Investigators Discover Potential Flaws in Blood Pressure Monitors Resulting in Misleading Readings

In a groundbreaking discovery, researchers at the University of Cambridge have shed light on a previously unidentified issue affecting the accuracy of cuff-based blood pressure monitors. The team, led by Anurag Agarwal, found that these monitors may underestimate systolic pressure, potentially missing up to 30% of high-blood-pressure cases.

The researchers built a simplified physical model that better replicates real artery behaviour, specifically tubes that flatten when deflated and fully close when the cuff is inflated. This new setup allowed them to isolate what happens below the cuff, revealing a mechanism that likely explains the inaccuracies.

Once blood flow is cut off, pressure downstream drops very low, keeping the artery closed for longer as the cuff deflates. This delay in the artery's reopening skews the measurement, leading to an underestimation of systolic pressure. The auscultatory method, the gold standard, overestimates diastolic pressure while underestimating systolic pressure.

The team's findings suggest that small protocol tweaks could already make a real difference in improving the accuracy of cuff-based blood pressure monitors. For instance, raising the arm before measurement could be a simple fix. If new devices are developed, they could incorporate factors like a person's age, BMI, or tissue traits to account for downstream pressure.

Kate Bassil, a co-author from Cambridge's Department of Engineering, emphasised the importance of the researchers' findings, stating that the discovery underscores the need for more accurate health checks to ensure proper diagnosis and management of high blood pressure cases.

While the search results do not provide information on how the researchers discovered the underestimation of systolic blood pressure, the team's work offers a promising step towards more accurate blood pressure readings and improved health outcomes.