Thirteen patients with cirrhosis and tense ascites (six with and seven without peripheral edema) underwent 4- to 15-liter paracentesis without intravenous "colloid" replacement. Cardiac output increased from 6.6 +/- 0.7 liters per min at baseline to 8.2 +/- 0.7 liters per min (p less than 0.003) 1 hr after large-volume paracentesis completion and fell to 7.5 +/- 0.69 liters per min (p less than 0.05 vs. baseline, p less than 0.02 vs. 1 hr) 24 hr after large-volume paracentesis completion. There was no change in mean arterial pressure or mean pulmonary artery pressure. Central venous pressure fell from 9.1 +/- 0.8 mm Hg at baseline to 8.6 +/- 1.4 mm Hg 1 hr post-large-volume paracentesis to 6.8 +/- 1.0 mm Hg (p less than 0.005 vs. baseline, p less than 0.02 vs. 1 hr value) at 24 hr, and pulmonary capillary wedge pressure fell from 13.1 +/- 0.9 to 11.1 +/- 1.3 mm Hg 1 hr after large-volume paracentesis and to 9.89 +/- 1.2 (p less than 0.01 vs. baseline, p less than 0.03 vs. 1 hr after large-volume paracentesis) at 24 hr. Heart rate fell from 90 +/- 3.0 to 85 +/- 2.9 beats per min (p less than 0.01) 1 hr after large-volume paracentesis completion, but increased to 89 +/- 2.5 beats per min (p less than 0.02 vs. 1 hr after large-volume paracentesis) at 24 hr.(ABSTRACT TRUNCATED AT 250 WORDS)