Fundamental knowledge about the physical and chemical properties of commercial albumin and its application in clinical practice

Introduction Human albumin (HA) or serum albumin is encoded by the ALB gene and is the most abundant plasma protein in mammals. HA is essential for maintaining the osmotic pressure needed for proper distribution of body fluids between intravascular compartments and body tissues. HA also acts as a plasma carrier by non-specifically binding several hydrophobic steroid hormones and as a transport protein for hemin and fatty acids. The advantages of albumin over less costly alternative fluids continue to be debated. Meta-analyses focusing on survival have been inconclusive, and other clinically relevant end-points have not been systematically addressed. Database searches (MEDLINE, EMBASE, Cochrane Library) and other methods were used to identify randomized controlled trials comparing albumin with crystalloid, artificial colloid, no albumin, or lower-dose albumin. Major findings for all end-points were extracted and summarized [1,2]. Seventy-nine randomized trials with a total of 4755 patients were included. No significant treatment effects were detectable in 20/79 (25%) trials. In cardiac surgery, albumin administration resulted in lower fluid requirements, higher colloid oncotic pressure, reduced pulmonary edema with respiratory impairment, and greater hemodilution compared with crystalloid and hydroxyethyl starch increased postoperative bleeding. In non-cardiac surgery, fluid requirements and pulmonary and intestinal edema were decreased by albumin compared with crystalloid. In hypoalbuminemia, higher doses of albumin reduced morbidity. In ascites, albumin reduced hemodynamic derangements, morbidity, and length of stay and improved survival after spontaneous bacterial peritonitis. In sepsis, albumin decreased pulmonary edema and respiratory dysfunction compared with crystalloid, while hydroxyethyl starch induced abnormalities of hemostasis. Complications were lowered by albumin compared with crystalloid in burn patients. Albumin-containing therapeutic regimens improved outcomes after brain injury [3]. Neither benefit nor harm was shown when using HA to maintain hemodynamic stability in the perioperative period when compared with crystalloids or any other colloidal volume substitute [4-6].