A Finger Volume-Oscillometric Device for Monitoring Ambulatory Blood Pressure: Laboratory and Clinical Evaluations

Abstract

A new portable device for the indirect measurement of ambulatory blood pressure in the finger was successfully applied to normotensive and hypertensive subjects in and outside a ward setting. The device uses the volume-oscillometric technique and, equipped with a microprocessor, permits long-term ambulatory monitoring of indirect systolic and mean blood pressure at desired intervals (once every 1–10 min). Systolic and mean blood pressures obtained by this method were well correlated with those measured by the direct (Oxford) and arm-cuff methods. Systolic and diastolic blood pressure obtained by the volume-oscillometric device were almost identical with those recorded by an arm-cuff. Systolic blood pressure obtained by the volume oscillometric method was, however, significantly lower than that measured by the direct raethod. The new device has also been used to measure blood pressure during treadmill exercise and ice-water immersion. Mean values of blood pressure and the SD of these averaged for 24 hours, or for every hour, were reproducible when the measurements were repeated under the same condition. The present device is portable, causes minimal noise, can detect rapid change in blood pressure and causes less discomfort when compared to the conventional arm-cuff method. Regular measurements can be made with minimal sleep disturbance. This fully automatic volume-oscillometric device allows reliable 24-hour monitoring of ambulatory blood pressure not only in but also outside a ward setting, and as such is useful for studies of hypertension.

Key Words:

• ambulatory blood pressure monitoring
• volume-oscillometric method
• arm-cuff method
• direct method
• hypertension
• blood pressure variability