Reduced use linked to better outcomes
Two companion studies have shown that use of saline as intravenous fluid therapy, compared to crystalloids, was associated with poor survival and increased risk of kidney complications.
Matthew Semler, MD, MSc, assistant professor of Medicine at Vanderbilt University School of Medicine, told ICU Management & Practice in an email: “Because saline and balanced fluids are similar in cost and use of saline is based on historical practice and not scientific evidence, the results of these two large, randomised trials both showing the same benefit in patient outcomes with balanced crystalloids rather than saline may be sufficient evidence to change practice for many clinicians”.
The research examined over 15,000 intensive care patients and over 13,000 emergency department patients, in pragmatic cluster randomised multiple crossover trials. Patients were assigned to receive saline (0.9% sodium chloride) or balanced fluids (lactated Ringer's solution or Plasma-Lyte A) if they required intravenous fluid. The primary outcome was a major adverse kidney event within 30 days.
Semler said the pragmatic trial aimed to answer the research question while keeping patient care during the trial as similar as possible to patient care outside of a study setting. “This improves the ease with which the study findings are applied to clinical practice. By comparing balanced fluids to saline without blinding clinicians, the trials provide an estimate of the effect of the fluids on outcomes that translates easily into clinical care”, he said.
In the critically ill patient group, of 7942 patients in the balanced fluids group, 1139 (14.3%) had a major adverse kidney event. In the saline group 1211 of 7860 patients (15.4%) had an adverse kidney event. The incidence of new renal replacement therapy was 2.5% and 2.9% respectively, and the incidence of persistent renal dysfunction as 6.4% and 6.6% respectively. In septic patients, 30-day in-hospital mortality was 25.2% with balanced crystalloids and 29.4% with saline. In the study comparing fluids in non-critically ill patients, balanced crystalloids did not result in shorter time to hospital discharge than saline, but did result in lower incidence of the composite of death, new renal replacement therapy and persistent renal dysfunction.