Prone Positioning and R/I Ratio in COVID-19 Patients With ARDS (SyDRAC-DV)

High positive end-expiratory pressure (PEEP) level and prone positioning (PP) are recommended in patients with moderate to severe acute respiratory distress syndrome (ARDS) in order to recruit lung and thus to improve oxygenation. Thus, high PEEP level and prone positioning will be more effective in patients with high potential for lung recruitment. Recently, the Recruitment-to-Inflation Ratio (R/I ratio) has been described and validated in patients with ARDS to estimate the potential for lung recruitment. In this regard, the R/I ration may be of interest to titrate PEEP level in patients with ARDS. This would be of particular interest in COVID-19 patients with ARDS, since different ARDS phenotypes with heterogeneous potential of lung recruitment have been described in these patients. However, the effects of prone positioning on R/I ratio have been scarcely described so far. Thus, the main goal of this study is to investigate the effects of prone positioning on the R/I ratio in COVID-19 patients with ARDS. The second goal of this study is to determine the effects of prone positioning on oxygenation and respiratory mechanics according to the R/I ratio.

Inclusion criteria

• Invasive mechanical ventilation
• Patients with acute respiratory distress syndrome according to the Berlin definition
• Positive COVID-19 real-time reverse transcriptase-polymerase chain reaction assay in nasal swabs or pulmonary samples.
• Indication to a prone positioning session by the attending physician

Exclusion criteria

• Age <18 years and pregnant women
• Patients under legal protection
• Acute core pulmonale
• Pneumothorax and/or chest drainage
• Hemodynamic failure

• Increase in norepinephrine dosage >30% within the last 6 hours
• Norepinephrine dosage > 0.5 mg/kg/min