Institutional Human Committee, consent and setting
In accordance with the current French law and Declaration of Helsinki, this study was approved by the institutional human investigation committee (Comité de Protection des Personnes, Sud Est V, Grenoble, France: 2017, A02790-53) and registered before starting on ClinicalTrials.gov (NCT03464721; March 8, 2018) [15]. This was a single-cohort, non-randomised, open, prospective trial conducted in a French University Hospital (Hôpital Carémeau, CHU Nîmes, France).
Written informed consent was obtained from all participants before inclusion.
Patients
Inclusion criteria:
All patients > 18 yrs (ASA 1–3), with the ability to understand French both orally and in writing, scheduled for intermediate or major ambulatory surgery were eligible and approached by the surgeon or the investigators. Surgeries were as follows: orthopaedic (shoulder repair, knee ligamentoplasty, hallux), abdominal (cholecystectomy, hernia) or gynaecological (hysterectomy, mastectomy).
Non-inclusion criteria were:
Age > 80 yrs, refusal to participate, ASA physical status > 3, emergency and inpatient surgery, psychiatric disorder.
Exclusion criteria:
If previously included, patients were excluded if they failed to use the remote technology.
The tablet and wireless Bluetooth monitor were presented by a nurse with the investigators and tested by patient before surgery. Their ability to perform remote monitoring involved switching the tablet on, using the login, completing the self-report questionnaire, adapting the monitor (for MAP, HR and SpO2) and starting the monitor using the app (see above). Connection to a 4G network at home was also required.
Intervention
After surgery and before discharge from the ambulatory centre, patients received standard information regarding postoperative recovery and all the necessary information concerning postoperative care at home (analgesia, changes of dressing …). They were instructed to contact a 24-h telephone helpline if they had any questions or concerns outside office hours. Participants were advised to contact the local hospital's emergency department should any emergency care be required.
The Smart Angel™ device was handed over to the patient who took the first measurements in the presence of the team to ensure that the system was properly working and understood. Functionalities of the Smart Angel™ system were carefully explained, and clear instructions for use were given by the research nurse and investigators, including how to move from question to question, how to enter an answer, and how to use the monitors. The Smart Angel™ system is a digital application using remote technology solutions and includes:
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1: a Web administration centre which collects, in real time, all the data transmitted by the remote technology for each patient. These remote data are exported via the web (4G collection) to a secure server (Adista™, France). All data are filtered and presented on a dashboard which summarizes all data so that the nurses and/or physicians can focus on any warning signs in the patient. Each patient is depicted on the dashboard in the form of a coloured square (green: in the normal range = no problem; yellow: in the limit of ranges = no sign of severity, red: warning signs = emergency action required). Using the dashboard, all investigators can (1) see all patients enrolled in the study, their assessment and their flags (2) see all the measurements for each patient on a specific new window (see Fig. 2).
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2: Remote physical parameters (HR, SpO2, MAP) with ranges (min, max) of normal values were defined before starting the study and included in the algorithm (Fig. 2). In the event of a specific pathology or treatment (e.g. patient on beta blocker treatment), ranges can be adapted to specific patient characteristics and/or treatment.
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3: The tablet and app. technology uses a tablet (Samsung™, Korea) integrating the software (Evolucarelabs™, France) that generates health questionnaires (scores of pain, quality of recovery, nausea, vomiting) which the patient answers (see above) and communicates with a connected monitor positioned by the patients themselves (discontinuous measurement for the patient: app assessing self-report questionnaires and wireless Bluetooth monitors to record physiological discontinuous measurement (heart rate, mean arterial blood pressure, blood oxygen saturation): wireless pulse oximeter (iHeathlabs™, USA) clipped to the finger and blood pressure monitor (iHeathlabs™, USA) at the wrist. When the patient is ready with the monitor, the software triggers the monitors and records the values. The patient can instantly see the tablet screen. Measurement data for each item is depicted with normal and abnormal value ranges. All these data are then exported via the web (4G collection) to a secure server (Adista™, France).
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Follow-up:
From the day of surgery to postoperative day 5, three times a day (morning, noon and evening), the application asks the patient to complete the health questionnaire and follow-up with the monitors. Seven measurements are performed for each assessment:
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Blood oxygen level (SpO2, %)
Mean arterial blood pressure (MAP, mmHg)
Pain score (scored on an 11-point numerical pain scale; 0: no pain-10: worst pain)
Quality recovery score (scored on an 11-point numerical pain rating scale; 0: bad condition, 10: excellent quality of postoperative recovery)
Outcomes and data collection
Surgical, anaesthetic and patient characteristics data were collected by the research nurse and investigators. Seven measurements (pain, quality of recovery, nausea, vomiting, HR, MAP, SpO2) were recorded by the app for all patients before their discharge from the centre and then three times a day from Day 1 to Day 5.
In addition, all the data measured by patient and monitor were noted on a conventional paper-basis and returned to the centre, along with the device, at end of the study.
On Day 5, the patient had to answer a 10-item questionnaire with five response options ranging from “Strongly agree” to “Strongly disagree” (total: 1-100 points) and the result was converted into a System Usability Scale (SUS) based on a Lickert scale.
Endpoints
The primary endpoint of this pilot study was the number of data recorded in the website using the app compared to the paper basis. The secondary objectives were to assess patient safety (medical rescue, readmission, and surgical complications) and patient use with this medical device.
Sample Size Calculation
As it is a pilot study, we predefined to test the system in 30 patients without sample size justification. Some published data showed that you need at least 12 patients for pilot studies [16]. The theoretical number of data collected by the app for 30 patients was 3360 = 30 patients x [7 measurements before discharge + 7 measurements 3 times per day for 5 days)]. The same number was required for the conventional paper basis.
Statistical analysis
Statistical analysis was conducted using SAS (9.4; SAS Inc., Cary NC).
Statistical results were expressed with mean (SD) or median with interquartiles [IQ] according to distribution. The numbers (with percentages, %) were given for categorical variables. The main judgment criterion was analysed in relation to a referential volume of theoretical information based on the following calculation: number of patients (n = 30) x number of data collection periods (i.e. one on D0 and 3 per day from D1 to D5, i.e. 16 in total) x number of parameters measured i.e. physiological parameters (heart rate, blood pressure, oxygen saturation and self-evaluation parameters (pain score, nausea, vomiting, comfort), i.e. 7 in total. Thus, the maximum reference volume of theoretical information is 30 × 16 × 7 = 3360. In addition, a referential volume of theoretical information was calculated per day and by parameters
Comparisons of continuous variables between the app and paper questionnaire were performed using a Student’s t-test or Wilcoxon-Mann-Whitney test according to distribution. Categorical variables were compared between groups by X2 or Fisher’s exact test. All statistical tests were conducted as 0.05 two-sided tests and the analysis of secondary outcomes was descriptive.