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Cardiac Physiome Society workshop: November 6-9, 2017 , Toronto


Hemoglobin O2 saturation curve at varied levels of PCO2 and pH.

Model number: 0032

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The program calculates Hb saturation with O2 at each PO2 from 0 to 100 mmHg, and Hb
saturations with CO2 over the same range of PCO2s, both at differing background levels of pH. 
Background DPG is normally about 4.65 mM and temperature is 37.5C. The P50 for Hb-O2 saturation 
is 26 mmHg when RBC pH is 7.4 and PCO2 is 40 mmHg. The Hb-O2 saturation curves show the Bohr 
effect: raising PCO2 or lowering pH reduces the affinity of Hb for O2. HbCO2 saturation curves 
show the Haldane effect: raising PO2 reduces Hb affinity for CO2.

The model is within about 1% accuracy through the physiological range of PO2s above 20 mmHg, 
but overestimates saturation at lower PO2s. Solutions are steady-state, calculated algebraically, 
assuming instantaneous binding. See Frauenfelder for rebinding rates on flash photolysis.

Parameters are from Dash and Bassingthwaighte 2004, 2010; the latter publication corrects
typographical errors introduced into the 2004 paper that was published without galley proofs 
being sent to the authors.   


The equations for this model may be viewed by running the JSim model applet and clicking on the Source tab at the bottom left of JSim's Run Time graphical user interface. The equations are written in JSim's Mathematical Modeling Language (MML). See the Introduction to MML and the MML Reference Manual. Additional documentation for MML can be found by using the search option at the Physiome home page.

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(Primary) Dash RK and Bassingthwaighte JB. Erratum to: Blood HbO2 and HbCO2 dissociation curves at 
varied O2, CO2, pH, 2,3-DPG and Temperature Levels. Ann Biomed Eng 38(4): 1683-1701, 2010.

Adair GS: The hemoglobin system. VI. The oxygen dissociation curve of hemoglobin. J Biol
Chem 63: 529-545, 1925.

Hill AV:The possible effects of the aggregation of the molecules of haemoglobin on its
dissociation curves. J Physiol 40: iv-vii, 1910

Hill R:Oxygen dissociation curves of muscle hemoglobin. Proc Roy Soc Lond B
120: 472-480, 1936.

Roughton FJW, Deland EC, Kernohan JC, and Severinghaus JW: Some recent studies of the
oxyhemoglobin dissociation curve of human blood under physiological conditions and the
fitting of the Adair equation to the standard curve. In: Oxygen Affinity of Hemoglobin and
Red Cell Acid Base Status. Proceedings of the Alfred Benzon Symposium IV Held at the
Premises of the Royal Danish Academy of Sciences and Letters, Copenhagen 17-22 May,
1971, edited by Rorth M and Astrup P. Copenhagen: Munksgaard, 1972, p. 73-81.

Winslow RM, Swenberg M-L, Berger RL, Shrager RI, Luzzana M, Samaja M,and
Rossi-Bernardi L: Oxygen equilibrium curve of normal human blood and its evaluation by
Adair's equation. J Biol Chem 252: 2331-2337, 1977.

Related Models

Key Terms

hemoglobin, oxygen, carbon dioxide, saturation, Haldane, Bohr, acidity, pH, blood gases, Hill equation, solubility, cooperativity, tutorial, Data

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Please cite in any publication for which this software is used and send one reprint to the address given below:
The National Simulation Resource, Director J. B. Bassingthwaighte, Department of Bioengineering, University of Washington, Seattle WA 98195-5061.

[This page was last modified 02Nov16, 3:59 pm.]

Model development and archiving support at provided by the following grants: NIH/NIBIB BE08407 Software Integration, JSim and SBW 6/1/09-5/31/13; NIH/NHLBI T15 HL88516-01 Modeling for Heart, Lung and Blood: From Cell to Organ, 4/1/07-3/31/11; NSF BES-0506477 Adaptive Multi-Scale Model Simulation, 8/15/05-7/31/08; NIH/NHLBI R01 HL073598 Core 3: 3D Imaging and Computer Modeling of the Respiratory Tract, 9/1/04-8/31/09; as well as prior support from NIH/NCRR P41 RR01243 Simulation Resource in Circulatory Mass Transport and Exchange, 12/1/1980-11/30/01 and NIH/NIBIB R01 EB001973 JSim: A Simulation Analysis Platform, 3/1/02-2/28/07.