Are colloids better than crystalloids for volume replacement?
No. Fluid repletion with colloid-containing solutions (albumin solution or hyperoncotic starch solutions) would seem to have potential advantages over fluid repletion with crystalloids (0.9% saline or lactated Ringer’s). Because the colloid remains in the vascular space, colloid-containing solutions should more effectively expand vascular volume. Also, because repletion with colloid-containing solutions increases plasma oncotic pressure and favors fluid movement from the interstitial space to the vascular space, repletion with colloid-containing solutions should lower the risk of pulmonary edema. However, studies have failed to demonstrate benefits from administration of colloid-containing solutions. In addition, administration of hyperoncotic starch solutions is associated with increased risk of acute kidney injury. Crystalloids are preferred to colloid-containing solutions, then, in the treatment of hypovolemia not due to bleeding. Because about three-fourths of administered isotonic saline will redistribute into the interstitial space, a much greater volume of crystalloid must be administered to achieve a similar degree of vascular volume expansion.