among lung compartments, it was expected that they correlate closely. EFFi is easier to study, as it is noninvasive and may be continuously monitored. The study is limited to small groups. However, at health, the results show a low degree of variation, as expected from absence of variability caused by disease. The total separation between health and ARDS indicates that, in mechanically ventilated patients, EFFi may be useful for monitoring of ARDS evolution. This aspect is strengthened by the fact that EFFi may automatically, continuously, and noninvasively be monitored in the individual patient, who then serves as his own standard of reference. EFFi merits further studies in broad materials covering ARDS and other diseases, performed with modern capnographic equipment. n Author disclosures are available with the text of this letter at www.atsjournals.org.

None.

Ventilation with low tidal volumes is associated with a lower risk of development of pulmonary complications in patients without acute respiratory distress syndrome.

No abstract