Splanchnic oxygen delivery in exomphalos detected with near infrared spectroscopy

2001 ◽  
Vol 160 (2) ◽  
pp. 144-145 ◽  
Author(s):  
Peter-Marc Fortune ◽  
Agostino Pierro ◽  
Andy Petros
1999 ◽  
Vol 158 (2) ◽  
pp. 173-174 ◽  
Author(s):  
A. J. Petros ◽  
R. Heys ◽  
R. C. Tasker ◽  
P.-M. Fortune ◽  
I. Roberts ◽  
...  

2000 ◽  
Vol 20 (2) ◽  
pp. 272-279 ◽  
Author(s):  
Stephen P. Wardle ◽  
C. William Yoxall ◽  
A. Michael Weindling

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.


2019 ◽  
Vol 126 (5) ◽  
pp. 1360-1376 ◽  
Author(s):  
Thomas J. Barstow

Near infrared spectroscopy (NIRS) is a powerful noninvasive tool with which to study the matching of oxygen delivery to oxygen utilization and the number of new publications utilizing this technique has increased exponentially in the last 20 yr. By measuring the state of oxygenation of the primary heme compounds in skeletal muscle (hemoglobin and myoglobin), greater understanding of the underlying control mechanisms that couple perfusive and diffusive oxygen delivery to oxidative metabolism can be gained from the laboratory to the athletic field to the intensive care unit or emergency room. However, the field of NIRS has been complicated by the diversity of instrumentation, the inherent limitations of some of these technologies, the associated diversity of terminology, and a general lack of standardization of protocols. This Cores of Reproducibility in Physiology (CORP) will describe in basic but important detail the most common methodologies of NIRS, their strengths and limitations, and discuss some of the potential confounding factors that can affect the quality and reproducibility of NIRS data. Recommendations are provided to reduce the variability and errors in data collection, analysis, and interpretation. The goal of this CORP is to provide readers with a greater understanding of the methodology, limitations, and best practices so as to improve the reproducibility of NIRS research in skeletal muscle.


1998 ◽  
Vol 332 (3) ◽  
pp. 627-632 ◽  
Author(s):  
Chris E. COOPER ◽  
David T. DELPY ◽  
Edwin M. NEMOTO

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.


2014 ◽  
Vol 90 (7) ◽  
pp. 371-375 ◽  
Author(s):  
Trijntje E. Schat ◽  
Michelle E. van der Laan ◽  
Maarten Schurink ◽  
Jan B.F. Hulscher ◽  
Christian V. Hulzebos ◽  
...  

2020 ◽  
Vol 11 ◽  
Author(s):  
Chuan Zhang ◽  
Kevin K. McCully

Diseases and associated fragility of bone is an important medical issue. There is increasing evidence that bone health is related to blood flow and oxygen delivery. The development of non-invasive methods to evaluate bone blood flow and oxygen delivery promise to improve the detection and treatment of bone health in human. Near-infrared spectroscopy (NIRS) has been used to evaluate oxygen levels, blood flow, and metabolism in skeletal muscle and brain. While the limited penetration depth of NIRS restricts its application, NIRS studies have been performed on the medial aspect of the tibia and some other prominent bone sites. Two approaches using NIRS to evaluate bone health are discussed: (1) the rate of re-oxygenation of bone after a short bout of ischemia, and (2) the dynamics of oxygen levels during an intervention such as resistance exercise. Early studies have shown these approaches to have the potential to evaluate bone vascular health as well as the predicted efficacy of an intervention before changes in bone composition are detectable. Future studies are needed to fully develop and exploit the use of NIRS technology for the study of bone health.


1997 ◽  
Vol 83 (6) ◽  
pp. 1842-1848 ◽  
Author(s):  
Yoko Hoshi ◽  
Osamu Hazeki ◽  
Yasuyuki Kakihana ◽  
Mamoru Tamura

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.


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