Tense ascites redefined: renal consequences of tense ascites in decompensated cirrhotics.

Cirrhotics with tense ascites fail to achieve increased diuresis in the supine position. To assess the role of inferior vena cava compression in this phenomenon, we studied cirrhotics with mild to moderate (n = 11) and tense (n = 2) ascites, and patients with membranous inferior vena cava obstruction (n = 2) before and after balloon dilatation, in the sitting, supine and 10 degrees head down tilted positions for 2 hours each. Urinary output (p < 0.005), creatinine clearance (p < 0.025) and sodium excretion (p < 0.025) increased in cirrhotics with mild to moderate ascites in the supine position, and further in the head down position. Similar changes occurred in patients with inferior vena cava membrane. In cirrhotics with tense ascites, these parameters did not change significantly in the supine position, but increased in the head down position. We conclude that failure to augment diuresis in the supine position in cirrhotics with tense ascites is not due to inferior vena cava obstruction alone but is probably also due to compression of the collateral vessels. This clinical observation may serve as a criterion for diagnosing tense ascites.