Cerebral monitors versus regional anesthesia to detect cerebral ischemia in patients undergoing carotid endarterectomy: A meta-analysis

Abstract

Purpose: The aim of this meta-analysis is to compare the ability of different types of brain monitoring systems vs clinical monitoring of the brain function to detect cerebral ischemia during cross-clamping of the carotid artery under regional anesthesia. Methods: In May 2012, a search was conducted in PubMed, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Ovid MEDLINE® for prospective trials with 20 patients or more where a cerebral monitoring system was compared with clinical brain monitoring during a carotid endarterectomy performed under regional anesthesia. The quality of the study was evaluated with the Cochrane Collaboration's tool. Data were extracted independently by the two investigators. Results: Data could be extracted for 4,664 measurements taken from 29 studies: transcranial Doppler (TCD) = 739; cerebral saturation = 320; stump pressure = 2,549; electroencephalography (EEG) = 742; evoked potentials = 187; jugular venous saturation = 79; and jugular venous lactate = 48. The pooled diagnostic odds ratios (DOR) and 95% confidence intervals (CI) were obtained for EEG, TCD, stump pressure, evoked potentials, and cerebral saturation: (DOR 65.3; 95% CI 20.5 to 207.7; I2 [56.8%]); (DOR 58.1; 95% CI 23.0 to 146.3; I2 [24.9%]); (DOR 27.8; 95% CI 13.4 to 57.9; I2 [59.9]); (DOR 17.2; 95% CI 2.4 to 123.9 I2 [69.1]); and (DOR 12.1; 95% CI 3.5 to 41.2; I2 [30.8]), respectively. Sequential testing with stump pressure 25 mmHg followed by either TCD or EEG delivered the best post-test probabilities. For EEG, the DOR increases with the number of channels used (P = 0.03). Conclusion: A combination of stump pressure and either TCD or EEG appears to deliver the best results for detecting brain ischemia during carotid artery cross-clamping. Electroencephalography should be used with a high number of channels. © 2013 Canadian Anesthesiologists' Society.