Selective cerebral perfusion is designed to provide flow to the brain via the right carotid artery and collateral intracranial vessels while the aortic arch is isolated for repair. It is felt that collateral vessels also allow some perfusion of the lower body, but the adequacy of lower body perfusion during selective cerebral perfusion has not been well documented. While it is clear that some blood reaches the lower body, the incidence of renal and gastrointestinal complications following cardiac repairs involving aortic arch reconstructions remains significant.