[Effects of norepinephrine on brain oxygen saturation].

BACKGROUND:In carotid endarterectomy (CEA), it is essential to maintain the systemic blood pressure (BP) and cerebral perfusion pressure, especially during cross clamping, and vasopressors are often required. To elucidate the effect of norepinephrine (NE) on the cerebral circulation in patients undergoing CEA, regional oxygen saturation (rSO2) in bilateral frontal poles was monitored by near infrared spectroscopy during NE infusion. METHODS:Seven patients undergoing CEA were enrolled. Bilateral frontal rSO2 was monitored with transcranial optical spectroscopy. Anesthesia was induced and maintained with propofol, fentanyl and vecuronium. RESULTS:NE increased MAP (P<0.001) and decreased HR (P<0.001) and bilateral rSO2 (ipsilateral P<0.01, contralateral P<0.05). CONCLUSIONS:NE used to maintain the MAP decreased the brain rSO2. NE would aggravate the balance between cerebral oxygen supply and consumption in patients undergoing CEA. Further investigations are necessary to clarify the effect of systemically administered norepinephrine on the cerebral circulation.