Respiratory system mechanics, gas exchange, and outcomes in mechanically ventilated patients with COVID-19-related acute respiratory distress syndrome: a systematic review and meta-analysis

Mallikarjuna Ponnapa Reddy, Ashwin Subramaniam, Clara ChuaRyan Ruiyang Ling et al.

Lancet Respir Med 2022; 10: 1178-1188 Published:November 03, 2022

DOI:https://doi.org/10.1016/S2213-2600(22)00393-9

Summary

The association of respiratory mechanics, particularly respiratory system static compliance (C_RS), with severity of hypoxaemia in patients with COVID-19-related acute respiratory distress syndrome (ARDS) has been widely debated, with some studies reporting distinct ARDS phenotypes based on C_RS. Ascertaining whether such phenotypes exist is important, because they might indicate the need for ventilation strategies that differ from those used in patients with ARDS due to other causes. In a systematic review and meta-analysis of studies published between Dec 1, 2019, and March 14, 2022, we evaluated respiratory system mechanics, ventilator parameters, gas exchange parameters, and clinical outcomes in patients with COVID-19-related ARDS. Among 11 356 patients in 37 studies, mean reported C_RS, measured close to the time of endotracheal intubation, was 35·8 mL/cm H₂O (95% CI 33·9–37·8; I²=96·9%, τ²=32·6). Pooled mean C_RS was normally distributed. Increasing ARDS severity (assessed by PaO₂/FiO₂ ratio as mild, moderate, or severe) was associated with decreasing C_RS. We found no evidence for distinct C_RS-based clinical phenotypes in patients with COVID-19-related ARDS, and we therefore conclude that no change in conventional lung-protective ventilation strategies is warranted. Future studies should explore the personalisation of mechanical ventilation strategies according to factors including respiratory system mechanics and haemodynamic status in patients with ARDS.