HEMODYNAMIC AND METABOLIC EFFECTS IN DIABETIC-KETOACIDOSIS IN RATS OFTREATMENT WITH SODIUM-BICARBONATE OR A MIXTURE OF SODIUM-BICARBONATE AND SODIUM-CARBONATE

To examine factors determining the haemodynamic and metabolic response s to treatment of diabetic ketoacidosis with alkali, groups of anaesth etised and ventilated rats with either diabetic ketoacidosis (mean art erial pH 6.86-6.96, mean arterial blood pressure 63-67 mm Hg) or hypov olaemic shock due to blood withdrawal (mean pH(a), 7.25-7.27, mean art erial blood pressure 36-41 mm Hg) were treated with sodium chloride (' saline'), sodium bicarbonate or 'Carbicarb' (equimolar bicarbonate plu s carbonate). In the diabetic ketoacidosis series, treatment with eith er alkali resulted in deterioration of mean arterial-blood pressure an d substantial elevation of blood lactate, despite a significant rise i n myocardial intracellular pH determined by P-31-magnetic resonance sp ectroscopy, These effects were accompanied by falling trends in the ra tios of myocardial phosphocreatine and ATP to inorganic phosphate. Ery throcyte 2,3-bisphosphoglycerate was virtually absent in animals with diabetic ketoacidosis of this severity and duration. In contrast, in s hock due to blood withdrawal, infusion of saline or either alkali was accompanied by a transient elevation of mean arterial blood pressure a nd no significant change in the already elevated blood lactate; erythr ocyte 2,3-bisphosphoglycerate was normal in these animals. The effect of alkalinization in rats with severe diabetic ketoacidosis was consis tent with myocardial hypoxia, due to the combination of very low initi al erythrocyte 2,3-bisphosphoglycerate, alkali-exacerbated left shift of the haemoglobin-oxygen dissociation curve and artificial ventilatio n. No evidence was found for any beneficial effect of 'Carbicarb' in e ither series of animals; 'Carbicarb' and sodium bicarbonate could be d eleterious in metabolic acidosis of more than short duration.