Multiple studies have suggested differences in patient outcomes with balanced solutions (e.g. plasmalyte) vs unbalanced solutions (e.g. normal saline) when large volumes are administered. But what about when giving smaller volumes of fluid? Does it matter which one you choose?
A recent study by Raes et al in the Journal of Nephrology looked at urine and serum effects of administering 1L of normal saline, vs 1L of plasmalyte, to ICU patients needing a fluid bolus. Chloride levels, strong ion difference (SID), and base excess were all significantly different between the two groups. There was no difference in blood pressure or need for vasopressors. As best I can tell, other clinically significant differences such as kidney injury were unfortunately not reported.
Bottom Line: When giving small (e.g. 1L) volumes of IVF, there ARE real physiologic differences seen between balanced and unbalanced solutions. Whether these differences translate to patient-oriented or clinically significant outcomes remains unclear.
References
Raes, M., Kellum, J. A., Colman, R., Wallaert, S., Crivits, M., Viaene, F., Hemeryck, M., Benoît, D., Poelaert, J., & Hoste, E. (2024). Effect of a single small volume fluid bolus with balanced or un-balanced fluids on chloride and acid–base status: a prospective randomized pilot study (the FLURES-trial). JN. Journal Of Nephrology (Milano. 1992). https://doi.org/10.1007/s40620-024-01912-z
