Hyponatraemia despite isotonic maintenance fluid therapy: a time series intervention study

Area of Science:

• Pediatric Surgery
• Intravenous Fluid Therapy
• Electrolyte Balance

Background:

• Dysnatraemia, including hyponatraemia and hypernatraemia, is a common complication in pediatric patients.
• Intravenous maintenance fluid therapy practices have evolved, with a shift from hypotonic to isotonic solutions.
• Understanding the impact of fluid therapy changes on electrolyte balance is crucial for patient safety.

Purpose of the Study:

• To investigate the prevalence of dysnatraemias in children undergoing surgery.
• To compare the incidence of hyponatraemia and hypernatraemia before and after a change in intravenous fluid therapy.
• To evaluate the effectiveness of isotonic maintenance fluids in preventing electrolyte disturbances.

Main Methods:

• A retrospective, consecutive time series intervention study was conducted over a 7-year period (2010-2017).
• Data from 1453 pediatric surgery patients were analyzed, comparing outcomes during periods of hypotonic and isotonic fluid administration.
• Sodium concentrations, hyponatraemia (<135 mmol/L), and hypernatraemia (>145 mmol/L) were the primary outcome measures.

Main Results:

• The transition to isotonic intravenous maintenance fluids significantly decreased the prevalence of hyponatraemia from 29% to 22%.
• The odds of hyponatraemia were reduced by 35% (adjusted OR 0.65) with isotonic fluids.
• No significant increase in hypernatraemia was observed, with prevalence rising slightly from 3.4% to 4.3%.

Conclusions:

• Routine use of intravenous isotonic maintenance fluids is associated with a lower prevalence of hyponatraemia in pediatric surgical patients.
• Despite the benefits, hyponatraemia still affects over 20% of patients, suggesting further optimization is needed.
• The study highlights the importance of considering both the composition and volume of administered intravenous fluids.