Colloid administration: Complications

There has been much debate regarding the choice between crystalloids and colloids as to which is the most appropriate resuscitation fluid. The Saline versus Albumin Fluid Evaluation (SAFE) study examined this in a study of ICU patients. It was determined that there was no difference in 28-day outcomes between the two groups. Therefore, due to cost, saline was determined to be the superior fluid. Other factors beyond cost have been attributed to pitfalls of colloids as well. Many of these shortcomings typically occur with the semisynthetic colloids (gelatins, hydroxyethyl starches, dextrans) including impacts on the immune system, renal function, and coagulation.

• The gelatins decrease vWF, factor VIIIc, and ex vivo clot strength. Despite these decreases, they still have the smallest impact of the synthetic colloids on hemostasis. Nevertheless, gelatins have the highest rate of anaphylactic and anaphylactoid reactions. These are used in Europe but are not approved for use in the US.
• Hydroxyethyl starches (i.e. hetastarch) are associated with an increased risk of renal replacement therapy and increased mortality in critically ill adult patients, especially patients with sepsis. Hetastarch is also associated with increased risk of bleeding (due to an anti-vWF effect) and increased transfusion requirements.
• Dextrans also have similar effects on coagulation leading to impaired hemostasis and increased blood loss during surgery, risk of anaphylaxis/anaphylactoid reactions, and renal dysfunction. In addition, they can interfere with blood type cross matching due to their propensity to coat the red cell membrane. The antithrombotic effect of dextrans (particularly dextran 40) can be advantageous in the perioperative management of patients undergoing microvascular surgery.
• Albumin (a human plasma derivative) along with not improving outcomes in ICU patients has been found to increase mortality in trauma, particularly traumatic brain injury. Subgroup analysis of the SAFE trial found increased mortality at 24 months. This effect was more profound with more severe injury. Along with the other colloids, albumin also seems to impact coagulation via a dilutional effect.

As noted above, most studies demonstrating increased morbidity and mortality were carried out in critically ill patients, often critically ill septic patients. Whether or not these results can be extrapolated to the perioperative environment is unknown.