How important is the measurement of extravascular lung water?

Accurate quantification of extravascular lung water is an important issue in the management of patients with pulmonary edema. The single transpulmonary thermal indicator method has been available since the late 1990s. Its simplicity and easy application make it clinically attractive.

Several experimental studies have confirmed the accuracy of the single transpulmonary thermal indicator technique in comparisons with postmortem gravimetric method. Whereas changes in extravascular lung water of less than 100-200% are undetectable by other clinically applicable methods of lung injury assessment (chest radiograph and oxygenation), the single transpulmonary indicator has proven highly sensitive to small (10-20%) increases and is therefore useful to detect incipient pulmonary edema. In patients with sepsis or acute respiratory distress syndrome, extravascular lung water measurement offers information unobtainable by other means.

Extravascular lung water can be considered a relevant parameter that contributes to rational management of fluid and vasoactive therapy of many critically ill patients and offers a fuller picture of their overall lung function.