Effect of hypoalbuminemia and parenteral nutrition on free water excretion and electrolyte-free water resorption.

Objective: To measure the effect of human albumin supplementation during parenteral nutrition on serum albumin concentrations, colloid oncotic pressure, free water clearance, electrolyte-free water resorption, and sodium excretion.

Design: Prospective, randomized, controlled trial.

Setting: Tertiary care center.

Patients: Thirty adult, hypoalbuminemic patients who required parenteral nutrition.

Interventions: Parenteral nutrition (control) or parenteral nutrition plus human albumin 25 g/L as a continuous infusion (treatment) for a 5-day study period.

Measurements: On days 1 and 5, serum albumin concentration, colloid oncotic pressure, free water clearance, electrolyte-free water resorption, and sodium excretion were measured.

Results: Serum albumin concentrations increased significantly from day 1 to day 5 in both groups (control: 2.0 +/- 0.1 [mean +/- SEM] vs. 2.3 +/- 0.1 g/dL [20 +/- 1 vs. 23 +/- 1 g/L], p = .02; treatment: 2.2 +/- 0.1 vs. 3.5 +/- 0.2 g/dL [22 +/- 1 vs. 35 +/- 2 g/L], p = .0001). Day 5 serum albumin concentrations were significantly higher in the treatment group compared with control (p = .0001). Colloid oncotic pressure increased significantly from day 1 to day 5 in the treatment group (17.8 +/- 0.8 vs. 25.1 +/- 1.0 mm Hg, p = .0001), and was significantly higher than control at day 5 (p = .0001). No significant differences were found for free water clearance, electrolyte-free water resorption, or sodium excretion within or between groups.

Conclusions: In hypoalbuminemic patients, human albumin supplementation during parenteral nutrition results in significant increases in serum albumin concentrations and colloid oncotic pressure, but has no apparent effect on free water clearance, electrolyte-free water resorption, or sodium excretion.