Somatosensory evoked potentials versus locoregional anaesthesia in the monitoring of cerebral function during carotid artery surgery: preliminary results of a prospective study.
OBJECTIVE
to relate changes in somatosensory-evoked potentials (SEPs) with onset of neurological deficits in patients having carotid endarterectomy (CEA) under locoregional anaesthesia.


METHODS
a prospective study of 50 consecutive patients.


RESULTS
SEPs yielded an accuracy of 98%, specificity 100%, and sensitivity 89%. In all concordant cases the onset of a neurological deficit in awake patients corresponded to a 30--40% reduction in amplitude of N20-P25 waveforms. After shunting, the N20-P25 took 2--3 min to return to normal.


CONCLUSIONS
SEPs are associated with a 2% false negative rate. Their threshold for detecting cerebral ischaemia is lower than the currently reported value for patients under general anaesthesia. The time needed for evoked potentials (2--3 min) to return to normal after shunting limits their usefulness in verifying effective shunting.
Sbarigia
E
E
I Cattedra di Chirurgia Vascolare, University of Rome La Sapienza, Rome, Italy.
Schioppa
A
A
Misuraca
M
M
Panico
M A
MA
Battocchio
C
C
Maraglino
C
C
Speziale
F
F
Fiorani
P
P
D000368:Aged; D000369:Aged, 80 and over; D000772:Anesthesia, Local; D016894:Endarterectomy, Carotid; D005073:Evoked Potentials, Somatosensory; D005260:Female; D006801:Humans; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012680:Sensitivity and Specificity