The Impact of Low Versus High Positive End-expiratory Pressure on Diaphragm Function, Ventilation Efficiency, and Lung Mechanics

The goal of this interventional study is to evaluate the effect of different positive end-expiratory pressures (PEEP) on lung and diaphragm function in patients mechanically ventilated with pressure support ventilation in the intensive care unit. The main questions aim to answer: Does higher PEEP level affect diaphragm contractions and ventilatory efficiency? Does higher PEEP level limit inspiratory efforts? Does higher PEEP level affect lung compliance? The participants will be subjected to three different PEEP levels during pressure support ventilation: Low PEEP (4 cmH2O), Medium PEEP (10 cmH2O), High PEEP (16 cmH2O). The lung and diaphragm function will be evaluated using high-resolution esophageal manometry, electrical activity of the diaphragm, external diaphragm ultrasound and spirometric ventilator data.