Prospective randomized trial comparing pressure-controlled ventilation and volume-controlled ventilation in ARDS

Study objectives: To compare in-hospital mortality of patients with ARDs ventilated with either pressure-controlled ventilation (PCV) or volume-controlled ventilation (VCV) with a square-wave inspiratory flow. Design: Multicenter and randomized trial. Setting: Twelve medical-surgical ICUs located in tertiary-care hospitals. Patients: Seventy-nine patients having ARDS, as defined by the American-European Consensus Conference. Interventions: Patients were randomly assigned to be ventilated with either PCV (n = 37) or VCV (n = 42). In both instances, inspiratory plateau pressure was limited to less than or equal to 35 cm H2O. Measurements and results: There were no significant differences among the studied groups at the moment of randomization, although there was a trend toward greater renal failure in patients assigned to VCV. Ventilatory settings and blood gases did not significantly differ over time between the two groups. Patients in the VCV group had both a significantly higher in-hospital mortality rate than those in the PCV group (78% vs 51%, respectively) and a higher number of extrapulmonary organ failures (median, 4 vs 2, respectively). The development of renal failure during the study period was also significantly more frequent among VCV patients (64% vs 32%, respectively). Multivariate analysis showed that factors independently associated with an increased mortality rate were the presence of two or more extrapulmonary organ failures (odds ratio [OR], 4.61%; 95% confidence interval [CI], 1.38 to 15.40) and acute renal failure (OR, 3.96; 95% CI, 1.10 to 14.28) but not the ventilatory mode used. Conclusions: The increased number of extrapulmonary organ failures developed in patients of the VCV group was strongly associated with a higher mortality rate. The development of organ failures was probably not related to the ventilatory mode.