Saline Substitute Doesn't Reduce Kidney Injury Incidence

Contrary to a prior theory, substituting saline with a buffered crystalloid solution doesn’t reduce the risk of kidney injury or failure in the intensive care unit (ICU).

Patients in the ICU frequently receive saline (0.9% sodium chloride) as a resuscitation fluid to increase their intravascular volume or maintain hydration.

Despite this widespread use, emerging data has suggested that saline may be harmful for critically ill patients because of its high chloride content, which could contribute to acute kidney injury.

In light of this theory, a recent study published in JAMA set out to determine whether using a buffered crystalloid solution instead of saline would reduce the incidence of kidney injury in the ICU, given that the solution has an electrolyte composition more closely resembling plasma’s.

Researchers studied 1152 patients receiving a buffered crystalloid and 1110 receiving saline across 4 different ICUs.

In the buffered crystalloid group, 9.6% of patients developed a kidney injury within 90 days, compared with 9.2% of the saline group. In addition, 3.3% of patients in the buffered crystalloid group needed dialysis, compared with 3.4% of the saline group.

Since this signals that there were no significant differences between a buffered crystalloid solution and saline, the authors concluded, “Further large, randomized clinical trials are needed to assess efficacy in higher-risk populations and to measure clinical outcomes such as mortality.”

Because there are currently no specific treatments to reduce the risk of kidney injury in the ICU, study author Paul Young, FCICM, told Pharmacy Times that “the key is prevention wherever possible.”

He explained that health care professionals should:

1. Avoid nephrotoxic drugs such as nonsteroidal anti-inflammatory drugs in at-risk patients,

2. Never use synthetic colloid fluids, and

3. Administer early antibiotics and obtain source control in patients with infections.

In the absence of a clear clinical benefit for one fluid therapy over another, Young said it is “appropriate [for clinicians] to use saline in most cases because it is cheaper.”

The study did demonstrate that Plasma-Lyte 148 did not worsen outcomes compared with saline, so Young said it is also a reasonable choice.

“Clinicians may choose to use one fluid or the other depending on the electrolyte and acid-base status, or [they] may use a combination of the fluid types,” he concluded.