Cerebral Near-Infrared Spectroscopy Monitoring and Neurologic Outcomes in Adult Cardiac Surgery Patients

Abstract

Background Near-infrared spectroscopy is used during cardiac surgery to monitor the adequacy of cerebral perfusion. In this systematic review, we evaluated available data for adult patients to determine (1) whether decrements in cerebral oximetry during cardiac surgery are associated with stroke, postoperative cognitive dysfunction (POCD), or delirium and (2) whether interventions aimed at correcting cerebral oximetry decrements improve neurologic outcomes. Methods We searched PubMed, Cochrane, and Embase databases from inception until January 31, 2012, without restriction on languages. Each article was examined for additional references. A publication was excluded if it did not include original data (e.g., review, commentary) or if it was not published as a full-length article in a peer-reviewed journal (e.g., abstract only). The identified abstracts were screened first, and full texts of eligible papers were reviewed independently by two investigators. For eligible publications, we recorded the number of subjects, type of surgery, and criteria for diagnosis of neurologic endpoints. Results We identified 13 case reports, 27 observational studies, and two prospectively randomized intervention trials that met our inclusion criteria. Case reports and two observational studies contained anecdotal evidence suggesting that regional cerebral O2 saturation (rScO2) monitoring could be used to identify cardiopulmonary bypass (CPB) cannula malposition. Six of nine observational studies reported an association between acute rScO2 desaturation and POCD based on the Mini-Mental Status Examination (n=3 studies) or more detailed cognitive testing (n=6 studies). Two retrospective studies reported a relationship between rScO2 desaturation and stroke or type I and II neurologic injury after surgery. The observational studies had many limitations, including small sample size, assessments only during the immediate postoperative period, and failure to perform risk adjustments. Two randomized studies evaluated the efficacy of interventions for treating rScO2 desaturation during surgery, but adherence to the protocol was poor in one. In the other study, interventions for rScO2 desaturation were associated with less major organ injury and shorter intensive care unit hospitalization compared with nonintervention. Conclusions Reductions in rScO2 during cardiac surgery may identify CPB cannula malposition, particularly during aortic surgery. Only low-level evidence links low rScO2 during cardiac surgery to postoperative neurologic complications, and data are insufficient to conclude that interventions to improve rScO2 desaturation prevent stroke or POCD.

Extracranial contamination in the INVOS 5100C versus the FORE-SIGHT ELITE cerebral oximeter: a prospective observational crossover study in volunteers

“…Patients undergoing cardiac surgery and various operations in the beach chair position may be at risk for cerebral ischemia and subsequent neurologic injury. [1][2][3] Early detection of any cerebral ischemia may allow clinicians to institute therapies that prevent permanent injury to the central nervous system (CNS). Several technologies have been applied in the perioperative setting that may permit real-time detection of cerebral ischemia.…”

“…4 In contrast, near-infrared spectroscopy (NIRS)-based cerebral oximetry is a noninvasive technology that is relatively easy to use and specifically developed to allow clinicians to detect and treat cerebral ischemia in the operating room. [1][2][3][4][5] The degree of oxygen saturation in cerebral tissue (SctO 2 ) can be determined through the use of multi-wavelength light emitters and detectors,. 6 Derived SctO 2 signals represent a mixture of venous and arterial blood (approximately 70% and 30%, respectively) in the cerebral frontal cortex.…”

“…The depth of the light penetration is proportional to the distance from the emitting light source to the receiving light detector. [1][2][3][4][5][6] The nearfield light detector, which is located closest to the light source, measures signals primarily within the extracranial tissues, while the far-field detector measures both cerebral and extracranial tissue saturation. [1][2][3][4][5][6] Though the exact algorithm for each of these devices is proprietary, both are spatially resolved spectrometers.…”

“…[1][2][3][4][5][6] The nearfield light detector, which is located closest to the light source, measures signals primarily within the extracranial tissues, while the far-field detector measures both cerebral and extracranial tissue saturation. [1][2][3][4][5][6] Though the exact algorithm for each of these devices is proprietary, both are spatially resolved spectrometers. [1][2][3][4][5][6] The INVOS 5100C used in this study uses two wavelengths of infrared light (730 and 810 nm) and two light detectors at two different fixed distances (proximal and distal) from the light source.…”

“…[1][2][3][4][5][6] Though the exact algorithm for each of these devices is proprietary, both are spatially resolved spectrometers. [1][2][3][4][5][6] The INVOS 5100C used in this study uses two wavelengths of infrared light (730 and 810 nm) and two light detectors at two different fixed distances (proximal and distal) from the light source. 1,[9][10][11][12] The secondgeneration FORE-SIGHT ELITE device used in this study uses an enhanced proprietary algorithm coupled with five wavelengths of infrared light (680, 730, 770, 805, and 870 nm) to improve the accuracy of the blood oxygenation measurements.…”