Selective cerebral perfusion: a review of the evidence.

OBJECTIVE: With the realization that hypothermia was neuroprotective, hypothermic selective antegrade cerebral perfusion was adopted by many surgical groups for aortic arch resection, prompting experimental and clinical studies to elaborate technical refinements and safe parameters of selective antegrade cerebral perfusion. We review the evidence for optimum management of perfusion pressure, flow, temperature, pH, hematocrit, and cannulation access.
METHODS: Underperfusion and overperfusion impair neurologic function after selective antegrade cerebral perfusion. Overperfusion--including excessive flow and pressure--is expressed experimentally as an increase in intracranial pressure, indicative of cerebral edema, and causes slow neurobehavioral recovery. As the safe limits of moderate and mild hypothermic selective antegrade cerebral perfusion are being explored in many aortic centers, the ischemic tolerance of the spinal cord during lower-body circulatory arrest becomes a new focus of concern.
RESULTS: Although a significant portion of the population has an incomplete circle of Willis, contralateral flow via extracranial collaterals has permitted the successful use of various cannulation techniques. Unilateral perfusion is adequate for short-term (<40 minutes) selective antegrade cerebral perfusion, even at higher temperatures (24 °C-28 °C). However, if prolonged periods of selective antegrade cerebral perfusion are anticipated, evidence suggests that better cerebral protection is obtained with bilateral selective antegrade cerebral perfusion.
CONCLUSIONS: On the basis of these experimental and clinical studies, certain recommendations for the use of nonpulsatile selective antegrade cerebral perfusion can be made.