Potential for lung recruitment in patients with SARS-CoV2-associated acute respiratory distress syndrome

Introduction: Many patients with SARS-CoV2 severe pneumonia received invasive mechanical ventilation and met the Berlin definition for ARDS However, there is an ongoing debate regarding their respiratory mechanics Several small studies found conflicting results: some showed a low potential for recruitability at an early stage of mechanical ventilation [1], others demonstrated a significant potential for recruitability, although with large variability between patients[2],[3] Objectives: We aimed to assess lung recruitability in the first days of invasive mechanical ventilation in patients with SARS-CoV2 induced ARDS Methods: Single-center study in a French medical ICU We included patients undergoing invasive mechanical ventilation for SARS-CoV2 ARDS Lung recruitability was assessed using recruitmentto- inflation ratio (R/I) measured within 72 hours after intubation R/I ratio was obtained with a drop in PEEP over a single breath manoeuver, as previously described[4] We also assessed airway opening pressure (AOP) by performing a low-flow inflation[5] Results: Twenty-three patients were included in this study;18 (78%) were men with a mean±SD age, body mass index, SAPS II and SOFA of respectively 57 ± 13, 29 ± 6 kg/m2, 45 ± 15 and 9 ± 4 at ICU admission The majority of them (65%, N = 15) had at least one comorbidity, including hypertension (48%, N = 11), diabetes (22%, N = 5) or immunocompromised status (22%, N = 5) R/I ratio was measured 1 [0;2 5] days after intubation and 14 patients (60 9%) were considered to have recruitable lung (R/I ratio 0 76 [0 61;1 01]) with no difference in baseline characteristics as compared to the 9 patients with a R/I 5 cmH2O (with a median of 6 50 cmH2O), with no significant difference between recruiters and nonrecruiters Overall survival rate was low (43 5%), 57% in the recruiter group (N = 8) and 22% in the non-recruiter group (N = 2), not reaching statistical difference (p = 0 197) Data are presented as median [interquartile range] or number (percentage) VT tidal volume, R/I ratio recruitment to inflation ratio, AOP airway opening pressure p-values refer to the comparison between recruiters and non-recruiters Conclusion: Of the 23 patients with SARS-Cov2-associated acute respiratory distress syndrome included in this study, a majority (61%) were considered as recruitable according to measured R/I ratio and 22% presented an AOP > 5 cmH2O Given the large variability of potential for recruitment in our study, R/I ratio and AOP should be assessed to individualize PEEP settings for each patient (Table Presented)