Fully Automated Remote Digital Blood Pressure Measurement From Repurposed Radio Telescope Radar Technology

Elevated blood pressure (BP) is the biggest risk factor for cardiovascular disease1,2. Several BP devices exist, but still missing is a cost-effective contactless system.

Radar BP systems to date only work at short range3 on single subjects4 and suffer from non-cardiac motion confounding5,6.

We partnered with astrophysicists and repurposed their radar systems and image-processing algorithms into a compact wall-mounted module with an optical camera that can derive synchronous ballistocardiograms (BCG)7 and distal pulse transit times8 (PTT) to independently measure systolic and diastolic BP from patients up to 3 metres away through clothing.

This Tier C radar-BP prototype is at Technology Readiness Level 3 and pilot data from 20 controls and 20 hypertensive patients demonstrates feasibility and validity with auscultatory BP measurements.

It was co-created with patients attending hypertension clinics, National Survey of Health and Development (NSHD) participants, nurses, physiologists and cardiologists. An educational seminar on remote digital phenotyping was held in 2022. We identify 4 unmet clinical needs: 1. Measuring cuff-based BP on wards consumes nursing staff time (~5 minutes per patient9 or ~1.5 hours per 12-hour shift).

Radar-BP on wards would take 30 seconds parsing results into the electronic health record without errors. With an estimated shortage of 40,000 nurses in the NHS10, developing tools to reduce their workload is imperative. It also measures heart rate, respiratory rate and body temperature. 2.

Remote BP will reduce cross transmission of infections caused by the reuse of cuffs and it is more comfortable for patients.

It permits unobserved BP, addressing the problem of white coat hypertension11 avoiding needless investigations and therapy. 3.

It also outputs other clinically useful biomarkers: aortic pulse wave velocity (PWV) and BCGs in a high-throughput way, without bulky equipment12-15. 4.

Cuffed-BP is inaccurate during exercise16 but our motion tracking algorithms can deal with this permitting exercise-BP measurement.