The impacts of baseline ventilator parameters on hospital mortality in acute respiratory distress syndrome treated with venovenous extracorporeal membrane oxygenation: a retrospective cohort study

Table 2 Ventilator parameters before venovenous extracorporeal membrane oxygenation

	All (n = 106)	Survivor (n = 50)	Non-survivor (n = 56)	P
Just after intubation
P_aO₂/F_iO₂ (mmHg)	112 ± 76	90 ± 55	129 ± 85	0.009*
Peak inspiratory pressure (cmH₂O)	33 ± 6	32 ± 5	33 ± 6	0.86
Mean airway pressure (cmH₂O)	18 ± 4	18 ± 4	18 ± 5	0.85
PEEP (cmH₂O)	12 ± 3	12 ± 3	12 ± 3	0.56
Dynamic driving pressurea^a (cmH₂O)	21 ± 5	21 ± 5	22 ± 5	0.86
Measured tidal volume (ml/kg)	7.7 ± 2.3	7.7 ± 2.3	7.8 ± 2.3	0.73
Dynamic compliance^b (ml/cmH₂O)	22 ± 9	23 ± 10	21 ± 8	0.15
Oxygen index^c	25 ± 19	29 ± 22	21 ± 15	0.11
Just before ECMO
P_aO₂/F_iO₂ (mmHg)	72 ± 17	72 ± 19	72 ± 16	0.93
Peak inspiratory pressure (cmH₂O)	36 ± 6	35 ± 5	37 ± 6	0.16
Mean airway pressure (cmH₂O)	21 ± 4	21 ± 4	22 ± 4	0.13
PEEP (cmH₂O)	14 ± 3	14 ± 3	14 ± 3	0.79
Dynamic driving pressure^a (cmH₂O)	22 ± 6	21 ± 5	23 ± 6	0.22
Measured tidal volume (ml/kg)	6.7 (6–7.8)	6.8 (6.1–8.7)	6.7 (5.8–7.7)	0.22
Dynamic compliance^b (ml/cmH₂O)	19 (15–23)	21 (15–25)	17 (12–21)	0.01*
Oxygen index^c	39 ± 13	39 ± 14	38 ± 13	0.66
Difference
∆ P_aO₂/F_iO₂ (mmHg)	−16 (−71–9)	0 (−51–21)	−31 (−95–5)	0.009*
∆ Peak inspiratory pressure (cmH₂O)	4 ± 6	4 ± 6	4 ± 7	0.18
∆ PEEP (cmH₂O)	3 ± 4	3 ± 3	3 ± 4	0.92
∆ Dynamic driving pressure^a (cmH₂O)	1 ± 6	1 ± 6	1 ± 7	0.33
∆ Measured tidal volume (ml/kg)	−0.3 (−1.9–0.8)	0 (−1.5–1.2)	−0.8 (−1.9–0.2)	0.05*
∆ Dynamic compliance^b (ml/cmH₂O)	−2 ± 11	−1 ± 11	−3 ± 11	0.72
∆ Oxygen index^c	14 ± 2	10 ± 21	17 ± 19	0.35

Data were presented as mean ± standard deviation in normal-distributed numerical variables, median (interquartile range) in numerical variables not normal-distributed, and n (%) in categorical variables. ECMO Extracorporeal membrane oxygenation, PEEP Positive end expiratory pressure. ^aDriving pressure = (Peak inspiratory pressure – Positive end-expiratory pressure)
^bDynamic pulmonary compliance = Measured tidal volume/ Driving pressure
^cOxygen index = [(Mean airway pressure□x□FiO₂□x 100)/ arterial oxygen tension]
*p < 0.05. ∆: The data obtained before ECMO - the data obtained after intubation

ISSN: 1471-2466