Table 2 Differences in respiratory mechanics during mechanical ventilation between influenza A- and COVID-19-induced ARDS.

Day 1

Characteristics

Total participants

(N = 87)

Influenza A induced ARDS

(N = 45)

COVID-19-induced ARDS

(N = 42)

p-value

Pco₂

38.9 (33.5–43.6)

37.5 (33.8–44.3)

40.0 (33.0–43.3)

0.584

Pa_O2:Fi_O2

184.7 (135.7–243.6)

216.1 (134.2–271.3)

167.9 (137.5–212.7)

0.009

Mve (L/min)

8.9 (7.6–10.3)

8.5 (7.2–10.2)

9.0 (8.0–10.3)

0.707

TV/PBW (ml/kg)

7.2 (6.3–8.4)

7.0 (6.3–8.3)

7.2 (6.3–8.5)

0.763

PIP (cm H₂O)

23.0 (20.0–26.0)

23.0 (20.5–27.0)

22.0 (19.0–25.0)

< 0.001

PEEP (cm H₂O)

8.0 (7.0–10.0)

8.0 (5.0–8.0)

10.0 (8.0–12.0)

< 0.001

Cdyn (cm H₂O) ^a

30.0 (23.7–37.9)

25.7 (21.3–34.4)

35.8 (28.9–41.6)

0.001

DP (cm H₂O) ^b

14.0 (12.0–17.0)

15.0 (13.5–19.0)

13.0 (9.8–16.0)

0.369

Day 3

Characteristics

Total participants

(N = 80)

Influenza A induced ARDS

(N = 39)

COVID-19-induced ARDS

(N = 41)

p-value

Pco₂

38.8 (33.3–44.2)

37.7 (30.3–47.1)

39.8 (35.0–42.8)

0.763

Pa_O2:Fi_O2

215.2 (158.2–309.0)

279.5 (172.0–333.0)

181.0 (141.0–252.0)

0.005

Mve (L/min)

8.4 (7.3–9.8)

7.9 (6.1–9.3)

8.4 (7.7–9.9)

0.072

TV/PBW (ml/kg)

7.3 (6.5–7.8)

7.2 (6.4–8.0)

7.3 (6.6–7.8)

0.969

PIP (cm H₂O)

23.0 (18.3–25.8)

22.0 (16.0–25.0)

24.0 (20.0–26.5)

0.051

PEEP (cm H₂O)

8.0 (6.0–10.0)

6.0 (5.0–8.0)

10.0 (8.0–11.0)

< 0.001

Cdyn (cm H₂O) ^a

28.4 (22.7–39.0)

28.2 (21.4–47.9)

28.6 (23.1–37.9)

0.935

DP (cm H₂O) ^b

14.0 (11.0–17.0)

14.0 (9.0–18.0)

14.0 (12.0–17.0)

0.817

Day 7

Characteristics

Total participants

(N = 64)

Influenza A induced ARDS

(N = 27)

COVID-19-induced ARDS

(N = 37)

p-value

Pco₂

38.2 (34.0–42.5)

36.9 (31.6–42.6)

39.1 (35.1–42.6)

0.799

P/F ratio

215.0 (146.4–310.7)

279.1 (143.6–353.3)

204.2 (147.6–282.5)

0.170

Mve (L/min)

8.8 (7.5–10.6)

8.6 (6.4–10.1)

8.9 (8.1–10.9)

0.123

TV/PBW (ml/kg)

7.4 (6.5–8.5)

7.4 (6.0–8.7)

7.4 (6.6–8.4)

0.838

PIP (cm H₂O)

21.0 (16.3–25.0)

18.0 (13.0–25.0)

22.0 (19.0–25.5)

0.108

PEEP (cm H₂O)

8.0 (5.0–10.0)

6.0 (5.0–7.0)

8.0 (8.0–10.0)

< 0.001

Cdyn (cm H₂O) ^a

31.3 (23.7–45.3)

32.5 (20.5–62.2)

31.3 (24.5–37.8)

0.951

DP (cm H₂O) ^b

13.5 (9.3–16.8)

12.0 (8.0–18.0)

15.0 (11.0–16.0)

0.643