A comparison of cerebral oxygenation as measured by the NIRO 300 and the INVOS 5100 Near‐Infrared Spectrophotometers

Thavasothy, M; Broadhead, Michael; Elwell, Clare E.; Peters, Mark; Smith, Martin

doi:10.1046/j.1365-2044.2002.02826.x

Cited by 144 publications

(111 citation statements)

References 29 publications

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“…Measurement of the absorption ratios at two different sites allows for the removal of the extracranial contribution via a subtraction algorithm, thus giving a mean value for cerebral saturation 10, 52,54,55 . In order to generate an rSO 2 value, cerebral oximetry makes several assumptions.…”

Section: Invos ® 5100c Cerebral/somatic Oximetermentioning

confidence: 99%

“…These optodes are set at fixed distances from the LED: the proximal detector, set at 3 cm, receives a reading from the extracerebral tissue whereas the distal detector, set at 4 cm, 14 receives a reading from the cortical and intracerebral structures 51,55 . Measurement of the absorption ratios at two different sites allows for the removal of the extracranial contribution via a subtraction algorithm, thus giving a mean value for cerebral saturation 10, 52,54,55 .…”

Section: Invos ® 5100c Cerebral/somatic Oximetermentioning

confidence: 99%

“…The INVOS ® 5100C Cerebral/Somatic Oximeter utilises a disposable sensor which incorporates a light emitting diode (LED) and two light-collecting optodes ( Figure 1) 55,58 .…”

Section: Invos ® 5100c Cerebral/somatic Oximetermentioning

confidence: 99%

“…There are three main principles on which NIRS relies in order to derive an rSO 2 value: 1) most living tissues, with the exception of haemoglobin (Hb) and cytochrome oxidase, are relatively transparent to infrared light in the range close to the visual spectrum (700-1000 nm); 2) the absorbance spectrum of Hb is dependant on it's oxygenation status (deoxyHb absorbs less infrared light than oxyHb) 55,56 ; and 3) the Beer-Lambert law, This ratio is shown as a percentage value and is reflective of rSO 2 10,56 .…”

Section: General Introductionmentioning

confidence: 99%

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Use of near‐infrared spectroscopy to identify trends in regional cerebral oxygen saturation in horses

McConnell

Rioja

Bester

et al. 2012

Equine Veterinary Journal

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Summary Reasons for performing study Alterations in cerebral haemodynamics may contribute to perianaesthetic complications in horses. Near‐infrared spectroscopy (NIRS) is frequently used intraoperatively in man to provide information regarding cerebral perfusion. Objectives To determine whether NIRS can identify trends in regional cerebral oxygen saturation (rSO2) in horses and whether there is a correlation between rSO2 and venous oxygen tensions. Methods A cerebral oximeter sensor recorded rSO2 from the dorsal sagittal sinus of 6 healthy horses. Values for rSO2, arterial and venous oxygen and carbon dioxide tensions (PaO2, PvO2, PaCO2 and PvCO2 respectively), along with arteriovenous oxygen saturations (SavO2) were recorded in unsedated (recording period [RP] 1), sedated (RP2) and anaesthetised horses (RP3–5) and during recovery (RP6–8). During anaesthesia, horses were ventilated to achieve states of normo‐ (RP3), hyper‐ (RP4) and hypocapnoea (RP5). Data were evaluated descriptively and analysed using linear mixed‐effects models and Pearson's correlation coefficient. Results Overall mean ± s.d. values for rSO2, PaO2, PvO2, PaCO2, SavO2 and mean arterial pressure varied significantly by RP (P<0.001). Significant decreases in rSO2 were identified between RP1 and the post anaesthetic periods (P<0.001). No significant differences in rSO2 values were identified between RP1 and the intra‐anaesthesia periods or between RP3, RP4 and RP5. Significant correlations were identified between rSO2 and PaO2 (r = 0.448, P<0.001), rSO2 and PvO2 (r = 0.512, P<0.001) and rSO2 and SavO2 (r = 0.469, P<0.001). Conclusions This is the first study to identify trends in rSO2 in horses using NIRS. A positive correlation was identified between rSO2 and PvO2, suggesting that alterations in cerebral oxygenation may be reflected in PvO2. Potential relevance Near‐infrared spectroscopy may be used to monitor trends in rSO2 during equine anaesthesia. Decreasing rSO2 values may act as an early warning signal, alerting clinicians to potential cerebral desaturation events and indicating a need for intervention.

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Section: Invos ® 5100c Cerebral/somatic Oximetermentioning

confidence: 99%

Section: Invos ® 5100c Cerebral/somatic Oximetermentioning

confidence: 99%

“…The INVOS ® 5100C Cerebral/Somatic Oximeter utilises a disposable sensor which incorporates a light emitting diode (LED) and two light-collecting optodes ( Figure 1) 55,58 .…”

Section: Invos ® 5100c Cerebral/somatic Oximetermentioning

confidence: 99%

Section: General Introductionmentioning

confidence: 99%

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Use of near‐infrared spectroscopy to identify trends in regional cerebral oxygen saturation in horses

McConnell

Rioja

Bester

et al. 2012

Equine Veterinary Journal

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“…Different manufacturers use different nomenclature, although most do provide an absolute measure of regional cerebral tissue saturation (rScO 2 ) in some form and display this as a simple percentage value. However, the algorithms used, and even the variables actually measured, vary between systems, and this leads to difficulty when selecting devices for clinical use and when comparing between devices or clinical studies using different devices [5,6]. Of particular relevance is the observation that the application of different algorithms produces significantly different chromophore concentrations from the same underlying optical data [7].…”

Section: Introductionmentioning

confidence: 99%

Shedding light on the adult brain: a review of the clinical applications of near-infrared spectroscopy

Smith

2011

Phil. Trans. R. Soc. A.

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Near-infrared spectroscopy (NIRS) has potential as a non-invasive brain monitor in a wide range of clinical scenarios. In the last decade, there has been a rapid expansion of clinical experience using NIRS to monitor cerebral oxygenation, particularly in cardiac surgery, where there is some evidence that NIRS-guided brain protection protocols might lead to a reduction in peri-operative neurological complications. There are no data to support the wider application of NIRS to monitor cerebral oxygenation during routine anaesthesia and surgery, and its application in brain injury, where it might be expected to have a key monitoring role, is as yet undefined. Technological developments, including the introduction of broadband and time-resolved spectrometers that are capable of reliably measuring changes in oxidized cytochrome c oxidase, offer real potential for a single NIRS-based device to provide multi-site, regional monitoring of cerebral metabolic status as well as oxygenation and haemodynamics.

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Hyperbaric Conditions

Doolette

Mitchell

2010

Comprehensive Physiology

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Exposure to elevated ambient pressure (hyperbaric conditions) occurs most commonly in underwater diving, during which respired gas density and partial pressures, work of breathing, and physiological dead space are all increased. There is a tendency toward hypercapnia during diving, with several potential causes. Most importantly, there may be reduced responsiveness of the respiratory controller to rising arterial CO₂, leading to hypoventilation and CO₂ retention. Contributory factors may include elevated arterial PO₂, inert gas narcosis and an innate (but variable) tendency of the respiratory controller to sacrifice tight control of arterial CO₂ when work of breathing increases. Oxygen is usually breathed at elevated partial pressure under hyperbaric conditions. Oxygen breathing at modest hyperbaric pressure is used therapeutically in hyperbaric chambers to increase arterial carriage of oxygen and diffusion into tissues. However, to avoid cerebral and pulmonary oxygen toxicity during underwater diving, both the magnitude and duration of oxygen exposure must be managed. Therefore, most underwater diving is conducted breathing mixtures of oxygen and inert gases such as nitrogen or helium, often simply air. At hyperbaric pressure, tissues equilibrate over time with high inspired inert gas partial pressure. Subsequent decompression may reduce ambient pressure below the sum of tissue gas partial pressures (supersaturation) which can result in tissue gas bubble formation and potential injury (decompression sickness). Risk of decompression sickness is minimized by scheduling time at depth and decompression rate to limit tissue supersaturation or size and profusion of bubbles in accord with models of tissue gas kinetics and bubble formation and growth.

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A comparison of cerebral oxygenation as measured by the NIRO 300 and the INVOS 5100 Near‐Infrared Spectrophotometers

Cited by 144 publications

References 29 publications

Use of near‐infrared spectroscopy to identify trends in regional cerebral oxygen saturation in horses

Use of near‐infrared spectroscopy to identify trends in regional cerebral oxygen saturation in horses

Shedding light on the adult brain: a review of the clinical applications of near-infrared spectroscopy

Hyperbaric Conditions

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