Maintenance fluids should contain at least 77 mmol sodium per liter for critically ill pediatric patients

Background

Disorders of sodium and water metabolism are frequently encountered in hospitalized patients. Hyponatremia in critically ill patients can cause significant morbidity and mortality. It remains uncertain what should be the composition of maintenance fluids for critically ill pediatric patients. We conducted a prospective randomized trial to compare the effect of fluids composition on hyponatremia in a heterogeneous population of pediatric patients.

Methods

We randomly assigned patients who had been admitted to hospital to receive maintenance fluids of 34 mmol/l (group I) or 50 mmol/l (group II) or 77 mmol/l (group III) sodium during the first 72 hours of hospitalization. The primary outcome measure was to determine the relation between hyponatremia and fluid composition, the secondary outcome was to identify the optimal maintenance fluids for critically ill children.

Results

Of the 77 patients who underwent randomization, 24 were assigned to group I, 27 to group II and 26 to group III; the three groups had similar baseline characteristics. There were 41.7% (n = 10) with hyponatremia in group I, 37% (n = 10) in group II as compared with 15.4% (n = 4) with hyponatremia in group III. The risk of hyponatremia was increase 3.92 times in group I and 3.23 times in group II according to group III (95% CI, 1.03–14.9 and 0.86–12.1, respectively). There were no significant differences between the groups in the proportions of patients who were treated in the PICU: 45.8% (n = 11) in group I, 44.4% (n = 12) in group II and 42.3% (n = 11) in group III (P = 0.78). In all the groups hyponatremia developed especially in PICU patients: 70% (n = 7) in group I, 80% (n = 8) in group II and 100% (n = 4) in group III (P < 0.001).

Conclusion

The most important factor for hospital-acquired hyponatremia is the administration of hypotonic fluid. Hyponatremia risk increases especially in critically ill pediatric patients. In patients in the PICU, for preventing of hyponatremia, maintenance fluids should contain at least 77 mmol/l sodium.