during deep hypothermic circulatory arrest. L: left rSO2, R: right rSO2. Initial 30 min of conventional retrograde cerebral perfusion (RCP), rSO2 gradually declined. When intermittent-pressure-augmented (45 mmHg) retrograde cerebral perfusion (IPA-RCP) was induced, rSO2 rose. The maximum duration of pressure augmentation was limited to 30 sec. A total of 10 augmentations at irregular intervals were tried. A. Start of deep hypothermic circulatory arrest and conventional RCP. B. Start of IPA-RCP. C. Final dip: Start of the antegrade perfusion to the left common carotid artery, and the left subclavian artery via graft branch. D. Start of antegrade perfusion via the brachiocephalic artery.