<qa>  What is the primary purpose of the study?Patients with acute lung injury ALI or acute respiratory distress syndrome ARDS are critically ill and have a high mortality associated with their illness approximately 50. Currently, esophageal pressure monitors are used to optimize inflation pressures and improve oxygenation in conventional mechanical ventilation in patients with ALIARDS. With this in mind, the purpose of this study is twofold: 1 demonstrate that esophageal pressure monitors can easily be inserted in patients undergoing HFO and 2 report the transpulmonary pressures in these patients. 