Hyponatremia among Postoperative Children Administered with Hypotonic Fluids in a Tertiary Care Hospital: A Descriptive Cross-sectional Study

INTRODUCTION: Hypotonic solutions in postoperative children may cause hyponatremia. Considering humidity and temperatures in India, this study was conducted to find out the prevalence of hyponatremia among postoperative children who were administered with hypotonic solutions in a tertiary care hospital. METHODS: A descriptive cross-sectional study was conducted at a tertiary care hospital. Ethical approval was taken from the institutional review board of Christian Medical College, Vellore, India (Reference number: 9177). Children aged less than 15 years undergoing elective surgery, requiring fasting for more than 12 hours post-operatively with normal preoperative electrolytes and renal functions were included. Hypotonic fluids were administered following existent protocol. Electrolytes were repeated immediate postoperatively and at 12-24 hours. Data was entered into and analyzed using the Statistical Package for the Social Sciences version 18.0. Point estimate at 90% Confidence Interval was calculated along with frequency and proportion for binary data. RESULTS: Among 109 participants, hyponatremia in the postoperative period was seen in 53 (48.6%) (40.7-56.5 at 90% Confidence Interval) children. Hyponatremia was found in the immediate postoperative period in 10 (9.2%) children. All received Ringer Lactate as maintenance intra-operatively and none were severe enough to need correction. In the 12-24-hour sample, 43 (39.41%) had hyponatremia and none in severe category. CONCLUSIONS: Asymptomatic hyponatremia was noted in normal children planned for elective surgery. Among children managed with the existing institutional perioperative (hypotonic) fluid management protocol, subclinical postoperative hyponatremia within 12-24 hours of surgery was noted in a significant proportion, which was more in the hot and warm months in tropics. There are grounds for switching to isotonic fluids for perioperative management.