Getting Blood Pressure Reading On A Smartphone?

Hypertension, or more commonly known as high blood pressure, is a growing worldwide problem. 45 percent of people in developed nations and 55 percent of people in developing nations have hypertension and do not even know it. Without appropriate control, hypertension can ultimately lead to heart disease, stroke and chronic kidney disease.

People with hypertension may not have any symptoms at all. So, the first step is to regularly check the blood pressure using sphygmomanometer or blood pressure monitor. The monitor can be manual or digital, battery-powered. The size of blood pressure monitor has been reduced since it was first made but they are still not small enough for users to carry around.

Good news is that, one can soon use a finger to touch a smartphone case to have instant and accurate blood pressure readings. Researchers from Michigan State University, University of Maryland, and Chonnam National University, Korea revealed in March 7, 2018 issue of ‘Science Translational Medicine’ that they developed a sensor that turns a smartphone into a device capable of checking a person’s blood pressure. Smartphones are very common nowadays, with 2.5-hour daily usage by average adult. The researcher argue that people are more apt to use a blood pressure monitor if it is embedded in a smartphone device.

According to researchers, they invented a special phone case, using high-tech 3-D printing, that contains an embedded optical sensor on top of a force sensor. The optical sensor is photoplethysmography (PPG), which is an inexpensive optical tool that measures blood volume changes, and the force sensor is a thin-filmed force transducer that measures applied pressure. PPG has already been used to measure heart rate. Some fitness trackers and even the Samsung Galaxy are equipped with PPG heart rate monitors.

When a user presses a finger onto the sensor, it provides measurable pressure on an artery in the finger in the same way that a blood pressure cuff squeezes an artery in the arm. That information is then fed to a smartphone app to convert the data to a real-time blood pressure reading, displayed on the phone. The usability of the device was tested on 30 people and found that about 90 percent could position their finger correctly and get consistent readings after only 1 or 2 attempts.

The new device could indeed help improve rates of blood pressure measurement, and lead to better blood pressure control so as to reduce the incidence of strokes and heart attacks. But as any other medical devices, more rigorous testing must be done before it can become standard and make available to the public for use.