Adaptive Support Ventilation in Acute Respiratory Distress Syndrome

This study will compare two different modes of mechanical ventilation: standard lung protective controlled mandatory ventilation and Adaptive Support Ventilation. The investigators will enroll adult patients with ARDS who are mechanically ventilated and admitted to intensive care units, capturing a population with respiratory failure and significant critical illness. Patient mechanics during each ventilation strategy will be compared before and after crossover.

After obtaining informed consent, the investigators will place an esophageal balloon which will be used for simultaneous measurements of airway pressures (Pao) and esophageal pressures (Pes), to estimate transpulmonary pressures (PL = Pao - Pes), while also measuring Flow and Volume. Use of esophageal balloon catheters is common practice in the ICUs, and standard of care at Beth Israel Deaconess Medical Center is to use these balloons in patients with ARDS. Both the respiratory therapy and physician staff are very comfortable with placement and use. The esophageal balloon will be left in place until extubation. If the balloon is dislodged or removed for clinical purposes, it will not be replaced solely for research purposes unless it occurs on the first day of study measurements.

Patients will then be randomized to be switched to ASV immediately or to be maintained on their current lung protective ventilation settings.