Can ICU Chloride Restriction Lower AKI Risk?

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A “chloride-restrictive” approach to fluid management may reduce the risk of acute kidney injury (AKI) in critically ill patients, according to a preliminary communication in The Journal of the American Medical Association.

In two sequential six-month periods, the researchers compared a chloride-restrictive versus a standard, “chloride-liberal” strategy to intravenous fluid management. In the first treatment period, adults in a university ICU received standard intravenous fluids. This was followed by a six-month phase-out period. Then in the second treatment period, chloride-rich fluids were given only with approval of the attending specialist, with alternative fluids specified. Cases of AKI were defined by the injury and failure class of the risk, injury, failure, loss, end-stage (RIFLE) classification.

The standard strategy was used in 760 patients and the chloride-restrictive strategy in 773. Total chloride administration decreased from 694 to 496 mmoL per patient. The mean increase in serum creatinine was 22.6 µmol/L during the control period versus 14.8 µmol/L during the intervention period.

The incidence of RIFLE-defined AKI decreased from 14.0 percent during the control period to 8.4 percent during the intervention period. Use of renal replacement therapy (RRT) decreased from 10.0 to 6.3 percent. These effects remained significant on covariate adjustment: odds ratio 0.52 for both AKI and RRT. In-hospital death, lengths of stay, and need for RRT after discharge were similar between groups.

Administration of chloride-containing intravenous fluids might contribute to the risk of AKI in critically ill patients. The new trial suggests that the use of a chloride-restrictive strategy might decrease this risk. While emphasizing the need for further study, the authors believe their results “suggest the need to exert prudence in the administration of fluids with supraphysiological concentrations of chloride, especially in critically ill patients with evidence of early acute renal dysfunction or at risk of acute dysfunction” [Yunos NM, et al: Association between a chloride-liberal vs chloride-restrictive intravenous fluid administration strategy and kidney injury in critically ill adults. JAMA. 2012; 308: 1556–1572].

January 2013 (Vol. 5, Number 1)