Colloid solutions are widely used for volume replacement therapy because of their high
oncotic pressure, which could reduce interstitial fluid shifting. Human albumin is the only
colloid solution of biologic origin with a molecular weight of 60 kDa. As the most abundant
plasma protein, it has physiological importance in the well-being of the endothelial
glycocalyx. Older studies in septic patients, however, did not show any benefit of albumin
over saline solution. Crystalloid solutions, such as Ringer's acetate, do not impair neither
renal function nor coagulation, but their volume expanding effect is questionable.
For several reasons (use of heart-lung machine, systemic inflammation, coagulation
disturbances), patients undergoing cardiac surgery need especially large amounts of fluids.
However, there are no large trials comparing albumin solutions to crystalloid solutions
cardiac surgery.
This double-blinded trial will randomize according to a power analysis 1250 cardiac surgery
patients (=625+625) at Meilahti hospital to use either 4% Albumin or Ringer's acetate
solutions for both priming of the heart-lung machine and perioperative volume replacement
therapy. The primary efficacy and safety endpoint of this study is the incidence of major
adverse events (MAE), defined as a composite endpoint of all-cause mortality, acute
myocardial infarction, acute heart failure or low output syndrome, resternotomy, stroke,
certain arrhythmias, major bleeding, infections compromising post-procedural rehabilitation,
acute kidney injury within 90 days postoperatively. The secondary outcomes are total number
of MAEs, major adverse cardiac events (MACE), perioperative fluid balance, blood product
transfusions, blood loss, acute kidney injury, days alive without mechanical
ventilation/outside ICU/at home in 90 days as well as 90-day mortality. Blood samples for
biochemical analyses will be collected at four perioperative time points.
This trial will provide data about efficacy and safety of 4% albumin in cardiac surgery
patients. The biochemical mechanisms of albumin will be assessed.