Fluid Resuscitation in Children With Acute Kidney Injury

Fluid resuscitation is an essential step in the early management of pediatric septic shock. The Surviving Sepsis Campaign guidelines recommend the use of crystalloid, up to 40- to 60-mL/kg in boluses within the first hour of resuscitation.¹ Although the guidelines suggest using a balanced crystalloid (BC) solution rather than 0.9% saline (NS), this recommendation is labeled weak, based on very low-quality evidence. Additionally, there are some conflicting studies regarding the use of BC versus NS.^2,3 Recently, the evidence supporting the use of BC compared with NS is becoming stronger in both clinical research³ and translational works.⁴ The reason is likely related to the increased chloride content found in NS, which is associated with the development of metabolic acidosis and acute kidney injury (AKI) in adults.
 
Sankar et al sought to determine whether the use of BC could lower the incidence of new or progressive AKI in critically ill children with septic shock.⁵ The authors’ secondary outcomes were to determine whether there was an association between the crystalloid used and mortality, hyperchloremia, acidosis, and other clinical findings.
 
The authors conducted a parallel-group, blinded controlled study over a three-year period in four tertiary-care centers in India. Children aged 15 years and younger with a diagnosis of septic shock who were deemed to need a fluid bolus were enrolled. Exclusion criteria included the administration of fluid before enrollment, chronic kidney disease, or the diagnoses of unrepaired cyanotic heart disease, severe malnutrition, or known metabolic disease. After randomization, the patients received at least one 20-mL/kg BC solution (PlasmaLyte A was used) or NS bolus in a blinded fashion. Further boluses comprised the same type of fluid, but maintenance fluids were determined at the discretion of the treating physician. Multiple laboratory tests, including electrolytes, lactate, serum creatinine, and blood gases, as well as clinical parameters were obtained at various times during the hospitalizations.
 
Overall, 1080 patients were screened and 708 were analyzed, 351 in the BC group and 357 in the NS group. The authors found that patients who received BC had a lower risk of developing new or progressive AKI in the first 7 days (21% vs. 33% respectively). The use of BC was also associated with lower incidences of AKI requiring dialysis, hyperchloremia, and metabolic acidosis. Other outcomes, including vasoactive therapy use, ventilator-free days, and mortality, differed between the groups.
 
Sankar et al have added more evidence for the use of BC compared with NS in children with septic shock. The recently published SMART trial concurred with these findings in adults with sepsis who had a lower incidence of adverse kidney events in the BC group.⁶ Sankar et al suggest that hyperchloremia may be the main culprit behind the AKI, as other studies have suggested, although this study was not designed to answer that question.
 
One of the limitations of this study is the choice of BC solution (PlasmaLyte A vs. the more readily available lactated Ringer solution), since different solutions have slightly different electrolyte compositions. This study provides more evidence for the use of BC, which may strengthen the recommendations for their use in the next Surviving Sepsis Campaign guidelines.

 
References

1. Weiss SL, Peters MJ, Alhazzani W, et al. Surviving Sepsis Campaign international guidelines for the management of septic shock and sepsis-associated organ dysfunction in children. Pediatr Crit Care Med. 2020 Feb;21(2):e52-e106.
2. Phillips CR, Vinecore K, Hagg DS, et al. Resuscitation of haemorrhagic shock with normal saline vs. lactated Ringer's: effects on oxygenation, extravascular lung water and haemodynamics. Crit Care. 2009;13(2):R30.
3. Semler MW, Self WH, Rice TW. Balanced crystalloids versus saline in critically ill adults. N Engl J Med. 2018 May 17;378(20):1951.
4. Fernández-Sarmiento J, Salazar-Peláez LM, Acevedo L, et al. Endothelial and glycocalyx biomarkers in children with sepsis after one bolus of unbalanced or balanced crystalloids. Pediatr Crit Care Med. 2023 Mar 1;24(3):213-221.
5. Sankar J, Muralidharan J, Lalitha AV, et al. Multiple electrolytes solution versus saline as bolus fluid for resuscitation in pediatric septic shock: a multicenter randomized clinical trial. Crit Care Med. 2023 Nov 1;51(11):1449-1460.
6. Brown RM, Wang L, Coston TD, et al. Balanced crystalloids versus saline in sepsis. A secondary analysis of the SMART clinical trial. Am J Respir Crit Care Med. 2019 Dec 15;200(12):1487-1495.