Strategy for monitoring decompensated heart failure treated by an oral vasopressin antagonist with special reference to the role of serum chloride: A case report.

Compared with conventional diuretic therapy, monitoring decompensated heart failure (HF) under treatment with a vasopressin antagonist is problematic because (1) use of this medication usually allows the patient free water intake to prevent drug-induced hypernatremia and (2) this medication often induces only minimal changes in the hemodynamics and blood concentration. In a 68-year-old female HF patient, use of tolvaptan did not induce much change in the urine output, presumably because of the low water intake due to a lack of thirst, but she did achieve a profound weight loss. Both the changes in chloride and sodium were negatively correlated with changes in the hemoglobin and serum creatinine, and positively correlated with changes in the mean red blood cell volume, but changes in the serum chloride were better correlated with each variable than were changes in the serum sodium. <Learning objective: The present case of heat failure therapy using a vasopressin antagonist highlights the importance of monitoring serum chloride concentration in relation to changes in the hemoglobin (to evaluate intravascular volume) and mean red cell volume (to estimate intracellular fluid status) in addition to changes in body weight.>.