Objectives: Describe the variation in practice and identify predictors of invasive mechanical ventilation (IMV) use in shock. Explore the association between the timing of IMV initiation ("Early" vs. "Delayed") on shock duration. Design: Multicenter, prospective, observational cohort study between September 2017 and February 2018 Setting: 34 hospitals in the United States and Jordan. Patients: Consecutive, adult, critically ill patients with shock, defined as a systolic blood pressure less than or equal to 90mm Hg, mean arterial pressure less than or equal to 65mm Hg, or need for a vasopressor medication. Interventions: None. Measurements and Main Results: "Early" IMV was defined as starting IMV 0-6 hours of shock onset and "Delayed" IMV was defined as starting IMV between 6 and 48 hours of shock onset. The primary outcome was shock-free days, defined as the number of days without shock after the first 48 hours of shock onset. Variation and predictors of IMV use were examined within the whole cohort as well as the subgroup of those intubated within 0-48 hours of shock onset. Mixed effects modeling with hospital site as a random effect showed that there was 7% variation by site in the use and timing of IMV in this shock cohort. In a propensity-matched model for the timing of IMV, "Early" IMV after shock onset was associated with more shock-free days when compared to "Delayed" IMV in those intubated within 0-48 hours of shock onset (Beta coefficient 0.65 days, 95% CI 0.14-1.16 days). Conclusions: Timing of IMV initiation for patients in shock has potentially important implications for patient outcomes and merits further study.
Keywords: invasive mechanical ventilation; shock; timing; variation in practice.