Mechanical Ventilation in the Acute Respiratory Distress Syndrome

I. Introduction Mechanical ventilation (MV) is critical for survival of many patients with acute lung injury and the acute respiratory distress syndrome (ALI/ARDS). Without MV death may occur within hours to days from acute hypoxemic and hypercarbic respiratory failure. With MV there is more time for administration of therapies specific to the cause of ALI/ARDS, such as antibiotics for pneumonia or sepsis, for the host's immune system to fight infections, and for natural healing processes to occur. However, MV can also cause additional lung injury (ventilator-induced lung injury, VILI), which may delay or prevent recovery from acute respiratory failure. Thus, clinicians are challenged to use MV in a manner that maintains acceptable gas exchange but also avoids VILI.