CBFV was measured in infants undergoing biventricular repair without aortic arch reconstruction as part of a trial of hemodilution during cardiopulmonary bypass ( CPB ) ; CBFV ( Vm , mean ; Vs , systolic ; Vd , end-diastolic ) in the middle cerebral artery and change in Vm ( rVm ) were measured intraoperatively and up to @ hours post-CPB .