Effect of Ventilator Mode on Ventilator-Free Days in Critically Ill Adults: A Randomized Clinical Trial.

Background: Whether the choice of ventilator mode affects outcomes for critically ill patients is unknown.

Research question: What are the effects of three common ventilator modes (volume control vs pressure control vs adaptive pressure control) on death and duration of mechanical ventilation among critically ill adults?

Study design and methods: We conducted a pragmatic, cluster-randomized, crossover pilot trial among adults receiving invasive mechanical ventilation in a medical intensive care unit between November 1, 2022 and July 31, 2023. Each month, patients in the participating unit were assigned to receive volume control, pressure control, or adaptive pressure control during continuous mandatory ventilation. The primary outcome was ventilator-free days through 28 days.

Results: Among 566 patients included in the primary analysis, the median proportion of ventilator mode assessments in the assigned mode during the first 72 hours was 100% in each group. The median number of ventilator-free days was 23 [IQR, 0-26] in the volume control group, 22 [0-26] in the pressure control group, and 24 [0-26] in the adaptive pressure control group (P=0.60). The median tidal volume was similar in the three groups, but the percentage of breaths larger than 8mL/kg of predicted body weight differed between volume control (median, 4.0%; IQR, 0.0-14.1), pressure control (10.6%; 0.0-31.5), and adaptive pressure control (4.7%; 0.0-19.2).

Interpretation: This pilot trial establishes the feasibility of conducting a cluster-randomized, crossover trial of ventilator mode among critically ill adults receiving invasive mechanical ventilation and demonstrates differences in intermediate outcomes that warrant further investigation in a larger trial.