Temperature and acid-base status of human blood at constant and variable total CO2 content.

The influence of temperature on the acid-base status of normal human blood was studied in closed systems (constant CCO2) and open systems (variable CCO2). pH-T coefficients of true plasma and erythrocytes in closed systems were similar to coefficients for water (dpH/dT = -0.017 U/degrees C at 25 degrees C). Between 26 degrees C and 42 degrees C there was no significant variation in the relative alkalinities [OH-]/[H+], the charge state of proteins in plasma and erythrocytes or the proton Donnan ration. The equations established enabled calculation of the pH of true plasma and erythrocytes and of blood PCO2 and temperature, using only one of these four parameters. Under open-system conditions, temperature was shown to cause a rise in the apparent buffer power of whole blood non-bicarbonate systems (28.8 and 34.8 mM.l-1.u-1 at 26 degrees C and 42 degrees C respectively). These results show (1) that erythrocytes in closed systems seem very well able to maintain proton distribution regardless of temperature fluctuations and (2) when blood temperature rises, it cannot be excluded that vital organs are better protected against respiratory disturbances.