Early vs. Delayed Switching from Controlled to Assisted Ventilation: A Target Trial Emulation

In critically ill patients receiving invasive mechanical ventilation, switching from controlled to assisted ventilation is a crucial milestone towards ventilator liberation. The optimal timing for switching to assisted ventilation has not been studied. Our objective was to determine whether a strategy of early as compared to delayed switching affects the duration of invasive mechanical ventilation, ICU length of stay, and mortality. We conducted a target trial emulation using the prospective, global WEAN SAFE dataset. Patients were eligible for switching if still on controlled mechanical ventilation, not receiving neuromuscular blockers, and PaO2/FiO2 ratio >150 mmHg. We compared an "early switching" strategy (switch within one day after reaching switching eligibility criteria) to a "delayed switching" strategy (switch one or more days after reaching the switching eligibility criteria). Primary outcome was the 28-day cumulative incidence of successful extubation. Secondary outcomes included 28-day and 90-day ICU discharge and ICU mortality. 1489 patients met the switching eligibility criteria. The early switch group had, on average, 4 additional days of being successfully extubated over the 28-day period (95% CI: 3, 6; P<0.001) compared to the delayed group, with a higher difference in cumulative incidence of successful extubation at day 28 (7%; 95% CI: 0, 13; P=0.04). Early switching was associated with an 11% higher cumulative incidence of ICU discharge at day 28 (95% CI: 7, 18; P<0.001) and an average of 7 additional days discharged from the ICU over the 90-day period (95% CI: 4, 12; P<0.001) compared to delayed switching. ICU mortality rates did not differ between the strategies. Early switching from controlled to assisted ventilation is associated with shorter duration of invasive mechanical ventilation and ICU stay compared to delayed switching.