Acute lung injury: an indicator of serious systemic illness.
The history of the acute respiratory distress syndrome (ARDS) parallels that of critical care. Descriptive and colorful names for the condition such as "shock lung," "post perfusion lung," and "traumatic wet lung" clearly communicate the reality that the pulmonary tissue is involved in a pathologic process. It is not difficult to speculate that the focus on the lung originated from the dramatic chest radiographs and gas exchange abnormalities frequently observed in association with the syndrome. However, a named condition does not necessarily dictate the therapeutic approach to it, and a review of some pertinent studies suggests the condition is in fact systemic in nature. Concurrent with this recognition, the need for markers of severity of illness has become more important. Rather than a process needing primarily pulmonary approaches to management, it now seems that ARDS is the result of systemic events with noticeable pulmonary manifestations, which may suffice as a clinical marker for severity of systemic inflammation. Because the pathophysiology has been described elsewhere, this article will focus on the clinical trials that are shaping our perception and management of the syndrome.