Quantitative analyses of the CO2 dissociation curve of oxygenated blood and the Haldane effect in human blood.

Abstract

The theoretical equations for the C02 dissociation curve derived by MocHIZUKI et al. (1983) have made it possible to estimate the C02 contents in blood at any Pco2 by putting the intra-and extracellular bicarbonate contents at a certain Pco2 into them. Moreover, according to their Haldane effect equation, the carbamate and bicarbonate contributions are evaluated, when the Haldane effect and its plasma component are known along the PCo2 range. In order to accomplish the above calculation the water shifts due to the Pc02 and 02 saturation changes were measured as the changes of hematocrit. The hematocrit of oxygenated blood was linearly correlated to pH with a factor of -0.037, and the difference in hematocrit between oxygenated and deoxygenated bloods was 0.004 in terms of fractional hematocrit. The blood and plasma C02 contents measured at four different Pco2's were compared with the ones calculated by use of the intra-and extracellular bicarbonate contents at 42 Torr Pco2. The measured and calculated C02 contents coincided fairly well with each other. Using intra-and extracellular bicarbonate contents in oxygenated blood together with the Haldane effect and its plasma component, the carbamate contribution was then calculated. The carbamate content was about 1.2 mmol/liter blood over a Pcp2 range of 20 to 100 Torr, and its ratio to the total Haldane effect decreased from 50 to 40 %, as PC0, was increased. The ratio of the bicarbonate shift to the total bicarbonate change due to the Haldane effect, ranging from 0.82 to 0.66, was significantly greater than that measured by changing PCO2.

Theoretical analyses for arterial-venous O2 content difference and Haldane effect during rebreathing.

“…The trPvco2 thereof has been estimated by assuming the HEC as 0.32 (KIM et al, 1966). The C02 diffusions curve used for computing the numerical solution of 02 and C02 diffusions was cited from the measured data of TAZAWA et al (1983). As shown in Fig.…”

“…8, the trPvco2 and oxPvco2 were obtained together with 0' by taking R = HEC and R = 0, respectively. Next, by setting the Pm2 into the following formula for the slope of the C02 dissociation curve (TAZAWA et al, 1983), a'(Pm2) was evaluated: a'(Pm2) = 3.962 • Pmt -0.5857 (8) Moreover, by inserting the (a-v)Co2* into Eq. (7) together with a'(pm2) and 0', the F(H) was calculated.…”

A new indirect method for measuring arteriovenous O2 content difference and cardiac output from O2 and CO2 concentrations by rebreathing air.

“…among individual dogs was 40 ml/min, suggesting no substantial difference (p>0.1). The C02 dissociation curves were somewhat different from those of human subjects (MocHIZUKI et al, 1982;TAZAWA et al, 1983). The slopes of the curve are similar to each other.…”

Cardiodynamic factors affecting hyperpnea during steady-state exercise in man.

“…We can calculate the avDo2 (vol%) by dividing the a' by the K. The C02 dissociation curve of oxygenated human blood within the physiological range may be expressed as follows (TAZAWA et al, 1983); C02 concentration in blood (vol%) = 9.562PC02(Torr) exp(0.4143) .…”