TRANSCRANIAL CEREBRAL OXIMETRY DURING CAROTID ENDARTERECTOMY - AGREEMENT BETWEEN FRONTAL AND LATERAL PROBE MEASUREMENTS AS COMPARED WITH ANELECTROENCEPHALOGRAM

Objective: Transcranial cerebral oximetry, which is considered a novel technique, was evaluated during carotid endarterectomy, For practical reasons, the use of a single probe attached to the forehead and overl ying the territory of the anterior cerebral artery is recommended. Oth er monitoring systems (transcranial Doppler, electroencephalograms (EE G)) focus more on the territory of the middle cerebral artery, The aim of this study was to evaluate whether a probe in the frontal area is as representative for monitoring cerebral ischaemia during carotid cro ssclamping as a probe in the lateral area. Design: Clinical prospectiv e study, Materials: Sixty patients who underwent carotid endarterectom y were studied with continuous and simultaneous EEG and transcranial c erebral oximetry, Forty-three patients (72%) simultaneously underwent frontal and lateral transcranial cerebral oximetry, The lateral probe was only used in 17 patients. Methods: The percentage decrease of tran scranial cerebral oximetry was calculated during cross-clamping. Using the EEC findings as the gold standard in order to detect cerebral isc haemia during carotid cross-clamping, the relationship with transcrani al cerebral oximetry was described in terms of sensitivity, specificit y and the area under the curve in a receiver operating characteristic curve, Results: The 95% confidence interval of the area under the curv e of the receiver operating characteristic of the lateral probe was 0. 61-1.00 and that of the frontal probe was 0.65-1.00; therefore there i s virtually no difference between the two methods. In 18% of the cases the lateral transcranial cerebral oximetry was hindered by practical failures. Conclusion: Considering the lack of additional information a nd the practical problems experienced with the lateral probe, it was c oncluded that transcranial cerebral oximetry with a single frontal pro be is a practical non-invasive monitoring system and is at least as re presentative for monitoring cerebral ischaemia during carotid cross-cl amping as a lateral probe. (C) 1998 The International Society for Card iovascular Surgery. Published by Elsevier Science Ltd. All rights rese rved.