Effects of Low Tidal Volume and Airway Pressure Release Ventilation on Lung Tissue Mechanics in ARDS Patients Under Mechanical Ventilation: A Prospective Randomized Crossover Study

In this arm, participants will receive airway pressure release ventilation (APRV), a form of pressure-controlled mechanical ventilation. The high pressure (Phigh) is set based on the plateau pressure of the LTV mode, with a low pressure (Plow) set at 0 cmH₂O. The high pressure time (Thigh) will be set to 4-6 seconds to maintain alveolar recruitment, while the low pressure time (Tlow) will be set to 0.2-0.6 seconds to optimize expiratory flow. This arm aims to evaluate the effects of APRV on lung tissue mechanics, oxygenation, and overall respiratory function in ARDS patients.