Driving Pressure Is Associated With Outcome in Pediatric Acute Respiratory Failure

OBJECTIVES: Driving pressure (ratio of tidal volume over respiratory system compliance) is associated with mortality in acute respiratory distress syndrome. We sought to evaluate if such association could be identified in critically ill children. DESIGN: We studied the association between driving pressure on day 1 of mechanical ventilation and ventilator-free days at day 28 through secondary analyses of prospectively collected physiology data. SETTING: Medical-surgical university hospital PICU. PATIENTS: Children younger than 18 years (stratified by Pediatric Mechanical Ventilation Consensus Conference clinical phenotype definitions) without evidence of spontaneous respiration. INTERVENTIONS: Inspiratory hold maneuvers. MEASUREMENTS AND MAIN RESULTS: Data of 222 patients with median age 11 months (2-51 mo) were analyzed. Sixty-five patients (29.3%) met Pediatric Mechanical Ventilation Consensus Conference criteria for restrictive and 78 patients (35.1%) for mixed lung disease, and 10.4% of all patients had acute respiratory distress syndrome. Driving pressure calculated by the ratio of tidal volume over respiratory system compliance for the whole cohort was 16 cm H2O (12-21 cm H2O) and correlated with the static airway pressure gradient (plateau pressure minus positive end-expiratory pressure) (Spearman correlation coefficient = 0.797; p < 0.001). Bland-Altman analysis showed that the dynamic pressure gradient (peak inspiratory pressure minus positive end-expiratory pressure) overestimated driving pressure (levels of agreement -2.295 to 7.268). Rematching the cohort through a double stratification procedure (obtaining subgroups of patients with matched mean levels for one variable but different mean levels for another ranking variable) showed a reduction in ventilator-free days at day 28 with increasing driving pressure in patients ventilated for a direct pulmonary indication. Competing risk regression analysis showed that increasing driving pressure remained independently associated with increased time to extubation (p < 0.001) after adjusting for Pediatric Risk of Mortality III 24-hour score, presence of direct pulmonary indication jury, and oxygenation index. CONCLUSIONS: Higher driving pressure was independently associated with increased time to extubation in mechanically ventilated children. Dynamic assessments of driving pressure should be cautiously interpreted.