Comparison of the Incidence of Postoperative Hyponatremia after Infusion of Hypotonic Versus Isotonic Intravenous Solutions in Children

Hyponatremia is the most common electrolyte disorder in patients following surgical interventions (19-50%). Hospital acquired hyponatremia is often due to using hypotonic solution s and can be lethal.
Between January and December 2014, 190 children (1 month to 12 years) who were admitted in the urology department of Children’s Hospital Medical Center for elective surgical procedures were enrolled in the study. The patients were randomly divided into two groups: group I received 50 mEq/L sodium and 20 mEq/L potassium in D/W 5% and group II received 154 mEq/l sodium and 20 mEq/L potassium in D/W 5% at the maintenance dose for a period of 6 hours following the operation. The patients did not have any oral fluid intake 6 hours postoperatively. The incidence of hyponatremia before and after maintenance IV fluid therapy was analyzed. Other characteristics of the patients such as age, gender, duration of hospitalization, other concomitant electrolyte disturbances, and symptoms of hypervolemia were also evaluated. The incidence of fluid-IV therapy-induced hyponatremia was investigated and analyzed in different categories of patients.
One hundred and ninety patients were enrolled. The mean age was 3.75 years (ranging from 1 month to 12years). One hundred and thirty-three patients (70%) were boys. The incidence of hyponatremia before and after maintenance IV fluid therapy was 9.5% and 36%, respectively. After the therapy, the incidence of hyponatremia was 54% and 17% in hypotonic and isotonic groups, respectively. Final multivariate logistic analysis showed that hyponatremia was common in patients that received hypotonic solution after surgery.
Hyponatremia was markedly induced in patients receiving hypotonic solution after surgery. It seems isotonic fluid therapy after surgery protects the patients from hyponatremia.