Effect of PEEP=5cmH2O vs PEEP=0cmH2O PSV Strategies During SBT on Successful Disconnection From Mechanical Ventilation

Mechanical ventilation is the most common means of life support in intensive care unit. Daily spontaneous breathing trial (SBT) is the most effective method to evaluate whether patients on mechanical ventilation can be removed from the ventilator, thus reducing mechanical ventilation duration and ventilator-related complications. Pressure support ventilation and T-piece ventilation are the two most commonly used SBT methods, lasting from 30 minutes to 2 hours. However, the parameter setting for SBT using PSV method has not been completely agreed, especially regarding the use of positive end-expiratory pressure (PEEP). Therefore, we intend to conduct a single-center, prospective, randomized, controlled study to evaluate the impact of PEEP=0cmH2O and PEEP=5cmH2O on extubation success rate and re-intubation rate in mechanically ventilated patients, to provide high-level clinical evidence on the use of PEEP for SBT in patients with mechanical ventilation, so as to reduce the duration of mechanical ventilation and complications related to mechanical ventilation.

Patients who met the withdrawal screening criteria were randomly divided into groups for self-breathing test by PSV method with low pressure support level. Parameters of each group were as follows. In the experimental group, PS = 8 cmH2O, PEEP= 5 cmH2O, and FiO2 level was consistent with that before SBT.The control group: PSV mode, PS = 8 cmH2O, PEEP=0 cmH2O, FiO2 level was consistent with that before SBT.The duration of the spontaneous breathing test was 30 minutes, and the results of the spontaneous breathing test were evaluated at the end of the test.Endotracheal intubation was removed if the patient was successfully assessed for spontaneous breathing. Record the date and time of extubation.Patients with endotracheal intubation were treated with nasal hyperflow oxygen therapy for respiratory support.Patients with SBT failure were reconnected to the ventilator, and mechanical ventilation was given according to the ventilation mode and parameters before the spontaneous breathing test.The reasons for SBT failure were recorded and these patients were not randomized to SBT.If respiratory failure occurs within 48 hours after extubation, the attending physician decides the respiratory treatment plan.These patients were also not included in the subsequent SBT randomization.

Eligibility Criteria:
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).