Abstract
Our objective is to evaluate intravenous (IV) fluid prescription practice patterns
in critically ill children in the first 72 hours of pediatric intensive care unit
(PICU) admission and to evaluate the incidence and predictors of hyperchloremic metabolic
acidemia (HCMA) and the association between HCMA and adverse outcomes. This retrospective
cohort study was conducted in two tertiary-care Canadian PICUs. Children aged 0 to
18 years admitted to the PICU between January 2015 and January 2016 who received at
least 50% of their calculated maintenance fluid requirements parenterally during the
first 24 hours of admission were included. Children with known preexisting conditions
associated with HCMA, such as renal tubular acidosis and gastrointestinal bicarbonate
losses, were excluded. Of the 771 children screened, 543 met eligibility criteria
and were included. The commonest prescribed maintenance fluid was 0.9% NaCl (72.9%)
followed by lactated Ringer's solution (19.6%) and hypotonic solutions (4.6%). Balanced
salt solutions (i.e., lactated Ringer's and Plasma-Lyte) were as commonly administered
as unbalanced solutions (0.9% NaCl) for volume expansion (49.6 vs. 48.5%, respectively).
Medications contributed to a significant proportion of total daily intake, in excess
of bolus fluids. The incidence of hyperchloremia and HCMA was 94.9% (95% confidence
interval [CI]: 93.2–96.9; 470/495) and 38.9% (95% CI: 34.6–43.2; 196/504), respectively.
Predictors of HCMA were increasing combined bolus and maintenance 0.9% NaCl intake
(odds ratio: 1.13; 95% CI: 1.04–1.23) and increasing severity of illness. HCMA was
not associated with an increased risk of acute kidney injury, feeding intolerance,
or PICU-acquired weakness. Isotonic fluids, specifically 0.9% NaCl, were the most
commonly administered maintenance IV fluid in critically ill children. Sources of
chloride load are not isolated to resuscitation fluids as previously suggested. Maintenance
fluids and fluids administered with medications and IV flushes (fluid creep) are under-recognized
significant sources of fluid and electrolyte intake in critically ill children. HCMA
is common, and further prospective research is required to determine whether HCMA
is indeed harmful in children. However, all significant sources of fluid should be
accounted for in the design of future trials comparing balanced and unbalanced salt
solutions.
Keywords
pediatrics - IV solutions - maintenance fluids - hyperchloremia - acidosis
