Hypovolemia is the most common cause of circulatory failure in children and may lead to critical tissue perfusion
and eventually multiple-organ failure. Administration of fluids to maintain or restore intravascular volume represents
a common intervention after hemorrhagic shock occurring during surgical procedures or in patients with trauma. Notwithstanding,
there is uncertainty whether the type of fluid may significantly influence the outcome, especially in pediatrics.
Both human albumin and crystalloids are usually administered: the advantages of crystalloids include low cost, lack of effect
on coagulation, no risk of anaphylactic reaction or transmission of infectious agents. However, large amount of crystalloid
infusion has been correlated with pulmonary oedema, bilateral pleural effusions, intestinal intussusception, excessive
bowel edema, impairing closure of surgical wounds and peripheral edema. Moreover, intravascular volume expansion
obtained by crystalloids is known to be significantly shorter and less efficacious than colloids. Among synthetic colloids,
gelatins have been used for many years in children, also in early infancy, to treat intravascular fluid deficits. Hydroxyethylstarch
(HES) preparations have been introduced recently, becoming very popular for vascular loading both in adults and
children. However, the number of pediatric studies aimed at evaluating HES efficacy and tolerance is limited. Given the
ongoing controversies on the use of colloids in childhood, this review will focus on the pharmacodynamics of synthetic
and non synthetic colloids for the treatment of critical blood loss in pediatrics.