No clinical differences were found between colloids and crystalloids in most of the studies analyzed. Given the significant difference in costs between both groups of expanders and in light of the currently available evidence, crystalloids should be used as first-choice expanders. If a colloid has to be chosen, HES could be a cheaper substitute than albumin in most cases; though its benefits have not been proven over jellies, it is the cheapest choice. The main adverse effects shown in HES were with older molecules with high molecular weight and high degree of substitution and not with the newer ones, such as Voluven, however given the evidence available, the use of HES in patients with kidney function impairment should be avoided.
