Does the Use of Saline vs Buffered Crystalloid Reduce Risk of Acute Kidney Injury in ICU?

By Kathryn Radigan, MD
Attending Physician, Division of Pulmonary and Critical Care, Stroger Hospital of Cook County, Chicago; Assistant Professor of Medicine, Rush University Medical Center

SYNOPSIS: This study determined that buffered crystalloid did not reduce risks of acute kidney injury among crystalloid fluid therapy patients in the ICU.

SOURCE: Young P Et al. Effect of a buffered crystalloid solution vs saline on acute kidney injury among patients in the intensive care unit. JAMA 2015;314:1701-1710.

Saline solutions are common intervention methods to increase intravascular volume in critical patients. Despite their ubiquity, the efficacy of saline solution treatments has come under scrutiny due to the growing concern that saline’s high chloride content substantially increases the risk for acute kidney injury, and that it may actually increase mortality rates among ICU patients. Buffered crystalloid solutions, as an alternative to saline solutions that more accurately mimic blood plasma, have been proposed as a potentially safer treatment method. It is not definitive, however, whether buffered crystalloid solutions would indeed improve observed patient outcomes.

As the association between saline use and renal failure among critical patients is not well understood, the authors conducted a 7-month, randomized, double-blind trial to discern the differing effects of saline and buffered crystalloid in crystalloid fluid therapy on ICU patients’ kidneys. Patients requiring renal therapy due to pre-existing acute kidney injury were excluded for the purposes of the study. The majority of patients included in the study were initially admitted to the ICU after undergoing elective surgery and only a few had other comorbid diseases. Two thousand two hundred and seventy-eight eligible patients partook in the studies, with researchers evaluating results from 2,262 of them. To ensure that each ICU used equitable amounts of tested fluids, two crossovers were installed at 7-week intervals during the study. At each ICU, the physician in charge of treatment was empowered to determine the frequency and rate of treatment administration. The primary outcome the authors were concerned with was the proportion of patients in each group that developed AKI. Among the secondary outcomes measured, the most important were the incidence rates of renal replacement therapy and in-hospital mortality.

Patients that did receive the buffered crystalloid treatment actually produced more cases of AKI (102) than the saline group patients did (94). Both groups saw similar rates of required renal replacement therapy and mortality rates. The authors conclude by reaffirming that patients receiving buffered crystalloid as opposed to saline in ICU-administered crystalloid fluid therapy do not see reduced risks of acute kidney injury, renal replacement therapy or hospitalized mortality.