Enough with the “Normal” Saline
So its been about a year since a JAMA
) finally showed that the downside of 0.9% saline isn’t just theoretical, but has some associated clinical morbidity (bad for the kidneys!). Sadly enough, it still seems to be the routine fluid used for boluses. Whether the ER
, hospitalist or intensivist, residents, students…it seems people are reluctant to let go.
Today, rounding in the ICU
, I was changing an order for a bolus from another doc from NS to RL, and a nurse asked me why. I gave her a capsule summary and she was in disbelief. “Come on Phil, they wouldn’t call it normal saline if it wasn’t!”
I’m an internist by training, so naturally I grew up using NS, since that’s what all the attendings and residents used around me. Ringer
‘s was the stuff the surgeons
used, so well, I guess it had to be wrong…no?
So forward to 2001 and John Kellum
‘s lecture on acid-base I’ve previously mentioned, and my exploring Stewart’s Physicochemical Approach, and wait, I look at the back of a bag of NS, and find out, much to my dismay, that the stuff I’ve been using like holy water has a pH
of 5.6. And who have I been giving liters and liters of this stuff to? Yup, mostly patients with acidosis. Hmmm. Interesting. So although I don’t necessarily advocate correcting metabolic acidosis for the sake of doing so (see my previous post on bicarb), I’m not a proponent of worsening acidosis either, even if by another mechanism.
I think there are a number of factors that have resulted in this situation. For starters, there is the issue of false advertising – the “normal saline” monicker has been influencing subliminal thought for decades (think Malcolm Gladwell
thin-slicing), making physicians feel they are giving and inherently “good” substance. Then there’s the whole tribalism thing with the surgeons vs non-surgeons making all the non-surgeons polarize away from RL (not that RL is perfect, just a bit better, and certainly closer to “normal”). Finally, there’s this sad, sad factor that makes people, even (or maybe even more) smart people reluctant to accept that they have been doing something wrong (or, for those who are offended right now, not ideal) for a long time (I sure was) and prefer to fight it and rationalize it for a few more years until, eventually, the evidence becomes overwhelming or the changing of the guard has fully taken place.
I think what we should be hanging on to is not a drug or a fluid but rather what we learned in the first couple of years of med school: physiology. Now mind you, at that point we (or most of us) didn’t have a clue how to use it for anything more that answering multiple choice questions
, but at some point, we have to go back to it and realize that is what we should be basing our assessment of our therapeutic acts and decisions.
So…if I have a situation where I am low on chloride, I might want to use NS. But otherwise, let try to give something whose composition is a bit closer to our own than NS is. So, for my students and residents, don’t let me see you prescribing boluses of NS. If you really, really need to, wait until your next rotation please.
ps for a great review of the original aritcle, please see Matt’s on PulmCCM at :
Reply: by Marco Vergano
I have been struggling for years with the bad habit of some of my colleagues prescribing NS as the most harmless and physiologic replacement fluid. Here in Italy we don’t have such a clear separation between internists and surgeons about NS/RL choice: the bad habit of easily prescribing NS is ubiquitous.
Given the results you mentioned about the increased incidence of renal failure with NS, I am wondering if the ban on ALL starch solutions would have been necessary after the introduction of new balanced starch/electrolyte solutions.
What I really don’t like about RL is that it’s not only hypotonic, but also low in sodium. In our ICU we often have many ‘neuro’ patients (trauma or vascular) and sodium variations become a major issue. Also I prefer Ringer’s acetate over lactate on most of the patients who struggle to ‘manage’ their own lactate.
So my favorite solution remains our good old “Elettrolitica reidratante III” (very similar to Plasma-lyte).