• Alessandro Ghiani, Joanna Paderewska, Alexandros Sainis, Alexander Crispin, Swenja Walcher, and Claus Neurohr.
• Department of Pneumology and Respiratory Medicine, Schillerhoehe Lung Clinic (Robert Bosch Hospital GmbH), Solitudestr. 18, 70839 Gerlingen, Germany.
• J Intensive Care. 2020 Jan 1; 8: 19.

BackgroundSeveral studies have assessed predictors of weaning and extubation outcome in short-term mechanically ventilated patients, but there are only few studies on predictors of weaning from prolonged mechanical ventilation.MethodsRetrospective, single-center, observational study at a specialized national weaning center in Germany. Patients' medical records were reviewed to obtain data on demographics, comorbidities, respiratory indices, and the result of a prospectively documented, standardized spontaneous breathing trial (SBT) upon admission to the weaning center. Respiratory indices assessed were the ventilatory ratio (VR) and parameters derived from calculated mechanical power (MP). Predictors associated with failure of prolonged weaning and failure of the SBT were assessed using a binary logistic regression model.ResultsA total of 263 prolonged mechanically ventilated, tracheotomized patients, treated over a 5-year period were analyzed. After 3 weeks of mechanical ventilation, patients with unsuccessful weaning failed a SBT more frequently and showed significantly increased values for inspiratory positive airway pressure, driving pressure, VR, absolute MP, and MP normalized to predicted body weight and dynamic lung-thorax compliance (LTC-MP). In the logistic regression analyses, variables independently correlated with weaning failure were female gender (adjusted odds ratio 0.532 [95% CI 0.291-0.973]; p = 0.040), obesity (body mass index ≥ 30 kg/m2) (2.595 [1.210-5.562]; p = 0.014), COPD (3.209 [1.563-6.589]; p = 0.002), LTC-MP (3.470 [1.067-11.284]; p = 0.039), PaCO2 on mechanical ventilation (1.101 [95% CI 1.034-1.173]; p = 0.003), and failure of the SBT (4.702 [2.250-9.825]; p < 0.001). In addition, female gender (0.401 [0.216-0.745]; p = 0.004), LTC-MP (3.017 [1.027-8.862]; p = 0.046), and PaCO2 on mechanical ventilation (1.157 [1.083-1.235]; p < 0.001) were independent risk factors for an unsuccessful SBT.ConclusionsIn the present study, the derived predictors of weaning point to a crucial role of the workload imposed on respiratory muscles during spontaneous breathing. Mechanical power normalized to lung-thorax compliance was independently correlated with weaning outcome and may identify patients at high risk for weaning failure.© The Author(s) 2020.

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