The impact of albumin on hydraulic permeability: comparison of isotonic and hypertonic solutions.

Hypertonic saline, Dextran, and albumin have been advocated for rapid restoration of intravascular volume. The goal of this study was to define how albumin impacts the effects of hypertonic saline and Dextran on hydraulic permeability. We hypothesized that albumin would decrease the hydraulic permeability (L(p)) of isotonic and hypertonic solutions containing Dextran. Using the modified Landis micro-occlusion technique, single rat mesenteric venules were perfused with either Ringer's + 1% albumin (RA) or hypertonic saline + 1% albumin (HSA). In sequential cannulations of the venules, 1%, 2%, and 3% Dextran was added to the RA perfusion (n = 6) and the HSA perfusion (n = 6). These results were compared with similar studies completed without albumin. Albumin significantly decreased L(p) with all HS solutions studied compared with HS without albumin. Baseline L(p) measurements for RA and HSA solutions were 1.08 +/- 0.07 and 0.51 +/- 0.03, respectively. In the RA group, 2% and 3% Dextran was associated with a lower L(p) of 0.83 +/- 0.04 (P = 0.002) and 0.67 +/- 0.05 (P = 0.002), respectively. In the HSA group, 2% and 3% Dextran was associated with a lower L(p) of 0.37 +/- 0.02 (P = 0.001) and 0.32 +/- 0.02 (P < 0.0001), respectively. All values for L(p) are x 10(-7) cm x s(-1) x cmH2O(-1). Albumin maintains low hydraulic permeability levels during perfusion with hypertonic saline. In the setting of sufficient of endothelial albumin levels, hypertonic saline and Dextran may be advantageous when used for resuscitation by decreasing trans-endothelial fluid flux and augmenting intravascular volume.