[ARDS and mechanical ventilation--"primum nil nocere"]

Abstract

Present evidence demonstrates that mechanical ventilation in patients with adult respiratory distress syndrome (ARDS) contributes to the ongoing pulmonary damage, a condition known as "ventilator lung". Data from various animal studies indicate that volume, rather than pressure, is probably the main culprit. Accordingly, clinicians should use tidal volumes smaller than those usually recommended. This approach leads to hypercapnia (i.e. so-called "permissive hypercapnia"), which seems to have very few adverse effects and might even be beneficial. Moreover, there is an added risk of atelectasis, which can be prevented by the application of positive end-expiratory pressure (PEEP). The present study reviews the pathophysiological mechanisms by which mechanical ventilation is injurious to the lung, and attempts to outline an approach aimed at minimizing such damage.