Received February 21, 2007
Accepted on June 21, 2007

ORIGINAL ARTICLES

Hypertonic Saline for Hyponatremia: Risk of Inadvertent Overcorrection

Hashim K. Mohmand ^*1, Dany Issa , Zubair Ahmad , Joseph D. Cappuccio , Ruth W. Kouides , and Richard H. Sterns

*Department of Medicine, University of Cincinnati Medical Center, Cincinnati, Ohio; Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania; and Department of Medicine, Rochester General Hospital, Rochester, New York

¹ To whom correspondence should be addressed. E-mail: hashimkm{at}yahoo.com.

	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 <12 mEq/L per d and <18 mEq/L per 48 h) in treating hyponatremia with hypertonic saline and to determine the predictive accuracy of the Adrogué-Madias formula.

Design, setting, participants & measurements: A retrospective review was conducted of all 62 adult, hyponatremic patients who were treated with hypertonic saline during 5 yr at a 528-bed, acute care, teaching hospital.

Results: Median infusion rate was 0.38 ml/kg per h, increasing serum sodium concentration by 0.47 ± 0.05 mEq/L per h, 7.1 ± 0.6 mEq/L per 24 h, and 11.3 ± 0.7 mEq/L per 48 h. In 11.3% of cases, the increase was >12 mEq/L per 24 h and in 9.7% was >18 mEq/L per 48 h. No patient's rate was corrected by >25 mEq/L per 48 h. Among patients with serum sodium \h120 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.