Evaluation of Esophageal Pressures in Mechanically Ventilated Obese Patients

BACKGROUND: Patients who are obese are at risk for developing high pleural pressure, which leads to alveolar collapse. Esophageal pressure (P_es) can be used as a surrogate for pleural pressure and can be used to guide PEEP titration. Although recent clinical data on P_es-guided PEEP has shown no benefit, its utility in the subgroup of patients who are obese has not been studied.

METHODS: The Medical Information Mart for Intensive Care-III critical care database was queried to gather data on P_es in subjects on mechanical ventilation. P_es in obese and non-obese groups were compared, and a subgroup analysis was performed in subjects with class III obesity. Thereafter, empirical and P_es-guided PEEP protocols of a recently published trial were theoretically applied to the obese group and ventilator outcomes were compared.

RESULTS: A total of 105 subjects were included in the study. The average end-expiratory P_es in the obese group was 18.8 ± 5 cm H₂O compared with 16.8 ± 4.8 cm H₂O in the non-obese group (P < .05). If P_es-guided PEEP protocol was to be applied to those in the obese group, then the PEEP setting would be significantly higher than empirical PEEP setting. These findings were accentuated in the subgroup of subjects with class III obesity.

CONCLUSIONS: Individualization of PEEP with P_es guidance may have a role in patients who are obese.