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

The FacED study is a multi-part feasibility trial held at St George's Hospital, a London based Major Trauma Centre. Its focus is on novel vital sign recording methods and exploring patient and staff thoughts on digital health. The protocol paper has been published as preprint.
"Welcome, please scan your face here" - Feasibility and acceptability of vital sign measurement via smartphones in the Emergency Department (The FacED study)
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medRxiv
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Feasibility and acceptability of smartphone technology for patients to self-record vital signs in the emergency department (The FacED Study): a study protocol

Introduction Overcrowding and nursing workload are two major issues within urgent and emergency care (UEC) settings and contribute to incompletion or omission of patient vital signs in initial assessment and patient monitoring. This could potentially have a negative impact on patient health outcomes. Software enabling contactless monitoring of patient vital signs using camera photoplethysmography (PPG) has been developed, where patients can measure their own vital signs by recording a 30-second video on their smartphone on the software platform. This software could prove beneficial within UEC settings to help to reduce nursing workload and allow prioritisation of higher order tasks and could help to reduce long wait times for initial triage assessment. Before any such software can be implemented, it is first necessary to assess the feasibility and acceptability of the software in situ among patients in UEC settings, as well as the acceptability among staff working in triage. Methods and Analysis To assess feasibility of the software, 1500 patients attending three UEC services at St George’s University Hospitals NHS Foundation Trust will be invited to take part in a study where vital signs will be measured manually and using smartphone PPG software. Feasibility will be measured using a survey after data collection. Staff acceptability will be measured using a short survey among 20-40 staff. Patient acceptability of digital health technology in UEC settings will be measured by a questionnaire among 10,000 patients. Ethics and Dissemination This research has been ethically approved by the NHS London – Surrey Research Ethics Committee and the Human Research Authority (reference: 25/PR/0222; IRAS project ID: 346745). Informed consent will be obtained prior to the participant undergoing any activities that are specifically for the purposes of the study. Findings from this research will be disseminated via journals and conferences and used to inform further research in the field. Strengths and Limitations ### Competing Interest Statement I have read the journal’s policy and the authors of this manuscript have the following competing interests: Dr Gabriel Jones: Unpaid role as medical officer at streamwave.ai. This may translate into shares or a paid position in the future. ### Funding Statement Yes ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Not Applicable The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study obtained UK NHS ethical approval by the London – Surrey Research Ethics Committee (REC number 25/PR/0222) on 4th April 2025. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Not Applicable I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Not Applicable I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Not Applicable No datasets were generated or analysed during the current study. All relevant data from this study will be made available upon study completion.

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

2. NHS England. Our Strategy to digitise, Connect and Transform [Internet]. NHS Transformation Directorate. NHS England; 2024. Available from: https://transform.england.nhs.uk/digitise-connect-transform/our-strategy-to-digitise-connect-and-transform/ 
3. Verkruysse W, Svaasand LO, Nelson JS. Remote plethysmographic imaging using ambient light. Optics Express. 2008 Dec 12;16(26):21434.

4. Bautista M, Cave D, Downey C, Bentham JR, Jayne D. Clinical applications of contactless photoplethysmography for vital signs monitoring in pediatrics: A systematic review and meta-analysis. Journal of Clinical and Translational Science. 2023;7(1):e144. doi:10.1017/cts.2023.557

5.  Rinaldi Anwar Buyung, Alhadi Bustamam, Muhammad. Integrating Remote Photoplethysmography and Machine Learning on Multimodal Dataset for Noninvasive Heart Rate Monitoring. Sensors [Internet]. 2024 Nov 26 [cited 2025 Apr 28];24(23):7537–7. Available from: https://www.mdpi.com/1424-8220/24/23/7537 

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