The SOMNOtouch device as a novel method for measuring short-term blood pressure variability: a comparison with the Finometer

BackgroundCurrent noninvasive techniques to capture short-term blood pressure variability (BPV) have methodological and practical limitations. This study assessed the ability of a novel device, the SOMNOtouch, which derives continuous blood pressure (BP) measures from pulse transit time, to estimate BPV, compared with the widely used Finometer.MethodsBP monitoring was performed simultaneously on the SOMNOtouch and Finometer devices in 16 healthy volunteers. Systolic and diastolic BPVs, defined as SD and coefficient of variation, were derived from measurements from each device for three predefined periods: 0-3, 7-10, and 0-10min.ResultsAgreement in BPV indices from the two devices was assessed using the Bland-Altman technique. For all BPV parameters, over all measurement periods, broad scatter was observed on Bland-Altman plots. Bias (limits of agreement) for minutes 0-10: SD of systolic BP, -3.03mmHg (-10.88 to +4.55), SD of diastolic BP -1.65mmHg (-4.41 to +1.11).ConclusionsThe poor agreement observed in BPV estimates between the devices may reflect the inability of the current pulse transit time method to sensitively detect changes in BP. Further investigation is needed before such methods can be reliably used to measure short-term BPV.