[Measurement of extravascular lung water by double-indicator dilution method amd its clinical assessment]

In this study, thermal-dye double-indicator dilution method using Lung water computer (Edwards Laboratories) was used to detect the changes of extravascular lung water (EVLW) in 14 patients, including 8 head injuries, one multiple injury, and 5 burns. The coefficient of variation of multiple readings at the same time was 5.04 +/- 3.64% (M +/- SD, n = 180), so reproducibility was excellent. EVLW showed no correlation with cardiac index, Qs/Qt ratio, PAO2/PaO2 ratio, and PaO2/FiO2 ratio, but did show significant correlation with pulmonary capillary wedge pressure (PCWP) (r = 0.50, n = 54, p less than 0.01). In non-septic period of burn patients, EVLW showed good correlation with COP-PCWP gradient (r = -0.75, n = 54, p less than 0.01), better correlation than with PCWP only. In septic period, it had no correlation with the gradient, probably due to the enhanced pulmonary capillary permeability. Although it is very difficult to determine the threshold of EVLW to diagnose pulmonary edema, the elevation of EVLW appeared earlier than the changes of X-ray films. In estimate of EVLW, we must always take into consideration changes in effective vascular bed and pulmonary capillary permeability. The measurement of EVLW was also of much help in the differential diagnosis of pulmonary edema and other lung diseases.