Adverse effects of crystalloid and colloid fluids.

Guidelines for infusion fluid therapy rarely take into account that adverse effects occur in a dose-dependent fashion. Adverse effects of crystalloid fluids are related to their preferential distribution to the interstitium of the subcutis, the gut, and the lungs. The gastrointestinal recovery time is prolonged by 2 days when more than 2 litres is administered. Infusion of 6-7 litres during open abdominal surgery results in poor wound healing, pulmonary oedema, and pneumonia. There is also a risk of fatal postoperative pulmonary oedema that might develop several days after the surgery. Even larger amounts cause organ dysfunction by breaking up the interstitial matrix and allowing the formation of lacunae of fluid in the skin and central organs, such as the heart. Adverse effects of colloid fluids include anaphylactic reactions, which occur in 1 out of 500 infusions. The possibility that hydroxyethyl starch causes kidney injury in patients other than those with sepsis is still unclear. For both crystalloid and colloid fluids, coagulation becomes impaired when the induced haemodilution has reached 40%. Coagulopathy is aggravated by co-existing hypothermia. Although oedema can occur from both crystalloid and colloid fluids, these differ in pathophysiology. To balance fluid-induced adverse effects, this review suggests that a colloid fluid is indicated when the infused crystalloid volume exceeds 3-4 litres, plasma volume support is still needed, and the transfusion of blood products is not yet indicated.