Experimental Hypothermia: Respiratory and Blood ph Changes in Relation to Cardiac Function

Abstract

Dogs were subjected to hypothermia to rectal temps. below 20[degree]C . Lightly anesthetized dogs hyperventilated and alkalosed during the early stages of cooling, then hypoventi-lated and respiratory-acidosed at temps. under 28[degree]C. The respiratory acidosis at temps. under 25[degree]C could be prevented only by extremely vigorous artificial hyperventiiation. Onset of spontaneous ventricular fibrillation was closely connected with the degree of acidosis; it was frequent in the presence of a low serum bicarbonate. Close control of arterial pH by positive control of the animal''s respiration appeared to contribute to successful recovery from hypothermia, as did preservation of high serum bicarbonate.