Prevalence of Reverse Triggering in Early ARDS: Results from a Multicenter Observational Study.

Abstract Background The prevalence of reverse triggering (RT) in the early phase of acute respiratory distress syndrome (ARDS) is unknown. Research Question During early ARDS, what is the proportion of patients affected by RT, its potential predictors and association with clinical outcomes? Study Design and Methods: This study is prospective, multicenter, and observational. Patients who met the Berlin definition of ARDS with less than 72 h of mechanical ventilation and were not under paralysis with neuromuscular blockers were screened. A 30-minute recording of respiratory signals was obtained from the patients as soon as they were enrolled, and the number of breaths with RT were counted. Results One hundred patients were included. ARDS was mild to moderate in 92% of them. The recordings were obtained after a median (interquartile range) of 1 (1–2) days of ventilation. Fifty subjects had RT, and most of these events (97%) were not associated with breath stacking. Detecting RT was associated with lower tidal volume and less opiate infusion. The presence of RT was not associated with time to discontinuation of mechanical ventilation (sub-distribution hazard ratio: 1.03; 95% CI: 0.6–1.77) but it was possibly associated with a reduced hospital mortality (hazard ratio: 0.65; 95% CI: 0.57–0.73). Interpretation Fifty percent of patients under assist-control ventilation for mild or moderate ARDS, sedated and non-paralyzed, present RT without breath-stacking on the first day of mechanical ventilation. RT may be associated with low tidal volumes.