Use of Esophageal Pressure Monitoring (EPM) in Morbidly Obese Patients on Mechanical Ventilation

SESSION TITLE: Critical Care Posters II SESSION TYPE: Original Investigation Poster PRESENTED ON: Wednesday, October 28, 2015 at 01:30 PM - 02:30 PM PURPOSE: Airway pressures are often elevated in morbidly obese patients when they are mechanically ventilated. The current standard of practice is to limit ventilator plateau pressure (PPLAT) to less than 30 cmH20 to prevent ventilation induced lung injury (VILI) and mechanical complications such as pneumothorax. In obese patients PPLAT may not be an accurate predictor of transpulmonary pressure as their pleural pressure is variable. EPM provides a more accurate estimate of transpulmonary pressure and more accurately informs the titration of Positive Pressure Ventilation. METHODS: In this retrospective study, we reviewed the charts of all mechanically ventilated adult patients in whom esophageal pressure monitoring was performed from April 2010 to February 2014. 26 patients had esophageal pressure monitoring. Full data sets were recorded for 17 patients and were included in the study. Their age, body mass index (BMI), as well as the tidal volume, plateau pressure, PEEP, esophageal pressure, intra-abdominal pressure and chest compliance were recorded. A linear regression analysis was performed. RESULTS: The mean and standard deviation of BMI, chest wall compliance, PPLAT, PEEP and tidal volumes were 44.5+ 15, 130+97 ml/cmH2O, 40+9.9 cmH2O, 22+6 cmH2O, 322+114 ml respectively. There was no correlation between intra-abdominal pressures and transpulmonary pressure or between chest wall compliance and body mass index. The P values on both sides were 0.47 and 0.67 respectively. The P value for transpulmonary pressure and plateau pressure was 0.0051 and it was significant. CONCLUSIONS: Morbidly obese patients with elevated plateau pressure demonstrated variable chest wall compliance. BMI and intra-abdominal pressure had no correlation with transpulmonary pressure (as estimated via EPM), Pplat significantly overestimated transpulmonary pressure, and therefore overestimates the risk of VILI. CLINICAL IMPLICATIONS: In morbidly obese patients with elevated Pplat, low dynamic and static lung compliance and/or difficulty oxygenating, EPM has value in more accurately assessing transpulmonary pressures, assessing compliance curves, and in titrating pressure-dependent ventilator settings. DISCLOSURE: The following authors have nothing to disclose: Arul Chandran, Stevan Whitt, Troy Whitacre, Yuji Oba, Eric Johnson, Joe Devasahayam, Fahad Omar No Product/Research Disclosure Information