Providing Optimal PEEP During Mechanical Ventilation for Obese Patients Using Esophageal Balloon

This is a research study to determine if identifying an optimal level of positive end-expiratory pressure (PEEP) targeted specifically to individualized patient characteristics will shorten the time on the ventilator. Participants will have catheter placed through the nose into the esophagus to measure the pressure inside the chest. This catheter will remain until the patient is freed from the ventilator. Participants will be randomized to usual care or to have the level of PEEP determined by the esophageal balloon pressure readings. The total time spent on the ventilator will be recorded.