Characterization of Oxygen-Hemoglobin Equilibrium Curves Using Nonlinear Regression of the Hill Equation: Parameter Values for Normal Human Adults
Measurements of oxygen concentration versus PO2 in blood from 33 normal adults were fitted, using a special nonlinear regression analysis, to the Hill equation to obtain the parameters describing the position (P50) and shape (n) of each oxygen-hemoglobin equilibrium curve (OHEC). Data between 20% and 97% saturation were described well by this empirical two-parameter model. The mean (+ SD) P50 and n were found to be 26.2 (+ 0.8) torr and 2.50 (+0.07), respectively, in good agreement with previously published values. Some normal individuals, however, deviated markedly from the averages indicating that the published values cannot be applied to everyone.
KeywordsDissociation Curve Hill Equation Scatchard Plot Equilibrium Curve Bohr Effect
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