Absence of alarm reactions with use of non-invasive blood pressure monitoring devices.

We have previously shown that blood pressure measurement by a doctor or a nurse is often accompanied by an alarm reaction and a marked blood pressure rise which leads to an overestimation of patients' daily blood pressure. To determine whether this phenomenon occurs to some extent also during automatic or semiautomatic measurements of blood pressure, we have studied 20 subjects in which blood pressure was recorded invasively for 24 hours by the Oxford method. During the day time of the recording the arm contralateral to the one used for the invasive procedure was equipped with a non-invasive blood pressure recorder (Vita-Stat 901) the blood pressure measurements being performed automatically (2 hours) or semiautomatically (2 hours) at intervals of 10 minutes. The analysis of the intra-arterial blood pressure trace during the periods preceding and following the beginning of the cuff inflations that started the non-invasive measurements showed that these procedures had caused no increment in systolic and diastolic blood pressure. In nearly all subjects this applied not only to the mean data for all automatic or semiautomatic measurements, but also to the individual observations including those made in the first part of each 2 hour period, when the emotional component might have been greater. It can be concluded that non-invasive blood pressure monitoring does not induce an alarm reaction and a blood pressure rise either when performed automatically and semiautomatically. Thus this approach does not overestimate patients' blood pressure, which adds to its reliability for the diagnosis of hypertension.