Blood loss should be replaced to prevent falling behind in intravascular volume. It is wise to choose an anesthetic technique that produces a relatively stable blood pressure throughout the surgery, so new downward trends in blood pressure can be easily attributable to blood loss and not to pharmacologic action. For instance, if a steady level of desflurane or sevoflurane is given at 1.25 minimal alveolar concentration (MAC) with MAP 15% lower than awake, further dips in MAP during surgical intervention can be taken as intravascular volume depletion secondary to bleeding and replaced accordingly. This interpretation would be obscured if there were frequent anesthetic interventions associated with MAP changes, such as intermittent opioids or titration of hypotension-inducing agents. An important clue to the blood volume loss is the blood pressure at 1 MAC of anesthesia. If a stable pressure is established at a given dose of inhalational agent, a lower-than-expected blood pressure at this dose is almost always indicative of hypovolemia and therefore calls for fluid or blood replacement. Another anesthetic technique for this procedure on a neonate is to use a high-dose opioid technique with paralysis, which will lessen the impact of inhalational agents on MAP. Serial hematocrit determinations drawn throughout the case should guide management. It is most unusual in an otherwise healthy infant to produce hypotension with intravascular overload unless there are other attendant problems.