Dynamic Airway Driving Pressure and Outcomes in Children With Acute Hypoxemic Respiratory Failure

BACKGROUND: Limited adult data suggest that airway driving pressure might better reflect the potential risk for lung injury than tidal volume based on ideal body weight, and the parameter correlates with mortality in ARDS. There is a lack of data about the effect of driving pressure on mortality in pediatric ARDS. This study aimed to evaluate the effect of driving pressure on morbidity and mortality of children with acute hypoxemic respiratory failure.

METHODS: This retrospective cohort study was performed in a tertiary level pediatric ICU. Children who received invasive mechanical ventilation for acute hypoxemic respiratory failure (defined as P_aO2/F_IO2 < 300 within 24 h after intubation), in a 2-y period were included. The cohort was divided into 2 groups based on the highest dynamic driving pressure (ΔP, calculated as the difference between peak inspiratory pressure and PEEP) in the first 24 h, with a cutoff value of 15 cm H₂O.

RESULTS: Of the 380 children who were mechanically ventilated during the study period, 101 children who met eligibility criteria were enrolled. Common diagnoses were pneumonia (n = 51), severe sepsis (n = 24), severe dengue (n = 10), and aspiration pneumonia (n = 7). In comparison to the group with high ΔP (ie, ≥ 15 cm H₂O), children in the group with low ΔP (ie, < 15 cm H₂O) had significantly lower median (interquartile range) duration of ventilation (5 [4–6] d vs 8 [6–11] d, P < .001], ICU length of stay (6 [5–8] d vs 12 [8–15] d, P < .001], and more ventilator-free days at day 28 (23 [20–24] vs 17 [0–22] d, P < .001). Logistic regression analysis also suggested driving pressure as an independent predictor of morbidity after adjusting for confounding variables. However, there was no statistically significant difference in mortality between the 2 groups (17% in low ΔP vs 24% in high ΔP, P = .38). Subgroup analysis of 65 subjects who fulfilled ARDS criteria yielded similar results with respect to mortality and morbidity.

CONCLUSIONS: Below a threshold of 15 cm H₂O, ΔP was associated with significantly decreased morbidity in children with acute hypoxemic respiratory failure.