That method is probably older than you think. The first measurement of blood pressure was made in 1896 by squeezing the flesh around an artery. This method remains pretty much the most common way to measure blood pressure 124 years later, something that seems remarkably anachronistic in the digital age.
Of course, there are many ways of tracking changes in blood pressure and a plethora of wearable and non-wearable devices now on the market that do it. These devices are not cuff-less, however. They require the input of cuff-measured blood pressure and then monitor changes over the next few days. Then a new calibration is necessary using a cuff again. That doesn’t help the one billion plus people in the world at risk of dying from hypertension because they do not know they have it – once they have used a cuff to calibrate a device, they will know that they’re ill and don’t need the device. Other wearable devices are simply not medically accurate, which is even worse.
The challenge
What is needed, then, is a device that can quickly and accurately measure blood pressure in a home environment; is not cuff-based and does not require calibration from a formal test by a medical professional. Ideally, the device should be small enough and cheap enough to be built into every mobile phone.
The idea we have in mind will be revealed in the February 2020 issue of Eureka! Until then, see what you can come up with. Submit your ideas by leaving a comment on the Coffee Time Challenge section of the Eureka! website or by emailing the editor: paul.fanning@markallengroup.com
The solution
The solution to last month’s Coffee Time Challenge of how to design a blood pressure measuring device that is accurate, can be used at home and doesn’t require calibration by the traditional cuff-based device comes in the form of the V-Sensor from Leman Micro Devices (LMD).
LMD’s unique and patented solution uses the same principle as a cuff but acts on the fingertip. Its V-Sensor module instructs the user to press harder or softer to occlude the arteries of the tip of the index finger and detects it optically using a pulse oximeter. The V-Sensor is small enough and cheap enough to be built into every mobile phone and is fully engineered for production in smartphone quantities. Its accuracy for both Systolic and Diastolic blood pressure measurement complies with international standard ISO 81060-2: mean error < 5 mmHg and standard deviation < 8 mmHg. With no personal calibration, V-Sensor has demonstrated accuracy for systolic blood pressure (SBP) of mean error -0.4 mmHg, standard deviation 7.2 mmHg, and for diastolic blood pressure (DBP) of mean error -0.2 mmHg, standard deviation 6.0 mmHg, both well within the deviation allowed by the ISO standard.
