New system offers more accurate blood pressure measurements
By Ben Coxworth
February 23, 2011
Traditionally, blood pressure is measured using the familiar inflatable cuff and stethoscope on the upper arm. While this method has sufficed for over a century, some people maintain that it is inaccurate – blood pressure in the arm is reportedly higher than at the heart, and not by a consistent, easily compensated-for amount. Because high blood pressure can cause the most damage at the heart and in the nearby brain, it would make sense to monitor it at the heart, too. That's just what a new device designed at the University of Leicester does ... in a roundabout way.
The Leicester device is called the CASPro, as it measures central aortic systolic pressure, or CASP. The patient wears a conventional inflatable cuff on their upper arm, that measures their blood pressure at that location, and a wireless sensor on their wrist, that measures their pulse wave. Software in the tablet-like control unit then takes that data, and uses a mathematical modeling procedure to eliminate the amplified portion of the wave, determining the true lower blood pressure at the aorta.
CASPro is said to be easier to use and more comfortable than traditional methods, although it takes a few minutes longer. Before it can come into common use, the researchers need to better define the normal values for central aortic pressures, and what they mean for clinical outcomes.
"It is not going to replace what we do overnight but it is a big advance," said Leicester's Prof. Bryan Williams. "Further work will define whether such measurements are preferred for everybody or whether there is a more defined role in selective cases to better decide who needs treatment and who doesn't and whether the treatment is working optimally."
The research has recently been published in the Journal of the American College of Cardiology.