Factors associated with increased extravascular lung water in cardiac tamponade and myocardial ischemia

Objective: To evaluate and compare the factors associated with pulmonary ed ema in cardiac tamponade and myocardial ischemia. Design:Prospective, controlled laboratory study. Setting: Animal research laboratory of a university hospital. Subjects: Fourteen anesthetized dogs. Intervention: Extravascular lung water (EVLW) was measured with thermal ind ocyanine green dye double-indicator dilution method and hemodynamic indices were determined by the pulmonary artery flotation catheter. Seven dogs wer e used in the tamponade model, and seven other dogs were used in the myocar dial ischemia model, Furthermore, ten dogs were dedicated to measure plasma colloid osmotic pressure (COP) and blood gas analysis during cardiac tampo nade and myocardial ischemia, Measurements and Main Results:Mean right atrial pressure (MRAP) (7-->10 mm Hg), pulmonary capillary wedge pressure (PCWP) (10-->13 mm Hg), and EVLW (5 .4-->10.1 mL/kg) increased during tamponade, but all of these indices retur ned to the control level after release of tamponade (MRAP, 7 mm Hg; mean PC WP, 11 mm Hg; mean EVLW, 5.2 mL/kg). Myocardial ischemia caused increases i n PCWP (10-->4 mm Hg) and EVLW (5.6-->9.6 mL/kg), Although PCWP returned to the control level, EVLW remained elevated (9.2 mL/kg) after reperfusion. E VLW had good correlations with MRAP (r(2) = .64, p < .05) and PCWP (r(2) = .62, p < .05) during cardiac tamponade. Despite a fair correlation between EVLW and PCWP during ischemia (r(2) = .73, p < .05), EVLW was not related t o PCWP after reperfusion. COP decreased during myocardial ischemia and at t he reperfusion period, but there was no significant change in COP in the ca rdiac tamponade model. Conclusions: In contrast to a close relation between hydrostatic pressure a nd EVLW in cardiac tamponade, hydrostatic pressure was not a determinant of pulmonary edema during the reperfusion period after myocardial ischemia.