Acid-Base Balance of Blood in Hyperthermia

Abstract

It was shown some time ago that voluntary hyperventilation induces an elevation of the blood pH and a lowering of the bicarbonate concentration. 1 , 2 Since fever, whether due to disease or produced by various physical means, is also accompanied by similar changes in the blood pH and bicarbonate concentration, hyperventilation has been suggested as the cause of the disturbance and the condition is considered to be one of a primary CO₂ deficit. 3 From the observations of Peters, Bulger, Eisenman and Lee 4 one infers that in instances of hyperventilation, the extent of the electrolyte changes depend upon the duration and intensity rather than the cause and nature of the hyperpnea.

Hyperthermia produced by means of the Kettering Hypertherm has been employed by one of us (R.M.S.) in the treatment of certain diseases. It is common for the patients receiving this form of therapy to perspire profusely and to consume considerable quantities of fluid. Some individuals prefer to drink water while others prefer a dilute salt solution. Occasionally some of the patients show somewhat violent systemic disturbances. The present investigation was undertaken to observe the differences in the total acid-base balance of the blood and salt concentration of the sweat when water or a dilute salt solution was drunk by the patient.

This is a preliminary report of the total acid-base balance changes of the serum obtained in 4 experiments on a single individual. In 2 of the experiments the patient was allowed to drink water and in the other 2 a 0.6% solution of sodium chloride. The body temperature was controlled at an average of 40°C. The serum acid-base changes observed when water was given were an elevation of the pH, a fall in the CO₂ tension and a fall in the bicarbonate, chloride, and total base concentrations.