Efficacy and Safety of Isotonic and Hypotonic Intravenous Maintenance Fluids in Hospitalised Children: A Systematic Review and Meta-Analysis of Randomised Controlled Trials

Hyponatraemia is a known complication in hospitalised children receiving maintenance intravenous fluid. Several studies have been published to investigate the efficacy and safety of intravenous fluids in children. However, there is still an ongoing debate regarding the ideal solution to be used in the paediatric population. Therefore, the aim of this meta-analysis was to investigate the safety and efficacy of administering isotonic versus hypotonic intravenous maintenance fluid in hospitalised children. An extensive search was undertaken on PubMed, Web of Science, Scopus, ScienceDirect, Google Scholar and Cochrane Library on 28 December 2020. Only randomised controlled trials (RCTs) were included. We used the random-effects model for all analyses. Risk ratio (RR) and mean difference with 95% confidence intervals (CIs) were used for dichotomous and continuous outcomes, respectively. The quality of each study was assessed using the Joanna Briggs Institute critical appraisal tool for RCTs. This study is registered with PROSPERO (CRD42021229067). Twenty-two RCTs with a total of 3795 participants were included. The studies encompassed surgical and medical patients admitted to intensive care unit as well as to general wards. We found that hypotonic fluid significantly increases the risk of hyponatremia at both <= 24 h (RR 0.34; 95% CI: 0.26-0.43, p < 0.00001) and >24 h (RR 0.48; 95% CI: 0.36-0.64, p < 0.00001). Isotonic fluid increases the risk of hypernatraemia at <= 24 h (RR 2.15; 95% CI: 1.24-3.73, p = 0.006). The prevalence of hyponatraemia was also higher in the hypotonic group at both <= 24 h (5.7% vs. 23.3%) and >24 h (6.0% vs. 26.3%). There was no statistically significant difference in the risk of developing adverse outcomes between the two groups. Mean serum and urine sodium as well as serum osmolality/osmolarity was lower in the hypotonic group. Isotonic solution is protective against the development of hyponatraemia while hypotonic solution increases the risk of hyponatraemia.

Automated summary

This meta-analysis aimed to compare the safety and efficacy of isotonic versus hypotonic intravenous maintenance fluid in hospitalized children. The study found that hypotonic fluid significantly increases the risk of hyponatremia, while isotonic fluid increases the risk of hypernatremia. There was no significant difference in adverse outcomes between the two groups.