Evaluation of Oxygenation in 129 Proning Sessions in 34 Mechanically Ventilated COVID-19 Patients

A minority of patients with Severe Acutre Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) disease-2019 (Covid-19) develop pulmonary features consistent with the Acute Respiratory Distress Syndrome (ARDS). Prone positioning (PP) is an intervention with proven survival benefits in moderate-to-severe and severe ARDS. It is advocated in international guidelines as an intervention in mechanically ventilated Covid-19 patients, despite very few published trials investigating its efficacy in Covid-19. There is an ongoing debate regarding the prevalence of reported mismatches between the severity of hypoxaemia and the preservation of pulmonary compliance in some patients, in the early stages of SARS-CoV-2 infection. This has led some to question its utility within this context. 129 proning sessions were identified in 34 consecutively prone patients admitted to the intensive care unit at a single center in the United Kingdom. Baseline characteristics of patients were consistent with previously published national and international reports and patients were ventilated in general concordance with the ARDSnet ventilation protocol. Paired analysis of the partial pressure of arterial oxygen(PaO₂): fraction of inspired oxygen(FiO₂) ratio (PF ratio) (n = 89) and FiO₂ (n = 129) was recorded within 3 hours of both the initiation and termination of PP and differences were assessed with the paired Student's t-test and Wilcoxon Signed-Rank test. Proning improved the PF ratio by 43.5 ± 54.9 from 99.8 ± 37.5 to 151.9 ± 58.9 (43.6% increase) [p < 0.0001] and reduced FiO₂ by 0.17 ± 0.2 from 0.68 ± 0.2 to 0.51 ± 0.2 (25% decrease) [p < 0.0001]. 82% of proning maneouveres resulted in an improvement in the PF ratio. In summary, PP improved arterial oxygenation and reduced oxygen requirements in most Covid-19 patients in this single- center, retrospective analysis.