To Örebro University

Background: Esophageal pressure, a surrogate for pleural pressure, is used to determine transpulmonary pressure and to set appropriate PEEP levels. There is no consensus on the representativity of esophageal pressure for pleural pressure and how to position and inflate the catheter balloon. The aim of this retrospective study1 was to analyze esophageal pressure using multi-level tip manometry (no balloon).

Methods: An esophageal catheter with 12 radially directed tip mano meters at 35 levels one centimeter apart, detecting pressure from pharynx to stomach was placed in 17 patients (BMI >35 kg/m2). Pressure was analyzed integrating measurements from five manometer levels at mid- and lower esophageal level and for all levels between the upper and lower esophageal sphincters at PEEP 0 cmH2O (ZEEP) and after increasing PEEP to 10 cmH2O.

Results: End-expiratory esophageal pressure (PESEE) was 10–12 cmH2O at ZEEP and increased minimally and transiently in whole and mid esophagus when PEEP was increased. Lower esophageal pressure increased more, but started to recede after approximately 20 breaths.

Conclusions: End-expiratory pressure is positive, 10–12 cmH2O at all esophageal levels at FRC in contrast to absolute pleural pressure, which according to established knowledge is negative. There was only a marginal, transient increase in PESEE in response to PEEP. The change in end-expiratory trans-pulmonary and respiratory system pressures in response to a PEEP increase is therefore equal, and lung elastance can be calculated as the chan ge in PEEP divided by the change in end-expiratory lung volume.