Clinical evaluation of the Pollenex BP-850 automatic sphygmomanometer

Eighty subjects were assigned to two conditions in which readings of blood pressure were taken simultaneously by an observer using a Hawkesley Random Zero Sphygmomanometer and by a Pollenex BP-850 Automatic Sphygmomanometer either in its standard form or silenced to stop it bleeping whilst recording blood pressure. Forty subjects were assigned to a comparison group, where simultaneous readings by two observers were taken from one Hawkesley. Analyses performed included correlations, t-tests, and Bland and Altman's (Lancet, 1986, i: 307-310) differences against the mean method. Cues from observer behaviours or the bleeping Pollenex resulted in higher concordance between measures in the standard condition and the Hawkesley comparison condition. However, even in the silent condition the Pollenex proved to be as reliable a monitor of blood pressure as the Hawkesley.