Effects of advanced age on extravascular lung water accumulation during coronary artery bypass surgery.

Pulmonary extravascular thermal volume (ETVL) accumulation during aortocoronary bypass grafting (CABG) was compared between nine patients (group 1) aged 49 +/- 2 (SEM) yr and nine patients (group 2) aged 65 +/- 1.2 yr, using the thermal-dye technique. Before extracorporeal bypass (ECB), ETVL was significantly correlated with age and mean ETVL was significantly lower in group 1 (3.93 +/- 0.48 ml/kg body weight) than group 2 (5.93 +/- 0.38 ml/kg). During ECB, ETVL rose to 5.15 +/- 0.65 ml/kg in group 1 (p less than .05) and to 6.38 +/- 0.56 ml/kg in group 2. By the next morning, ETVL had returned to pre-ECB levels. Post-ECB, cardiac index decreased in group 1 and colloid osmotic pressure decreased in both groups, but all values returned to pre-ECB levels by the next morning. Although PaO2 had decreased and pulmonary shunt fraction had increased by this time, changes in these variables did not correlate with changes in ETVL. During ECB, ETVL increased transiently but returned to pre-ECB levels by the next morning.