Automated blood pressure reading--its claims and its reliability.

Advances in technology have made available automated devices for rapid and easy measurements of arterial blood pressure. This study evaluates the performance of one such device, the Hitachi Digital Blood Pressure and Pulse Monitor, Model HME-20, against a standard mercury sphygmomanometer, the Accoson . Fifty four sets of systolic and diastolic readings were simultaneously obtained using the two instruments. The readings obtained by both methods correlated significantly with each other (p less than 0.001). However, the mean diastolic pressure obtained by HME-20 is significantly lower than that obtained by the Accoson (p less than 0.05). There is also a consistent underestimation of systolic and diastolic pressures of 8 mm Hg by HME-20. Moreover, linear correlation studies between HME-20 and Accoson readings reveal that the 95% confidence limits are fairly wide, which limit, therefore, the value of a single reading by HME-20. Our preliminary evaluation suggests that HME-20 is more suited to monitor the trend of blood pressure changes rather than to provide precise determination of arterial blood pressures.