Regional differences in oxygen saturation in retinal arterioles and venules

2012 ◽  
Vol 250 (10) ◽  
pp. 1429-1434 ◽  
Author(s):  
Rebekka Heitmar ◽  
Saima Safeen
Keyword(s):  
Oxygen Saturation ◽  
Regional Differences ◽  
Retinal Arterioles

Oxygen deficiency impacts on burying habitats for lesser sandeel, Ammodytes tobianus, in the inner Danish waters

2009 ◽  
Vol 66 (6) ◽  
pp. 883-895 ◽  
Author(s):  
Jane W. Behrens ◽  
Gunni Ærtebjerg ◽  
Jens Kjerulf Petersen ◽  
Jacob Carstensen
Keyword(s):  
Oxygen Saturation ◽  
Temperature Increase ◽  
Regional Differences ◽  
Oxygen Deficiency ◽  
Open Water ◽  
Monitoring Data ◽  
Interannual Variations ◽  
Sediment Composition ◽  
Temporal Interpolation ◽  
Bottom Oxygen

Starting in 1980s, the inner Danish waters have yearly been exposed to seasonal oxygen deficiency (hypoxia). Through spatial–temporal interpolation of monitoring data (1998–2005), we investigated oxygen deficiency impacts on suitable burying habitats for lesser sandeel ( Ammodytes tobianus ). Furthermore, the consequences of a predicted 4 °C temperature increase within this century were investigated. Maps of bottom oxygen deficiency (oxygen saturation ≤ Scrit of sandeel) were overlaid on maps of sediment composition. Throughout the study period (1998–2005), about 8% of the suitable sediments were affected by oxygen deficiency during an average year and 23% in the most severe year. Regional differences underlay the interannual variations. The extent of oxygen deficiency in enclosed regions varied from 20% to 33% of the suitable seabed being affected, whereas in open-water regions oxygen deficiency problems were limited during average years. However, large areas of the open-water seabed experienced oxygen deficiency during severe years. In such years, under a 4.0 °C temperature increase scenario, the extent of oxygen deficiency on open-water suitable patches was predicted to increase from 25% to about 40%.

scholarly journals Application of Multiple NIRS Imaging Device to the Exercising Muscle Metabolism

2003 ◽  
Vol 17 (2-3) ◽  
pp. 549-558 ◽  
Author(s):  
Hajime Miura ◽  
Kevin McCully ◽  
Britton Chance
Keyword(s):  
Oxygen Saturation ◽  
Blood Volume ◽  
Regional Differences ◽  
Near Infrared ◽  
Plantar Flexion ◽  
Muscle Metabolism ◽  
Arterial Disease ◽  
Light Sources ◽  
Imaging Device ◽  
Peripheral Arterial

Near infrared spectroscopy (NIRS) is a developing technique that measures the balance between muscle oxygen consumption and oxygen supply that is noninvasive and potentially portable. Differential absorption of light in the 600−900 nm region detects the changes in small vessel hemoglobin oxygen saturation and blood volume. Recent developments include the combining of multiple light sources and photodetectors to provide “images” of oxygen saturation and blood volume of wide regions of muscle. Using multiple NIRS imaging device, we monitored localized muscle metabolism during various exercises in the field as well as in the laboratory. In healthy subjects, the regional differences in oxygen saturation and blood volume were detected in the medial head of the gastrocnemius muscle during a standing plantar flexion exercise, consistent with differences in intramuscular pressure. Patients with peripheral arterial disease (PAD) showed slower recovery for both oxygenation and blood volume after exercise. Treatment for PAD resulted in improvements in NIRS-measured recovery times. In summary, NIRS devices have the ability to detect and monitor impaired muscle circulation. In addition, NIRS devices with multiple channels have the potential to evaluate the regional differences in oxygen status. Multiple NIRS imaging devices have the potential to play an important role in monitoring exercise prescription and clinical uses.

Retinal oxygen saturation is an independent risk factor for the severity of diabetic retinopathy

2018 ◽  
Vol 103 (8) ◽  
pp. 1167-1172 ◽  
Author(s):  
Toke Bek ◽  
Einar Stefánsson ◽  
Sveinn Hákon Hardarson
Keyword(s):  
Risk Factors ◽  
Diabetic Retinopathy ◽  
Risk Factor ◽  
Oxygen Saturation ◽  
Independent Risk Factor ◽  
Haemoglobin A1c ◽  
Retinal Arterioles ◽  
Explained Variation ◽  
Endothelial Growth Factor ◽  
Growth Factor Treatment

BackgroundThe oxygen saturation in larger retinal vessels has been shown to increase with increasing diabetic retinopathy (DR) grade and to help predict the effect of antivascular endothelial growth factor treatment in patients with diabetic maculopathy. However, it is unknown to what extent the increased oxygen saturation co-varies with other risk factors and whether it is an independent risk factor for the severity of DR.MethodsSeven hundred and twenty-two successive patients referred for specialist evaluation of diabetic retinopathy including retinal oximetry were studied. Multiple regression analysis was used to investigate whether oxygen saturation in the larger retinal arterioles and venules contributed to the severity of diabetic retinopathy, independently of gender, age, diabetes duration, diabetes type, body mass index, blood pressure, haemoglobin A1c, visual acuity and central retinal thickness.ResultsThe included parameters could explain less than 15% of the variation in retinopathy grade. Approximately, one-third of the explained variation was related to the retinal oxygen saturation.ConclusionsProspective studies are needed to evaluate whether retinal oxygen saturation is predictive for the development of diabetic retinopathy and how it interacts with other biomarkers and risk factors over time.

scholarly journals The Changes of Retinal Saturation after Long-Term Tamponade with Silicone Oil

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Bingsheng Lou ◽  
Zhaohui Yuan ◽  
Liwen He ◽  
Lixia Lin ◽  
Qianying Gao ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
Silicone Oil ◽  
Oxygen Metabolism ◽  
Oil Removal ◽  
Silicone Oil Removal ◽  
Retinal Arterioles ◽  
Silicone Oil Tamponade ◽  
The Mean ◽  
Arteriovenous Difference

Purpose.To evaluate the effects of long-term tamponade with silicone oil on retinal saturation.Methods.A total of 49 eyes that received tamponade with silicone oil were included. The patients were divided into 3 groups (3–6 months, 6–9 months, and >9 months) according to the duration of silicone oil tamponade. Retinal oximetry was performed using the Oxymap system before and 2 months after silicone oil removal.Results.The mean retinal oxygen saturation before silicone oil removal was 107% ± 12% in the arterioles and 60% ± 10% in the venules, with an overall arteriovenous difference (AVD) of 47% ± 14%. The AVD in the >9-month group was significantly higher than that in the 3–6-month group (54% ± 16% versus 44% ± 11%,P=0.042). After silicone oil removal, the AVD in the >9-month group was significantly decreased (45% ± 9% versus 54% ± 16%,P=0.009); additionally, the arterioles were significantly wider than before surgery (10.8 ± 0.7 pixels versus 10.4 ± 0.9 pixels,P=0.015).Conclusions.The tamponade with silicone oil for more than 9 months will cause the alterations of retinal saturation and the narrowing of retinal arterioles, which may further interfere with the oxygen metabolism in the retina.

Reflectance spectrophotometry for the assessment of gastroduodenal mucosal perfusion

1987 ◽  
Vol 252 (6) ◽  
pp. G797-G804 ◽  
Author(s):  
F. W. Leung ◽  
T. Morishita ◽  
E. H. Livingston ◽  
T. Reedy ◽  
P. H. Guth
Keyword(s):  
Blood Flow ◽  
Oxygen Saturation ◽  
Regional Differences ◽  
Hemoglobin Concentration ◽  
Mucosal Blood Flow ◽  
Celiac Artery ◽  
Artery Occlusion ◽  
Reflectance Spectrophotometry ◽  
Vein Occlusion ◽  
Mucosal Perfusion

Reflectance spectrophotometry in assessing gastroduodenal mucosal perfusion was evaluated. Ischemia without congestion, e.g., during hemorrhagic hypotension or celiac artery occlusion, was associated with a reduction in the indexes of mucosal hemoglobin concentration and of oxygen saturation. Ischemia with congestion, e.g., during portal vein occlusion, or in absolute ethanol or suction-induced mucosal lesions, was associated with an increase in the index of mucosal hemoglobin concentration but a reduction in the index of oxygen saturation. An increase in the index of mucosal hemoglobin concentration associated with a normal index of oxygen saturation was found in the postischemic hyperemia after release of celiac artery occlusion and during the sustained increase in corpus mucosal blood flow induced by vagus nerve stimulation. Thus reflectance spectrophotometric measurements reflected ischemia, without or with congestion, and hyperemia. Additionally, although regional differences in reflectance spectrophotometric measurements were demonstrated in the duodenal, antral, and corpus mucosa, such differences bore no consistent relationship to regional differences in blood flow demonstrated in previous studies.

scholarly journals OCTA reveals remodeling of the peripheral capillary free zones in normal aging

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Edmund Arthur ◽  
Jessica Alber ◽  
Louisa I. Thompson ◽  
Stuart Sinoff ◽  
Peter J. Snyder
Keyword(s):  
Oxygen Saturation ◽  
Optical Coherence Tomography Angiography ◽  
Tissue Oxygenation ◽  
Neurovascular Unit ◽  
Normal Aging ◽  
Retinal Neurons ◽  
Free Zone ◽  
Retinal Tissue ◽  
Retinal Arterioles ◽  
Cell Layers

AbstractThe retinal neurovascular unit consists of blood vessel endothelial cells, pericytes, neurons, astrocytes, and Müller cells that form the inner retinal blood barrier. A peripheral capillary free zone (pCFZ) represents the distance that oxygen and nutrients must diffuse to reach the neural retina, and serves as a metric of retinal tissue oxygenation. The pCFZs are formed based on oxygen saturation in the retinal arterioles and venules. Because retinal arterioles contain a larger concentration of oxygenated blood than venules, there is a reduced need for capillaries to exist closely to arterioles compared to venules. Therefore, in a healthy individual, larger periarteriole CFZs are expected compared to perivenule CFZs. With normal aging, there is atrophy of the inner retinal neurons, and consequently reduced extraction of oxygen and nutrients from the retinal vessels (i.e., increased oxygen saturation). Therefore, we hypothesized that the peripheral CFZ will remodel with normal aging. Using Optical Coherence Tomography Angiography, we showed that the pCFZs do remodel in normal aging with large (perivenule: η2p = 0.56) and moderate (periarteriole: η2p = 0.12) effect sizes, opening the possibility that such changes may be further increased by neurodegenerative diseases that adversely impact the health of the retinal neural cell layers.

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