To the Editor
During recent last months, a pandemic by a novel coronavirus (Sars-Cov-2) has spread worldwide,1–3 putting hospitals under enormous pressure with a huge number of patients in need of hospitalization.4 This brought with it the necessity to discharge patients earlier to make the hospital turnover as fast as possible. Home monitoring programs have been suggested as a feasible strategy to facilitate the clinical management of the postacute phase in different clinical scenarios. Although follow-up data in this setting are scarce, early reports suggested that more than 80% of patients who had recovered from coronavirus disease-2019 (COVID-19) reported persistence of at least one symptom during follow-up, particularly fatigue and dyspnea.5 Therefore, prolonged postdischarge monitoring for long-lasting effects is advisable.
We assessed the feasibility of cardiorespiratory home monitoring through a wearable device in post-COVID-19 patients.
Methods
In this pilot study, we enrolled patients with a confirmed diagnosis of COVID-19 after hospital discharge at home. The function of the wearable device used (L.I.F.E.) was previously described.6 In brief, it is a technologically advanced T-shirt device composed of ink-based dry electrodes linked to standard 12-lead ECG monitoring, 5 respiratory strain sensors, and 1 accelerometer, the latter for monitoring subject's activity and position (Fig. 1a). Moreover, a digital pulse oximeter is connected to the patient's finger. All data are transferred to an embedded logger that communicates with a center for data recovery and analysis. We previously described the reliability of L.I.F.E. during day and nighttime.6
;)
Fig. 1: L.I.F.E. T-shirt wearable device can detect sleep apneas. The L.I.F.E. T-shirt wearable device (a) includes 12 ink-based dry electrodes linked to ECG monitoring, 5 respiratory strain sensors, and 1 accelerometer (embedded in the control unit for monitoring the activity and position of subjects). (b) An example of sleep apnea during nighttime monitoring in a postrecovery COVID-19 patient. COVID-19, coronavirus disease 2019; HR, heart rate; RR, respiratory rate; SpO2, blood oxygen saturation.
Monitoring was carried out for at least 7 days and comprehended a 2-h monitoring period a day during rest and a short exercise (6 min of brisk walking) and overnight sleep monitoring on the last day.
Results
Seventeen COVID-19 patients (men 8; age 54.4 ± 15.3 years; BMI 25.1 ± 3.1) were enrolled at hospital discharge. They underwent 12.5 ± 2.5 (7–17) days of monitoring. Clinical characteristics of the population and data monitoring are shown in Table 1. All the patients completed the 2-h monitoring period a day (rest and short exercise) during the days of monitoring. At hospital discharge, cardiorespiratory parameters were good, and no significant changes were observed between the first and the last day of monitoring. Twelve patients (70.6%) performed the nighttime monitoring. Among them, one showed an apnea--hypopnea index (AHI) of 20, suggestive of moderate sleep apnea syndrome (Fig. 1b). A monitoring screen example with a 12-lead ECG is shown in Fig. 2. No major technical problems were observed. Small technical problems (e.g. connection of the device to the Wi-Fi line) were solved with remote assistance. In particular, two patients (11.8%) reported a logger connection problem to the T-shirt and three patients (17.6%) reported difficulties in transmitting data through the Wi-Fi line. In both cases, the problem was solved with telephone support on the first day and did not compromise the monitoring.
Table 1 -
Clinical characteristics and monitoring data of postrecovery coronavirus disease 2019 patients
|
Baseline (first day) |
Last day of monitoring |
P value |
| Clinical characteristics |
| Male sex |
8 (47%) |
– |
– |
| Age (years) |
54.4 ± 15.3 |
– |
– |
| Weight (kg) |
72.4 ± 13.2 |
– |
– |
| Height (cm) |
169.1 ± 7.6 |
– |
– |
| BMI (kg/m2) |
25.5 ± 3.1 |
– |
– |
| Chest circumference (cm) |
99.4 ± 10.5 |
– |
– |
| Abdominal circumference (cm) |
93.8 ± 15.3 |
– |
– |
| Days of monitoring |
12.5 ± 2.5 |
– |
– |
| Rest parameters |
| SpO2 (baseline) |
96.9 ± 1.8 |
96.8 ± 1.8 |
0.676 |
| SpO2 (mean) |
95.8 ± 1.4 |
95.8 ± 1.6 |
1.000 |
| SpO2 (min) |
89.6 ± 3.0 |
91.0 ± 1.6 |
0.083 |
| Respiratory rate (mean) |
17.5 ± 3.3 |
17.6 ± 3.5 |
0.661 |
| Respiratory rate (min) |
13.4 ± 3.0 |
14.3 ± 3.5 |
0.394 |
| Respiratory rate (max) |
24.1 ± 6.3 |
23.6 ± 4.6 |
0.741 |
| Heart rate (mean) |
73.8 ± 10.8 |
74.6 ± 13.3 |
0.953 |
| Heart rate (min) |
64.4 ± 9.8 |
64.1 ± 11.2 |
0.754 |
| Heat rate (max) |
89.8 ± 13.1 |
93.2 ± 16.9 |
0.388 |
| Exercise parameters |
| SpO2 during exercise (mean) |
95.7 ± 2.7 |
95.7 ± 1.8 |
1.000 |
| SpO2 during exercise (min) |
91.2 ± 4.4 |
91.8 ± 2.0 |
0.845 |
| Respiratory rate during exercise (mean) |
25.5 ± 6.5 |
23.5 ± 4.8 |
0.295 |
| Nighttime monitoring |
| SpO2 (baseline) |
– |
96.4 ± 2.3 |
– |
| SpO2 (mean) |
– |
95.1 ± 2.2 |
– |
| SpO2 (min) |
– |
89.2 ± 4.3 |
– |
| Respiratory rate (mean) |
– |
16.3 ± 2.3 |
– |
| Respiratory rate (min) |
– |
12.1 ± 2.6 |
– |
| Respiratory rate (max) |
– |
19.6 ± 3.3 |
– |
| Apnea--hypopnea index (events/hour) |
– |
3.1 ± 5.5 |
– |
| Apnea episodes |
– |
17.1 ± 38.0 |
– |
| Hypopnea episodes |
– |
8.8 ± 8.7 |
– |
| Total apnea time (s) |
– |
757.2 ± 1178.7 |
– |
| Total time with SpO2 less than 90% (s) |
– |
577.8 ± 534.6 |
– |
| Mean desaturation |
– |
3.3 ± 0.7 |
– |
Clinical characteristics and monitoring at rest, during exercise (6 min of brisk walking) and during nighttime monitoring are shown. Data are presented as mean ± standard deviation. SpO2, blood oxygen saturation.
Fig. 2: Monitoring screen example of a postdischarge coronavirus disease 2019 patient transmitted to the hospital. A 12-lead ECG is shown. The arrhythmic events are signalled as alarms (see right side of the figure) and must then be verified by the operator.
Comment
Our study demonstrated that a postdischarge home monitoring program for COVID-19 patients is feasible and well tolerated. The L.I.F.E. T-shirt device was able to collect a full set of cardiorespiratory parameters (i.e. heart rate, a full ECG, respiratory rate, SpO2), both at rest and during brief exercise, which are valuable in patients suffering from respiratory diseases. As the medium-term and long-term consequences of COVID-19 infection are still unknown, implementing strategies of postrecovery monitoring are useful to identify patients at risk of clinical deterioration.7,8 Moreover, it could help to shorten hospital stays, a particularly desirable goal, given the lack of beds typically experienced during a pandemic crisis and, keeping people at home, it could mitigate the in-hospital transmission of COVID-19.7,8 In addition, despite the lack of a specific questionnaire on satisfaction and acceptance, telephone contact was performed on a daily basis to confirm that the study procedures were well tolerated, with most of the patients reporting feeling reassured by being monitored. Our population, as shown by baseline cardiorespiratory parameters, was at low risk of events. The full potential of this kind of home monitoring will not only be probably experienced in the clinical context of more severe COVID-19 patients but also in other clinical scenarios. Finally, given the small sample size, we were able to identify only one patient without any previous disease who presented post-COVID sleep apnea syndrome. Further studies are certainly needed to assess the prevalence and the clinical impact of this complication in post-COVID-19 patients.
Acknowledgements
We thank Mrs. Michela Palmieri for the English revision of the text. This clinical research has been awarded the “Vincenzo Masini 2021” prize assigned by ANMCO (Associazione Nazionale Medici Cardiologi Ospedalieri).
Conflicts of interest
Daniela Fumagalli is a L.I.F.E. employee.
References
1. World Health Organization. Coronavirus disease (
COVID-19) outbreak. 2020; Available at:
https://www.euro.who.int/en/health-topics/health-emergencies/coronavirus-covid-19. [Accessed 19 August 2020].
2. Holshue ML, DeBolt C, Lindquist S, et al. Washington State 2019-nCoV Case Investigation Team. First case of 2019 novel coronavirus in the United States.
N Engl J Med 2020; 382:929–936.
3. National Health Commission of the People's Republic of China. 2020. Available at:
http://www.nhc.gov.cn. [Accessed 19 August 2020].
4. Fagiuoli S, Lorini FL, Remuzzi G. Adaptations and lessons in the province of Bergamo.
N Engl J Med 2020; 382:e71.
5. Carfi A, Bernabei R, Landi F. Gemelli Against
COVID-19 Post-Acute Care Study Group. Persistent symptoms in patients after acute
COVID-19.
JAMA 2020; 324:603–605.
6. Sarmento A, Vignati C, Paolillo S, et al. Qualitative and quantitative evaluation of a new
wearable device for ECG and respiratory Holter monitoring.
Int J Cardiol 2018; 272:231–237.
7. Abraham WT, Fiuzat M, Psotka MA, O’Connor CM. Heart failure collaboratory statement on remote monitoring and social distancing in the landscape of
COVID-19.
JACC Heart Fail 2020; 8:692–694.
8. U.S. Food and Drug Administration. Enforcement policy for noninvasive remote monitoring devices used to support patient monitoring during the coronavirus disease 2019 (
COVID-19) public health emergency (Revised). 2020, June. Available at:
https://www.fda.gov/regulatory-information/search-fda-guidance-documents/enforcement-policy-noninvasive-remote-monitoring-devices-used-support-patient-monitoring-during.
