Noninvasive cerebral oximetry: is there light at the end of the tunnel?
ABSTRACT There is increasing interest in the application of near infrared spectroscopy (NIRS) as a noninvasive monitor of cerebral oxygenation. This review will briefly describe the principles of NIRS and examine current evidence for its clinical application as a monitor of the adequacy of cerebral oxygenation in adults.
There has been a recent surge of interest in the clinical application of NIRS following studies that have quantified the benefits of NIRS-guided management of cerebral oxygenation during cardiopulmonary bypass. However, there are limited data to support its widespread application in other clinical scenarios. New NIRS systems are being introduced to the market and technological advancements have improved their accuracy and extended the range of variables measured.
NIRS offers noninvasive monitoring of cerebral oxygenation over multiple regions of interest in a wide range of clinical scenarios. It has many potential advantages over other neuromonitoring techniques, but further technological advances are necessary before it can be introduced more widely into clinical practice.
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ABSTRACT: Maintenance of adequate oxygenation is a mainstay of intensive care, however, recommendations on the safety, accuracy, and the potential clinical utility of invasive and non-invasive tools to monitor brain and systemic oxygenation in neurocritical care are lacking. A literature search was conducted for English language articles describing bedside brain and systemic oxygen monitoring in neurocritical care patients from 1980 to August 2013. Imaging techniques e.g., PET are not considered. A total of 281 studies were included, the majority described patients with traumatic brain injury (TBI). All tools for oxygen monitoring are safe. Parenchymal brain oxygen (PbtO2) monitoring is accurate to detect brain hypoxia, and it is recommended to titrate individual targets of cerebral perfusion pressure (CPP), ventilator parameters (PaCO2, PaO2), and transfusion, and to manage intracranial hypertension, in combination with ICP monitoring. SjvO2 is less accurate than PbtO2. Given limited data, NIRS is not recommended at present for adult patients who require neurocritical care. Systemic monitoring of oxygen (PaO2, SaO2, SpO2) and CO2 (PaCO2, end-tidal CO2) is recommended in patients who require neurocritical care.Neurocritical Care 09/2014; 21(S2). DOI:10.1007/s12028-014-0024-6 · 3.04 Impact Factor
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ABSTRACT: Several near-infrared spectroscopy oximeters are commercially available for clinical use, with lack of standardization among them. Accordingly, cerebral oxygen saturation thresholds for hypoxia/ischemia identified in studies conducted with INVOS(TM) models do not necessarily apply to other devices. In this study, the measurements made with both INVOS(TM) and EQUANOX(TM) oximeters on the forehead of 10 patients during conventional cardiac surgery are directly compared, in order to evaluate the interchangeability of these two devices in clinical practice.03/2014; 6(3):197-203.This article is viewable in ResearchGate's enriched formatRG Format enables you to read in context with side-by-side figures, citations, and feedback from experts in your field.
Article: Cerebral and tissue oximetry.[Show abstract] [Hide abstract]
ABSTRACT: The use of near-infrared spectroscopy (NIRS) has been increasingly adopted in cardiac surgery to measure regional cerebral oxygen saturation. This method takes advantage of the fact that light in the near-infrared spectrum penetrates tissue, including bone and muscle. Sensors are placed at fixed distances from a light emitter, and algorithms subtract superficial light absorption from deep absorption to provide an index of tissue oxygenation. Although the popularity of NIRS monitoring is growing, definitive data that prove outcome benefits with its use remain sparse. Therefore, widespread, routine use of NIRS as a standard-of-care monitor cannot be recommended at present. Recent investigations have focused on the use of NIRS in subgroups that may benefit from NIRS monitoring, such as pediatric patients. Furthermore, a novel application of processed NIRS information for monitoring cerebral autoregulation and tissue oxygenation (e.g., kidneys and the gut) is promising. Copyright © 2014 Elsevier Ltd. All rights reserved.Baillière' s Best Practice and Research in Clinical Anaesthesiology 12/2014; 28(4):429-439. DOI:10.1016/j.bpa.2014.09.002