ABSTRACT
Background Many coronavirus disease 2019 (COVID-19) patients suffering acute hypoxemic respiratory failure (AHRF), fail to respond to conventional oxygen therapy (COT). Subsequently, some centers escalate to continuous positive airway pressure (CPAP), while others resort directly to invasive mechanical ventilation (IMV). We conducted a study to compare the use of CPAP versus COT alone in COVID-19-related AHRF. Patients and methods It is a retrospective cohort study of laboratory-confirmed COVID-19 patients suffering AHRF and deemed eligible for IMV escalation at three university hospitals (United Kingdom) during a 3-month period. The primary endpoint was the need for intubation and the secondary endpoint was 60-day mortality. Results In total, 174 patients were included. In total, 84 patients received CPAP (group 1) and 90 received only COT (group 2). Both groups had comparable demographic criteria and disease severity. There was nonsignificant reduction in the need for IMV when using CPAP compared with COT alone (50 vs. 76.6%, P=0.866). Sixty-day mortality was significantly higher in group 2 (25 vs. 37.8%, P=0.02). COT as stand-alone therapy for COVID-19 patients (group 2) was associated with a significant increased relative risk of death (relative risk 2.14, 95% confidence interval 1.39–3.29) corresponding to a number needed to treat of 3.74 (95% confidence interval 2.47–7.73). Among patients who progressed to IMV, there was no difference in the risk of mortality between the two groups. Conclusion Introducing CPAP rather than escalating FiO2 or endotracheal intubation in COVID-19 cases refractory to COT is safe and associated with improved mortality. Clinical trials are needed to guide the optimum timing and selection of patients most likely to benefit.
ABSTRACT
Introduction: Severe acute hypoxemic respiratory failure (AHRF) in COVID-19 pneumonia is associated with a high mortality rate, resulting in mounting pressures on intensive care units worldwide. Different oxygenation management protocols are used in different centres. Most centres switch patients who fail to oxygenate adequately using conventional oxygen therapy (COT) methods to non-invasive positive pressure ventilation (NIPPV), usually continuous positive airway pressure (CPAP). Other centres resort to invasive mechanical ventilation (IMV) directly, without a trial of NIPPV. In this trial, we aim to compare the efficacy of different approaches in managing COVID-related AHRF, and ascertain if CPAP therapy reduces the need for IMV. Methods: We carried out a retrospective cohort study on patients with laboratory-confirmed COVID-19 at three university hospitals in Essex, United Kingdom. We included all patients with significant AHRF (defined as needing oxygen therapy FiO2 more than 0.4 to maintain an oxygen saturation of 92%) who were deemed eligible for IMV escalation during a 3-month period (1st March to 31st May 2020).Results: Out of 174 patients who met the criteria, 84 patients received CPAP (Group 1). Half needed intubation (n=42). 90 patients did not have a CPAP trial (Group 2). 76.6% needed intubation (n=69). No difference was found between the two groups in demographic criteria or disease severity. Our results show a significant difference in 60-day mortality between group 1 and 2 (25% versus 37.8%, p=0.02). COT as standalone therapy for COVID-19 patients (group 2) was associated with a trend of more increased risk of intubation and an increased relative risk of death (RR 2.14, 95% CI 1.39 to 3.29). This corresponds to a number needed to treat (NNT) of 3.74 (95% CI 2.47 to 7.73). Patients in group 1 who failed CPAP trial and required intubation did not have an increased risk of mortality when compared to group 2 patients who required intubation.Conclusion: Our results support introducing CPAP rather than escalating FiO2 in cases refractory to COT. Our study suggests CPAP can be safely used to treat patients with AHRF. Clinical trials are needed to guide recommendations for optimum timing and selection of patients most likely to benefit.