Development and evaluation of a home nocturnal blood pressure monitoring system using a wrist-cuff device

The conventional nocturnal blood pressure monitoring (NBPM) systems can disturb sleep and lead to false measurements. The present study compared the validity and acceptability of a newly developed wrist-cuff system with that of the conventional upper arm-cuff system for NBPM.

Home blood pressure (BP) and pulse rate (PR) were measured in hypertensive patients (n=57) every 30 min at night using a wrist-cuff system and at 2 am (fixed time) and 4 h after going to bed (flexible time) using an upper arm-cuff system. The nocturnal BPs with the wrist-cuff system at 2 am and at 4 h after going to bed were selected from the measurements taken every 30 min at night. The same systems were used to measure the morning and evening home BP and PR, after rising and before going to bed. Measurements were taken for two nights separately for each system. BP, PR, sleep quality, and the perception of several stimuli during NBPM were compared between the two systems. Systolic BP/diastolic BP (DBP) in the supine position at 2 am and at 4 h after going to bed were corrected by the mean difference between the wrist-cuff and the arm-cuff systems.

Compared with the arm-cuff system, the wrist-cuff system had significantly lower systolic BP (mean±SD: 106.3±13.4 vs. 109.8±10.8 mmHg, P<0.05), DBP (59.4±11.0 vs. 64.5±7.8 mmHg, P<0.005), and PR (53.8±7.1 vs. 60.5±8.1 bpm, P<0.0005) at 2 am and significantly lower DBP (60.2±10.3 vs. 66.0±9.8 mmHg, P<0.005) and PR (53.6±7.4 vs. 60.9±8.5 bpm, P<0.0005) at 4 h after going to bed. Among the participants, sleep disturbance during NBPM was reported in less than 20% with the wrist-cuff system and in 70% with the arm-cuff system. A significantly higher rate of participants who wore the wrist-cuff system reported that they were not bothered by various stimuli, such as noise, during NBPM.

The newly developed wrist-cuff home NBPM system provided information on BP as a function of time, especially at night, with minimal sleep disturbance and with more frequent BP measurements.