A Graphical Analysis of the Influence of Red Cell Transit Time, Carrier-Free Layer Thickness, and Intracellular PO2 on Blood-Tissue O2 Transport

Gayeski, T. E. J.; Federspiel, William J.; Honig, Carl R.

doi:10.1007/978-1-4615-9510-6_3

Cited by 22 publications

(7 citation statements)

References 17 publications

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“…Given that estimates of the mean time for diffusion of O 2 from RBC to mitochondria are around 1 sec or less, it would suggest that the whole diffusion pathway, including vascular Hb and intracellular Mb, desaturate with a similar time course (Gayeski et al, 1988). If true, then a potentially greater contribution of Mb to the NIRS deoxy signal would not invalidate the approach of estimating capillary blood flow described above.…”

Section: Implications Of Increased [Mb] Contribution To Nirsmentioning

confidence: 99%

“…It has been suggested that the cell can modulate its own PO 2 gradient with Mb facilitated diffusion contributing significantly to oxygen transport to the mitochondria (Gayeski et al, 1988, Wittenberg, 1970, Wittenberg and Wittenberg, 2003. However, assessing the capillary to mitochondria PO 2 gradient is exceptionally challenging in humans.…”

Section: Chapter 1 -Introductionmentioning

confidence: 99%

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Estimated contribution of hemoglobin and myoglobin to near infrared spectroscopy

Davis

Barstow

2013

Respiratory Physiology & Neurobiology

108

107

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Section: Implications Of Increased [Mb] Contribution To Nirsmentioning

confidence: 99%

Section: Chapter 1 -Introductionmentioning

confidence: 99%

Estimated contribution of hemoglobin and myoglobin to near infrared spectroscopy

Davis

Barstow

2013

Respiratory Physiology & Neurobiology

108

107

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“…Some structure between the hemoglobin (intraerythrocyte) and myoglobin (intramyocyte) oxygen storage pools offers considerable resistance to oxygen diffusion since there is normally a marked difference in their respectwe p02 [I], [2], [3]. Some structure between the hemoglobin (intraerythrocyte) and myoglobin (intramyocyte) oxygen storage pools offers considerable resistance to oxygen diffusion since there is normally a marked difference in their respectwe p02 [I], [2], [3].…”

Section: Introductionmentioning

confidence: 99%

Concepts of “Tissue PO₂” In Relation to O₂Delivery

Weiner

1994

Artificial Cells, Blood Substitutes, and Biotechnology

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Resistance to O2 diffusion is reflected in the difference in pO2 between O2 reservoirs of hemoglobin (Hb) and myoglobin. The very low normal myocyte pO2 (less than one torr but adequate for optimal oxidative ATP synthesis) compared to venous pO2 indicates that blood does not achieve equilibrium with tissue during its passage through capillaries. In the lung, diffusion rate of O2 from alveolus to capillary is normally sufficient to achieve essential equilibrium. However, system-wide capillary pathology and reduced Hb saturation has been observed with distal local ischemia. In peripheral vascular disease (PVD) patients, we found a mean arterial pO2 of 77 torr (normal over 90 torr). Classical concepts based on "tissue pO2" values derived from venous blood or oxygen electrodes inserted into tissue need re-evaluation. Readings of O2 electrodes moved through tissue range widely from intracapillary levels down toward intracellular levels and do not reflect the pO2 of any particular site. Intravenous pO2 is the result of residual O2 after incomplete diffusion out of capillaries during transit through a tissue, and is not an equilibrium value with some tissue pool. The effect of HbO2 p50 on oxygen release during the passage of blood through a capillary bed, generally judged on the basis of percentage percent saturation at "tissue pO2", should be judged on the basis of the change in pO2 (the diffusion driving force) associated with a particular degree of HbO2 saturation at a particular p50. The thesis that O2 diffusion rate is a major determinant of oxygen delivery is supported by pO2 responses to treatment of PVD that does not alter blood flow or p50.

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“…Hundlicka, personal communication) of older observations (29) that p02 determined continuously with a fine electrode moving slowly through tissue yields serial PO, peaks and troughs, with the peaks approximating intracapillary PO, and troughs (presumably representing the myocyte environment between capillaries) that are generally below 10 torr. Based on PO, gradients, aqueous plasma and interstitial fluid offer relatively little resistance to oxygen diffusion compared to the capillary wall (9). Calculations show that the area of capillaries through which oxygen must diffuse is about three orders of magnitude smaller than that of the mitochondrial membranes that oxygen must cross to reach mitochondrial ATPase (37).…”

Section: Physiologic Conceptsmentioning

confidence: 99%

“…Even though the pericapillary PO, is low and not in equilibrium with capillary blood PO,, it is nevertheless a function of capillary blood PO,, which changes during the course of its flow from arteriole to venule. Thus, the qualitative aspects of the calculations of tissue oxygen supply by the Krogh concept (17) remains valid as blood loses oxygen during the flow from arteriole to venule, even though equilibrium of PO, across the capillary wall is not achieved (9).…”

Section: Physiologic Conceptsmentioning

confidence: 99%

Oxygen Transport in Peripheral Vascular Disease: A Novel Approach to the Search for Effective Agents

Weiner¹

1991

Cardiovascular Drug Reviews

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Peripheral vascular disease (PVD) is one of several types of disturbances that can interfere with the transport of oxygen from atmospheric air in the alveoli to the ATPasecontaining inner surface of the inner mitochondria1 membrane. The consequences can include functional and structural tissue degeneration. The preferred therapeutic approach to PVD, as with any disease, is to identify and remove the cause. When this approach is not feasible, the therapist seeks to influence any aspect of the mechanism that may alleviate the damage to function and structure.The rational classical approaches to the ischemia of PVD include widening vascular channels by the surgical or medical removal of obstructing materials, vasodilation, and neovascularization. More recently, effective therapeutic agents have been developed on the basis of pathophysiologic mechanisms that do not involve an increase in the total cross-sectional area of the lumen of the vessels involved. These include drug-enhanced red cell deformability (35) and hemodilution (12) to reduce blood viscosity as a means of increasing blood flow without widening narrowed vascular channels, the trapping of free radicals that form on reperfusion of ischemic tissue (13), and better survival of injured cells by controlling the intracellular calcium ion concentration with drugs that act on calcium channel receptors (31). This discussion will deal with still another hypothesis not directly concerned with vascular channel caliber, i.e., oxygen diffusion. Impaired oxygen diffusion as a possible contributing factor to the inadequate delivery of oxygen from alveolus to mitochondria has received little attention even though limitations to oxygen diffusion are recognized (25). While good experimental data support the commonly accepted thesis that the rate of diffusion is not a limiting factor in the normal chain of oxygen transport (4), recent observations suggest the possibility that limitations of oxygen diffusion may in fact contribute significantly to the consequences of PVD,

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A Graphical Analysis of the Influence of Red Cell Transit Time, Carrier-Free Layer Thickness, and Intracellular PO2 on Blood-Tissue O2 Transport

Cited by 22 publications

References 17 publications

Estimated contribution of hemoglobin and myoglobin to near infrared spectroscopy

Estimated contribution of hemoglobin and myoglobin to near infrared spectroscopy

Concepts of “Tissue PO₂” In Relation to O₂Delivery

Oxygen Transport in Peripheral Vascular Disease: A Novel Approach to the Search for Effective Agents

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A Graphical Analysis of the Influence of Red Cell Transit Time, Carrier-Free Layer Thickness, and Intracellular PO2 on Blood-Tissue O2 Transport

Cited by 22 publications

References 17 publications

Estimated contribution of hemoglobin and myoglobin to near infrared spectroscopy

Estimated contribution of hemoglobin and myoglobin to near infrared spectroscopy

Concepts of “Tissue PO2” In Relation to O2Delivery

Oxygen Transport in Peripheral Vascular Disease: A Novel Approach to the Search for Effective Agents

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Product

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Concepts of “Tissue PO₂” In Relation to O₂Delivery