Incidence of hyponatraemia following the use of three different intravenous fluids in paediatric surgery.

Background: It is a common practice to administer 4.3% dextrose in 0.18% saline peri-operatively and for routine fluid maintenance in the paediatric age group. Concerns have been expressed about the risk of hyponatraemia associated with the administration of hypotonic intravenous fluids, hence the need to re-evaluate our practice. This study aims to evaluate the relative incidence of intra-operative hyponatraemia following the use of isotonic and hyopotonic intravenous fluids.

Patients And Methods: This randomised double-blind clinical trial recruited consecutive American Society of Anaesthesiologists physical status Class I and II children aged between 6 months and 17 years scheduled for various minor elective surgical procedures. The patients received one of 3 intravenous infusions for intra-operative fluid management. Group I received 4.3% dextrose in 0.18 saline (n = 25), Group II received normal saline (n = 20) and Group III received Ringer's lactate (n = 20). Blood samples were collected before the surgery and at the end of surgery for serum electrolytes.

Results: One patient in each group developed moderate hyponatraemia intraoperatively. This constituted a 4% (1/25) incidence of intra-operative hyponatraemia among patients who had hypotonic maintenance fluid and a 5% (2/40) incidence in the isotonic maintenance groups. The incidence of hyponatraemia was therefore comparable between patients who had hypotonic and isotonic intra-operative maintenance fluids (P = 1.000).

Conclusion: We conclude that healthy children who have intraoperative hypotonic maintenance fluids during minor elective surgeries are not exposed to the additional risk of hyponatraemia compared to those who have isotonic fluids. The study of a larger sample size is recommended to further validate our findings.