Pharmacokinetics of Dextran-70 in patients with cirrhosis and ascites undergoing therapeutic paracentesis.

BACKGROUND/AIM: Dextran-70 is frequently used as a plasma expander in patients with cirrhosis treated with large-volume paracentesis to prevent post-paracentesis hypovolemia, which is thought to develop after 24 h following the procedure. However, there are no studies on Dextran-70 pharmacokinetics in cirrhosis. METHODS: Nine patients with alcoholic cirrhosis and tense ascites treated with a 5-1 paracentesis were given 500 ml of Dextran-70. Blood samples to measure the plasma concentration of dextran were obtained 15 and 30 min, 1, 2, 3, 6, 12 and 24 h and 2 and 6 days after the end of the infusion. Nine healthy volunteers were studied in identical fashion after infusion of 100 ml of Dextran-70. The plasma concentration of dextran was determined by the anthrone method. A bicompartmental model was used to analyze the pharmacokinetic parameters. RESULTS: There were no significant differences between patients with cirrhosis and controls in the volume of distribution (7.7 +/- 0.6 vs. 7.3 +/- 1.21), half-life of the first and second component of plasma disappearance (2.96 +/- 0.69 and 80.3 5.9 h in patients with cirrhosis vs 2.82 +/- 0.69 and 67.1 +/- 10.7 h in controls). CONCLUSIONS: The pharmacokinetics of Dextran-70 in patients with cirrhosis and ascites after large-volume paracentesis is similar to that in controls. This may explain why Dextran-70 is less effective than albumin in preventing paracentesis-induced hypovolemia, which starts after most Dextran fraction has disappeared from plasma.

Comparison of hypertonic saline/dextran versus hypertonic saline/hetastarch for resuscitation of hypovolemia.

In the present study, we compare resuscitation of bled sheep with hypertonic saline/dextran or hypertonic saline/hetastarch. Unanesthetized sheep were subjected to 2 h of hemorrhagic hypotension and then resuscitated with 200 ml of 7.5% NaCl solution made up to include either 6% dextran 70 (Macrodex) or 6% hetastarch (Hespan). Both solutions provided an immediate and sustained improvement in arterial pressure and cardiac output. The hypertonic saline/dextran provided a slightly better overall response as mean arterial pressure, cardiac output and central venous pressure were higher in the dextran group at all times post resuscitation. However, only the differences in arterial pressure and initial plasma volume expansion were statistically significant. The somewhat better response to hypertonic saline/dextran may be explained by the higher oncotic pressures generated by dextran compared to equal concentrations of hetastarch.

Comparison of hypertonic saline/dextran versus hypertonic saline/hetastarch for resuscitation of hypovolemia

In the present study, we compare resuscitation of bled sheep with hypertonic saline/dextran or hypertonic saline/hetastarch. Unanestherized sheep were subjected to 2h of hemorrhagic hypotension and then resuscitated with 200 ml of 7.5% NaCl solution made up to include either 6% dextran 70 (Macrodex) or 6% hetastarch (Hespan). Both solutions provided an immediate and sustained improvement in arterial pressure and cardiac output. The hypertonic saline/dextran provided a slightly better overall response as mean arterial pressure, cardiac output and central venous pressure were higher in the dextran group at all times post resuscitation. However, only the ddifferences in arterial pressure and initial plasma volume expansion were statistically significant. The somewhat better response to hypertonic saline/dextran may be explained by the higher oncotic pressures generated by dextran compared to equal concentrations of hetastarch