IMPORTANCEThe use of isotonic fluid therapy is currently recommended in children, but there is limited evidence of optimal fluid therapy in acutely ill children.OBJECTIVE To evaluate the risk for electrolyte disorders, including hyponatremia, hypernatremia, and hypokalemia, and the risk of fluid retention in acutely ill children receiving commercially available plasmalike isotonic fluid therapy.DESIGN, SETTING, AND PARTICIPANTS This unblinded, randomized clinical pragmatic trial was conducted at the pediatric emergency

Aim The aim was to evaluate the incidence, hospitalisations and deaths in acutely ill children with dysnatraemias. Methods This was a register‐based cohort study of 46 518 acutely ill children aged <16 years who visited a paediatric emergency department. Risk factors were assessed using two nested case–control studies. Results Moderate to severe hypernatraemia occurred in 92 children (0.20%; 95% confidence interval [CI]: 0.16%–0.24%) and moderate to severe hyponatraemia in 131 children (0.28%; 95% CI: 0.24%–0.33%). Underlying medical conditions increased the risk of both moderate to severe hypernatraemia (odds ratio [OR]: 17; 95% 5.5–51) and moderate to severe hyponatraemia (OR: 3.5; 95% CI: 2.0–5.9). The use of a feeding tube (OR: 14; 95% CI: 3.2–66) and intellectual disability (OR: 7.3; 95% CI: 3.0–18) was associated with moderate to severe hypernatraemia. The risk of death was associated with moderate to severe hypernatraemia (OR: 19; 95% CI: 2.0–2564) and moderate to severe hyponatraemia (OR: 33; 95% CI: 3.7–4311). Conclusions Severe dysnatraemias were more prevalent in acutely ill children with underlying medical conditions and were markedly associated with the risk for death.

Background Hypotonic fluids have been associated with hospital-acquired hyponatremia. The incidence of life-threatening severe hyponatremia associated with hypotonic fluids has not been evaluated. Methods This was a population-based cohort study of 46,518 acutely ill children 15 years of age or under who visited the pediatric emergency department (ED) at Oulu University Hospital, Finland, between 2007 and 2017. We retrieved all electrolyte measurements from the comprehensive electronic laboratory system and reviewed medical records for all patients with severe hyponatremia. Results The overall occurrence of severe hyponatremia (serum sodium < 125 mmol/L) was found in 27 out of 46,518 acutely ill children (0.06%, 95% confidence interval 0.04–0.08%). After admission, severe hyponatremia developed in seven of 6,984 children receiving moderately hypotonic fluid therapy (0.1%, 95% confidence interval 0.04–0.2%), usually within 8 h of admission. All children who developed severe hyponatremia during hospitalization were severely ill. Conclusion In this register-based cohort study of children presenting to the ED, severe hyponatremia developed in one of 998 acutely ill children receiving moderately hypotonic fluid therapy. Graphical abstract A higher resolution version of the Graphical abstract is available as Supplementary information