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A Journal on Angiology

Official Journal of the International Union of Angiology, the International Union of Phlebology and the Central European Vascular Forum
Indexed/Abstracted in: BIOSIS Previews, Current Contents/Clinical Medicine, EMBASE, PubMed/MEDLINE, Science Citation Index Expanded (SciSearch), Scopus
Impact Factor 0,899

Frequency: Bi-Monthly

ISSN 0392-9590

Online ISSN 1827-1839


International Angiology 1998 March;17(1):10-4


Intraoperative assess­ment of cere­bral ischae­mia dur­ing carot­id sur­gery

Pedri­ni L., Taran­ti­ni S., Cir­el­li M. R., Bal­lest­er A., Cifiel­lo B. I., D’addato M.

From the Institute of Vascular Surgery, University of Bologna, Bologna, Italy

Background. This study aimed to eval­u­ate the reliabi-lity of som­a­tos­en­so­ry ­evoked poten­tials (SEPs) in iden­ti­fy­ing clamp­ing ischae­mia dur­ing carot­id sur­gery under gen­er­al anaesthe­sia.
Methods. We ­reviewed the ­records of 196 con­sec­u­tive carot­id endar­te­rec­to­mies (CEA) per­formed under gen­er­al anaesthe­sia, out of 1550 ­patients oper­at­ed on ­between 1975 and 1993. SEPs were mon­i­tored after con­tro­lat­er­al ­median nerve stim­u­la­tion at the wrist in all ­patients. Moreover they ­received an intra­ve­nous bolus of 2500 IU of hep­ar­in and the stump pres­sure was meas­ured. A com­ple­tion angio­gra­phy was per­formed in all ­patients. An intra­lu­mi­nal shunt was insert­ed when the ampli­tude of the N20-P25 SEPs com­plex ­decreased by more than 50% of pre-clamp­ing value (path­o­log­ic SEPs) or when a pre­op­er­a­tive CT-scan ­showed an ischaem­ic area in the con­tra­lat­er­al hem­i­sphere. In some ­patients the shunt was not insert­ed ­because of tech­ni­cal dif­fi­cul­ties or ­because the path­o­log­i­cal SEP com­plex ­decrease devel­oped when the ­suture of the arter­i­ot­o­my was ­almost com­plete.
Results and con­clu­sions. As the pre­clamp­ing ampli­tude (Ab) of N20-P25 was extreme­ly var­i­able, rang­ing from 0.9 and 7.5 µV, we adopt­ed the ratio: ∆A=(At-Ab)/Ab (At=ampli­tude meas­ured dur­ing clamp­ing every 2 min at time t). Mean ­decrease of ∆A meas­ured in the whole group ­ranged ­between 15% and 20%, but mean ∆A val­ues in ­patients with path­o­log­i­cal SEPs were ­around 60%. Even ­patients with pos­i­tive CT-scans or with a back-pressure lower than 50 mmHg devel­oped a mean ∆A ­decrease of about 20%. A path­o­log­i­cal SEP was ­present in 50 ­patients, but devel­oped in only 12 dur­ing the clamp­ing trial. An intra­lu­mi­nal shunt was insert­ed in 22 cases; the other ­patients ­received phar­mac­o­log­i­cal treat­ment with anaesthet­ic or vasoac­tive drugs. Among the ­patients with path­o­log­i­cal SEPs, 3 pre­sent­ed post­op­er­a­tive symp­toms relat­ed to carot­id cross-clamp­ing; only 1 of these was shunt­ed but with­out SEPs nor­mal­isa­tion. No ­patients with nor­mal SEPs devel­oped a post­op­er­a­tive neu­ro­log­i­cal def­i­cit, giv­ing a reli­abil­ity of 86.7%, a sen­si­tiv­ity of 100% and a spec­i­fic­ity of 86.5%.

language: English


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