[Reliability of an automatic monitor for blood pressure measurement]

Background A correct blood pressure (BP) measurement is essential for the diagnosis and control of high BP.

To evaluate the agreement and repeatability of BP measurements with the OMRON HEM-7320-LA device compared to a mercury sphygmomanometer.

A cross-sectional study comparing BP measurements made by two randomly selected trained nurses and an automatic oscillometric device. The mercurial sphygmomanometer was connected to the automated device via a "T" type connector and a dual-head stethoscope was used, allowing simultaneous measurements. The results were analyzed with one-factor analysis of variance, Bland-Altman's test, repeatability coefficient (RC), and intra-class correlation coefficient (ICC).

Forty-nine participants aged 56 ± 19 years were included. Nineteen had hypertension (38%). We did not observe a significant difference in either systolic (SBP) or diastolic blood pressure (DBP) pressure measurements between the observers and the device. The mean difference was -0.09 mmHg (95% confidence intervals (CI)-0.9 to 0.7) for SBP and -0.9 mmHg (95% CI -1.7 to -0.13) for DBP. The RC for SBP (6.2, 5.2 and 5.8 mmHg) and DBP (4.7, 4.2 y 5.2 mmHg) was similar between the observers and the device. The ICC for SBP was 0.990 (95% CI 0.983 to 0.995, p < 0.01) and 0.986 (95% CI 0.977 to 0.991, p < 0.01) for DBP.

There was a high level of agreement and similar measurement repeatability in the measurements performed by the automatic device and the mercurial sphygmomanometer. No differences in BP measurements were observed.