Regional oxygen delivery in oxygen supply-dependent states

1990 ◽  
Vol 16 (S2) ◽  
pp. S169-S171 ◽  
Author(s):  
M. R. Pinsky ◽  
R. Schlichtig
Keyword(s):  
Oxygen Delivery ◽  
Oxygen Supply

scholarly journals Association between Oxygen Delivery and Consumption in Patients Undergoing Cardiac Surgery. is There Supply Dependence?

1996 ◽  
Vol 24 (6) ◽  
pp. 651-657 ◽  
Author(s):  
P. S. Myles ◽  
R. Mcrae ◽  
I. Ryder ◽  
J. O. Hunt ◽  
M. R. Buckland
Keyword(s):  
Cardiac Surgery ◽  
Oxygen Delivery ◽  
Oxygen Supply ◽  
Gas Analysis ◽  
Surgical Patients ◽  
Poor Agreement ◽  
Oxygen Extraction Ratio ◽  
Expired Gas Analysis ◽  
Expired Gas ◽  
The Relationship

We studied the relationship between oxygen delivery (DO2) and consumption (VO2) in twenty patients undergoing cardiac surgery, in order to determine if VO2was dependent on DO2(pathological oxygen supply dependence). We measured VO2from expired gas analysis (VO2G) and compared this to that calculated using the reverse Fick method (VO2F). Both VO2Gand VO2Fincreased after cardiopulmonary bypass (P<0.001), without change in DO2(i.e. oxygen extraction ratio increased). There was a significant relationship between changes in DO2and VO2F, both before bypass (r=0.74, P < 0.001) and after bypass (r=0.69, P < 0.001), while changes in DO2and VO2Ghad no such relationship (pre-bypass: r=0.38, P=0.094; post-bypass: r=0.10, P=0.68). There was poor agreement between VO2Fand VO2Gperioperatively. We could not demonstrate supply dependence in elective cardiac surgical patients.

scholarly journals The Oxygen Paradox of Neurovascular Coupling

2013 ◽  
Vol 34 (1) ◽  
pp. 19-29 ◽  
Author(s):  
Christoph Leithner ◽  
Georg Royl
Keyword(s):  
Brain Tissue ◽  
Oxygen Content ◽  
Neuronal Activity ◽  
Oxygen Delivery ◽  
Brain Function ◽  
Oxygen Supply ◽  
Neurovascular Coupling ◽  
Tissue Oxygen ◽  
Brain Tissue Oxygen ◽  
Oxygen Paradox

The coupling of cerebral blood flow (CBF) to neuronal activity is well preserved during evolution. Upon changes in the neuronal activity, an incompletely understood coupling mechanism regulates diameter changes of supplying blood vessels, which adjust CBF within seconds. The physiologic brain tissue oxygen content would sustain unimpeded brain function for only 1 second if continuous oxygen supply would suddenly stop. This suggests that the CBF response has evolved to balance oxygen supply and demand. Surprisingly, CBF increases surpass the accompanying increases of cerebral metabolic rate of oxygen (CMRO2). However, a disproportionate CBF increase may be required to increase the concentration gradient from capillary to tissue that drives oxygen delivery. However, the brain tissue oxygen content is not zero, and tissue pO2 decreases could serve to increase oxygen delivery without a CBF increase. Experimental evidence suggests that CMRO2 can increase with constant CBF within limits and decreases of baseline CBF were observed with constant CMRO2. This conflicting evidence may be viewed as an oxygen paradox of neurovascular coupling. As a possible solution for this paradox, we hypothesize that the CBF response has evolved to safeguard brain function in situations of moderate pathophysiological interference with oxygen supply.

scholarly journals Large arteriolar component of oxygen delivery implies a safe margin of oxygen supply to cerebral tissue

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Sava Sakadžić ◽  
Emiri T. Mandeville ◽  
Louis Gagnon ◽  
Joseph J. Musacchia ◽  
Mohammad A. Yaseen ◽  
...  
Keyword(s):  
Oxygen Delivery ◽  
Oxygen Supply ◽  
Cerebral Tissue

Stroma-free hemoglobin: its presence in plasma does not improve oxygen supply to the resting hindlimb vascular bed of hemodiluted dogs

1991 ◽  
Vol 69 (11) ◽  
pp. 1656-1662 ◽  
Author(s):  
George P. Biro ◽  
Peter J. Anderson ◽  
Scott E. Curtis ◽  
Stephen M. Cain
Keyword(s):  
Vascular Resistance ◽  
Oxygen Delivery ◽  
Oxygen Supply ◽  
Oxygen Extraction ◽  
Free Hemoglobin ◽  
Hemoglobin Solution ◽  
Arterial Blood ◽  
Vascular Bed ◽  
Critical Oxygen ◽  
Plasma Phase

In hemodilution, red cell spacing in the microcirculation is increased, flow distribution may become more heterogeneous, and, as a result, oxygen supply to tissues may suffer. We tested the hypothesis that oxygen extraction from diluted blood may be enhanced by the presence of hemoglobin in the plasma phase in relatively low concentrations. In anesthetized dogs, the hindlimb vascular bed was isolated and perfused with the animal's own blood by a roller pump. One group of dogs (n = 6) was hemodiluted (hematocrit = 15.0 ± 1.0%) with a 6% solution of dextran. A second group of dogs (n = 6) was similarly hemodiluted (hematocrit = 16.0 ± 0.4%) with dextran containing stroma-free hemoglobin solution whereby plasma-phase hemoglobin concentration was raised to 1.1 ± 0.1 g∙dLé−1. Systemic hemodynamic observations were made repeatedly over the subsequent 2.5 h, while blood flow to the hindlimb was progressively reduced in stepwise decrements. The hemoglobin-hemodiluted group showed increased systemic arterial blood pressure and total peripheral resistance when compared with the control (dextran diluted) group. The isolated hindlimb also showed evidence of increased vascular resistance in the hemoglobin-treated group. In each individual animal, critical oxygen delivery and extraction were determined by finding the intercept of the supply-independent and supply-dependent portions of the oxygen uptake/oxygen delivery relationship. Neither the critical oxygen delivery rates (5.75 ± 0.83 vs. 6.41 ± 0.53 mL∙kg−1 min−1) nor critical oxygen extraction ratios (0.75 ± 0.03 vs. 0.76 ± 0.04) were found to be significantly different in the two groups. We conclude that hemoglobin in solution in the plasma at a concentration of about 1 g∙dL−1 induces significant increase in vascular resistance and fails to augment oxygen extraction from diluted blood by the resting hindlimb.Key words: stroma-free hemoglobin solution, oxygen extraction, vasoconstriction, isolated hindlimb vascular bed, oxygen supply.

scholarly journals Do fluorocarbons substantially increase transdermal oxygen delivery? A proof-of-principle study in mice

2021 ◽  
Vol 1 ◽  
pp. 39
Author(s):  
Lars Kaestner ◽  
Matthias W. Laschke ◽  
Thomas John ◽  
Christian Wagner ◽  
Anna Bogdanova
Keyword(s):  
Medical Care ◽  
Nude Mice ◽  
Oxygen Delivery ◽  
Critical State ◽  
Oxygen Supply ◽  
Blood Oxygenation ◽  
Entire Body ◽  
Hypoxic Conditions ◽  
The World ◽  
Proof Of Principle

Background: Coronavirus disease 2019 (COVID-19) patients who need intensive medical care often require oxygen ventilation, but the number of ventilation machines is limited, and in some parts of the world, they are not available at all. In addition to patients for whom there is no access to ventilation machines there is also a considerable population of patients for whom ventilation is not sufficient for them to survive a critical state. Methods: Here, we propose and test an alternative oxygen supply through accelerated transdermal oxygen delivery. Covering the entire body with liquid fluorocarbons, which can dissolve 20 times more oxygen than water, we hypothesized to increase the contribution of transcutaneous respiration by a sustained amount. Results: Experiments applying pure medical grade perfluorodecalin on nude mice did not change their oxygenation in the blood under induced hypoxic conditions compared to control mice. However, increases in blood oxygenation below 2% could not be detected with the applied method. Conclusions: We could not establish a proof-of-principle for a substantial increase in oxygen supply by transdermal oxygen delivery in mammals.

Cerebral Blood Flow and Metabolic Correlates of Near Infrared Spectroscopy in Patients with Sickle Cell Disease

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 1386-1386
Author(s):  
Adam M Bush ◽  
Matthew Borzage ◽  
Thomas Coates ◽  
John C Wood ◽  
Soyoung Choi
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Infrared Spectroscopy ◽  
Oxygen Delivery ◽  
Oxygen Supply ◽  
Near Infrared ◽  
Cell Disease ◽  
T2 Relaxation ◽  
Total Hemoglobin ◽  
The Relationship

Abstract Introduction Tissue oxygen index (TOI), by near Infrared Spectroscopy (NIRS), is a valuable tool for noninvasive, indirect measurement of oxygen supply-demand balance. Cerebral TOI is decreased in sickle cell disease (SCD), and correlates with disease severity. Previous work suggests that cerebral TOI is inversely correlated with hemoglobin S level and chronic transfusion therapy restores TOI to normal values. Nahavandi et al. have proposed that low cerebral TOI in SCD disease can be attributed to impaired oxygen delivery and/or carrying capacity of sickle blood. Unfortunately, the specificity of cerebral TOI is still an area of active debate. In order to elucidate these mechanisms we measured global cerebral blood flow (CBF),arterial oxygen content (CaO2), oxygen delivery (DO2), arterial and venous oxygen saturation (SaO2 and SvO2) and oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO2) in 12 healthy controls and 15 SCD patients using magnetic resonance imaging (MRI). Methods All patients were recruited with informed consent or assent and this study was approved by the CHLA IRB. Fifteen patients with SCD and 12 healthy ethnicity matched controls (CTL) were studied. MRI compatible NIRS probes were placed on the forehead and TOI was recorded throughout the entire MRI examination. SaO2 was measured via peripheral pulse oximetery. Phase Contrast (PC) of the carotid and vertebral arteries was used to measure global CBF. T2 Relaxation Under Spin Tagging (TRUST) was used to measured T2 relaxation of blood within the sagittal sinus. T2 relaxation was converted to SvO2 via calibration curves. Blood draw for hemoglobin and electrophoresis was performed. Exclusion criteria included pregnancy, previous stroke, acute chest or pain crisis hospitalization within one month. Results Table 1 summarizes the relationship between cerebral TOI, age, laboratory values, and hemodynamic variables. Surprisingly, TOI was independent of indices of oxygen supply (SaO2, CBF, oxygen delivery) and oxygen demand (CMRO2); cerebral venous saturation and OEF were the only hemodynamic correlate of TOI. Total hemoglobin and percent sickle hemoglobin were equally and independently correlated with TOI with a combined r2 of 0.59 on multivariate regression (p<0.0001). Discussion This represents the first study comparing TOI to direct measurements of cerebral oxygen supply and consumption in SCD patients. We demonstrate that TOI tracks SvO2 and OEF, suggesting that it is weighted toward venous vascular beds. The relationship of TOI and HbS% has been previously described and could either shifting of the oxygen dissociation curve or mechanical disruption of microvascular integrity. TOI's strong dependence on total hemoglobin (after correction for HbS%) is particularly startling given its independence with oxygen delivery, suggesting that total hemoglobin is acting as a surrogate marker of microvascular disease severity in SCD patients. TableParameterR2pAge (Years)0.0127nsHemoglobin (gm/dl)0.295<0.05Hemoglobin S %0.229<0.05WBC (103/uL)0.0020nsCBF ml/100g/min0.018nsSaO2 (%)0.034nsO2 delivery0.071nsSvO2 (%)0.290<0.05OEF (%)0.238<0.05CMR020.112ns Disclosures Coates: novartis: Honoraria, Speakers Bureau; shire: Consultancy, Honoraria; apo pharma: Consultancy, Honoraria, Speakers Bureau; acceleron: Consultancy, Honoraria.

Hypothermia, hepatic oxygen supply-demand, and ischemia-reperfusion injury in pigs

1990 ◽  
Vol 258 (6) ◽  
pp. G910-G918 ◽  
Author(s):  
K. Nagano ◽  
S. Gelman ◽  
E. L. Bradley ◽  
D. Parks
Keyword(s):  
Reperfusion Injury ◽  
Oxygen Delivery ◽  
Oxygen Supply ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Venous Blood ◽  
Oxygen Demand ◽  
Base Line ◽  
Hepatic Oxygen Delivery ◽  
Normothermic Group

We examined the effects of two degrees of hypothermia on hepatic oxygen delivery and uptake, hepatic lactate uptake as a marker of hepatic function, and the effect of hypothermia on ischemia-reperfusion injury in the liver in miniature pigs (n = 18, 21-30 kg body wt). Hepatic arterial and portal venous blood flows were measured while hepatic oxygen delivery was progressively decreased without venous congestion in the preportal area. With decreases in hepatic blood and oxygen supply, oxygen extraction gradually increased from 50 to 90% in the normothermic group and from 25 to 70 and 84% in the hypothermic (30. and 34 degrees C, respectively) groups. The values of critical hepatic oxygen delivery were between 7.3 and 11.9 ml O2.min-1.100 g-1 without significant differences among the groups. During reperfusion after ischemic insult, hepatic oxygen uptake returned to base-line values in both hypothermic groups but remained substantially below base-line values in normothermic groups of animals. Hepatic enzyme concentrations (lactate dehydrogenase, alanine aminotransferase, aspartate aminotransferase, and alcohol dehydrogenase) were substantially increased (up to 30-fold) in normothermic animals, but the concentrations did not increase in either of the hypothermic groups. These results demonstrated that hypothermia per se does not affect hepatic oxygen delivery but decreases hepatic oxygen demand and uptake, provides an effective protection from hepatic oxygen deprivation, and lessens reperfusion injury.

Capillary density in mammals in relation to body size and oxygen consumption

1961 ◽  
Vol 200 (4) ◽  
pp. 746-750 ◽  
Author(s):  
Knut Schmidt-Nielsen ◽  
Pamela Pennycuik
Keyword(s):  
Oxygen Consumption ◽  
Body Size ◽  
Small Mammals ◽  
Oxygen Delivery ◽  
Oxygen Supply ◽  
Size Range ◽  
Small Animal ◽  
Capillary Density ◽  
High Rate ◽  
High Metabolic Rate

The high metabolic rate per gram of tissue in small mammals requires that oxygen be supplied to the tissues at a higher rate than in larger animals. The high rate of oxygen delivery in the small animal can be accomplished by a) higher capillary density and b) higher unloading tension for oxygen. Both these factors in the oxygen supply vary with body size in such a manner that delivery of oxygen to the tissues is facilitated in the small animal. This paper gives comparative data on capillary density in muscles from 10 mammals of various size. The smallest mammals have significantly higher capillary densities, but the trend is not evident throughout the size range examined. It is therefore reasonable to assume that the factors that relate capillary density and body size are overshadowed by variables such as activity, domestication, cold acclimation, etc., and, perhaps primarily, the size of the muscle fibers, which (although dependent on body size) varies considerably with the type of muscle and its use.

The effect of vasopressin on fetal oxygenation in sheep

1984 ◽  
Vol 62 (1) ◽  
pp. 27-30 ◽  
Author(s):  
D. W. Rurak ◽  
N. C. Gruber
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Arterial Pressure ◽  
Oxygen Delivery ◽  
Oxygen Supply ◽  
Base Excess ◽  
Percentage Increase ◽  
Umbilical Blood ◽  
Umbilical Blood Flow ◽  
Fetal Oxygenation

To examine the effects of vasopressin on fetal oxygenation the hormone was infused intravenously for 1 h (1.4–3.5 mU∙min−1∙kg fetal weight−1) to chronically catheterized fetal lambs in utero (113–137 days gestation). Arterial pressure rose (48.3 to 59.6 mmHg) (1 mmHg = 133.322 Pa) and heart rate fell (185.3 to 141.0 beats/min) during the infusion. There was a significant increase in fetal arterial [Formula: see text] (20.0 to 23. 1 mmHg) and significant declines in pH (7.414 to 7.381) and base excess. Umbilical blood flow rose, and the percentage increase in flow (23%) was identical to the proportional rise in arterial pressure. Accompanying the rise in umbilical blood flow was a rise in umbilical oxygen delivery. But as there was no change in fetal oxygen consumption, fractional oxygen extraction by the fetus fell significantly (0.31 to 0.25). These data indicate that the vasopressin-induced rise in fetal vascular [Formula: see text] results from an increase in umbilical oxygen delivery and concomitant fall in fractional extraction. Fetal vasopressin levels are greatly elevated during hypoxia, and under conditions of reduced oxygen supply, the effects of the hormone on umbilical oxygen delivery and vascular [Formula: see text] could have definite survival value.

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