Lack of alerting reactions to intermittent cuff inflations during noninvasive blood pressure monitoring.

Intermittent noninvasive blood pressure monitoring is becoming increasingly popular because of the belief that a daytime blood pressure profile can provide a better clinical evaluation of hypertension than that provided by casual blood pressure measurements. This approach has potential limitations, however, one of which is that the cuff inflations permitting blood pressure to be repeatedly measured may induce an alerting reaction and a pressor response in the patients and lead to an overestimation of their daytime blood pressure. Blood pressure in 22 subjects was invasively recorded for 24 hours by the Oxford method. During the day of the recording blood pressure was also measured by a noninvasive device (Vita-Stat 901), which had its cuff applied to the opposite arm from which the intra-arterial signal was derived. For 2 hours the device provided automatic cuff inflations at 10-minutes intervals. For another 2 hours it was programmed to provide cuff inflations only following patients' commands, also at 10-minute intervals. Analysis of the intra-arterial blood pressure trace during the periods preceding and following the automatically or semiautomatically induced cuff inflations showed that these procedures caused no increment in systolic and diastolic blood pressure. This finding applied not only to the mean data but also to each individual measurement considered separately, including the initial one. Our results indicate that automatic and semiautomatic blood pressure monitorings do not induce an alarm reaction and a blood pressure rise and thus do not overestimate daytime blood pressure values.