In this double-blind randomized clinical trial , we recruited 110 children admitted to a general pediatric unit of a tertiary care children 's hospital from March 1 , 2008 , through August 31 , 2012 ( age range , 1 month to 18 years ) , with normal baseline serum sodium levels who were anticipated to require intravenous maintenance fluids for 48 hours or longer ( intent-to-treat analyses ) .