Inclusion Criteria:  1) Older than 18; 2) Patients with mechanical ventilation for 24h; 3) Meet the screening standards for daily disconnection; 4) The study complies with the Declaration of Helsinki and China's regulations on clinical trial research, and the patient or his/her family members have informed and agreed to participate in the study.  Exclusion Criteria:  1) Patients undergoing tracheotomy; 2) Patients who refuse to be intubated again after endotracheal intubation is removed; 3) Patients on long-term mechanical ventilation: mechanical ventilation duration was continuous for 21 days, >6 h/d; 4) The attending physician decides the withdrawal plan (e.g., the potential pathology is more favorable to the specific withdrawal plan).