An appraisal of respiratory system compliance in mechanically ventilated COVID-19 patients

ABSTRACT

Rationale Heterogeneous respiratory system static compliance (CRS) values and levels of hypoxemia in patients with novel coronavirus disease (COVID-19) requiring mechanical ventilation have been reported in previous smallcase series or studies conducted at a national level.Methods We designed a retrospective observational cohort study with rapid data gathering from the international COVID-19 Critical Care Consortium study to comprehensively describe the impact of CRS on the ventilatory management and outcomes of COVID-19 patients on mechanical ventilation (MV), admitted to intensive care units (ICU) worldwide.Results We enrolled 318 COVID-19 patients enrolled into the study from January 14th through September 31th, 2020 in 19 countries and stratified into two CRS groups. CRS was calculated as tidal volume/[airway plateau pressure-positive endexpiratory pressure (PEEP)] and available within 48h from commencement of MV in 318 patients. Patients were mean±SD of 58.0±12.2, predominantly from Europe (54%) and males (68%). Median CRS (IQR) was 34.1 mL/cmH2O (26.5-45.5) and PaO2/FiO2 was 119 mmHg (87.1-164) and was not correlated with CRS. Female sex presented lower CRS than in males (95% CI-13.8 to-8.5 P<0.001) and higher body mass index (34.7±10.9 vs 29.1±6.0, p<0.001). Median (IQR) PEEP was 12 cmH2O (10-15), throughout the range of CRS, while median (IQR) driving pressure was 12.3 (10-15) cmH2O and significantly decreased as CRS improved (p<0.001). No differences were found in comorbidities and clinical management between CRS strata. In addition, 28-day ICU mortality and hospital mortality did not differ between CRSgroups.Conclusions This multicentre report provides a comprehensive account of CRS in COVID-19 patients on MV-predominantly males or overweight females, in their late 50s-admitted to ICU during the first international outbreaks. Phenotypes associated with different CRS upon commencement of MV could not be identified.