Defense of Hydrogen Ion Concentration in Chronic Metabolic Acidosis

Publisher Website
Google Scholar
Abstract
The limits within which blood [H+] and [HCO3-] vary when normal subjects are acutely equilibrated with varying levels of CO2 have recently been described. We have sudied the limits of variations in blood [H+] and pCO2 with stable graded variations of [HCO3-] in normal adults before and during chronic NH.C1 acidosis and in patients with renal acidosis before and during chronic NaHCO3 therapy. No subject had lung disease. The variations in [H+] and pCO2 at any level of [HCO3-] were identical in the normals and the patients. The relationship between pCO2 and [HCO3-] was linear: PCO2 mmHg = 18.3 + 1.1 HCO3 meq/l (r = 40.87). As required by Henderson''s equation, the relationship between [H+] and [HCO3-] was Inverse and curvilinear: [H+] nanoeq/l [image] meq/1 (r = -0.81). When these responses together with a smaller number of observations in acute metabolic acidosis are contrasted with the results of others in acute and chronic hyper-capnia important quantitative and temporal differences in the defense of blood [H+] are emphasized. While [H+] is virtually undefended in acute hypercapnia, partial and comparable compensation occurs in both chronic respiratory and metabolic acidosis. In acute metabolic acidosis defense of [H+] is nearly complete.