This document discusses the risks and complications of mechanical ventilation. It describes how mechanical ventilation can affect hemodynamics by impacting venous return and the right and left ventricles. It also explains how mechanical ventilation can cause ventilation-induced lung injury if high tidal volumes or pressures are used. The document recommends using low tidal volumes of 6 ml/kg for patients with acute lung injury or ARDS to reduce this risk. Finally, it discusses how mechanical ventilation can lead to ventilator-induced diaphragm dysfunction over time if passive ventilation is used for too long without allowing the diaphragm to rest. The document advocates limiting the duration of passive ventilation and aiming for a resting effort level to help prevent this complication.