THE USE OF hypothermia to reduce metabolism has introduced new problems in the acid-base field. Since induced hypothermia necessitates artificial ventilation of the patients, knowledge of the correct Pco2 and pH at which to maintain these patients is essential. This calls for determinations of blood pH and Pco2 in hypothermic patients. As a result methodological and theoretical problems have arisen. How should these measurements be carried out? At the usual measuring temperature (37 C or 38 C), or at the temperature of the patient, or at both temperatures? In any case it is necessary to know how the change of temperature itself affects the pH and Pco2 of the blood. In this paper we will discuss physicochemical and methodological problems of pH and Pco2 measurements at different temperatures as well as some physiological problems.
Physicochemical and Methodological Problems
The acid-base changes of plasma and whole blood with temperature are caused