Clinical evaluation of a finger oscillometric blood pressure device

An oscillometric blood pressure (BP) device designed for recording systemic BP from a finger was compared with a random-zero, mercury-column sphygmomanometer in 76 subjects recruited from the patient population and staff of a primary-care center. After both devices were placed on the left arm or finger of the left hand, three BP readings were obtained with each device in alternating fashion, thereby according random assignment. The mean for all measurements was 119.2/72.4 mm Hg for the finger device and 118.6/75.3 mm Hg for the random-zero sphygmomanometer; systolic readings were not different (p = 0.53) but diastolic readings were different (p = 0.001). There were considerable differences among the readings obtained with the two devices in individual patients: the mean differences +/- tolerance limits for readings obtained with the finger device compared with the random-zero device were 0.6 +/- 33.5 mm Hg for systolic and -2.9 +/- 25.3 mm Hg for diastolic readings. There was also considerable variability in the readings obtained with the finger device; the minimum to maximum differences in 39 systolic (51 percent) and 26 diastolic readings (34 percent) were greater than 10 mm Hg with the finger device; 24 systolic (32 percent) and 11 diastolic readings (14 percent) differed by this amount with the random-zero device. The variability in measurements made with the finger device was significantly different from the random-zero device for diastolic pressure (p = 0.0048) but not for systolic pressures (p = 0.8729). Based on the experience obtained in this study, devices to measure BP from the finger cannot be recommended for routine use.