Hypertonic Saline for Hyponatremia

Abstract

Background and objectives: Data regarding dosage–response relationships for using hypertonic saline in treatment of hyponatremia are extremely limited. Objectives of this study were to assess adherence to previously published guidelines (limiting correction to 18 mEq/L per 48 h. No patient's rate was corrected by >25 mEq/L per 48 h. Among patients with serum sodium <120 mEq/L, the observed increase in sodium exceeded the rise predicted by the Adrogué-Madias formula in 74.2%; the average correction in overcorrectors was 2.4 times the predicted. Inadvertent overcorrection was due to documented water diuresis in 40% of cases. Conclusions: The Adrogué-Madias formula underestimates increase in sodium concentration after hypertonic saline therapy. Unrecognized hypovolemia and other reversible causes of water retention pose a risk for inadvertent overcorrection. Hypertonic saline should be infused at rates lower than those predicted by formulas with close monitoring of serum sodium and urine output.