1. Carbon dioxide titration curves were determined in vivo in dog and man at various degrees of acute non-respiratory acidaemia and alkalaemia. 2. The slope of the CO 2 titration curve (Δlog Pco 2 /ΔpH) was found to increase with the severity of the acute non-respiratory acidaemia. In states of acute non-respiratory alkalaemia the slope (Δlog Pco 2 /ΔpH) tended towards unity. 3. A simple scheme based on the CO 2 titration curves determined in vivo has been proposed for the assessment of acute acid-base disturbances in man. 4. Carbon dioxide titration curves were also determined in vivo in patients with chronic respiratory and non-respiratory acidaemia and it was found that these curves were not significantly different from those obtained in states of acute acid-base disturbances. It is therefore suggested that the scheme described in this paper is applicable to all acid-base disturbances.
1. Simultaneous CO 2 titration curves of arterial and mixed venous blood were determined in both dog and man in vivo. 2. The slopes of the CO 2 titration curves of mixed venous blood were significantly less than those of the corresponding arterial curves. 3. The non-respiratory pH values of the CO 2 titration curves of mixed venous blood were significantly greater than those of the corresponding arterial curves. 4. The theoretical explanations of these differences have been discussed.
1. The existing methods for assessing states of acidosis are discussed with particular reference to non-respiratory acidosis. Most of these methods are based either on the Henderson—Hasselbalch equation or on the direct extrapolation of in vitro studies on blood to the whole animal. The evidence available shows that these methods cannot be used to obtain an accurate assessment of disturbances of acid-base balance in the whole animal. 2. The experiments were designed to investigate the acid-base parameters of an animal when a respiratory acidosis was superimposed on a non-respiratory acidosis caused by the infusion of n HCl; from these experiments it was possible to construct CO 2 titration curves at various levels of non-respiratory acidosis. 3. A scheme which is based upon the CO 2 titration curves, has been proposed for assessing an acute acid-base disturbance in terms of its respiratory and non-respiratory components. 4. The use of sodium bicarbonate to correct a non-respiratory acidosis was investigated, and it was shown that the amount of sodium bicarbonate required varied with the rate of infusion. No firm predictions could be made regarding the dose of bicarbonate required, but from the results of the present experiments an infusion rate of 0·1 mEq kg −1 min −1 is recommended in dogs.