Feasibility of Remote Digital Monitoring Using Wireless Bluetooth Monitors, the Smart Angel™ App and an Original Web Platform for Patients Following Outpatient Surgery

A Prospective Observational Pilot Study

Thierry Chevallier; Gautier Buzancais; Bob-Valéry Occean; Pierre Rataboul; Christophe Boisson; Natacha Simon; Ariane Lannelongue; Noémie Chaniaud; Yann Gricourt; Jean-Yves Lefrant; Philippe Cuvillon


BMC Anesthesiol. 2020;20(259) 

In This Article


Ambulatory procedures have become a standard of care for all types of surgery, including more and more invasive or complex surgery (abdominal, gynaecological coelioscopic or robotic approaches, hip or knee arthroplasties etc.).[1,2] However, safety and adverse events with these procedures remain debated in the literature with regard to potential medical or surgical complications at home.[3–7] Recently, digital technologies have been proposed to remotely monitor outpatients at home and in hospital in order to detect patients with early signs of disease progression or deterioration.[8–10]

In ambulatory surgery, patients would normally inform institutions about their perceived condition at home through a text message survey (mobile phone application) or e-mail.[11] Previous studies have described the effect of patients reporting their postoperative recovery after day surgery.[11] Web-based systems collecting alerts, managing and analysing patient-reported outcomes have been added to provide more valuable feedback.[12] The main limitation of these systems is the absence of remote data on physical parameters such as heart or respiratory rates, oxygen saturation and blood pressure. This appears to be a major limitation although several studies have demonstrated that remote monitoring of physiological parameters can significantly reduce morbidity or mortality over the perioperative period.[13,14]

Using a wireless Bluetooth monitor, heart and respiratory rate (HR, RR), mean arterial blood pressure (MAP) or oxygen saturation (SpO2) can be recorded via a tablet or smartphone that transmits data from remote monitoring to a web service (central server) (Figure 1a). Using algorithms and a dashboard, the centre can automatically filter data so that nurses or physicians can focus on patients with early warning signs. Smart Angel™ (Evolucare, France) is a new digital technology for remotely monitoring patients at home using both text messages (self-report questionnaires) and wireless Bluetooth monitors (SpO2, HR and MAP). The patient can thus evaluate pain relief on a numerical rating scale (NRS), comfort and adverse events (nausea, vomiting) via self-report questionnaires. The Smart Angel system is initialized at the ambulatory centre before discharge (login) and continued at home by patients using a specific application on a dedicated tablet used to record their self-assessment and start the wireless Bluetooth monitor. Remote data are collected three times a day (Figure 1a, b, c). This study represents the first stage in testing the device on patients in real-life situations to evaluate its technological capacities and usability by the patient, before applying and testing this technology in current care.

Figure 1.

(All illustrations and images provided by the author and never published elsewhere): a: System overview: Data are transmitted from the patient's home to a central server, using a dedicated web-based software package. The data are subsequently processed and presented to health care workers at the hospital. b: Range of MAP, SpO2, HR for the remote monitoring. c: Overview of app and monitor: remote wireless monitoring (a), patient with monitors (b) and tablet screen (c) (Illustration provided by the author and never published elsewhere). a: Monitor, tablet and bag. 1: Heart rate and SpO2 monitor. 2: MAP monitor. 3: Cables for USB connection or battery. 4: Tablet. 5: Dedicated briefcase. b: Connected monitor positioned by the patients themselves and tablet used by patients. c: App screen and questionnaires (showing pain on the NRS)

Using the Smart Angel™ app (Evolucare, France), we hypothesized that this system would be able to record and transmit seven variables (pain, quality of recovery, nausea, vomiting, HR, MAP and SpO2) for the first 5 days following ambulatory surgery. Before transmission to the website, these data were also reported by the patient on a paper form.

The primary outcome was the proportion of clinical variables (self-monitored physiological data + questionnaire scores) transmitted correctly to the hospital via the IT system. This proportion was also compared with the number of time-matched measurements simultaneously recorded by the patients on the paper form as instructed. Causes of app errors and usability were also recorded.