Saline in IV bags linked to higher risks of kidney failure, death
Vanderbilt University conducted the research and has begun phasing the fluid out of its emergency department after finding that the alternative fluid worked just as well as saline and reduced kidney risks.
“We’ve been sounding the alarm for 20 years’ about possible harms from saline,” said Dr John Kellum, a critical care specialist at the University of Pittsburgh. “It’s purely inertia’ that prevents a change,” he said.
Kellum had no role in the studies, which were discussed Tuesday at a critical care conference in San Antonio and published by the New England Journal of Medicine.
IVs are one of the most common things in health care. They are used to prevent dehydration, maintain blood pressure or give patients medicines or nutrients if they cannot eat.
Saline – salt dissolved in water – has been the most widely used fluid in the US for more than a century even as evidence has emerged that it can harm kidneys, especially when used a lot.
Other IV solutions called balanced crystalloid fluids include saline but also contain potassium and other things that make them more like plasma, the clear part of blood. They are widely used in Europe and Australia.
Oddly, there is no clear reason that saline has become the historically favoured IV fluid.
The two forms have both been around for more than 100 years, their costs are comparable – and, a dollar or two per bag, negligible – and they are used interchangeably.
“There is no evidence or rationale, it is just kind of the way things were,” says Dr. Matthew Semler, a Vanderbilt University doctor who led the new studies.
“It’s kind of an industry joke that what [specialty] you trained in determined what you use,” says Dr Semler.
Saline “is one of those things that we do so commonly that we don’t even think to examine it,” he says. “It got grandfathered in before we were so focused on evidence-based medicine.”
But in recent years, more researchers, including Dr. Kellum and Dr. Semler, have taken a fresh look at saline’s real effects.
Dr. Semler’s two studies involved 28,000 patients at Vanderbilt University who were given IVs of saline or a balanced fluid. For every 100 people on balanced fluids, there was one fewer death or severe kidney problem.
Scientists do not yet know all the potential physical problems saline could be linked to, but Dr Kellum’s research has explored at least one.
Saline contains salt, which is composed of sodium and chloride. But its chloride content is actually higher than that of human blood.
Research has suggested that chloride might cause blood vessels to constrict, limiting blood flow to the kidneys. Other studies, like Dr Kellum’s, have posited that the overall chlorine may stoke inflammation in general.
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