Hypernatremic alkalosis or chloride depletion alkalosis? Reply to Vasconcelos et al.

Abstract

Dear Editor,We would like to thank Vasconcelosand colleagues for their interestingremarks and their data presented.These authors conclude that the term‘‘chloride depletion alkalosis’’ shouldbe used instead for hypernatremicalkalosis, as was suggested in ourarticle [1]. However, as the authorsmentioned, our collective of medicalcritically ill patients is most definitelynot comparable to the patient pre-senting to the emergency department.We know from previous studies thatthe etiology and prognosis varybetween patients who acquiredhypernatremia in the ICU/hospital orin an ambulatory setting [2, 3].In our study, we saw that patients,while developing hypernatremia dur-ing their ICU stay, experienced a risein serum chloride. However, theincrease in chloride concentrationwas significantly exceeded by the risein serum sodium. This was accom-panied by the development ofmetabolic alkalosis and a rising baseexcess sodium. Taken together, we dobelieve that a metabolic alkalosis,which is mostly attributable to a ris-ing serum sodium as expressed bybase excess sodium, should be termedhypernatremic alkalosis. This termhas been used before by others todescribe the alkalosis accompanyinghypernatremia [4]. However, weagree that the pathophysiology of theobserved alkalosis is probably multi-factorial and that therefore thepredominant mechanism should beassessed in the individual patients.