P. Sheeran, Pilar Anton-Martin, M. Thompson
Pediatric Critical Care Medicine
494 www.pccmjournal.org June 2015 • Volume 16 • Number 5 and without) fully supported on ECMO for acute respiratory distress syndrome (ARDS) (3) developed very high transpulmonary pressures. We used to measure transpulmonary pressure (4, 5) using an esophageal balloon (SmartCath esophageal tube; CareFusion, Yorba Linda, CA) in all severe pediatric ARDS to manage ventilator-induced lung injury, and we used this system also in some extubated patients while on ECMO to minimize the barotrauma. We found a high transpulmonary pressure (> 27 cmH 2 O) only in patients with ARDS (4), whereas other lung diseases fully supported with ECMO (eg, cystic fibrosis patients awaiting for a lung transplantation, patients with bacterial or viral pneumonia or interstitial lung disease) did not show this feature. This aspect is still not well understood; however, we found that the patients with ARDS, even if “fully” supported with ECMO, can develop very high negative pleural pressure when breathing spontaneously. This could be probably due to the fact that these patients maintain a very high respiratory drive that contributes to the increase of the transpulmonary pressure during the dynamic phase of inspiration, this pressure is also increased by the fact that in the ARDS patients there is also an increase of the airways resistances dependent by the flow. We are aware that the esophageal pressure used to estimate the pleural pressure can be limited by the pleural pressure gradient that is normally present in the standing up position; however, according to the best of our knowledge, this measurement is the easiest one to monitor the transpulmonary pressure. We know that our observations are limited to few cases and should be confirmed enrolling some more pediatric spontaneous breathing patients; however, we feel confident to suggest to measure the transpulmonary pressure in all pediatric patients with ARDS supported with ECMO especially when extubated. The authors have disclosed that they do not have any potential conflicts of interest.