In this study we examined whether continuous monitoring of jugular bulb venous oxygen saturation (SjO2) is applicable for the evaluation of cerebral hypoperfusion during carotid endarterectomy (CEA). The subjects were 25 patients who underwent elective CEA under general anaesthesia. After the carotid stump pressure (SP) was measured, SjO2 and the somatosensory evoked potentials (SEP) were monitored during the carotid test clamping for 10 min.　　

There was no alteration in cardiovascular and respiratory status during the test clamping. No correlation was observed between SEP amplitude and SP (r=0.16, p=0.25). However, at clamping, SjO2 decreased from 70 to 64% (p<0.01) with a reduction in SEP amplitude from 2.0 to 1.6μV (p<0.01). After declamping, SjO2 increased from 65 to 70% (p<0.01) with a recovery in SEP from 1.6 to l.9μV (p<0.01). The changes in SEP amplitude and SjO2 correlated (r=0.66, p<0.001).　　

These results suggest that continuous monitoring of SjO2 is superior to SP measurement in the prediction of cerebral hypoperfusion caused by carotid clamping and applicable to CEA.