Existing and commonly used automatic blood pressure meters suffer from inaccuracies. An old fashioned auscultatory blood pressure test can avoid inaccurate results, but it has to be performed by a medical professional.
Now researchers at the Jerusalem College of Technology in Israel have developed a new method that may be more accurate than common oscillometric automatic blood pressure cuffs at measuring the systolic blood pressure.
The method uses photoplethysmography, which is an optical way of detecting the changes in blood volume within tissue, to work in conjunction with a conventional upper arm cuff. The patient simply slips on what look like pulse oximeters onto both of the index fingers, and the inflatable cuff is wrapped around the upper arm as usual. The cuff is inflated to a high pressure and then let go to deflate as is done typically. But, instead of using cuff pressure oscillations to estimate the systolic blood pressure, the new system instead watches how blood saturates the tissue within the fingers as the pressure in the cuff changes. Since one of the arms has the cuff and the other doesn’t, the system compares the saturation between the left and right side. As the pressure goes up above the systolic blood pressure, the detected pulse disappears and returns when the cuff pressure drops below the systolic blood pressure.
The technology was just presented this past weekend at the Cardiovascular Aging: New Frontiers and Old Friends conference in Westminster, Colorado.