New Blood Pressure Monitoring Device Developed to Make it More Accurate

Amid recent reports of blood pressure devices not being accurate, a team of doctors from Jerusalem have come up with a new oscillometry device to measure it accurately.

The device, developed by a group of researchers from the Jerusalem College of Technology and the Shaare Zedek Medical Center in Israel, uses photoplethysmography technique, a pressure cuff wrapped around the arm and an electro-optic probe on the finger.

The finger probe acts as pulse oximeter that emits light into the finger and the detector measures the light transmitted through the finger. “The transmitted light exhibits pulses at the heart rate, due to cardiac-induced blood volume changes in the finger tissue,” explained lead author Meir Nitzen.

When the cuff pressure increases beyond the systolic blood pressure these pulses disappear and vice versa, enabling the correct determination of systolic blood pressure. Since the device does not eliminate the “white coat syndrome”, wherein a patient’s fear or anxiety during the test increases the measurement, they propose to avoid the effect advising the device to be used at home and in a relaxed atmosphere.

Since the old oscillometry-based automatic meters offer a low level of accuracy than the manual auscultatory technique, they advise the use of an electro-optic probe on the finger as well. The error inaccuracy levels of 10 to 15 mmHg seen in available in automatic oscillometric technique is attributed to air-pressure wave measurements in these devices.

A systolic blood pressure (BP) that measures 140 mmHg or higher and a diastolic measurement of 90 mmHG or higher (140/90 mmHg) is considered high.

The research findings have been presented at the “Cardiovascular Aging: New Frontiers and Old Friends conference” in Westminster, Colo.

However, past studies have shown that blood pressure monitoring may help patients with hypertension and stroke but did not improve blood pressure control for patients who had normal blood pressure at the start.

A study published in CMAJ (Canadian Medical Association Journal) said, “Home monitoring depended on patients taking their blood pressure, recognizing if readings were consistently over target, understanding the need for intensification of treatment, visiting their physician for review and appropriate management by their physician.”

Sally Kerry, Centre for Primary Care and Public Health, Queen Mary, University of London, UK, said good blood pressure control can significantly reduce the risk of recurrent stroke in the estimated 15 million people who have strokes each year worldwide.

“Home monitoring depended on patients taking their blood pressure, recognizing if readings were consistently over target, understanding the need for intensification of treatment, visiting their physician for review and appropriate management by their physician,” wrote the authors.

The study involved 381 participants aged 30 (mean 72) years from three stroke units in London, using home monitoring from March 2007 to August 2009. A total of 23% of participants were from ethnic minorities, and 45% had some disability due to stroke, including many frail, elderly patients.