Driving Pressure Is a Risk Factor for ARDS in Mechanically Ventilated Subjects Without ARDS

BACKGROUND: Driving pressure (Delta P) has been described as a risk factor for mortality in patients with ARDS. However, the role of Delta P in the outcome of patients without ARDS and on mechanical ventilation has received less attention. Our objective was to evaluate the association between Delta P on the first day of mechanical ventilation with the development of ARDS. METHODS: This was a post hoc analysis of a multicenter, prospective, observational, international study that included subjects who were on mechanical ventilation for > 12 h. Our objective was to evaluate the association between Delta P on the first day of mechanical ventilation with the development of ARDS. To assess the effect of Delta P, a logistic regression analysis was performed when adjusting for other potential risk factors. Validation of the results obtained was performed by using a bootstrap method and by repeating the same analyses at day 2. RESULTS: A total of 1,575 subjects were included, of whom 65 (4.1%) developed ARDS. The Delta P was independently associated with ARDS (odds ratio [OR] 1.12, 95% CI 1.07-1.18 for each cm H2O of Delta P increase, P < .001). The same results were observed at day 2 (OR 1.14, 95% CI 1.07-1.21; P < .001) and after bootstrap validation (OR 1.13, 95% CI 1.04-1.22; P < .001). When taking the prevalence of ARDS in the lowest quartile of Delta P (<= 9 cm H2O) as a reference, the subjects with Delta P > 12-15 cm H2O and those with Delta P > 15 cm H2O presented a higher probability of ARDS (OR 3.65, 95% CI 1.32-10.04 [P 5.01] and OR 7.31, 95% CI, 2.89-18.50 [P < .001], respectively). CONCLUSIONS: In the subjects without ARDS, a higher level of Delta P on the first day of mechanical ventilation was associated with later development of ARDS.