Respiratory Physiology of COVID-19-Induced Respiratory Failure Compared to ARDS of Other Etiologies

Domenico Luca Grieco; Filippo Bongiovanni; Lu Chen; Luca S. Menga; Salvatore Lucio Cutuli; Gabriele Pintaudi; Simone Carelli; Teresa Michi; Flava Torrini; Gianmarco Lombardi; Gian Marco Anzellotti; Gennaro De Pascale; Andrea Urbani; Maria Grazia Bocci; Eloisa S. Tanzarella; Giuseppe Bello; Antonio M. Dell'Anna; Salvatore M. Maggiore; Laurent Brochard; Massimo Antonelli

Disclosures

Crit Care. 2020;24(529) 

In This Article

Background

Around 5% of patients affected by the novel 2019 coronavirus disease (COVID-19) require intensive care unit (ICU) admission due to acute respiratory distress syndrome (ARDS), with a case-fatality rate ranging between 30 and 60%.[1–8] Invasive mechanical ventilation is required in most of the patients to treat gas exchange abnormalities and represents the mainstay of supportive therapy.[4,7,9] In this setting, mechanical ventilation is aimed at restoring adequate gas exchange while limiting ventilator-induced lung injury (VILI).[10] During ARDS, proper ventilatory management reduces the risk of VILI and is among the potentially modifiable factors capable of improving survival.[11]

The effects of ventilator settings (tidal volume, positive end-expiratory pressure [PEEP]) on VILI and clinical outcome are mediated by respiratory mechanics that have wide inter-individual variability.[12–14] Thorough understanding of respiratory mechanics is essential to limit the risk of VILI and, possibly, improve clinical outcome.[15,16] Some reports suggested that patients with COVID-19 ARDS may have different phenotypes (high vs. low elastance), independently from gas exchange.[17] This could have important implications regarding ventilator management. Some authors claim that COVID-19 patients (or, at least, part of them) may not necessarily benefit from usual ARDS management.[18] However, whether or not the heterogeneity in respiratory mechanics observed in COVID-19 patients is different from conventional ARDS remains unclear.[19–23]

We assessed respiratory mechanics, potential for lung recruitment, and PEEP effects in 30 consecutive mechanically ventilated patients with COVID-19-induced moderate-to-severe ARDS. After 1:1 matching based on the degree of oxygenation impairment at same PEEP and FiO2, we then compared these results with those obtained from a multicenter cohort of patients with ARDS of other origins who underwent the same procedures in a previous study.

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