Hypotonic versus isotonic maintenance fluids in critically ill children: a multicenter prospective randomized study

Area of Science:

• Pediatric Critical Care Medicine
• Pediatric Nephrology
• Fluid and Electrolyte Balance

Background:

• Dysnatraemia, particularly hyponatraemia, is a common complication in critically ill children.
• The choice of maintenance fluid therapy can significantly impact electrolyte balance.

Purpose of the Study:

• To investigate the influence of hypotonic (HT) versus isotonic (IT) maintenance fluids on the incidence of dysnatraemia in critically ill children.
• To determine the safety and efficacy of different fluid tonicities in pediatric intensive care settings.

Main Methods:

• A prospective, randomized study involving 125 critically ill children requiring maintenance fluid therapy across three pediatric intensive care units (PICUs).
• Participants were randomized to receive either HT fluids (50-70 mmol/L tonicity) or IT fluids (156 mmol/L tonicity).
• Blood electrolytes were monitored at admission, 12 hours, and 24 hours, with data on age, weight, and fluid/sodium intake collected.

Main Results:

• Children receiving HT fluids showed significantly lower blood sodium levels at 12 hours (133.7±2.7 mmol/L) compared to those receiving IT fluids (136.8±3.5 mmol/L) (p=0.001).
• HT fluids were associated with a 3.22 mmol/L decrease in blood sodium levels (p=0.000) and a 5.8-fold increased risk of developing hyponatraemia (p=0.000) during the study.
• No significant increase in dysnatraemia incidence was observed with IT maintenance fluids.

Conclusions:

• Hypotonic maintenance fluids increase the incidence of hyponatraemia in critically ill children by lowering blood sodium levels.
• Isotonic maintenance fluids are a safer alternative, do not increase dysnatraemia risk, and should be considered the standard of care.