ACID-BASE BALANCE AND BLOOD AND URINE ELECTROLYTES OF MAN DURING ACCLIMATIZATION TO CO2.

Abstract

Acid-base balance regulation and changes in electrolyte metabolism have been studied in 20 subjects exposed to 1.5% CO2 over a period of 42 days with control periods preceding and subsequent to exposure. During exposure to CO2 a slight uncompensated respiratory acidosis was present during the first 23 days followed by a compensated respiratory acidosis. Deacclimatization was incomplete, even after 4 weeks of recovery on air. Arterial CO2 tension increased 5 mm Hg during exposure and remained at this elevated level during the first 9 days of recovery on air. In chronic respiratory acidosis the concentration of chloride in the red cells and in plasma remains practically normal, indicating that the chloride shift does not operate. Cation exchange was observed under these conditions. Sodium increased while potassium showed an approximately equivalent decrease. Sodium and potassium balance studies indicated that only sodium exhibits a pattern paralleling the two phases of acid-base balance regulation, retention being followed by increased excretion. Body weight was maintained throughout the experiment in spite of a 24–30% reduction in food intake. mild respiratory acidosis and compensation; 1.5% CO2 exposure and recovery; arterial pCO2, chloride shift, and cation exchange; sodium and potassium excretion; sodium potassium and nitrogen balance; acid-base regulation in chronic hypercapnia; time course in acid-base regulations during chronic exposure to low concentration of CO2; acclimatization and deacclimatization to low concentration of CO2 Submitted on July 22, 1963