Balanced crystalloids versus saline in critically ill adults with low plasma bicarbonate: A secondary analysis of a clinical trial

J Crit Care. 2021 Jun;63:250-253. doi: 10.1016/j.jcrc.2020.12.016. Epub 2021 Jan 15.


Purpose: We aimed to determine if balanced crystalloids compared with saline improve outcomes in critically ill adults admitted with low plasma bicarbonate.

Materials and methods: We performed a secondary analysis of the Isotonic Solutions and Major Adverse Renal Events Trial (SMART). We included patients who presented to the Emergency Department with a first measured plasma bicarbonate less than 20 mmol/L. Among these patients, we compared the effect of balanced crystalloid versus saline on the primary outcome of major adverse kidney events within 30 days (MAKE30), defined as a composite of death, new renal-replacement therapy, or persistent renal dysfunction (final inpatient creatinine ≥200% baseline). Secondary outcomes included 30 day in-hospital mortality, receipt of new RRT, persistent renal dysfunction, incident AKI, and vasopressor-free days.

Results: Among the 2029 patients with an initial plasma bicarbonate concentration < 20 mmol/L, there was no difference in the incidence of MAKE30 between those assigned to balanced crystalloid versus saline (21.8% vs 21.3%; P = 0.93). Secondary outcomes were similar between the balanced crystalloid and saline groups.

Conclusions: Among critically ill adults presenting to the Emergency Department, initial plasma bicarbonate concentration does not appear to be a useful marker to guide the selection of balanced crystalloid versus saline.

Keywords: Acidosis; Balanced crystalloid; Bicarbonate; Saline.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Bicarbonates*
  • Critical Illness*
  • Cross-Over Studies
  • Crystalloid Solutions
  • Fluid Therapy
  • Humans
  • Isotonic Solutions


  • Bicarbonates
  • Crystalloid Solutions
  • Isotonic Solutions