Research on Intravenous Fluids: Balanced Crystalloids vs. Saline

Overview of the Study

A recent article published in the British Medical Journal presents new research that compares the safety of balanced crystalloids to saline. The findings indicate that the incidence of deaths and kidney complications was lower among patients receiving balanced crystalloids, without adversely affecting overall patient outcomes.

Common Use of Saline in Hospitals

Saline is routinely administered to many patients in hospitals as a standard intravenous fluid. Two studies conducted in a clinical setting evaluated the outcomes of critical and non-critical patients who were given either saline or balanced crystalloid solutions. Both saline and balanced crystalloids are frequently used intravenous fluids designed to address fluid or electrolyte imbalances in the body.

Support for the Research

These studies were conducted with support from the Vanderbilt Institute for Clinical and Translational Research and were highlighted in a recent article in the British Medical Journal. Intravenous fluids are typically supplied in emergency rooms, intensive care units, inpatient wards, and outpatient departments.

Composition of Intravenous Fluids

Saline contains a higher concentration of the negatively charged ion chloride compared to blood plasma. In contrast, balanced crystalloids contain various negative ions like lactate and acetate, which are absent in saline. The inclusion of these negative ions aims to provide a physiological safety net to prevent abnormal fluctuations in blood acidity.

Details of the First Study

The first study, published in the New England Journal of Medicine, involved all patients admitted to the emergency department at Vanderbilt University Medical Center in Nashville, USA. Between January 1, 2016, and April 30, 2017, 13,347 non-critically ill adults were randomly assigned to receive either saline or balanced crystalloids as intravenous fluids. The results revealed negligible differences in patient outcomes; however, the balanced crystalloid group experienced fewer deaths and kidney complications.

Findings from the Second Study

A second study focused on critically ill patients in the intensive care unit (ICU), recruiting 15,802 individuals from five different ICUs. This study measured mortality rates and the occurrence of kidney complications within 30 days. The findings mirrored those of the first study, showing that balanced crystalloids were linked to a significantly lower rate of major adverse kidney events compared to saline.

Need for Further Research

Given that this research was conducted at a single hospital, additional studies are necessary to determine whether these results can be generalized to other settings. Should a transition from saline to balanced crystalloids be considered, it would require validation through evidence from large multisite trials. Nevertheless, these studies pave the way for critical investigations aimed at identifying the most effective intravenous fluid for patients.

Author Information

Written by Dr. Apollina Sharma, MBBS, GradDip EXMD

Reference

Mayor, Susan. “Saline may raise risk of death and kidney complications more than balanced crystalloids.” The BMJ. (2018): k950.