Recent Advances in Application of Cerebral Oximetry in Adult Cardiovascular Surgery

Abstract

Cerebral oximetry is a noninvasive technology that continuously monitors cerebral tissue oxygen saturation, which is a sensitive index of global cerebral hypoperfusion. On the basis of near-infrared spectroscopy technology, information is provided on the availability of oxygen in brain tissue at risk during numerous pathological conditions. Complementary to the arterial oxygen saturation measured by pulse oximetry, cerebral tissue oxygen saturation reflects regional cerebral metabolism and the balance of local cerebral oxygen supply/demand. Recently, patient management with the guidance of cerebral oximetry has resulted in improved patient outcomes. This review will briefly describe the physics behind cerebral oximetry and will provide an overview of the literature focusing primarily on articles published within the past 5 years.

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

“…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.…”

“…6 Derived SctO 2 signals represent a mixture of venous and arterial blood (approximately 70% and 30%, respectively) in the cerebral frontal cortex. [3][4][5] The INVOS TM 5100C oximeter (Medtronic, Minneapolis, MN, USA) uses two wavelengths of infrared light (730 and 810 nm), while the newer generation FORESIGHT-ELITE (CAS Medical Systems Inc, Branford, CT, USA) uses five wavelengths (680, 730, 770, 805, and 870 nm) A of light that may enhance accuracy and reduce extracranial contamination. As brain oxygen demand remains relatively stable under anesthesia, changes in SctO 2 typically represent reductions in cerebral oxygen supply, which are often due to reductions in blood pressure, carbon dioxide partial pressure, cardiac output, hemoglobin concentration, and/or arterial oxygen content.…”

“…As brain oxygen demand remains relatively stable under anesthesia, changes in SctO 2 typically represent reductions in cerebral oxygen supply, which are often due to reductions in blood pressure, carbon dioxide partial pressure, cardiac output, hemoglobin concentration, and/or arterial oxygen content. [5][6][7][8][9][10][11][12] The accuracy of SctO 2 measurements under a variety of clinical conditions is essential if appropriate assessment and management of brain oxygenation is to be possible. Nevertheless, previous studies suggest that extracranial contamination can influence the measurement of SctO 2 and result in measured values that do not entirely reflect the status of oxygenation in the brain.…”

“…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.…”