Blood Pressure Monitoring at Your Fingertips: Super Low-Cost Smartphone clip

A team of engineers from the University of California San Diego (UCSD) has developed an affordable and user-friendly solution for blood pressure monitoring. The engineers have created a low-cost clip that can be attached to a smartphone, enabling blood pressure measurement through the phone's camera and flash.

This innovative clip, which costs less than a dollar to produce and does not require calibration, offers an accessible alternative to traditional blood pressure monitoring methods. The technology has already shown promising results in early tests, proving its effectiveness compared to blood pressure cuffs. Billion Labs Inc., a company set to commercialize the product, plans to make it widely available to the public.

The clip, designed by UCSD engineers, can be easily attached to a smartphone, and it utilizes the phone's camera and flash in conjunction with a custom app to measure blood pressure at the user's fingertip. Currently, the clip costs approximately 80 cents to manufacture, but the researchers anticipate that the cost could be further reduced to as low as 10 cents per unit with large-scale production.

The research findings highlighting this groundbreaking technology were recently published in the journal Scientific Reports on May 29. The engineers believe that this innovation has the potential to revolutionize blood pressure monitoring by making it affordable, convenient, and accessible to individuals in resource-poor communities. The elderly and pregnant women, for example, could greatly benefit from this advancement in managing hypertension and other related conditions.

Lead author of the study, Yinan (Tom) Xuan, a Ph.D. student in electrical and computer engineering at UC San Diego, stated, "We've created an inexpensive solution to lower the barrier to blood pressure monitoring." Edward Wang, the senior author of the study, a professor of electrical and computer engineering at UC San Diego, and the director of the Digital Health Lab, added, "Because of their low cost, these clips could be handed out to anyone who needs them but cannot go to a clinic regularly." He further compared the distribution of these clips to the practice of receiving a pack of floss and toothbrush during a dental visit.

One notable advantage of the clip is that it eliminates the need for calibration with a cuff. Wang explained that this feature distinguishes their device from other cuffless blood pressure monitoring systems being developed for smartwatches and smartphones. These other systems require obtaining a separate set of measurements with a cuff to fine-tune their models. In contrast, the UCSD clip functions independently and provides accurate readings without calibration.

The clip itself is a 3D-printed plastic attachment that fits over a smartphone's camera and flash. Its optical design resembles that of a pinhole camera. When pressure is applied to the clip, the smartphone's flash illuminates the fingertip, and the resulting light is projected through a pinhole-sized channel to the camera, appearing as a red circle in the image. The clip incorporates a spring mechanism that allows users to apply different levels of force. The size of the red circle captured by the camera corresponds to the pressure applied by the fingertip, while the brightness of the circle indicates the volume of blood flowing in and out of the finger. Through an algorithm, the smartphone app converts these measurements into systolic and diastolic blood pressure readings.

To validate the effectiveness of the clip, the researchers conducted tests on 24 volunteers at the UC San Diego Medical Center. The results obtained from the clip were comparable to those obtained using a traditional blood pressure cuff. Alison Moore, a co-author of the study and chief of the Division of Geriatrics in the Department of Medicine at UC San Diego School of Medicine, expressed enthusiasm for this innovation, stating, "Using a standard blood pressure cuff can be awkward to put on correctly, and this solution has the potential to make it easier for older adults to self-monitor blood pressure."

While the clip has currently been tested on a single smartphone model, the researchers are confident that the clip's design can be adapted to work with other phone models as well. Yinan (Tom) Xuan, the study's lead author, mentioned that the clip's current design is theoretically compatible with various phone models, which would further expand its reach and accessibility.

The development of this low-cost clip and smartphone app for blood pressure monitoring represents a significant step forward in healthcare technology. By providing an affordable and easy-to-use solution, it has the potential to improve the lives of individuals who require regular blood pressure monitoring, particularly those in underserved communities and those who face barriers to accessing medical care. With the upcoming commercialization efforts by Billion Labs Inc., the clip is expected to become widely available to the public, empowering individuals to monitor their blood pressure conveniently and proactively.

The breakthrough achieved by the engineers at UCSD highlights the transformative power of technological innovation in healthcare. By leveraging the capabilities of smartphones and utilizing cost-effective materials, they have created a solution that has the potential to revolutionize the field of blood pressure monitoring. With further advancements and refinements, this technology could pave the way for similar developments in other areas of healthcare, making essential medical monitoring more accessible and affordable to people worldwide.