[Studies on pre- and postoperative extravascular lung water changes in patients with esophageal cancer]

Pre- and postoperative extravascular lung water (EVLW) changes in a series of twenty patients with esophageal cancer were studied using thermal-dye double-indicator dilution method. Preoperative EVLW was 8.2 +/- 2.3 ml/kg (M +/- SD), being greater as compared to the normal range of EVLW. The pattern of postoperative EVLW changes varied between patients and changes could not be predicted by the conventional examinations including chest X-ray, determination of pulmonary hemodynamics and blood gas analysis. Analysing the relationship between the changes in COP-PWP gradient and EVLW, COP-PWP gradient decreased on the first postoperative day regardless of the EVLW changes. With regard to the changes for the 2nd to the 3rd day or for the 3rd to the 4th day, however, the patients with elevating EVLW showed falling COP-PWP gradient, whereas the patients having decreasing EVLW had an increase in COP-PWP gradient. Especially, the patients in which EVLW had increased during the 3rd to the 4th day showed a remarkable rise of PWP possibly due to depressed left ventricular function. It is considered that the EVLW increase on the first postoperative day is attributable to an alteration of the permeability characteristics of alveolar capillary but that the increase in the 3rd to 4th day is simply due to an elevated hydrostatic pressure. This suggests that there are two different kinds of mechanism involving in the production of wet lung following esophageal cancer surgery.