Determination of urinary electrolyte concentrations is helpful for identifying causal and maintenance factors in metabolic alkalosis, and for monitoring the treatment efficiency. Chloride concentration allows patients to be separated into two major groups and to predict their response to therapy. Urinary chloride is generally lower than 10 mmol/l in patients with digestive losses, post-hypercapnic state, and after diuretic therapy. It is typically higher than 50 mmol/l (if chloride intake is preserved) in the case of alkali intake, urinary acid losses, and during diuretic therapy. Metabolic alkalosis is responsive to chloride in the former group, but is chloride resistant in the latter. Urinary pH is of little diagnostic value in metabolic alkalosis, particularly in critically ill patients.
Was this article helpful?