The oxygen dissociation curve: quantifying the shift

Perfusion ◽  
2004 ◽  
Vol 19 (3) ◽  
pp. 141-144 ◽  
Author(s):  
Carole Hamilton ◽  
Barbara Steinlechner ◽  
Eva Gruber ◽  
Paul Simon ◽  
Gregor Wollenek

An oxyhaemoglobin dissociation curve (ODC) quantifies the most important function of red blood cells and that is the affinity for oxygen and its delivery to the tissues. Oxygen affinity for haemoglobin plays a critical role in the delivery of oxygen to the tissues and is changed by shifting to the left or right. A shift to the left implies an increased oxygen affinity and, hence, tighter binding due to the higher oxygen saturation in relation to the pO2.On the other hand, a shift to the right corresponds to a decreased oxygen affinity and easier release of oxygen to the tissues. It is well known that the ODC shifts in response to changes in pH, pCO2 and 2,3 diphosphoglycerate. However, how much the ODC shifts has never been quantified. Arterial and venous blood gases were taken during cardiopulmonary bypass and two indices were used to quantify the shift of the ODC; the p50 shift and the SO2 difference. Arterial blood shifted to the right by 49-0.1 mmHg at a pH of 7.24 and shifted to the left by -3.59-0.05 mmHg at a pH of 7.51. The change in arterial saturation was minimal, rising by 0.8% and dropping by -5% and did not correlate to p50 shifting and changes in pH, but demonstrated changes dependent on the concentration of dyshaemoglobins. The venous blood exhibited a greater range of p50 shifting at each pH value. At a pH of 7.24, the p50 shifted to the right by 4.89-2 mmHg and at a pH of 7.51 the p50 shifted to the left by -4±1.8 mmHg. Unlike the arterial blood, the change in saturation correlated well to p50 shifting. It is shown here for the first time how much the curve shifts with changes in pH and how this may be used to evaluate treatment strategies.

1965 ◽  
Vol 208 (4) ◽  
pp. 798-800 ◽  
Author(s):  
Hugo Chiodi ◽  
James W. Terman

Individual blood samples were collected anaerobically from the brachial arteries of adult White Rock hens and were analyzed for Po2, Pco2, pH, oxygen content and capacity, and CO2 content and capacity. A dissociation curve was constructed from data on equilibration of pooled venous blood. The average arterial oxygen saturation was 90%, the Pco2 was about 32 mm Hg, the Po2 was between 94 and 99 mm Hg, and the pH averaged 7.49. The dissociation curve, as has been shown before, was shifted to the right of most homeothermic species.


1975 ◽  
Vol 38 (2) ◽  
pp. 250-256 ◽  
Author(s):  
B. Rasmussen ◽  
K. Klausen ◽  
J. P. Clausen ◽  
J. Trap-Jensen

In two groups of young healthy subjects who performed arm training (N = 5) and leg training (N = 5), respectively, the respiratory adaptation to submaximal exercise with trained and nontrained muscle groups was compared by measurement of the ventilatory equivalent (Ve/Vo2, pH, and blood gases (Pco2, Po2, and So2) in arterial blood and in venous blood from exercising extremities. After training Ve/Vo2 was significantly reduced during exercise with trained muscles, but unchanged during exercise with nontrained muscles. The reduction in Ve/Vo2 was closely related to a less pronounced increase in heart rate and in arterial lactate content, but showed no quantitative correlation to changes in arterial adaptations in trained muscles are mainly responsible for the reduction in Ve/Vo2. After training during exercise with trained as well as nontrained muscles a shift to the right of the blood oxygen dissociation curve occurred as extremities was lower while corresponding Po2 was higher.


1963 ◽  
Vol 205 (2) ◽  
pp. 337-340 ◽  
Author(s):  
Peter Hilpert ◽  
Renate Gislinde Fleischmann ◽  
Doris Kempe ◽  
Heinz Bartels

The Bohr effect of the blood and the red cell hemolysates of adult and newborn humans, goats and kids, and sheep and lambs were determined and the physiological significance is discussed. Similar determinations were made on blood from an African elephant, yak, camel, Dybowski deer, and llama. The strong displacement to the right of the oxygen dissociation curve which occurs in kids and lambs during the first 5 days of life can be largely explained by a change in the pH value within the erythrocytes. When the oxygen affinity is expressed by the oxygen pressure necessary for half saturation (T50) at a constant cell pH, considerable differences exist between species.


1974 ◽  
Vol 60 (1) ◽  
pp. 71-83 ◽  
Author(s):  
F. B. EDDY

1. The respiration of tench at 13°C was investigated, particular attention being given to the role of the blood in uptake and transport of oxygen. 2. In well aerated water the mean value for arterial blood was 36 mmHg, for PCOCO2 3.3 mmHg and for pH 8.16; the respective venous values were 7 mmHg, 5 mmHg and 8.08. Arterial blood averaged about 75% and venous blood about 40° oxygen saturation. The mean value for oxygen uptake was 0.5 ml/min/kg and for ventilation volume 132/ml/mm/kg. 3. The oxygen tension and the percentage saturation of the blood determined in vivo are discussed in terms of the oxygen dissociation curve determined in vitro. 4. When the environmental POO2 was decreased, tench responded by increasing breathing rate and ventilation volume. Arterial POO2 and PCOCO2 decreased but arterial pH tended to remain steady. There was also a significant increase in blood lactate. 5. That tenth can withstand severe hypoxic conditions is attributed to blood of high oxygen affinity and the ability to maintain a favourable acid-base status in the blood for oxygen transport. 6. Respiration in tench is compared with that in other fish species.


Animals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2277
Author(s):  
Melina Marie Yasuoka ◽  
Bruno Moura Monteiro ◽  
Paulo Fantinato-Neto ◽  
Renan Braga Paiano ◽  
Denise Tabacchi Fantoni ◽  
...  

The neonatal period is a challenging phase for calves, and during this phase constant adaptations are required. The aim of the present study was to evaluate the invasive hemodynamics with the Swan-Ganz catheter in neonate calves to understand adaptive changes during the first 30 days of life. A prospective and observational study was conducted with 10 Holstein calves. Assessments of the right atrial pressure (RAP), right ventricular pressure (RVP), pulmonary artery pressure (PAP), pulmonary capillary pressure (PW), cardiac output (CO), heart rate (HR), pulmonary vascular resistance (PVR), and blood gas levels were performed. The analyses of PAP, PVR, PW, HR, sO2, and arterial blood gases differed (p < 0.05) between the evaluated periods. Our results indicated transient pulmonary artery hypertension during the process of extrauterine adaptation during the first 30 days of life. This hypertension must be considered as physiological and consequent to the neonatal adaptation process.


1995 ◽  
Vol 269 (1) ◽  
pp. H282-H287 ◽  
Author(s):  
D. A. Ogunyemi ◽  
B. J. Koos ◽  
C. P. Arora ◽  
L. C. Castro ◽  
B. A. Mason

The effects of adenosine on atrial natriuretic peptide (ANP) secretion were determined in chronically catheterized fetal sheep (> 0.8 term). Adenosine was infused into the the right jugular vein for 1 h at 8 +/- 0.4 (5 fetuses), 160 +/- 8 (6 fetuses), and 344 +/- 18 micrograms.min-1.kg estimated fetal wt-1. Fetal arterial blood gases and pH were generally unaffected by adenosine, although mean arterial CO2 tension increased transiently by 2-5 Torr and pH fell progressively during the highest rate of infusion. During the intermediate and high infusion rates, fetal hemoglobin concentrations increased by 11-13% and mean fetal heart rate rose by 18% from a control value of approximately 167 beats/min. Mean arterial pressure was not affected during adenosine infusion. Adenosine significantly increased fetal plasma ANP levels, with maximum concentrations 1.80, 2.36, and 2.51 times greater than control means (142-166 pg/ml) for the respective infusion rates of 8, 160, and 344 micrograms.min-1.kg estimated fetal wt-1. In seven fetuses, reducing fetal arterial O2 tension by approximately 9-10 Torr from a control of 23 +/- 1.3 Torr increased plasma ANP concentrations approximately 2.4 times the control mean of 176 pg/min. Adenosine-receptor blockade with 8-(p-sulfophenyl)-theophylline reduced by 50% the maximum hypoxia-induced rise in plasma ANP concentrations. It is concluded that adenosine causes a dose-dependent rise in fetal plasma ANP concentrations and modulates fetal ANP release during hypoxia.


1977 ◽  
Author(s):  
M.H. Todd ◽  
J.B. Forrest ◽  
J. Hirsh

Embolisation of the pulmonary vasculature with microspheres releases prostaglandin-1ike substances, PGLS (Piper and Vane, N.Y. Acad. Sei. 180: 363, 1971) but the capacity of autologous blood clots (ABC) to release pulmonary vasoactive substances is disputed. Ten normal mongrel dogs were anesthetised with pentobarbitone sodium and instrumented. Pulmonary venous blood was continuously superfused over isolated tissues for bioassay and then returned to the animal. Injection of ABC into the right atrium increased pulmonary artery pressure from 21 ± 6.5 mm Hg to 38 ± 15 mm Hg (mean ± S.D.), increased arterial pCO2 and decreased arterial pO2. No significant changes in heart rate, systemic arterial blood pressure or cardiac output occurred. In three animals contractions of the blood superfused assay tissues occurred following embolism. This effect was produced in normal assay tissues and those pretreated with antagonists of ACh, Serotonin, Histamine and Catecholamines and could therefore be attributed to PGLS. No cardiovascular or assay tissue tension changes were observed when equivalent volumes of saline or clot lysate were injected into the right atrium.Therefore, pulmonary embolism with ABC can release PGLS which may contribute to the pulmonary artery pressure rise. Vasoactive substances may normally be inactivated in the lung but in some animals appear in pulmonary venous blood.(Supported by the Ontario Heart Foundation)


2015 ◽  
Vol 35 (5) ◽  
pp. 873-881 ◽  
Author(s):  
Christopher K Willie ◽  
David B MacLeod ◽  
Kurt J Smith ◽  
Nia C Lewis ◽  
Glen E Foster ◽  
...  

The effects of partial acclimatization to high altitude (HA; 5,050 m) on cerebral metabolism and cerebrovascular function have not been characterized. We hypothesized (1) increased cerebrovascular reactivity (CVR) at HA; and (2) that CO2 would affect cerebral metabolism more than hypoxia. PaO2 and PaCO2 were manipulated at sea level (SL) to simulate HA exposure, and at HA, SL blood gases were simulated; CVR was assessed at both altitudes. Arterial–jugular venous differences were measured to calculate cerebral metabolic rates and cerebral blood flow (CBF). We observed that (1) partial acclimatization yields a steeper CO2-H+ relation in both arterial and jugular venous blood; yet (2) CVR did not change, despite (3) mean arterial pressure (MAP)-CO2 reactivity being doubled at HA, thus indicating effective cerebral autoregulation. (4) At SL hypoxia increased CBF, and restoration of oxygen at HA reduced CBF, but neither had any effect on cerebral metabolism. Acclimatization resets the cerebrovasculature to chronic hypocapnia.


1962 ◽  
Vol 17 (4) ◽  
pp. 656-660 ◽  
Author(s):  
Ronald L. Wathen ◽  
Howard H. Rostorfer ◽  
Sid Robinson ◽  
Jerry L. Newton ◽  
Michael D. Bailie

Effects of varying rates of treadmill work on blood gases and hydrogen ion concentrations of four healthy young dogs were determined by analyses of blood for O2 and CO2 contents, Po2, Pco2, and pH. Changes in these parameters were also observed during 30-min recovery periods from hard work. Arterial and mixed venous blood samples were obtained simultaneously during work through a polyethylene catheter in the right ventricle and an indwelling needle in an exteriorized carotid artery. Mixed venous O2 content, Po2 and O2 saturation fell with increased work, whereas arterial values showed little or no change. Mixed venous CO2 content, Pco2, and hydrogen ion concentration exhibited little change from resting levels in two dogs but increased significantly in two others during exercise. These values always decreased in the arterial blood during exercise, indicating the presence of respiratory alkalosis. On cessation of exercise, hyperventilation increased the degree of respiratory alkalosis, causing it to be reflected on the venous side of the circulation. Submitted on January 8, 1962


1988 ◽  
Vol 64 (5) ◽  
pp. 1870-1877 ◽  
Author(s):  
M. A. Bureau ◽  
J. L. Carroll ◽  
E. Canet

This study was undertaken to measure the neonate's response to CO-induced hypoxia in the first 10 days of life. CO breathing was used to induce hypoxia because CO causes tissue hypoxia with no or minimal chemoreceptor stimulation. An inspired gas mixture of 0.25 to 0.5% CO in air was used to raise the blood carboxyhemoglobin (HbCO) progressively from 0 to 60% over approximately 20 min. The study, conducted in awake conscious lambs aged 2 and 10 days, consisted in measuring the response of ventilation and the change in arterial blood gases during the rise of HbCO. The results showed that the 2- and 10-day-old lambs tolerated very high HbCO levels without an increase in minute ventilation (VE) and without metabolic acidosis. At both ages, HbCO caused no VE change until HbCO levels rose to between 45 and 50% after which the VE change was exponential in some animals but minimal in others. The VE change was brought about by a rise in tidal volume and respiratory frequency. During the period of maturation from 2 to 10 days, there was a small shift to the right in the VE-HbCO response. In the 10-day-old lambs the VE response to high HbCO was greater than that of the 2-day-olds because of the lambs' higher respiratory frequency response. Six of the 10-day-old lambs but only two of the 2-day-old lambs showed a hypoxic tachypnea to HbCO of 55–65%. None of the lambs developed periodic breathing, dysrhythmic breathing, or recurrent apneas with an HbCO level as high as 60%.(ABSTRACT TRUNCATED AT 250 WORDS)


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