Factors affecting the timing of ventilator liberation among patients requiring prolonged mechanical ventilation (≥21 consecutive days) are poorly understood. After tracheostomy placement, ventilator liberation typically involves daily reductions in ventilator support as patients regain the capacity to breathe independently.
To determine the association between ventilator requirements on the day after tracheostomy placement and subsequent weaning duration.
Retrospective review of medical records of adults with tracheostomies treated at an academic medical center from 2011 to 2015. A new ventilator independence score based on ventilator settings on the day after tracheostomy was developed. Scores range from 0% to 100%; higher scores reflect greater levels of unassisted breathing for a greater proportion of the day. A multi-variable competing-risk survival regression model was used to determine the association between the ventilator independence score and time from tracheostomy placement to ventilator liberation.
Of 372 patients, 72% were liberated from mechanical ventilation. The ventilator independence score measured on the day after tracheostomy placement had an area under the receiver operating characteristic curve value of 0.71 (95% CI, 0.65–0.76) for differentiating patients who were liberated within the next 14 days from those who were not. Median time from tracheostomy placement to ventilator liberation was 41 days for patients with a score of 0%, 20 days for scores between 0% and 50%, 15 days for scores between 50% and 75%, and 10 days for scores between 75% and 100%.
A score derived from ventilator settings may help clinicians predict the timing of ventilator liberation in patients requiring prolonged mechanical ventilation.