This study aims to determine if provider-recommended guidance on supine (on back) vs. prone (on stomach) positioning of patients testing positive for COVID-19 requiring supplemental oxygen, but not yet mechanically ventilated, improves outcomes in the inpatient setting. This study will be performed as a pragmatic clinical trial.

Disease Progression and Timing of Intervention The intervention described herein focuses on adjustment of patient positioning aimed at improving gas exchange and lung function in patients harboring COVID-19. This intervention will target the inpatient setting generally.

Scientific/Clinical Rationale for Approach Since emergence of the novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) now designated coronavirus disease 2019 (COVID-19), one in six affected patients becomes seriously ill. The lung appears to be the most susceptible target organ, with a large swath of symptomatic patients struggling with mild upper respiratory tract illness and severe viral pneumonia resulting in respiratory failure. This respiratory failure is often fatal, with one study showing 28% non-survivors having experienced respiratory failure. Moreover, 81-97% of patients requiring mechanical ventilation do not survive.

Like its interaction with Severe Acute Respiratory Syndrome (SARS-CoV), angiotensin converting enzyme 2 (ACE2) is the functional receptor for COVID-19. Viral adherence to host-cell membrane associated ACE2 facilitates the proximity required for viral "spike" mediated genetic material injection. In COVID-19, this spike is 10-20 times more likely to bind ACE2 than SARS. ACE2 is expressed in 0.64% of all human lung cells, with 83% of those cells being alveolar epithelial type II. In addition, gene ontology enrichment analysis showed that the ACE2-expressing alveolar epithelial type II have high levels of multiple viral process-related genes, including regulatory genes for viral processes, viral life cycle, viral assembly, and viral genome replication, suggesting that the ACE2-expressing alveolar epithelial type II cells facilitate coronaviral replication in the lung. Thus, these cells likely serve as a ready reservoir for viral invasion. Perhaps more importantly, alveolar type II cells function to generate and recycle surfactant essential to respiratory activity. Surfactant defends against alveolar collapse at low lung volume and protects the lung from injuries/infections caused by inhaled particles and micro-organisms. In COVID-19, if these vital cells are being destroyed, alveolar failure may ensue with severe lung impairment. Thus, interventions that are aimed at improving pressure normalization and alveolar protection may be beneficial in these patients.

Prone positioning (PP) has long been used to combat hypoxemia in acute respiratory distress syndrome (ARDS). Improvements in gas exchange result from improved alveolar ventilation and blood flow redistribution with enhanced perfusion following. PP reduces lung over inflation and bolsters alveolar recruitment. PP also promotes uniformity of vertical pleural pressure gradients resulting in more uniform alveolar size. Considering these physiologic factors together, the investigators hypothesize PP serves to balance stress and strain within the lungs of non-critically ill patients with COVID-19 leading to improved outcomes compared to traditional supine positioning.

Prior Research Supporting the Positioning Model:

Multiple studies have been conducted that support the use of PP as a proactive treatment to combat hypoxemia in ARDS. Each year, approximately 170,000 people are diagnosed with ARDS, and those diagnosed face mortality rates between 25% and 40%. The use of PP stretches back to the 1970s, as providers began to search for ways to ameliorate ARDS symptomatology and reduce the then even higher levels of mortality associated with it. Following initial reports that PP significantly improved oxygenation in 70-80% of patients with ARDS, it was adopted as a standard treatment option. Initially, randomized clinical trials struggled to replicate these findings, citing multiple limitations to study enrollment and treatment standardization that made ascertaining conclusive results difficult. Only as RCT construction has been refined to accommodate for these limitations have the benefits of PP been more clearly demonstrated.

These beneficial effects have been recently upheld by the landmark PROSEVA study, a multicenter, prospective, randomized, controlled trial, that randomly assigned 466 patients with severe ARDS to undergo prone-positioning sessions of at least 16 hours or to be left in the supine position. Their results demonstrated a significant improvement in both 28- and 90-day mortality rates: "the 28-day mortality was 16.0% in the prone group and 32.8% in the supine group (P<0.001). The hazard ratio for death with prone positioning was 0.39 (95% confidence interval [CI], 0.25 to 0.63). Unadjusted 90-day mortality was 23.6% in the prone group versus 41.0% in the supine group (P<0.001), with a hazard ratio of 0.44 (95% CI, 0.29 to 0.67)".

Per these positive findings, PP has been consistently shown to be an effective mechanism to increase oxygenation in patients with ARDS when implemented under the following conditions: early enlisting of treatment and its consistent maintenance for at least 16 hours per day, and with concurrent use of lung-protective therapies. Translating these findings towards treatment of COVID-19 positive patients seems promising given the similarity of manifested symptoms and complications.

Inclusion Criteria:

• This study will enroll all patients admitted to VUMC who test positive for COVID-19 and require supplemental oxygen, but are not yet mechanically ventilated.

Exclusion Criteria:

• Patients admitted on mechanical ventilation will be excluded from enrollment.

Individual participant data that underlie the results reported will be made available (including data dictionaries) after de-identification.

The data will become available 3 months following publication of outcomes and will remain available for at least 5 years.

Data will be made available to researchers who provide a methodologically sound proposal that has been approved by the Vanderbilt Institutional Review Board and the study executive committee.

28 days

Adverse event information was collected for any untoward or unfavorable medical occurrence in a participant, including any abnormal sign, symptom, or disease, temporally associated with the participant's participation in the research, whether or not considered related to the participant's participation in the research.

Patients and providers will necessarily be unblinded, but outcomes will be analyzed by a blind assessor.