PURPOSE: This study aims to evaluate the role of diaphragmatic dysfunction in extubation failure among patients at high risk of reintubation. MATERIAL AND METHODS: This prospective cohort study was carried out at a intensive care unit in China. Adult patients who had been intubated for more than 24 h and ready for extubation were included in the study if they exhibited a high risk of extubation failure. Diaphragm dysfunction was defined as a diaphragmatic thickening fraction <
30 % or diaphragmatic excursion <
10 mm. The primary outcome was defined as extubation failure, which includes either reintubation or death within the initial 7 days following extubation. RESULTS: Out of the 113 patients, 27 (23.89 %) experienced extubation failure, with diaphragm dysfunction diagnosed in 63 (55.75 %) individuals. Patients who failed extubation were significantly more likely to have diaphragm dysfunction (85.19 % vs. 46.51 %, p <
0.01). In the Cox-proportional hazards regression analysis, diaphragm dysfunction and the Medical Research Council score were found to be associated with extubation failure. The adjusted hazard ratios were 4.56 [95 % CI: 1.56-13.33] and 0.93 [95 % CI: 0.88-0.99]. Both variables were closely correlated with extubation failure showing statistical significance. CONCLUSION: Diaphragm dysfunction could contribute to an elevated extubation failure rate.