EFFECTS OF THE ACID-BASE STATE UPON THE TEMPERATURE COEFFICIENT OF pH OF BLOOD

When gaseous exchange is avoided, a change in temperature ofoxygenated blood alters its pH. Within the range of values forPco₂ at 38°C of 25 and 130 mm Hg, and base excess of +10and –14 m.equiv/l., we have found this effect to be dependentupon the respiratory state, there being an approximately linearinverse relationship between the temperature coefficient ofpH and the log Pco₂. Changes in metabolic state produced bythe addition of acid or alkali did not significantly affectthis relationship. The slope and position of pH: log Pco₂ bufferlines are altered by changes in temperature. At reduced temperaturesthe buffering capacity is increased, so that the addition ofacid or alkali gave rise to smaller changes in pH. However,in view of the increased solubility of carbon dioxide, alterationsin Pco₂ produced greater changes in pH. In the presence of ametabolic acidosis, reduction in temperature gave a shift tothe right of the buffer line.