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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 2006 December;25(4):401-6

    Original articles

Invos® Cerebral Oximeter compared with the transcranial Doppler for monitoring adequacy of cerebral perfusion in patients undergoing carotid endarterectomy

Fassiadis N. 1, Zayed H. 1, Rashid H. 1, Green D. W. 2

1 Department of Vascular Surgery, King’s College Hospital, London, UK
2 Department of Anaesthesia, Intensive Care and Pain Relief, King’s College Hospital, London, UK

Aim. The aim of this prospective study was to assess the correlation between signals obtained during carotid endarterectomy (CEA) under local (LA) or general anesthesia from the Somanetics Invos® cerebral oximeter (CO) and transcranial Doppler (TCD).
Methods. Forty patients were enrolled in the study. The percentages fall in TCD mean flow velocity (FVm) and CO regional oxygen saturation (rSO2) on the ipsilateral side following clamping were recorded and the correlation coefficient and Spearman’s coefficient of rank correlation were calculated.
Results. Fourteen patients were not included in the statistical analysis because either no TCD window or reliable TCD signal was obtained. The remaining 26 patients had a fall in either FVm, rSO2 or both during carotid clamping. There was a highly statistically significant correlation between the percentage fall in FVm and rSO2 with a correlation coefficient of 0.73, P<0.0001, with a 95% confidence interval (CI) for r=0.48 to 0.87; Spearman’s coefficient of rank correlation (ρ) =0.67, P=0.0008, with a 95% CI for ρ=0.384 to 0.84. A significant decline in both TCD and rSO2 was noted in 3 patients under LA out of which 2 required shunts for alteration in conscious level. In 2 LA patients there was a significant decline in TCD but not in rSO2 and the endarterectomy was completed without a shunt.
Conclusions. Regional oxygen saturation correlates well with FVm during carotid clamping. However, the inability to obtain reliable TCD FVm readings in 35% of patients is a serious disadvantage for this monitor. It appears that CO is a satisfactory and possibly superior device for monitoring adequacy of cerebral perfusion and oxygenation during CEA in comparison with the TCD.

language: English


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