PMI Guide PS Setting in Pressure Support-ventilated Patients

Pressure support ventilation (PSV) is an assistant mechanical ventilation mode, that is widely implemented in mechanical ventilation treatment but there are no exact guidelines to guide PS setting. Traditional PS setting strategy (VT/PBW 6-8ml/kg and RR 20-30 breaths/min)has risks of excessive or insufficient assistance. Inspiratory muscle pressure index (PMI) is a noninvasive respiratory mechanical indicator and is available at the bedside. PMI was correlated with inspiratory effort and has the potential ability to predict low inspiratory effort and high inspiratory effort. The primary objective of this study is to investigate the clinical validity of a PMI-guided PS setting strategy. Specifically, the investigators aim to evaluate its impact on inspiratory effort as well as its potential for lung and diaphragm protection. Additionally, the investigators seek to assess the effect of this ventilation strategy on mechanical ventilation outcomes while evaluating the feasibility of our trial protocol.