OBJECTIVE: To explore the correlation between mechanical power normalized to dynamic lung compliance (Cdyn-MP) and weaning outcomes and prognosis in mechanically ventilated patients. METHODS: A prospective, observational cohort study was conducted. Patients who underwent invasive mechanical ventilation (IMV) for more than 24 hours and used a T-tube ventilation strategy for extubation in the intensive care unit (ICU) of Lianyungang First People's Hospital and Lianyungang Second People's Hospital between January 2022 and December 2023 were enrolled. The collected data encompassed patients' baseline characteristics, primary causes of ICU admission, vital signs and laboratory indicators during the initial spontaneous breathing trial (SBT), respiratory mechanics parameters within the 4-hour period prior to the SBT, weaning outcomes and prognostic indicators. Mechanical power (MP) and Cdyn-MP were calculated using a simplified MP equation. Univariate and multivariate Logistic regression analyses were utilized to determine the independent risk factors associated with weaning failure in patients undergoing mechanical ventilation. Restricted cubic spline (RCS) analysis and Spearman rank-sum test were employed to investigate the correlation between Cdyn-MP and weaning outcomes as well as prognosis. Receiver operator characteristic curve (ROC curve) was constructed, and the area under the ROC curve (AUC) was computed to evaluate the predictive accuracy of Cdyn-MP for weaning outcomes in mechanically ventilated patients. RESULTS: A total of 366 patients undergoing IMV were enrolled in this study, with 243 cases classified as successful weaning and 123 cases classified as failed weaning. Among them, 23 patients underwent re-intubation within 48 hours after the successful withdrawal of the first SBT, non-invasive ventilation, or died. Compared with the successful weaning group, the patients in the failed weaning group had significantly increased levels of sequential organ failure assessment (SOFA) score, body temperature and respiratory rate (RR) during SBT, and respiratory mechanical parameters within the 4-hour period prior to the SBT [ventilation frequency, positive end-expiratory pressure (PEEP), platform pressure (Pplat), peak inspiratory pressure (Ppeak), dynamic driving pressure (ΔPaw), fraction of inspired oxygen (FiO CONCLUSION: Cdyn-MP is related to weaning outcomes and prognosis in mechanically ventilated patients, and has good predictive ability in assessing the risk of weaning failure.