Pleural Effusion

Pleural effusion is a fluid collection within the pleural space and is a common finding in mechanically ventilated patients. It is frequently related to fluid overload, hypnotic states, heart failure, and altered pleural pressure due to atelectasis or pneumonia. Recent literature has shown that its incidence within ARDS is increasing, even if, in most cases, at least in the early phases, it seems of limited clinical relevance.

Most of the knowledge of Pleural Effusion and of its interaction with lung/chest wall mechanics derives from a small number of experimental studies and from some clinical studies, in most of the cases performed with normal lung parenchyma. In ARDS, however, Pleural Effusion seems to have a little effect “per se” on tidal mechanics and oxygenation (increasing elastance and reducing PO2), which are already profoundly affected by the lung injury itself.