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


In this first study reporting the use of a real-time remote monitoring device for outpatient surgery, the Smart Angel™ enabled patients to record > 60% of the required information. However, many technological failures were reported. These findings imply that real-time remote monitoring technology is feasible for outpatient surgery but still requires improvement, especially regarding connection to the central computer.

To our knowledge, the use of remote monitors for MAP, HR and SpO2 has never been evaluated in ambulatory surgery. Similar systems have been extensively tested and evaluated in cardiology, oncology and diabetes.[17–20] In these cases, they have contributed to optimising remote medical monitoring and adapting treatments.[20] In this sense, after ambulatory surgery, these monitors may be effective in detecting early postoperative adverse events in patients at home.

Out of 29 patients evaluated, 80% were able to visualize the values for MAP, HR and SpO2 on their monitors and could copy these values onto paper (Table 1). The originality of our study was to show that digital technology facilitates transmission of these data to a centre without any action from the patient (no recopying of data by the patient onto a smartphone or a web server). In this digital setting, the 62% data transmission rate by the SmartAngel™ device was disappointing. Apart from the fact that patients forgot to note their measurements, several technological reasons explain this lack of data feedback and our study has allowed us to better understand them.

  1. An ineffective 4G environment at the patient's home. The 4G defect altered data transmission between the tablet and the central web service in 3% of patients corresponding to the rates reported in teletransmission studies.[16]

  2. Malfunctioning of the SmartAngel™ program installed on the tablet. Computer program patches were required to stabilize the program for 3 patients as it had failed to activate the remote MAP monitors (confidential data provided upon request).

  3. Insufficient battery charge for discontinuous but frequent use of the monitors. This is crucial for patients and they must be informed of the need to charge up the batteries regularly.

For the 62% of patients for whom all the data were correctly transmitted (Figure 2b), the Smart Angel™ tool represented a truly original monitoring dashboard which had never been proposed before, providing questionnaire data combined with physiological data. The number of patients included was insufficient to demonstrate the interest of the system as an aid to follow-up, but the data presented are a step forwards in ambulatory follow-up and would be useful for a multicentric study.

Our study shows a decrease in the data collected on paper on Days 4 and 5 (Figure 2a). This may suggest that optimal monitoring should be begun from the evening of Day 0 to the evening of Day 3 (with systematic measurements morning, noon and evening) and at least one measurement per day from Day 3 onwards to optimize patient adherence. Interestingly, the peak of postoperative complications classically occured between Day 1 and Day 3.[7]

In this study, the patient was monitored over the 5-day postoperative period without any manipulation from the expert centre. The high SUS score suggests good acceptance and usability by the patients.[21] Indeed, they willingly accepted the small-sized connected objects and the fact that there was a bag to transport all the objects home probably facilitated acceptance of the device. Several questions remains: the optimal time for instructing patients, the necessity to repeat instructions and the possibility of access to an on-line manual to help patient at home.

Limitations of the Study

The main limitations of the study are the monocentric design and the small number of patients included. However, the main objective of this first pilot study was to validate the concept and identify technological errors before carrying out a multicentric study. From this viewpoint, the present study provided the opportunity to report all potential issues with this technology, essentially, connection to the central computer, whatever the cause. Furthermore, we did not analyse whether age or intellectual level could influence the proper functioning of the system. Younger patients, who seem more likely to be tech-savvy, would have been able to troubleshoot issues with their iPads and bluetooth connections. However, it is the older patients who are more likely to have the kinds of operations where such remote real-time monitoring of vital signs and patient condition could be important or even life-saving. As these patients are also the ones who struggle the most with new technology, this would limit usability. Therefore this aspect needs to be evaluated.