Volume resuscitation: crystalloid versus colloid.

Adequate circulating volume to maintain mean arterial blood pressure above a critical value is necessary to reverse bradycardia by positive-pressure ventilation during resuscitation after asphyxia. A variety of circumstances can lead to visible or occult blood loss in the perinatal period; however, distinguishing hypovolemic shock from asphyxial shock can be difficult in the delivery room. Small, randomized, controlled trials support the usefulness of isotonic crystalloid rather than albumin-containing solutions for acute volume expansion; ready availability, lower cost, and lesser risk of infectious complications favor the use of isotonic crystalloid as well. No trials have compared crystalloid and colloid for volume expansion in the setting of immediate resuscitation after birth. Further work is needed to refine the approach to infants in whom adequate positive-pressure ventilation fails and to better discriminate between shock on the basis of hypovolemia versus decreased myocardial function.