Wearable Non-invasive Continuous Cuff-

less Blood Pressure Measurement

Ghalib Janjua

ESR 8

Supervised by Jim McLaughlin

This project has received funding from the European Union's Horizon 2020 research and innovation programme under the

Marie Sklodowska-Curie grant agreement No 676201

Hypertension Hypertension is biggest challenge worldwide in public health [1].

Hypertension Mortality: according to WHO, death toll due to

hypertension is 9.4 million every year [2], which is 55.3% of total

death due to cardiovascular disease (CVD). CVD causes one third of

total deaths around the globe. Hypertension Morbidity: there is

dramatic increase of 600 Million to 1 Billion patients suffering from

hypertension since 1980 to 2008; almost 40% of adults of age 25 and

above had been diagnosed with hypertension worldwide, in 2008.

The Joint National Committee 7th report (JNC 7) [3] stated that

unawareness of hypertension is over 30% in hypertensive patients,

which more complicate the public-Health system worldwide [2].

Cancer 21%

Diabetic 6%

Cardiovascular Dieases

51%

Respiratory Dieases

22%

Chart Title

In Practice System Blood pressure (BP) measurement is performed either invasively by

an intra-arterial catheter (continuous and accurate but has increased

risk), noninvasively by cuff sphygmomanometer (safe but less

reliable and very infrequent), on finger by pressurized cuff

(continuous monitoring system but non wearable and very expansive)

and arterial tonometry requires skill operator to measure it.

State of the Art Over the past decade, pulse transit time methodology have

shown promising result to calculate BP. Evolution of BP &

PTT measurement devices are shown in Fig 3 below, but to

date, there is no standard independent wearable cuff-less

non-invasive continuous BP measurement device in the

market.

Research Methodology Pulse Transit Time (PTT) and Pulse Wave Velocity (PWV)

have been shown to co-relate with arterial BP and have

been reported to be suitable for indirect BP measurement

[5]. Arterial PTT can be estimated from ECG and PPG

waveforms. A method for continuous BP monitoring not

requiring a cuff and only requires ECG electrodes and a

PPG Sensor is the non-invasive protocol involving PTT. To

date, r-squared correlations are low, much work is required

on improving signal quality, signal processing, and optimum

capture of the key signal parameters which will be the

focus for this research. Currently, we are comparing PTT

measurement using three methods: by measuring time

difference (Delta T) between: Firstly, ECG R and PPG 1st

derivative, Secondly, Inline PVD signal peaks and thirdly,

Inline PPG signals peaks on Brachial Artery, as shown below.

[1] Patricia M Kearney, Megan Whelton, Kristi Reynolds, Paul Muntner, Paul K Whelton, and J. He, “Global burden of hypertension-analysis of worldwide data” Lancet, vol. 365, pp. 217–223, 2005.

[2] W. H. Day, “World Health Day 2013, A Global Hypertension”, p. 9, 2013.

[3] A. V Chobanian, “The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. The JNC 7 Report,” JAMA, vol. 289, no. 19, p. 2560, 2003.

[4] Based on the Global Economic Burden of Non-communicable Diseases, Prepared by the World Economic Forum and the Harvard School of Public Health, 2011.

[5] G. Jeong, K. Yu, and N. Kim, “Continuous Blood Pressure Monitoring using Pulse Wave Transit Time,” Measurement, pp. 2–5, 2005.

Fig 1. Cost of Care by Diseases [4]

Fig 2. Cuff BP(Top left), CNAP System(top Right), Arterial line(lower left) & Tonometry(lower right)

Fig 3. VisiMobile(Top left), Scanadu (Top right) & ST+D by Intelesense (bottom )

Fig 4. PTT calculation using ECG & PPG signal (on left), inline PVD Sensor on Brachial artery (in middle)

& Inline PPG Sensor at wrist and index finger (on Right)