Metabolic responses to spontaneous breathing trial modalities predict liberation from prolonged mechanical ventilation in tracheostomized patients: A prospective cohort study

Whether metabolic parameters can predict liberation from prolonged mechanical ventilation remains unclear. In the prospective cohort study at a university-affiliated respiratory care center (2020–2025), tracheostomized adults with prolonged mechanical ventilation underwent sequential indirect calorimetry during automated tube compensation (ATC) and T-piece breathing. The primary endpoint was successful liberation at discharge, defined as five consecutive days of unassisted breathing. Among 84 patients, 65 (77.4%) achieved successful weaning. Transition from ATC to T-piece significantly increased oxygen consumption (202.0 vs. 219.5 mL/min; P = 0.02). Compared with successfully weaned patients, those who failed demonstrated markedly greater increases in oxygen consumption (30.6% vs. 8.0%; P = 0.004), CO₂ production (26.0% vs. 5.2%; P = 0.04), and energy expenditure (27.7% vs. 7.1%; P = 0.004). Change in energy expenditure yielded the highest discriminatory capacity for weaning failure (area under curve 0.73, 95% confidence interval 0.59–0.86). On multivariable analysis, metabolic changes and inadequate maximal inspiratory pressure showed adjusted association, with effects most pronounced in patients with diabetes or impaired respiratory muscle strength. Exaggerated metabolic responses during ATC-to-T-piece transition independently predict weaning failure. Dynamic metabolic monitoring may complement traditional respiratory indices in assessing weaning readiness.