Early Detection of Deterioration in COVID-19 Patients by Continuous Ward Respiratory Rate Monitoring: A Pilot Prospective Cohort Study

Background: Tachypnea is among the earliest signs of pulmonary decompensation. Contactless continuously respiratory rate monitoring might beuseful in isolated COVID-19 patients admitted in wards. We aim to determine whether continuous untethered ward respiratory rate patterns in hospitalized COVID-19 identify patients who require escalation of pulmonary management 24 hours ahead of time. Methods Single-center pilot prospective cohort study in COVID-19 patients who were cared for in routine wards. COVID-19 patients who has at least one escalation of pulmonary management were matched to 3 non-escalated patients. Contactless Breathing Monitoring was instituted after patients enrolled, and continued for 15 days unless hospital discharge, initiation of invasive mechanical ventilation, or death occurred. Respiratory rate data from the continuous monitor was not available to clinicians. The exposures were respiratory features over rolling periods of 30 min, 24 hours, and 72 hours before respiratory care escalation. The primary outcome was escalation in the pulmonary care beyond Venturi-mask. Results Among 125 included patients, 13 exhibited at least one escalation and were each matched to 3 non-escalated patients. A total of 28 escalation events were matched to 84 non-escalation episodes. The 30-min mean respiratory rate in escalated patients was 23 breaths per minute (bpm) ranging from 13 to 40 bpm, similar to the 22 bpm in non-escalated patients, although with less variability (range 14 to 31 bpm). However, higher respiratory rate variability, especially skewness over 1 day, was associated with higher incidence of an escalation event. Our overall model, based on continuous data, had a moderate accuracy with an AUC 0.81 (95%CI:0.73,0.88) and a good specificity 0.93 (95%CI:0.87,0.99). Conclusions Our pilot observational study suggests that continuous respiratory monitoring and respiratory rate variability are associated with the need for care escalation 24 hours in advance. ur results suggest that continuous respiratory monitoring is a valuable increment over intermittent monitoring.