title: Intraoperative transcranial Doppler sonography monitoring during carotid surgery under locoregional anaesthesia.
abstract: OBJECTIVE
  Studies comparing transcranial Doppler ultrasonography (TCD) with other intraoperative monitoring techniques for detecting clamping ischaemia during carotid endarterectomy under general anaesthesia suggest that a reduction of > two-thirds in the mean middle cerebral artery velocity (mMCAv) or a reduction of > 0.4 in the preclamping mMCAv: clamping mMCAv ratio warrants cerebral protection. Our aim was to study the relationship between mMCAvs and clamping ischaemia during carotid endarterectomy in awake patients.
  
  
  METHODS
  In a consecutive series of 57 patients undergoing carotid endarterectomy under locoregional anaesthesia 51 were monitored by intraoperative TCD, continuous EEG, and neurologic awake testing.
  
  
  RESULTS
  Five of the 51 (9.8%) patients had transient clamping ischaemia, which carotid shunting reversed. TCD showed that these five patients had significant lower mean mMCAvs than the other 46 patients, who had no deficits (1.8 +/- 1.1 cm/s vs. 26.2 +/- 8.5, p = 0.0003). Current TCD criteria indicated that four other patients (7.8%) should have been shunted. All four had significantly higher clamping mMCAvs than the five shunted patients (11.5 +/- 1.9 vs. 1.8 +/- 1.1, p = 0.0012).
  
  
  CONCLUSIONS
  Intraoperative TCD detected cerebral ischaemia and yielded no false-negative. An mMCAv of 10 cm/s or less may indicate the risk of clamping ischaemia better than the higher threshold currently proposed. This would avoid unnecessary shunting due to false-positives.
authors.affiliation: I Cattedra di Chirurgia Vascolare, Università di Roma, La Sapienza, Italy.
authors.forename: M F
authors.initials: MF
authors.lastname: Giannoni
authors.forename: E
authors.initials: E
authors.lastname: Sbarigia
authors.forename: M A
authors.initials: MA
authors.lastname: Panico
authors.forename: F
authors.initials: F
authors.lastname: Speziale
authors.forename: M
authors.initials: M
authors.lastname: Antonini
authors.forename: C
authors.initials: C
authors.lastname: Maraglino
authors.forename: P
authors.initials: P
authors.lastname: Fiorani
mesh_terms: D000368:Aged; D000772:Anesthesia, Local; D001783:Blood Flow Velocity / Q000502:physiology; D001921:Brain / Q000000981:diagnostic imaging; D002343:Carotid Artery, Internal / Q000601:surgery; D016893:Carotid Stenosis / Q000175:diagnosis / Q000601:surgery*; D002536:Cerebral Arteries / Q000000981:diagnostic imaging*; D004569:Electroencephalography; D004691:Endarterectomy; D005260:Female; D006801:Humans; D007432:Intraoperative Period; D002546:Ischemic Attack, Transient / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D009407:Nerve Block; D011237:Predictive Value of Tests; D017585:Ultrasonography, Doppler, Transcranial