Moderate-to-severe ARDS: COVID-19 patients compared to influenza patients for ventilator parameters and mortality.

Background: This study aimed to compare ventilatory parameters recorded in the first days of acute respiratory distress syndrome (ARDS) and mortality at day 60 between coronavirus disease 2019 (COVID-19) and influenza ARDS patients with arterial oxygen tension (P aO2 )/inspiratory oxygen fraction (F IO2 ) ≤150 mmHg. Methods: We compared 244 COVID-19 ARDS patients with 106 influenza ARDS patients. Driving pressure, respiratory system compliance (C rs), ventilator ratio, corrected minute ventilation (V'Ecorr) and surrogate of mechanical power (index=(4×driving pressure)+respiratory rate) were calculated from day 1 to day 5 of ARDS. A propensity score analysis and a principal component analysis (PCA) were performed. Results: On day 1 of ARDS, COVID-19 patients had significantly higher P aO2 /F IO2 (median (interquartile range) 97 (79-129.2) versus 83 (62.2-114) mmHg; p=0.001), and lower driving pressure (13.0 (11.0-16.0) versus 14.0 (12.0-16.7) cmH2O; p=0.01), ventilatory ratio (2.08 (1.73-2.49 versus 2.52 (1.97-3.03); p<0.001), V'Ecorr (12.7 (10.2-14.9) versus 14.9 (11.6-18.6) L·min-1; p<0.001) and index (80 (70-89) versus 84 (75-94); p=0.004). PCA demonstrated an important overlap of ventilatory parameters recorded on day 1 between the two groups. From day 1 to day 5, repeated values of P aO2 /F IO2 , arterial carbon dioxide tension, ventilatory ratio and V'Ecorr differed significantly between influenza and COVID-19 patients in the unmatched and matched populations. Mortality at day 60 did not differ significantly after matching (29% versus 21.7%; p=0.43). Conclusions: Ventilation was more impaired in influenza than in COVID-19 ARDS patients on the first day of ARDS with an important overlap of values. However, mortality at day 60 did not differ significantly in the matched population.

Moderate to severe ARDS: COVID-19 patients compared to influenza patients for ventilator parameters and mortality

Background This study aimed to compare ventilatory parameters recorded the first days of ARDS, and mortality at day 60 between COVID-19 and influenza ARDS patients with PaO2/FiO2≤150 mmHg. Methods We compared 244 COVID-19 ARDS patients with 106 influenza ARDS patients. Driving pressure (DP), respiratory system compliance (CRs), ventilator ratio (VR), corrected minute ventilation (VEcorr), and surrogate of mechanical power [index=(4×DP)+respiratory rate] were calculated from day1 to day 5 of ARDS. A propensity score analysis and a principal component analysis (PCA) were performed. Results On day 1 of ARDS, COVID-19 patients had significantly higher PaO2/FiO2 ratio (median [IQR], 97 mmHg [79–129] versus 83 [62.2–114]), p=0.001), and lower DP (13 cmH20 [11–16.0] versus 14 [12.0–16.7], p=0.01), VR (2.08 [1.73–2.49 versus 2.52 [1.97–3.03], p<0.001), VEcorr (12.7 L·mn−1 [10.2–14.9] versus 14.9 [11.6–18.6], p<0.001), index (80 [70–89] versus 84 [75–94], p=0.004). PCA demonstrated an important overlap of ventilatory parameters recorded on day 1 between the two groups. From day 1 to day 5 repeated values of PaO2/FiO2 ratio, PaCO2, VR and VEcorr differed significantly between influenza and COVID-19 patients in the unmatched and matched populations. Mortality at day 60 did not differ significantly after matching (29% versus 21.7%, p=0.43). Conclusions Ventilation was more impaired in influenza than in COVID-19 ARDS patients the first day of ARDS with important overlap of values. However, mortality at day 60 did not differ significantly in the matched population. In COVID-19 and influenza patients with mild to moderate ARDS managed similarly for mechanical ventilation, dead space estimates were higher in COVID-19 patients than in influenza patients the first days of ARDS and short-term mortality similar.