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Table 4 Ventilatory characteristics and adjunctive therapies during the first week after ARDS onset in university and non-university hospitals

From: Outcome of acute respiratory distress syndrome in university and non-university hospitals in Germany

 

University hospital (n = 87; 592 days of mechanical ventilation)

Non-university hospital (n = 111; 599 days of mechanical ventilation)

p value

Ventilatory parameters averaged over the first week after ARDS onset, mean (SD); median (IQR)

 Driving pressurea (cmH2O)

15.7 (5.1); 15 (13–19)

16.3 (4.7); 16 (13–19)

0.40

 Driving pressure when FiO2 > 0.4 and PEEP ≥ 5 (cmH2O)b

15.1 (4.4); 16 (12–19)

17.0 (5.0); 18 (14–20)

0.02

 PEEP (cmH2O)

10.1 (4.2); 10 (7–13)

8.4 (3.9); 8 (6–11)

0.005

 PEEP when FiO2 > 0.4 and PEEP ≥ 5 (cmH2O)b

11.7 (4.7); 10 (8–15)

9.7 (3.7); 9 (7–12)

0.005

 PEEP categories, n (%)

  ≤5 cmH2O

11 (12.6)

24 (21.8)

0.05

  ≤10 cmH2O

41 (47.1)

58 (52.7)

  ≥11 cmH2O

35 (40.2)

28 (25.5)

 Tidal volume (ml/kg PBW)

8.9 (2.0); 8.6 (7.6–10.0)

8.9 (2.4); 8.7 (7.6–10.0)

0.99

 Plateau pressure (cmH2O)

26.4 (5.8); 27 (23–31)

25.3 (5.4); 25 (22–28)

0.18

 Plateau pressure categories, n (%)

  ≤30 cmH2O

54 (70.1)

89 (86.4)

0.007

  >30 cmH2O

23 (29.9)

14 (13.6)

 Compliancec (ml/mbar; ml/mbar/kg PBW)

42 (32–54); 0.62 (0.49–0.80)

38 (29–48); 0.59 (0.45–0.73)

0.06; 0.23

 Respiratory frequency (breaths/min)

20 (16–22)

18 (13–22)

0.17

 FiO2

0.44 (0.40–0.54)

0.48 (0.41–0.57)

0.07

 PaO2 (mmHg)

91 (84–105)

92 (78–107)

0.64

 PaO2/FiO2 (mmHg)

208 (169–250)

194 (155–248)

0.19

 PaCO2 (mmHg)

42 (38–47)

42 (37–48)

0.91

 pHa

7.41 (7.36–7.45)

7.42 (7.36–7.46)

0.59

Days with ventilatory mode during the first week after ARDS onset, n (% of all days of mechanical ventilation)

 

<0.001

 Biphasic intermittent positive airway pressure

281 (47.5)

271 (45.2)

0.44

 Pressure controlled ventilation

69 (11.7)

111 (18.5)

0.001

 Pressure support ventilation

105 (17.7)

75 (12.5)

0.01

 SIMV + pressure support ventilation

31 (5.2)

41 (6.8)

0.24

 SIMV

24 (4.1)

10 (1.7)

0.01

 Volume-controlled ventilation (assist/control)

28 (4.7)

15 (2.5)

0.04

 Non-invasive ventilation

31 (5.2)

38 (6.3)

0.41

 Other

9 (1.5)

7 (1.2)

0.60

 Not specified

14 (2.4)

31 (5.2)

0.01

Days applying adjunctive therapies, n (% of all days of mechanical ventilation); median (IQR)

 Prone positioning or rotation bed, all days

44 (7.4)

22 (3.7)

0.005

 Sedatives all days, duration/patient (days)

439 (74.2); 12 (7–21)

411 (56.8); 5 (2–10)

0.03; <0.001

 Neuromuscular blocking agents, all days

11 (1.9)

7 (1.2)

0.33

  1. ARDS acute respiratory distress syndrome, FiO 2 fraction of inspired oxygen, PaO 2 partial pressure of arterial oxygen tension, PaO 2 /FiO 2 arterial-to-inspired oxygen ratio, PEEP positive end-expiratory pressure, PBW predicted body weight, SIMV Synchronized intermittent mandatory ventilation, SD standard deviation, IQR interquartile range
  2. aDriving pressure = plateau pressure – PEEP
  3. bAll other ventilatory parameters during therapeutic ventilation did not differ between groups in this sensitivity analysis, including only those ventilation days – during the first week after ARDS onset with FiO2 > 0.4 and PEEP ≥ 5 cmH2O – that represented minimum values as criteria for the start of weaning in the low tidal volume trial of the ARDS Network [12] (261 of 592 days (44.1%) in university hospitals and 299 of 599 days (49.9%) in non-university hospitals)
  4. cCompliance = tidal volume / (plateau pressure – PEEP)