Journal of Applied Physiology, Vol 55, Issue 3 1002-1007, Copyright © 1983 by American Physiological Society
Bohr effect data for blood gas calculations
M. P. Hlastala and R. D. Woodson
The oxygen dissociation curve (ODC) and Bohr effect of human blood were
measured over a wide range of acid-base conditions and blood-O2 saturations
at normal and low 2,3-diphosphoglycerate (DPG) concentrations. The
fixed-acid Bohr factor (H+ titration) was relatively constant as a function
of O2 saturation. At normal DPG levels, the H+ Bohr factor was not
dependent on PCO2 except for a modest increase (in absolute magnitude) at
very low PCO2 (7 Torr). For low DPG blood, the H+ Bohr factor decreased
markedly with increasing PCO2 such that at PCO2 101 Torr, delta log
PO2/delta pH varied between 0 and -0.13. The CO2 Bohr factor (CO2
titration) was strongly dependent on O2 saturation, being greatest at low
O2 saturation. For normal DPG blood, this factor did not differ
significantly at base excess (BE) +0.1 and +19.5 mmol/l, but decreased
slightly at BE -20.3 mmol/l. For low DPG blood this factor showed a modest
decrease with BE from -0.5 to +19.5 mmol/l but increased appreciably at BE
-18.6 mmol/l. The data indicate that the Bohr factor may vary from
unmeasurable levels to -0.93 under physiological and pathophysiological
conditions. Results allow calculation of the shape and position of the ODC
under the diverse conditions which may attend gas exchange.
