ACCURACY OF AN AUTOMATED BLOOD-PRESSURE DEVICE IN STABLE INPATIENTS -OPTIMUM VS ROUTINE USE

Background: Despite widespread use of the automated blood pressure (BP ) device (IVAC model +200, IVAC Corporation, San Diego, Calif), there is little formal validation in the literature on its accuracy. Objecti ve: To assess the accuracy of the IVAC 4200 device, both under standar dized conditions and as routinely used by ward staff, compared with th e true indirect BP measured by mercury manometer (MM). Methods: One hu ndred forty-five stable inpatients were randomly selected for BP measu rements by 3 randomly ordered protocols: (1) MM performed by certified investigators, (2) IVAC 4200 BP performed by trained investigators (r esearch automated [RA]), and (3) IVAC 4200 BP performed by ward person nel (ward automated [WA]). Results: For RA compared with MM (''true'' indirect BP), 59% of systolic and 54% of diastolic readings were withi n 5 mm Hg and 83% of systolic and 86% of diastolic were within 10 mm H g for a British Hypertension Society grade C for both. For WA compared with MM, 40% of systolic and 50% of diastolic readings were within 5 mm Hg and 70% of systolic and 80% of diastolic readings were within 10 mm Hg for British Hypertension Society grades D and C, respectively. The presence of arrhythmias and/or low K5 values (fifth phase of Korot koff sounds <30 mm Hg) significantly increased the inaccuracy for dias tolic values. Inappropriate cuff selection significantly increased ina ccuracy of systolic BP (WA vs MM). Conclusions: The IVAC 4200 yields s ubstandard estimates of systolic and diastolic BP even under standardi zed, thus optimum conditions. The presence of arrythmias or low K5 val ues and the selection of inappropriate cuff size by the ward staff als o contributed to inaccuracy.