Effects of Sevoflurane on Extravascular Lung Water and Pulmonary Vascular Permeability in Patients With ARDS

The study will investigate the effects of inhaled sedation with sevoflurane using the AnaConDa device on extravascular lung water index (EVLWi) and the pulmonary vascular permeability index (PVPI) in patients with moderate to severe acute respiratory distress syndrome (ARDS). Improvement in oxygenation and decreases in lung inflammatory response has been demonstrated in patients with ARDS compared with intravenous sedation. However, preclinical data showing a decrease in lung edema has not been confirmed. The hypothesis is that inhaled sedation with sevoflurane reduces EVLWi and PVPI in patients with ARDS, assessed with the PiCCO device. Patients will receive either inhaled sedation (interventional group), or a sedation with propofol (control group). Both will be associated with remifentanil. Sedation will be monitored by bispectral index with a targeted value of 30-50. The primary outcome will be daily assessment of EVLWi and PVPI over time in patients sedated with sevoflurane compared to propofol. Secondary outcomes will include value of PVPI and EVLW at 48h after intubation, fluid administration, need in norepinephrine, time between cessation of sedation and trial of weaning sedation, ventilation free days, mortality at day 28, the partial pressure of arterial oxygen to fraction of inspired oxygen ratio (PaO2/FiO2), plasma and alveolar levels of cytokines (tumor necrosis factor (TNF)-α, interleukine (IL)-1β, IL-6, IL-8). These blood and alveolar samples will be done at baseline, on day 2 and on day 5. A sub-group analysis will be done in Covid-19 related ARDS. Decrease in PVPI and EVLWi with inhaled sevoflurane may be related to the decrease in lung edema in ARDS patients and may ultimately improve patient outcome.