Is Unique The controversy regarding office BP measurement has recently escalated, with the introduction of an automated oscillometric instrument that, in the office setting, can be programmed to measure BP at intervals, usually after a 5-minute rest period (some instruments) and then at 1-minute intervals, for a total of 3 measurements following the rest period. The device also allows measurement to occur without an observer in the room with the patient. This BP measurement method is usually ref-erenced as automated office blood pressure (AOBP) measurement. 7-9 The purpose of this article is to review the reasons that this BP measurement device and approach should be the preferred approach for measuring office BP in clinical practice and in clinical research. AOBP measurement is gaining popularity as an approach to office blood pressure (BP) measurement. As evidence has evolved that among available BP measurement methodolo-gies, ambulatory BP measurement best predicts future CVD, measurement methods have been compared with this standard. The use of AOBP has increased as evidence of the close correlation between AOBP measurements and daytime ambulatory BP measurement results have been reported. For the foreseeable future, both in-office and out-of-office BP measurement will be needed. This article does not address whether office BP measurement of any kind should be abandoned in favor of only measuring BP out of the office. AOBP is simply a