Changes in concentrations of oxidised cytochrome oxidase measured using both broadband and four wavelength near infrared spectroscopy reflect changes in oxygen delivery during hypoxaemia in healthy volunteers

2006 ◽  
Author(s):  
Martin Tisdall ◽  
Martin Smith ◽  
Ilias Tachtsidis ◽  
Clare E. Elwell
Keyword(s):  
Infrared Spectroscopy ◽  
Healthy Volunteers ◽  
Cytochrome Oxidase ◽  
Near Infrared Spectroscopy ◽  
Oxygen Delivery ◽  
Near Infrared

scholarly journals The relationship of oxygen delivery to absolute haemoglobin oxygenation and mitochondrial cytochrome oxidase redox state in the adult brain: a near-infrared spectroscopy study

1998 ◽  
Vol 332 (3) ◽  
pp. 627-632 ◽  
Author(s):  
Chris E. COOPER ◽  
David T. DELPY ◽  
Edwin M. NEMOTO
Keyword(s):  
Infrared Spectroscopy ◽  
Cytochrome Oxidase ◽  
Near Infrared Spectroscopy ◽  
Oxygen Delivery ◽  
Redox State ◽  
Near Infrared ◽  
Adult Brain ◽  
Mitochondrial Cytochrome ◽  
The Brain ◽  
Mitochondrial Cytochrome Oxidase

Near-infrared spectroscopy was used to determine the effect of changes in the rate of oxygen delivery to the adult rat brain on the absolute concentrations of oxyhaemoglobin, deoxyhaemoglobin and the redox state of the CuA centre in mitochondrial cytochrome oxidase. The cytochrome oxidase detection algorithm was determined to be robust to large changes in haemoglobin oxygenation and concentration. By assuming complete haemoglobin deoxygenation and CuA reduction following mechanical ventilation on 100% N2O, the absolute concentration of oxyhaemoglobin (35 µM), deoxyhaemoglobin (27 µM) and the redox state of CuA (82% oxidized) were calculated in the normal adult brain. The mean arterial blood pressure was decreased by exsanguination. When the pressure reached 100 mmHg, haemoglobin oxygenation started to fall, but the total haemoglobin concentration and oxidized CuA levels only fell when cerebral blood volume autoregulation mechanisms failed at 50 mmHg. Haemoglobin oxygenation fell linearly with decreases in the rate of oxygen delivery to the brain, but the oxidized CuA concentration did not start to fall until this rate was 50% of normal. The results suggest that the brain maintains more than adequate oxygen delivery to mitochondria and that near-infrared spectroscopy may be a good measure of oxygen insufficiency in vivo.

Redox behavior of cytochrome oxidase in the rat brain measured by near-infrared spectroscopy

1997 ◽  
Vol 83 (6) ◽  
pp. 1842-1848 ◽  
Author(s):  
Yoko Hoshi ◽  
Osamu Hazeki ◽  
Yasuyuki Kakihana ◽  
Mamoru Tamura
Keyword(s):  
Infrared Spectroscopy ◽  
Rat Brain ◽  
Cytochrome Oxidase ◽  
Near Infrared Spectroscopy ◽  
Oxygen Delivery ◽  
Near Infrared ◽  
Cerebral Oxygenation ◽  
Redox Behavior ◽  
Hypoxic Conditions

Hoshi, Yoko, Osamu Hazeki, Yasuyuki Kakihana, and Mamoru Tamura. Redox behavior of cytochrome oxidase in the rat brain measured by near-infrared spectroscopy. J. Appl. Physiol. 83(6): 1842–1848, 1997.—Using near-infrared spectroscopy, we developed a new approach for measuring the redox state of cytochrome oxidase in the brain under normal blood-circulation conditions. Our algorithm does not require the absorption coefficient of cytochrome oxidase, which differs from study to study. We employed this method for evaluation of effects of changes in oxygen delivery on cerebral oxygenation in rats. When fractional inspired oxygen was decreased in a stepwise manner from 100 to <10%, at which point the concentration of oxygenated hemoglobin ([HbO2]) decreased by ∼60%, cytochrome oxidase started to be reduced. Increases in arterial [Formula: see text] under hyperoxic conditions caused an increase in [HbO2], whereas further oxidation of cytochrome oxidase was not observed. The dissociation of the responses of hemogloblin and cytochrome oxidase was also clearly observed after the injection of epinephrine under severely hypoxic conditions; that is, cytochrome oxidase was reoxidized with increasing blood pressure, whereas hemoglobin oxygenation was not changed. These data indicated that oxygen-dependent redox changes in cytochrome oxidase occur only when oxygen delivery is extremely impaired. This is consistent with the in vitro data of our previous study.

scholarly journals Use of Mitochondrial Inhibitors to Demonstrate That Cytochrome Oxidase Near-Infrared Spectroscopy Can Measure Mitochondrial Dysfunction Noninvasively in the Brain

1999 ◽  
Vol 19 (1) ◽  
pp. 27-38 ◽  
Author(s):  
Chris E. Cooper ◽  
Mark Cope ◽  
Roger Springett ◽  
Philip N. Amess ◽  
Juliet Penrice ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Cytochrome Oxidase ◽  
Near Infrared Spectroscopy ◽  
Redox State ◽  
Near Infrared ◽  
Blood Oxygenation ◽  
Concentration Addition ◽  
Pig Brain ◽  
Infrared Measurements ◽  
Neonatal Pig

The use of near-infrared spectroscopy to measure noninvasively changes in the redox state of cerebral cytochrome oxidase in vivo is controversial. We therefore tested these measurements using a multiwavelength detector in the neonatal pig brain. Exchange transfusion with perfluorocarbons revealed that the spectrum of cytochrome oxidase in the near-infrared was identical in the neonatal pig, the adult rat, and in the purified enzyme. Under normoxic conditions, the neonatal pig brain contained 15 μmol/L deoxyhemoglobin, 29 μmol/L oxyhemoglobin, and 1.2 μmol/L oxidized cytochrome oxidase. The mitochondrial inhibitor cyanide was used to determine whether redox changes in cytochrome oxidase could be detected in the presence of the larger cerebral hemoglobin concentration. Addition of cyanide induced full reduction of cytochrome oxidase in both blooded and bloodless animals. In the blooded animals, subsequent anoxia caused large changes in hemoglobin oxygenation and concentration but did not affect the cytochrome oxidase near-infrared signal. Simultaneous blood oxygenation level-dependent magnetic resonance imaging measurements showed a good correlation with near-infrared measurements of deoxyhemoglobin concentration. Possible interference in the near-infrared measurements from light scattering changes was discounted by simultaneous measurements of the optical pathlength using the cerebral water absorbance as a standard chromophore. We conclude that, under these conditions, near-infrared spectroscopy can accurately measure changes in the cerebral cytochrome oxidase redox state.

Accuracy of a Cerebral Oximeter in Healthy Volunteers under Conditions of Isocapnic Hypoxia 

1998 ◽  
Vol 88 (1) ◽  
pp. 58-65 ◽  
Author(s):  
Lindsey C. Henson ◽  
Carolyn Calalang ◽  
John A. Temp ◽  
Denham S. Ward
Keyword(s):  
Infrared Spectroscopy ◽  
Oxygen Saturation ◽  
Healthy Volunteers ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Cerebral Oxygenation ◽  
Jugular Bulb ◽  
Wide Range ◽  
Cerebral Oximeter ◽  
End Tidal

Background A cerebral oximeter measures oxygen saturation of brain tissue noninvasively by near infrared spectroscopy. The accuracy of a commercially available oximeter was tested in healthy volunteers by precisely controlling end-tidal oxygen (P[ET]O2) and carbon dioxide (P[ET]CO2) tensions to alter global cerebral oxygen saturation. Methods In 30 healthy volunteers, dynamic end-tidal forcing was used to produce step changes in P[ET]O2 resulting in arterial saturation ranging from approximately 70% to 100% under conditions of controlled normocapnia (each person's resting P[ET]CO2) or hypercapnia (resting plus 7-10 mmHg). Blood arterial (SaO2) and jugular bulb venous (S[jv]O2) saturations during each P(ET)O2 interval were determined by co-oximetry. The cerebral oximeter reading (rSO2) and an estimated jugular venous saturation (S[jv]O2), derived from a combination of SaO2 and rSO2, were compared with the measured S(jv)O2. Results The S(jv)O2 was significantly higher with hypercapnia than with normocapnia for the same SaO2. The rSO2 and S(jv)O2 were both highly correlated with S(jv)O2 for individual volunteers (mean r2 = 0.91 for each relation); however, the slopes and intercepts varied widely among volunteers. In three of them, the cerebral oximeter substantially underestimated the measured S(jv)O2. Conclusions During isocapnic hypoxia in healthy persons, cerebral oxygenation as estimated by near infrared spectroscopy precisely tracks changes in measured S(jv)O2 within individuals, but the relation exhibits a wide range of slopes and intercepts. Therefore the clinical utility of the device is limited to situations in which tracking trends in cerebral oxygenation would be acceptable.

Near infrared spectroscopy can detect changes in splanchnic oxygen delivery in neonates during apnoeic episodes

1999 ◽  
Vol 158 (2) ◽  
pp. 173-174 ◽  
Author(s):  
A. J. Petros ◽  
R. Heys ◽  
R. C. Tasker ◽  
P.-M. Fortune ◽  
I. Roberts ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Oxygen Delivery ◽  
Near Infrared ◽  
Splanchnic Oxygen ◽  
Splanchnic Oxygen Delivery

scholarly journals Determinants of Cerebral Fractional Oxygen Extraction Using Near Infrared Spectroscopy in Preterm Neonates

2000 ◽  
Vol 20 (2) ◽  
pp. 272-279 ◽  
Author(s):  
Stephen P. Wardle ◽  
C. William Yoxall ◽  
A. Michael Weindling
Keyword(s):  
Infrared Spectroscopy ◽  
Oxygen Saturation ◽  
Near Infrared Spectroscopy ◽  
Negative Correlation ◽  
Oxygen Delivery ◽  
Near Infrared ◽  
Oxygen Extraction ◽  
Arterial Oxygen ◽  
Cerebral Oxygen ◽  
Short Period

Cerebral fractional oxygen extraction (FOE) represents the balance between cerebral oxygen delivery and consumption. This study aimed to determine cerebral FOE in preterm infants during hypotension, during moderate anemia, and with changes in the PaCO2. Three groups of neonates were studied: stable control neonates (n = 43), anemic neonates (n = 46), and hypotensive neonates (n = 19). Cerebral FOE was calculated from the arterial oxygen saturation measured by pulse oximetry, and cerebral venous oxygen saturation was measured using near infrared spectroscopy with partial jugular venous occlusion. Mean ± SD cerebral FOE was similar in control (0.292 ± 0.06), anemic (0.310 ± 0.08; P = 0.26), and hypotensive (0.278 ± 0.06; P = 0.41) neonates. After anemic neonates were transfused, mean ± SD cerebral FOE decreased to 0.274 ± 0.05 ( P = 0.02). There was a weak negative correlation with the hemoglobin concentration (n = 89, r = −0.24, P = 0.04) but not with the hemoglobin F fraction (n = 56, r = 0.24, P = 0.09). In the hypotensive neonates, there was no relationship between cerebral FOE and blood pressure (n = 19, r = 0.34, P = 0.15). There was a significant negative correlation between cerebral FOE and PaCO2 within individuals (n = 14, r = −0.63, P = 0.01), but there was no relationship between individuals (n = 14, r = 0, P = 1). Cerebral FOE was not significantly altered in neonates with either mild anemia or hypotension. There were, however, changes in cerebral FOE when physiological changes occurred over a relatively short period; Cerebral FOE decreased after blood transfusion and increased with decreasing PaCO2. As no change in cerebral FOE was seen during hypotension, it was speculated that cerebral oxygen delivery may have been maintained by cerebral blood flow autoregulation.

Near-infrared spectroscopy of the brain: relevance to cytochrome oxidase bioenergetics

1994 ◽  
Vol 22 (4) ◽  
pp. 974-980 ◽  
Author(s):  
C. E. Cooper ◽  
S. J. Matcher ◽  
J. S. Wyatt ◽  
M. Cope ◽  
G. C. Brown ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Cytochrome Oxidase ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
The Brain
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