Albumin Versus Crystalloids in ARDS

Experimental and clinical data show that, compared with crystalloids, colloid fluid therapy mediates multiple beneficial effects in the lungs of patients suffering from acute respiratory distress syndrome (ARDS), including reduced alveolar-capillary permeability, reduced histological damage, reduced inflammatory cell infiltration and faster hemodynamic stabilization. With recent evidence associating use of hydroxyethyl starch products with increased risk of kidney injury and death in septic patients, there is growing interest in the use of albumin to increase intravascular volume expansion in ARDS.

A systematic review of four databases by this study’s authors yielded 4,130 publications addressing the use of colloids and crystalloids with respect to oxygenation and/or mortality in adults with ARDS. Three of these studies (totaling 206 patients) met predefined inclusion criteria: the ARDS patient subgroup from the large Saline Versus Albumin Fluid Evaluation (SAFE) trial comparing 4% albumin to saline, and two U.S. trials comparing 25% furosemide plus albumin or saline for the treatment of acute lung injury.

The weighted mean difference (WMD) in change in PaO2/FiO2 significantly increased for patients receiving albumin therapy in the first 48 hours (WMD = 62 mm Hg, 95% confidence interval [CI] 47 to 77, P < 0.0002) and after seven days (WMD = 20 mm Hg, 95% CI 4 to 36, P < 0.017). The calculated pooled risk of death was 34 percent (34 of 100) for patients receiving albumin versus 38.5 percent (40 of 104) for patients receiving saline; this relative risk of 0.89 was not statistically significant (95% CI 0.62 to 1.28, P = 0.539). Given these findings indicating improved oxygenation using albumin and the small size and limited outcomes data from this meta-analysis, the investigators proposed a double-blinded trial comparing colloid and crystalloid fluid resuscitation in ARDS patients.