Session P34.1

A New Blood Pressure Measurement Using Dual-Cuffs

TK Kim*, YJ Chee, JS Lee, SW Nam, IY Kim

Hanyang University
Seoul, Korea

In the conventional oscillometric method, when cuff pressure is greater than systolic pressure, it is impossible to completely occlude the brachial artery and stop arterial pulsation of the cuff even if the central part of the cuff blocks the brachial artery. Since the lateral part of the cuff has lower pressure than the center and takes arterial pulsation, it is not easy determining systolic pressure. When the cuff pressure is decreased below diastolic pressure, the interference of the arterial pulsation makes judgment of diastolic pressure hard.
For this reason, the estimation method is used to get systolic and diastolic pressure. The estimation process starts with measuring mean arterial pressure in which the highest pulse is shown. After taking linear regression analysis of the pulse heights from the mean pressure to higher and to lower, it can be considered that the systolic pressure is the point where the pulse height is 40 percent of the mean pressure pulse and diastolic pressure is the point where the pulse height is 60 percent of it. Therefore, the conventional oscillometric method has inaccurate blood pressure.
To solve this problem mentioned above, we added one more blood pressure cuff. Each cuff has an independent pump, valve and pressure sensor so that they can be handled separately. We placed a cuff on the upper arm(proximal) and another cuff on the forearm(distal) in order to occlude the region between the proximal and distal cuff. We inflated both cuffs to occlude the brachial artery above systolic pressure and deflated them by 2mmHg/sec. During deflation, there is no pulse if the cuff pressure is greater than systolic pressure and it appears when the cuff pressure is dropped as high as systolic pressure. Similarly, if the cuff pressure is in between systolic and diastolic pressure, the pulse height measured on proximal is much higher than on distal. When the cuff pressure is decreased below diastolic pressure level, the pulse size measured on both cuffs is almost the same.
Our experiments shows that it is possible to measure blood pressure using dual-cuff.

(Abstract Control Number: 240)