Hospital blood pressure measurement: staff and device assessment

Evaluation of the ability of clinical staff to measure blood pressure as well as the functional state of hospital sphygmomanometers has consistently demonstrated marked deficiencies. In this study, the working order of all sphygmomanometers (manual and automated) in a teaching hospital was evaluated. Nursing staff were tested on their knowledge and use of such devices and were also asked to estimate the blood pressure from videotape. The accuracy of a commonly used automated device, Dinamap 8100, was also measured. Of 543 manual sphygmomanometers, 14% were in perfect working order although portable devices were more likely to be functional (47% of 36 units). In contrast, all 135 automated portable devices were in perfect working order although service requirements were seldom met. The mean time since last service was 18 months. There appeared to be an inverse correlation between the availability of automated and manual devices and the maintenance of wall-mounted bedside sphygmomanometers. Staff knowledge about manual devices was adequate as was their ability to accurately measure blood pressure using standardised videotape. Forty-two per cent of 31 nurses who completed the test were correct in 9 of 12 blood pressures. A comparison of this result with a comparable group of nurses tested in 1990 did not detect a significant change in competence. Direct evaluation of the commonly used Dinamap 8100 in 47 hospital patients demonstrated a poor correlation with a mercury sphygmomanometer with a D grade (fail) for systolic and a C grade for diastolic pressure. In summary, maintenance of manual sphygmomanometers was very poor, probably due to their lack of use by clinical staff. This was particularly true for units attached to bedside walls. Nursing staff demonstrated significant deficiencies in manual sphygmomanometer use although their skills were similar to those measured several years earlier. Because of the demonstrated inaccuracy of the Dinamap 8100 automated device, the strong trend towards the use of automated devices instead of manual sphygmomanometers within hospitals cannot be supported.