Small increases in extravascular lung water are accurately detected by transpulmonary thermodilution.

Background: Detection of small (10-20%) increases in lung water may be relevant to detect incipient pulmonary edema but no clinically usable method has demonstrated this capability to date.

Methods: In six pigs weighing 28 to 35 kg, we performed 18 determinations of extravascular lung water (EVLW; transpulmonary thermodilution method) before and immediately after the intratracheal introduction of 50 mL of saline solution. Six determinations were performed in normal lung and 12 in edematous lung.

Results: In normal lung, the mean of EVLW increased from 245 +/- 18 mL to 288 +/- 19 mL (p < 0.001) after the intratracheal introduction of 50 mL of saline solution; therefore, 43 of the 50 mL (84%) were detected (range, 37-48 mL). In edematous lung, the EVLW increased from 491 +/- 106 mL to 530 +/- 108 mL after the introduction of 50 mL of saline solution; therefore, 39 of the 50 mL (77%) were detected (range, 15-67 mL).

Conclusion: The transpulmonary thermodilution technique accurately detects small increases in extravascular lung water and may permit accurate diagnosis of incipient pulmonary edema.