Hyponatraemia in Hospitalised Children: A Retrospective Survey in Acute Paediatric Admissions in Hong Kong with Focus on Intravenous Fluid Practices

Purpose: Recent intravenous fluid (IVF) guidelines advocate empirical isotonic maintenance fluids in children to prevent potentially dangerous hyponatraemia. To see if this practice is appropriate for Hong Kong, we aimed to review the frequency and nature of hyponatraemia in acute paediatric settings, and its association with hypotonic IVF usage. Methods: Using Hospital Authority CDARS, we identified all public hospitalisation episodes of children aged 1 month to 18 years with hyponatraemia (Na<135 rnmol/L) during 2015. Those with severe hyponatraemia (Na<127 mmol/L) had their clinical details and IVF use analysed. Findings: Hyponatraemia occurred in 8.8% of 60,960 paediatric admissions. True severe hyponatraemia occurred in 0.22% of all admissions, with 56% occurring at admission. Five cases had hyponatraemic seizures. Of 110 cases with hypovolaemic or euvolaemic severe hyponatraemia, 22 cases of hospital-acquired hyponatraemia were identified where hypotonic fluids likely contributed, as replacement, hyperhydration or maintenance fluids. Conclusions: Serious hyponatraemia may occur in association with hypotonic IVF. Paediatricians must prescribe IVF with care. Safe prescription practices are discussed.