Case scenario: power of positive end-expiratory pressure: use of esophageal manometry to illustrate pulmonary physiology in an obese patient.

1320 December 2014 H YPOXEMIA is a commonly encountered problem in mechanically ventilated patients. Treatment of hypoxemia relies on the titration of FIO2 and positive end-expiratory pressure (PEEP) to optimize PaO2. Modern ventilation strategies aimed at minimizing lung injury while simultaneously managing hypoxemia have improved mortality in respiratory failure, but the ideal strategy for lung-protective ventilation remains controversial.1,2 PEEP has a variety of positive effects, including improved oxygenation,3,4 decreased ventilator-induced lung injury,5,6 and decreased ventilator-associated pneumonia.7 However, its routine use, and the most appropriate value, continues to be debated.8 Furthermore, PEEP titration can be challenging in an individual patient, and data on how to best titrate PEEP to improve outcomes are lacking.9 Use of an esophageal balloon can facilitate a physiologic approach to PEEP titration based on respiratory mechanics.9,10 Esophageal pressure can be used to estimate pleural pressure and assist in titrating PEEP to a positive end-exhalation transalveolar pressure. We describe an obese patient with intracerebral hemorrhages and persistent hypoxemia in the neuroscience intensive care unit whose hypoxemia improved with increased PEEP, titrated using esophageal manometry. We provide a discussion of the rationale and process for the titration of PEEP in mechanically ventilated patients using esophageal manometry.