Clinical Outcomes in Proning Critically Ill Obese Patients Infected with COVID-19 Pneumonia - The PROSECOVA Trial

Rationale: Obese patients represent a vulnerable population at risk of developing severe COVID-19 infections. Patients with COVID-19 pneumonia are at increased risk for developing acute hypoxemic respiratory failure (AHRF) and acute respiratory distress syndrome (ARDS). Prone positioning has long been studied as a measure to improve hypoxemia in ARDS. We hypothesize that the critically ill obese patient may represent a unique subset of the population when considering their innate respiratory mechanic variations and distinctive physiology who may benefit most from prone positioning as an adjunctive measure to improve oxygenation in COVID-19 pneumonia. Methods: We conducted a retrospective, dual-hospital, single institution cohort analysis of confirmed diagnosed COVID-19 infection patients admitted to our 1227-bed tertiary care center. The data pool was subdivided into obese and non-obese adult patients, defined by body mass index ≥ 30 kg/m2. Proning was defined by at least 4 hours a day spent fully pronated. The primary outcome was in-hospital mortality. Secondary outcomes included the requirement of mechanical ventilation (MV) and ICU length of stay (LOS). Results: Between February and August 2020, 55% (144/259) of the total study population patients admitted to our ICU for AHRF secondary to COVID-19 pneumonia were obese. Of these obese patients, 25% (36/144) were proned and 75% (108/144) were not proned. In-hospital mortality was 11.11% in the proned/obese patients compared to 30.55% in the non-proned/obese patients (p=0.0207). In comparison, 26% (30/115) of the non-obese patients were proned and 74% (85/115) were not proned. In-hospital mortality was 36.66% in the proned/nonobese patients compared to 34.11% in the non-proned/non-obese patients (p=0.8010). A total of 43.05% (62/144) of obese versus 43.47% (50/115) of the non-obese patients required mechanical ventilation (MV) at some point in their ICU stay. In the obese population, 41.66% of proned/obese patients compared to 43.51% of the non-proned/obese patients required MV (p=0.8459). While in the non-obese population 46.66% of proned/non-obese patients compared to 42.35% of the non-proned/non-obese patients required MV (p=0.6819). The average ICU LOS was 8.17 days in non-proned compared to 6.77 days in proned obese patients. Conclusion: In regards to obese patients, there was a clinically significant improvement in mortality between patients that were proned versus non-proned patients. There was no clinically significant difference in the effect of proning on non-obese patients in terms of mortality. There was also no clinically significant difference in the effects of proning in obese and non-obese patients in regards to the requirement of mechanical ventilation.