Variability and similarity of manual office and automated blood pressures

The evaluation and management of hypertension is based on indirect blood pressures obtained in the office (COBPs) using the mercury sphygmomanometer. The usefulness of COBPs is limited by factors such as observer bias, which confound the ability to discern the true blood pressure value. Automated portable monitors have been marketed, which also measure blood pressure (ABP) indirectly throughout 24 hours, but without human intervention. Acceptance of a new device that indirectly records blood pressure depends largely on its the agreement with the established method of blood pressure measurement. This review compares the variability of blood pressures collected indirectly by standard mercury sphygmomanometer and by an auscultatory automated portable blood pressure monitor. The results indicate that blood pressure, when measured indirectly in a hypertensive patient, is quite variable. Automated blood pressures were lower and demonstrated less within-subject variability during repeated measures than COBPs. The agreement between ABPs and COBPs was better than the agreement between COBPs alone on successive visits. In addition, the mean hourly blood pressure profiles recorded throughout 24 hours by automated and manual methods from ten hypertensive patients were nearly identical. These data suggest that blood pressures measured by auscultatory automated methods are similar to and representative of those obtained manually.