Balanced Fluids in Critically Ill Children

September 13, 2021

Written by Clay Smith

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There was no difference in acute kidney injury (AKI) on ICU day 3 or other longer-term outcomes after a single PICU switched from normal saline (NS) to balanced fluid.

Why does this matter?
NS has 154 meq/L of chloride. Hyperchloremia is associated with metabolic acidosis, decreased renal blood flow, and acute kidney injury. When this PICU changed from NS to balanced fluids, did it reduce the rate of AKI on ICU day 3 in these children?

A balanced perspective

• Design: This was a single center before and after study in a PICU setting that switched from NS to balanced fluid.

• Results: There were ~1,400 children before and after (total N = 2,863) included, with no major differences in the before/after cohorts except PlasmaLyte became the dominant bolus fluid and LR the dominant maintenance fluid instead of NS. For the primary outcome of AKI on day 3, there was no difference. For secondary outcomes after the switch, there was a lower rate of hyperchloremia. There was also lower hyperkalemia with balanced fluid. On the downside, there was a higher rate of hypokalemia after the switch. There was no difference in need for renal replacement therapy, length of stay, ventilator-free days, or in-hospital mortality after the switch.

• Implications: Balanced fluids alone appeared to have little or no short or long term benefit in a PICU population. These data are so messy, it will take a well designed RCT to sort this out.

• Limitations: After the switch to balanced fluid, children were statistically more likely to have >10% fluid overload on day 3. In other words, they not only changed fluid, they gave more than before. This could confound results, as fluid overload is associated with adverse outcomes. We also have no idea what fluid or what volume patients received prior to arrival in the PICU, which could significantly confound outcomes.

Source
Association between the use of balanced fluids and outcomes in critically ill children: a before and after study. Crit Care. 2021 Jul 29;25(1):266. doi: 10.1186/s13054-021-03705-3.