Oxygen equilibrium curve of normal human blood and its evaluation by Adair's equation.

Winslow, Robert M.; Swenberg, M.-L.; Berger, Robert L.; Shrager, Richard I.; Luzzana, M.; Samaja, Michele; Rossi-Bernardi, L.

doi:10.1016/s0021-9258(17)40559-x

Cited by 104 publications

(20 citation statements)

References 16 publications

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“…To determine the P 50 , heparinized venous blood samples were analysed for haemoglobin oxygen saturation and partial pressure of oxygen by dual wavelength spectrophotometry and a Clark electrode, respectively (Haemox Analyzer, TCS Medical Products, Huntington Valley, PA, USA). After deoxygenation with nitrogen, the compressed air reoxygenation curve was measured at pH 7.6 and 37°C using a laboratory developed protocol (Winslow et al 1977).…”

Section: Data Processing and Analysismentioning

confidence: 99%

Influence of high affinity haemoglobin on the response to normoxic and hypoxic exercise

Dominelli

Wiggins

Baker

et al. 2020

The Journal of Physiology

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Key pointsr Theoretical models suggest there is no benefit of high affinity haemoglobin to preserve maximal oxygen uptake in acute hypoxia but the comparative biology literature has many examples of species that are evolutionarily adapted to hypoxia and have high affinity haemoglobin.r We studied humans with high affinity haemoglobin and compensatory polycythaemia. These subjects performed maximal exercise tests in normoxia and hypoxia to determine how their altered haemoglobin affinity impacts hypoxic exercise tolerance.r The high affinity haemoglobin participants demonstrated an attenuated decline in maximal aerobic capacity in acute hypoxia.r Those with high affinity haemoglobin had no worsening of pulmonary gas exchange during hypoxic exercise but had greater lactate and lower pH than controls for all exercise bouts.r High affinity haemoglobin and compensatory polycythaemia mitigated the decline in exercise performance in acute hypoxia through a higher arterial oxygen content and an unchanged pulmonary gas exchange.Abstract The longstanding dogma is that humans exhibit an acute reduction in haemoglobin (Hb) binding affinity for oxygen that facilitates adaptation to moderate hypoxia. However, many animals have adapted to high altitude through enhanced Hb binding affinity for oxygen. The objective of the study was to determine whether high affinity haemoglobin (HAH) affects maximal and submaximal exercise capacity. To accomplish this, we recruited individuals (n = 11, n = 8 females) with HAH (P 50 = 16 ± 1 mmHg), had them perform normoxic and acute hypoxic (15% inspired oxygen) maximal exercise tests, and then compared their results to matched controls (P 50 = 26 ± 1, n = 14, n = 8 females). Cardiorespiratory and arterial blood gases were collected Paolo Dominelli is an Assistant Professor at the University of Waterloo. He completed his post-doctoral fellowship at the Mayo Clinic with Dr Michael Joyner. His research seeks to understand the integrative mechanisms underpinning the oxygen cascade under physiologically relevant conditions of exercise and hypoxia. He accomplishes this by studying the conductance of oxygen across multiple physiological systems (pulmonary, cardiac and muscle) and their interaction. P. B. Dominelli and others J Physiol 598.8throughout both exercise tests. Despite no difference in end-exercise arterial oxygen tension in hypoxia (59 ± 6 vs. 59 ± 9 mmHg for controls and HAH, respectively), the HAH subjects' oxyhaemoglobin saturation (S a,O 2 ) was ß7% higher. Those with HAH had an attenuated decline in maximal oxygen uptake (V O 2 max ) (4 ± 5% vs. 12 ± %, p < 0.001) in hypoxia and the change inV O 2 max between trials was related to the change in S aO 2 (r = −0.75, p < 0.0001). Compared to normoxia, the controls' alveolar-to-arterial oxygen gradient significantly increased during hypoxic exercise, whereas pulmonary gas exchange in HAH subjects was unchanged between the two exercise trials. However, arterial lactate was significantly higher and arterial pH significantly lower in the HAH s...

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Section: Data Processing and Analysismentioning

confidence: 99%

Influence of high affinity haemoglobin on the response to normoxic and hypoxic exercise

Dominelli

Wiggins

Baker

et al. 2020

The Journal of Physiology

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“…The authors are correct in that the process developed by Winslow (Winslow et al . 1977) predates the Hemox analyzer. Rather, the clinical protocol developed at our institution was based on this work and provide consistent results used for clinical diagnosis.…”

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confidence: 99%

Reply from P. Dominelli, C. Wiggins, S. E. Baker, J. R. A. Shepherd, S. Roberts, T. K. Roy, T. Curry, J. Hoyer, J. L. Oliveira and M. J. Joyner

Dominelli

Wiggins

Baker

et al. 2020

The Journal of Physiology

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“…To assess the fit of any model to the standard curve, the gold standard data were used as input pairs to the model in question in order to calculate the P50 for each pair. The reference P50 was calculated from published values of P50 that included an assessment of either standard deviation or standard error [32][33][34][35][36][37] . A running mean and pooled variance were calculated to give a final value of 26.71±0.50 mmHg as the gold standard P50±95%CI.…”

Section: Methodsmentioning

confidence: 99%

“…Several authors [32][33][34][35][36][37] have mapped the standard human OHDC, and in order to select an appropriate gold standard, each available dataset was converted to logit (S)/ln(PO 2 ) (Hill Plot) format and analysed using Lagrangian interpolation. Emphasis was placed on the terminal slopes and half saturation point as these parameters provide comparable data when dealing with Hill Plot kinetics.…”

Section: Selection Of Gold Standard Datamentioning

confidence: 99%

A New Model for the Oxyhaemoglobin Dissociation Curve

Anstey

2002

Anaesth Intensive Care

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This paper describes a new model for the oxygen-haemoglobin dissociation curve in humans. The model is based on the known structural alterations that occur in the quaternary haemoglobin molecule during oxygenation and deoxygenation. The two alternative structures, tense and relaxed, are described using hyperbolic tangent curves and linked with a probability function to obtain the completed mathematical description of the oxygen-haemoglobin dissociation curve. Model accuracy is assessed by a bias/precision analysis of calculated logit (S) and P50 against gold standard data. A mechanism for the transition between the two structures involving the chloride ion as a major allosteric effector is proposed. Results were analysed against the Siggaard-Andersen model for bias, precision and calculated P50 in four saturation ranges—0.00<SO 2< 1.00, 0.20<SO 2< 0.80, 0.90<SO 2< 1.00 and 0.97<SO 2< 1.00. In each range except for 0.20<SO 2 <0.80, bias, precision and calculated P50 for the new model are significantly better (P<0.05). Analysis of calculated P50 across the entire saturation range revealed significant drift out of the acceptable range in the Siggaard-Andersen model for SO 2 >0.92. The new model remained within tolerance across the saturation range 0.00<SO 2 <1.00. The new model is significantly more accurate than the popular Siggaard-Andersen model, particularly in the range SO 2> 0.90.

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Oxygen equilibrium curve of normal human blood and its evaluation by Adair's equation.

Cited by 104 publications

References 16 publications

Influence of high affinity haemoglobin on the response to normoxic and hypoxic exercise

Influence of high affinity haemoglobin on the response to normoxic and hypoxic exercise

Reply from P. Dominelli, C. Wiggins, S. E. Baker, J. R. A. Shepherd, S. Roberts, T. K. Roy, T. Curry, J. Hoyer, J. L. Oliveira and M. J. Joyner

A New Model for the Oxyhaemoglobin Dissociation Curve

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