Middle cerebral artery flow velocity and cerebral oxygenation during abdominal aortic surgery

Cerebral perfusion was evaluated in twelve patients undergoing elective inf ra-renal abdominal aortic aneurysmectomy by transcranial Doppler ultrasonog raphy-determined middle cerebral nicely mean flow velocity, near-infrared s pectroscopy-assessed cerebral oxygen saturation and systemic haemodynamic v ariables, The middle cerebral artery mean flow velocity and cerebral oxygen saturation decreased during cross-clamping of the aorta, and both increase d upon declamping of the aorta with the oxygen saturation change lagging be hind the change in the flow velocity. The changes in cerebral flow velocity and oxygen saturation paralleled the deviations in cardiac output and end- tidal carbon dioxide tension.