Alkalemia in diabetic ketoacidosis.

A patient with a history of diabetes mellitus and congestive heart failure was taking furosemide and metolazone as diuretics. Diabetic ketoacidosis developed, and the patient became lethargic and confused. Initial biochemical determinations showed an alkalemic pH, serum and urine ketones with an anion gap, and hyperventilation. The hyperventilation was appropriate for the degree of ketoacidosis but it was grossly inappropriate for the alkalemia. This could be explained by a direct effect of ketones on the respiratory center or a sudden increase in hydrogen ion concentration superimposed on previously chronic alkalemic pH due to the potent combination of furosemide and metolazone.