"Welcome, please scan your face here" - Feasibility and acceptability of vital sign measurement via smartphones in the Emergency Department (The FacED study)

Overcrowding and long waits have become the norm in Emergency Departments (ED) across the country. Some studies have shown that these extended waits have led to excess deaths.¹ Decreasing these waits, and ultimately improving the experience of patients has become a priority for the UK government and the National Health Service (NHS). 

One aspect the government is keen to explore is incorporating digital technologies into the healthcare system.² This has taken various guises, but it has not  previously explored the use of contactless vital sign monitoring in the ED triage setting. 

Vital sign monitoring is part of the foundation of good patient care, and it can be difficult to maintain a regular observation in an overcrowded waiting room and in an often understaffed ED. Finding a novel way to get around this problem may decrease the workload burden on staff whilst simultaneously identifying patients who may be clinically deteriorating. 

One potential solution is the use of smartphone cameras and web-based applications to scan patients faces to provide measurements. This technology utilises photoplethysmography (PPG), using the phones inbuilt infra-red camera to detect subtle changes in patient facial colour and translates this into a set of vital signs.³ 

The team at St George's Hospital Emergency Department Collaborative Research Group aim to explore patient and staff thoughts on incorporating this technology into the triage process. Studies have previously been undertaken using this technology in an outpatient setting,⁴ or for insurance companies,⁵ but never in an urgent or emergency care setting. 

Thanks to a grant from the Royal College of Emergency Medicine, the research group will undertake three simultaneous studies. These consist of a 1500 patient feasibility study focusing on using the technology, a 10,000 patient acceptability questionnaire focusing on patient's thoughts and feelings about smartphone utilisation as part of their care, and finally a staff survey looking at acceptability of this (and similar) technology in the ED. 

A closer look at the studies:

The 1500 patient feasibility study will focus on a convenience sample of ambulatory adult patients in our Emergency Department waiting room. The team of research nurses will approach prospective patients from triage. Once consented the patients will use their own smartphone to access the web-based PPG scanner. Vitals from this will be recorded against ones formed via the normal method. These patients will then complete an online questionnaire focusing on their experience with the technology, and perceptions about using this technology as part of their ED journey. The survey will also collect relevant demographic data and information about smartphone make/model/operating system. Finally, the nurses will record outcome data including length of stay and triage category. 

The 10,000 patient questionnaire will focus more on patient's thoughts about the incorporation of technology into their time in the Emergency Department, and explore more about how they see this to exist. It will again be a convenience sample of ambulatory adult ED patients recruited via posters and staff prompts in the primary site at St George's Hospital but also at a local minor injuries unit at Queen Mary's Hospital, Roehampton.  

Finally, the staff questionnaire will be sent to triage trained nursing and senior medical staff (~30 to 40 in total). It will be an online questionnaire focusing on staff perception about the technology and what their thoughts are on incorporating this (or similar technology) into the triage process in ED. 

The results will undergo statistical analysis by colleagues at City St George's University before being sent for publication. It is hoped that this feasibility study will lay the foundation for larger studies looking to find sustainable ways to evolve the triage process in terms of efficiency but also patient safety.

Keep an eye out for when we post the results! If anyone is interested and wants to hear more about the study please get in contact with myself or email ed.research@stgeorges.nhs.uk 

References:

1. O’Dowd A. Excess deaths: Data show rise in number linked to long emergency waits. BMJ [Internet]. 2025 May 15 [cited 2025 Jun 20];389:r1008–8. Available from: https://www.bmj.com/content/389/bmj.r1008

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