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Hypotonic versus isotonic saline in hospitalised children: a systematic review
1Department of Paediatrics, McMaster University, Hamilton, Ontario, Canada. choongk@mcmaster.ca
Insights
Hypotonic intravenous (i.v.) fluids increase the risk of hyponatraemia and morbidity in children. Isotonic solutions are a safer alternative for paediatric maintenance fluids, offering better physiological balance.
Area of Science:
- Pediatric critical care medicine
- Intravenous fluid therapy
- Clinical pharmacology
Background:
- Traditional recommendations favor hypotonic intravenous (i.v.) fluids for pediatric maintenance.
- These recommendations lack rigorous clinical trial evidence and may not suit all children.
Purpose of the Study:
- To systematically review evidence on the safety of hypotonic versus isotonic i.v. maintenance fluids in hospitalized children.
- To evaluate the risk of hyponatraemia and patient morbidity associated with different fluid types.
Main Methods:
- Systematic review of studies comparing hypotonic and isotonic maintenance solutions in children.
- Searched Medline, Embase, Cochrane Library, and other sources (1966-2006).
- Excluded case reports, neonates, and patients with pre-existing hyponatraemia.
Main Results:
- Six studies met inclusion criteria; meta-analysis revealed a significantly increased risk of acute hyponatraemia with hypotonic solutions (OR 17.22).
- Hypotonic solutions were associated with greater patient morbidity.
- Evidence suggests current practices are based on limited, potentially biased studies.
Conclusions:
- Hypotonic i.v. fluids pose potential harm to children, evidenced by increased hyponatraemia and morbidity.
- Isotonic or near-isotonic solutions appear more physiological and safer for pediatric maintenance, especially during acute illness and perioperative periods.
- Optimal fluid therapy requires individualized assessment; isotonic solutions are recommended over hypotonic ones.
Background:
The traditional recommendations which suggest that hypotonic intravenous (i.v.) maintenance fluids are the solutions of choice in paediatric patients have not been rigorously tested in clinical trials, and may not be appropriate for all children.
Aims:
To systematically review the evidence from studies evaluating the safety of administering hypotonic versus isotonic i.v. maintenance fluids in hospitalised children.
Data Sources:
Medline (1966-2006), Embase (1980-2006), the Cochrane Library, abstract proceedings, personal files, and reference lists. Studies that compared hypotonic to isotonic maintenance solutions in children were selected. Case reports and studies in neonates or patients with a pre-existing history of hyponatraemia were excluded.
Results:
Six studies met the selection criteria. A meta-analysis combining these studies showed that hypotonic solutions significantly increased the risk of developing acute hyponatraemia (OR 17.22; 95% CI 8.67 to 34.2), and resulted in greater patient morbidity.
Conclusions:
The current practice of prescribing i.v. maintenance fluids in children is based on limited clinical experimental evidence from poorly and differently designed studies, where bias could possibly raise doubt about the results. They do not provide evidence for optimal fluid and electrolyte homoeostasis in hospitalised children. This systematic review indicates potential harm with hypotonic solutions in children, which can be anticipated and avoided with isotonic solutions. No single fluid rate or composition is ideal for all children. However, isotonic or near-isotonic solutions may be more physiological, and therefore a safer choice in the acute phase of illness and perioperative period.
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