RESUMEN
Background and Aims: The timing of transition from non-invasive ventilation (NIV) to invasive ventilation in the intensive care unit (ICU) is uncertain due to a lack of clinical evidence. This study aimed to identify the optimal timing of intubation in patients with respiratory failure managed with NIVs. Methods: A single-center observational study was conducted in Tokyo, Japan. Patients in the ICU managed with NIV between 2013 and 2022 were screened. The primary outcome was 28-day invasive ventilator-free days. Statistical analyses used locally estimated scatter plot smoothing (LOESS) and generalized linear mixed models to estimate the association between the timing of transition and prolonged intubation duration. Results: During the study period, 139 of 589 adult ICU patients receiving NIV transitioned to invasive ventilation. The LOESS curve indicated the longest 28-day ventilator-free days around 24 h after NIV initiation, after which the primary outcome decreased linearly. Late intubation after 24 h of NIV initiation was associated with fewer 28-day ventilator-free days (adjusted mean difference: -0.22 days [95% confidence interval: -0.31, -0.13]). Conclusion: We identified a non-linear association between the timing of intubation and 28-day invasive ventilator-free days. The critical 24-h time window for patients on NIV was associated with longer 28-day invasive ventilator-free days.