Normal saline preservation solution increases serum sodium and blood pressure versus half saline in critically ill pediatric patients

This study was a double-blind randomized controlled trial conducted in a pediatric intensive care unit (PICU) setting. The population consisted of 88 critically ill pediatric patients. The study phase and specific inclusion/exclusion criteria beyond this description were not reported. The follow-up period for outcomes was 72 hours.

The intervention was normal saline (0.9% sodium chloride) used as a preservation solution. The comparator was half saline (0.45% sodium chloride) used as a preservation solution. The specific dosing protocol, volume administered, and the precise clinical context for the use of these 'preservation solutions' (e.g., for maintaining vascular access patency, as a carrier fluid) were not detailed in the provided data.

The primary outcome was the change in serum sodium concentration. At 72 hours, the mean serum sodium concentration was significantly higher in the normal saline group (137.63 ± 2.99 mEq/L) compared to the half saline group (135.33 ± 2.46 mEq/L), with a P-value of .007. The specific effect size (e.g., mean difference) and confidence intervals were not reported.

Key secondary outcomes included blood pressure and acid-base status. Systolic blood pressure measured at 24 hours was significantly higher in the normal saline group (98.78 ± 8.08 mm Hg) versus the half saline group (92.70 ± 9.24 mm Hg), with a P-value of .002. For acid-base status, there were no significant differences reported between groups for pH or bicarbonate concentrations. Potassium levels also showed no significant differences. The incidence of hyponatremia at 72 hours was similar between groups (normal saline: 15.9%; half saline: 13.6%). Numerical data and statistical comparisons for potassium, pH, bicarbonate, and hyponatremia incidence were not fully reported.

Detailed safety and tolerability findings were not reported. The data provided no information on adverse events, serious adverse events, discontinuations due to the intervention, or general tolerability profiles of the two solutions in this population.

This study adds to the ongoing debate about isotonic versus hypotonic maintenance fluids in children, a topic explored in larger trials like the SPLIT and PLUS trials which focused on different patient populations and fluid strategies. While those landmark studies examined maintenance fluids for general hydration, this trial specifically examines 'preservation solutions,' potentially for different indications. The finding of higher sodium with normal saline aligns with the physiological expectation, but the blood pressure finding at 24 hours is a notable secondary outcome that merits context against broader hemodynamic management goals in critical illness.

Key methodological limitations include a modest sample size of 88 patients, which may limit the power to detect differences in less common outcomes or safety signals. The lack of reported data on several secondary outcomes (exact numbers, p-values, confidence intervals) and the complete absence of safety/tolerability reporting are significant gaps. The clinical context for the use of 'preservation solutions' is unclear, affecting generalizability. The study setting was a single PICU, and funding sources or author conflicts of interest were not reported, which are important for assessing potential bias.

The clinical implications are nuanced. For clinicians managing critically ill children, this RCT provides evidence that normal saline as a preservation solution leads to higher serum sodium and higher systolic blood pressure in the short term compared to half saline. The 6 mm Hg difference in systolic blood pressure at 24 hours, while statistically significant, requires careful interpretation regarding its clinical relevance for organ perfusion or outcomes. The similar rates of hyponatremia and lack of difference in acid-base markers are reassuring. Decisions should weigh the potential for avoiding hyponatremia against the observed hypernatremic trend and blood pressure effect, within the specific and possibly limited context of using a 'preservation solution.'

Several important questions remain unanswered. The effect of these fluid choices on patient-centered outcomes like length of PICU stay, mortality, or neurological outcomes is unknown. The safety profile, including risks of hyperchloremic acidosis or fluid overload with normal saline, was not reported. The optimal patient subgroups (e.g., those with sepsis, traumatic brain injury) who might benefit most from one solution over the other are undefined. Furthermore, the volume and rate of administration for these 'preservation solutions' and how they integrate with overall fluid management strategy are critical details that require clarification for practical application.