Usefulness and limits of near infrared spectroscopy monitoring during endovascular neuroradiologic procedures

Background. Transcranial cerebral oximetry (TCCO) with near-infrared spectroscopy (NIRS) is a non-invasive, bedside technique, which allows the continuous measurement of regional cerebral oxygenation. The aim of this study was to evaluate TCCO monitoring during endovascular neuroradiologic procedures. Methods. Adult patients undergoing elective endovascular embolization of cerebral aneurysms, arteriovenous malformations, dural arteriovenous fistulas and meningiomas under general anesthesia were included in the study, over a period of 12 months. Twenty-eight procedures in 25 patients were analyzed. Results. Regional cerebral oxygenation rSO(2) readings were significantly different according to the different phases of the neuroendovascular procedure. An effect of the underlying cerebral pathology on regional cerebral oxygenation rSO(2) recording, in relation to the different stage of the interventional procedure, was also evident, the more invasive the procedure the greater the impact on rSO(2) reading. NIRS monitoring contributed to a prompt diagnosis and management of two adverse intraoperative events and helped in early evaluation of prognosis. Conclusion. TCCO with NIRS is a promising monitoring tool to assess the balance between oxygen supply and demand during neuroradiologic procedures. Nevertheless, some limits should be acknowledged, such as the study of the posterior circulation and artefacts related to contrast agent injection. A careful understanding of the undergoing step of the procedure as well of the possible influence of intrinsic and extrinsic factors affecting recording is important for interpretation of data.