Cuffless blood pressure estimation using only a smartphone

Abstract

Cuffless blood pressure (BP) measurement is an all-inclusive term for a method that aims to measure BP without using a cuff. Recent cuffless technology has made it possible to estimate BP with reasonable accuracy. However, mainstream methods require an electrocardiogram and photoplethysmogram measurements, and frequent calibration procedures using a cuff sphygmomanometer. We therefore developed a far simpler cuffless method, using only heart rate (HR) and modified normalized pulse volume (mNPV) that can be measured using a smartphone, based on the knowledge that ln BP = ln cardiac output (CO) + ln total peripheral resistance (TPR), where CO and TPR are correlated with HR and mNPV, respectively. Here, we show that mean arterial pressure (MAP), systolic BP (SBP), and diastolic BP (DBP) could be estimated using the exponential transformation of linear polynomial equation, (a × ln HR) + (b × ln mNPV) + constant, using only a smartphone, with an accuracy of R > 0.70. This implies that our cuffless method could convert a large number of smartphones or smart watches into simplified sphygmomanometers.

Wearable Sensing and Telehealth Technology with Potential Applications in the Coronavirus Pandemic

“…Apart from the PTT-based BP estimation method, some other physiological features have been investigated to indicate BP changes, including PPG intensity ratio [109], Womersley number [110], radial electrical bioimpedance [111], modified normalized pulse volume [112], acceleration plethysmography (APG) [113], and diameter of a pulsating blood vessel [114]. Additionally, machine learning has also been applied to BP estimation to develop regression models between signal features and BP, and demonstrating promising estimation accuracy [115][116][117][118][119][120].…”

“…Cuffless continuous monitoring approaches can be implemented into wearable and unobtrusive devices, such as watch [121], glasses [122,123], a wrist/armband [99,124,125], shirt [126], sleeping cushion [127], chair [128], smartphone [112], camera and flexible patch [114,129,130] as summarized in Fig. 8.…”

“…Such mobile imaging technologies can be used in mobile emergency units or improvised hospitals. As an example, a CT mobile platform that is self-contained with automated scanning workflow has been reported for remote diagnosis of patients in temporary mobile cabin hospitals and at the Fangcang Shelter Hospital [112,182]. To minimize contact, streamline patient throughput, reduce radiation exposure, and improve imaging quality, one of the principal aspects for tele-imaging is automatic patient positioning and anatomical localization.…”

Differential Effect of Two Mental Stress Tasks on Arterial Stiffness

“…During the MA task, participants were instructed to subtract 13 sequentially from 5,000 (to get 4,987, 4,974, 4,961, …) as quickly and accurately as possible (Matsumura, Rolfe, Toda, & Yamakoshi, ; Matsumura & Yamakoshi, ). They were given Yes or No voice feedback for every answer, and, in case of a wrong answer, continued subtractions after giving correct answers accompanying No voice feedback.…”

Dempster–Shafer Fusion Based on a Deep Boltzmann Machine for Blood Pressure Estimation

“…Recently, Simjanoska et al [6] studied a method using electrocardiogram (ECG) signals for BP estimation. A simple cuffless technique based on ECG using machine learning was developed by Matsumura et al [7].…”