The rapid shallow breathing index (RSBI), the diaphragmatic displacement (DD) and diaphragmatic thickening fraction (DTF) are considered accurate weaning predictors. This study was conducted to investigate new promising tools that predict successful and failed weaning of COPD patients from the ventilatory support. The diaphragmatic rapid shallow breathing index (D-RSBI), which is the ratio between respiratory rate (RR) and the diaphragmatic displacement (DD) is a new promising tool to predict weaning outcome. Aim of work: The aim of this study was to compare the ability of the traditional RSBI and D-RSBI and D-BLI (DD/ B line score) to predict successful weaning in ready-to-wean COPD patients. Methods: We performed a prospective cohort observational study. The study included 100 patients admitted to the Critical Care Department, Faculty of medicine; Cairo University with acute exacerbation of COPD and intubated for more than 48 hours. Results: A total of 66 (66%) patients had successful weaning trial, while 34 (34%) patients failed the weaning trial from which 10 patients had failed SBT from the start and 24 patients were reintubated within 48 hours of extubation. The cutoff value of the new composite parameter (D-BLI) for successful weaning is greater than or equal to 1.48 with (AUC= 0.992), with sensitivity and specificity of 95% and 95%, respectively. The cut-off value of D-RSBI for failed weaning from mechanical ventilation was > 1.7 breaths/min/mm showed 100% sensitivity and 97% specificity (AUC=0.996). The cut-off value of RSBI for failed weaning from mechanical ventilation was > 73.5 breaths/min/L showed 80% sensitivity and 100% specificity (AUC=0.957). There is a strong positive correlation between D-RSBI and RSBI (r = 0.678) (P = < 0.001). Conclusion: D-RSBI (RR/DD) and D-BLI (DD/B line score) were more promising tools than classic RSBI in predicting the weaning outcome. However, further larger studies are needed to validate these results