Colloid osmotic pressure in pulmonary edema clearance with furosemide.

After tripling of baseline lung water (EVLW), decreasing wedge pressure (PWP) alone for two hours did not decrease EVLW. In 11 of 16 dogs, triple baseline EVLW and a decrease in plasma colloid osmotic pressure (COP) from 21.1 +/- 0.8 to 17.8 +/- 0.8 mm Hg resulted from left atrial balloon inflation at PWP of 28 to 30 mm Hg. With subsequent lowering of PWP to 10 mm Hg, intravenously administered furosemide (1 mg/kg) was given to these 11 dogs. One half hour after furosemide, shunt decreased slightly without decreasing EVLW in all 11 dogs, but by two hours, seven dogs (group 1) decreased EVLW (from 23.2 +/- 1.8 to 11.1 +/- 1.4 ml/kg) and shunt (37.4 +/- 2.0 to 12.9 +/- 2.9 percent), while four dogs (group 2) did not (EVLW: 22.3 +/- 1.4 to 22.5 +/- 0.6 ml/kg: shunt, 36.8 +/- 1.7 to 36.5 +/- 1.9 percent). Group 1 had diuresis, maintained normal blood urea nitrogen and creatinine levels, and increased COP from 17.7 +/- 0.7 to 23.6 +/- 0.5 mm Hg while group 2 was oliguric with elevated BUN and creatinine values and showed no change in COP (17.9 +/- 0.9 to 18.3 +/- 0.6 mm Hg) after furosemide. After decreasing PWP in massive pulmonary edema (triple baseline EVLW), furosemide appeared to enhance edema clearance by changes in COP with diuresis.