Cardiovascular disease is the major cause of deaths worldwide, causing 31% of all global deaths in 2015. One major risk for cardiovascular disease is high blood pressure, but many individuals with hypertension are unaware of their condition and do not have their blood pressure under control. The most common method of measuring blood pressure is using inflatable cuff, which is oftentimes inconvenient and inaccessible. A more accessible way of monitoring blood pressure could help individuals become aware of hypertension and improve hypertension control. Accordingly, a study from Michigan State University in the U.S. and recently published in Science Translational Medicine demonstrated that smartphones could be adapted to be portable blood pressure monitors.
3D-Printed Case Allows Blood Pressure Measurements
The authors of this study present new technology that allows cuff-less blood pressure measurements using a smartphone. Instead of using a cuff that presses down onto an artery to measure blood pressure, this group devised a finger-pressing method that would achieve a similar goal. They designed a 3D-printed case, which has special sensors and can attach to the back of a smartphone. The device requires the individual to press their finger down onto a sensor with progressively more force, guided by visual feedback from the phone. The sensor also shines a light on the finger to detect blood volume variations or oscillations and ultimately determine blood pressure. The study had participants test the usability and accuracy of a prototype of this device to ensure feasibility.
Similar Results Compared to FDA-Approved Finger Cuffs
There were 30 participants in the study that tested the device and measurements were taken to confirm accuracy. Firstly, the authors noted that around 90% of participants, after one or two tries, could effectively apply finger pressure on the device according to visual feedback provided by the application. There were some instances of computation failure, but that could easily be fixed with multiple attempts. Moreover, they compared the results to a U.S. FDA-approved finger cuff device and saw very similar results in terms of the readout and variations in the measurement. The accuracy of these two devices were compared the standard arm cuff device, and there some differences in the measurements. However, the authors argued that due to the ease of use and availability of their device, consistent and numerous readings would improve the accuracy of their device overall.
The results of this study indicate that smartphone-based blood pressure monitoring can be easily used. The study also shows similar accuracy between a U.S. FDA-approved finger cuff device, demonstrating the reliability of this new device. Furthermore, the widespread availability and use of smartphones allow for the distribution of this technology worldwide, and especially in developing countries where there is limited access to cuff-based devices. The authors hope that the use of this device will translate to more awareness of hypertension and more motivation to actively control this condition.
Written by Branson Chen, BHSc
Reference: Chandrasekhar A, Kim C-S, Naji M, Natarajan K, Hahn J-O, Mukkamala R. Smartphone-based blood pressure monitoring via the oscillometric finger-pressing method. Sci Transl Med. 2018 Mar 7;10(431).