Multimodality neuromonitoring for carotid endarterectomy surgery: Determination of critical cerebral ischemic thresholds

As a result of advances in microcomputer technology over the past several decades, a number of new and improved intraoperative and ICU monitors have emerged for safer anesthetic, surgical, and postoperative management of patients. rn particular, those developed for neuromonitoring are some of the most recent and potentially most important. One of the most common applications of intraoperative neuromonitoring is for the detection of cerebral ischemia and embolism during carotid endarterectomy surgery. By examining the period following crossclamping of the carotid arteries for plaque removal, thresholds for cerebral ischemia have been determined for a host of neuromonitoring techniques: electrical brain-waves, cerebral perfusion, and cerebral oxygenation. information provided by these various techniques can be used to influence the surgeon's decision for selective shunting. With the introduction of continuous transcranial Doppler, the detection of emboli is now possible, also providing the surgeon with additional information to improve the surgical technique. No single method, however, has proven entirely reliable in the detection of cerebral ischemia and embolization, nor is there universal agreement for specific alarm criteria characterizing critical, cerebral, ischemic thresholds for most of the neuromonitoring techniques. Consequently, a multimodality strategy that combines several of these intraoperative techniques potentially affords a better neurological outcome.