Reducing Chloride in IV Fluids May Improve Renal Outcomes

A new study suggests that chloride-restrictive intravenous (IV) fluid strategy could reduce acute kidney injury (AKI) in the intensive care unit (ICU).

Researchers at Austin Hospital (Melbourne, VIC, Australia) conducted a prospective study of 1,533 patients (773 intervention patients, 760 controls) admitted consecutively to the ICU. During the control period, patients received standard IV fluids; after a 6-month phase-out period, any use of chloride-rich IV fluids (0.9% saline, 4% succinylated gelatin solution, or 4% albumin solution) was restricted to attending specialist approval. Patients instead received a lactated solution (Hartmann solution), a balanced solution (Plasma-Lyte 148), and chloride-poor 20% albumin. The primary outcome measures included peak creatinine level and incidence of AKI. Other outcomes included the need for renal replacement therapy (RRT), length of stay in ICU and hospital, and survival.

The results showed that the change in IV chloride levels was associated with a significantly smaller mean serum creatinine level increase (14.8 versus 22.6 µmol/L), a lower rate of AKI as defined by to the risk, injury, failure, loss, end-stage (RIFLE) classification (8.4% versus 14%), and a lower rate of renal replacement therapy use (6.3% versus 10%). After adjustment for potential confounders, the rates of AKI and RRT were both a relative 48% lower during the intervention phase. There was no difference in mortality between the control and intervention periods. The study was published in the October 17, 2012, issue of the Journal of the American Medical Association (JAMA).

“These findings, together with the previously reported observations that a chloride-liberal intravenous strategy can be associated with higher cost and the easy availability of cheap alternatives, suggest the need to exert prudence in the administration of fluids with supra-physiological concentrations of chloride, especially in critically ill patients with evidence of early acute renal dysfunction or at risk of acute dysfunction,” concluded senior author Rinaldo Bellomo, MD, and colleagues.

Traditional fluids used for hydration and resuscitation in the ICU, such as normal (0.9%) saline, 4% succinylated gelatin solution, or 4% albumin solution, usually include high concentrations of chloride. Several studies have shown that rapid infusion of normal saline during anesthesia and surgery inevitably leads to metabolic acidosis, which is associated with hyperchloremia. The same was not observed after administration of lactated Ringer's solution.
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