As any
medical professional – or anyone with a taste for medical dramas – knows, an IV
of saline is often the first and most basic intervention in a medical
emergency. It’s a task that seems almost as easy and natural as breathing for
EMTs and nurses alike. Recently, it’s something that’s been getting a lot more
complicated due to saline bag shortages following Hurricane Maria’s devastation
of Puerto Rico-based medical supply companies in September. And now it’s
something, as a recent study suggests, that might be harming patients rather
than helping them.
That study,
out of Vanderbilt University, looked at patients in five ICUs at Vanderbilt
University Medical Center (VUMC), who were given either normal saline or what
are termed “isotonic crystalloids,” such as Lactated Ringer’s solution or Plasma-Lyte.
In simple terms, normal saline (NS)
is a solution of 0.9% sodium chloride, or table salt, in sterile water.
Isotonic crystalloids, on the other hand, contain a mixture of electrolytes or
other molecules, such as potassium or lactate, dissolved in water. Both kinds
of solutions are isotonic – that is, they have the same concentration as our
normal body fluids, so our cells do not become over- or dehydrated.
The researchers’ hypothesis was
that patients receiving intravenous isotonic crystalloids would be less likely
to have an adverse effect, such as kidney damage or death, than the patients
receiving intravenous saline. At the culmination of the study, the data showed
that “a total of 1139 patients (14.3%) in the balanced-crystalloids group and
1211 patients (15.4%) in the saline group had a major adverse kidney event” and
that “a total of 818 patients (10.3%) in the balanced-crystalloids group died
before hospital discharge and within 30 days of ICU admission as compared with
875 patients (11.1%) in the saline group” (NEJM, 2018).
Essentially, about 1% more patients
suffered an adverse effect from receiving IV saline solution than those
receiving other forms of isotonic IV solutions. The Vanderbilt researchers
noted that more studies should be conducted because, since this study was only
performed at one medical center, they are unable to generalize the results to
the population at large.
However, if these results hold true
in a larger population of research participants, they would be truly alarming.
1% seems like an incredibly small number, but more than 5.7 million people are
admitted to an ICU in the United States each year (SCCM). 1% of that number
would equate to 5,700 serious injuries or deaths per year due to use of IV
saline solution, which is an incredibly troubling statistic.
Any impact from this study is yet
to be seen, but it surely has the potential to change how we do medicine. If
something so routine, so seemingly harmless, is killing people, what other
dangers are we inflicting on our patients?
Critical Care Statistics. (n.d.). Retrieved March 02, 2018,
from http://www.sccm.org/Communications/Pages/CriticalCareStats.aspx
Semler, M. W., Self, W. H., Wanderer, J. P., Ehrenfeld, J.
M., Wang, L., Byrne, D. W., . . . Rice, T. W. (2018). Balanced crystalloids
versus saline in critically ill adults. New
England Journal of Medicine, 378(9), 829-839. doi:10.1056/nejmoa1711584
This was an interesting post. I did not know that saline could be a potentially dangerous chemical. It interesting to think that we cannot even take the most basic of medical chemicals to be entirely safe. This could speak to a lack of trust in medical personnel in that a substance used for so long is now being investigated as a health risk. I would be curious to know the context in which this question was initially asked.
ReplyDeleteI was also wondering how they came up with the idea for this study. As far as I could tell, most likely because it's such a brand new study, the reasons for deciding to research this topic have not been widely reported upon so far. I was guessing it might be related to the current shortage of saline IV bags after the hurricane in Puerto Rico, but I'm not sure. Thank you for your response!
DeleteThis is such an interesting study. Thanks for sharing the findings. Looking back on the history of medicine, it can be really scary to see what well meaning doctors (or nurses, or pharmacists) truly thought was helping people. Take for example, bloodletting, or really aggressive surgical cancer treatment. I often ask the same question you did and to be honest, I’m sometimes scared of the answers.
ReplyDeleteWow, bloodletting... I don't know how anyone ever thought that was a good idea. Yes, as I was researching this topic I started to get a little nervous thinking about all the other things we as medical professionals are doing and using that could be potentially seriously harming or even killing patients! I wonder what sorts of things people 100 years from now will look back on and think we were idiots for using. Thanks for your response!
DeleteWow, fantastic post! It's quite paradoxical that something used to save lives could possibly be a reason for ending them. Looking at the chemistry behind saline solutions, made of sodium chloride and water, I can see how biologically the kidneys could be affected by the large incoming amount of salt. But, wouldn't have someone recognized the consequences when making the solution in the first place? And every other medical professional after that analyze the solution before giving it to patients? Kind of scary that something so commonplace in hospitals could possibly be something so harmful. I would definitely like to see more research on this, from other hospitals and many more patients. I appreciated your time and effort in this post, and for finding such an interesting topic.
ReplyDeleteThank you!! I think the idea behind using saline is that it is considered isotonic to our body fluids and therefore the sodium and chloride ions in the solution would not be in a high enough concentration to do much damage to our kidneys... except now we're discovering that that line of thinking might not be quite true. The study did specify that they think the Cl- in IV saline is more to blame for the adverse effects than the Na+, which was surprising to me because I guess I expected it to be sodium causing most of the problem. Either way, it is a pretty scary conclusion and I'm eager to see what future studies find.
DeleteReally great post! It makes sense that isotonic fluids would be thought to be harmless. They have the same composition/balance as our own blood and they do not have any kind of biologic ingredient (like blood) that would cause our body to sense it and see it as foreign or spread disease. I would be very interested to know what these adverse effects found in the study were. Most adverse effects that we learn about as health professionals result from infiltration, a current but unidentified electrolyte imbalance, hypervolemia (fluid overload) and pulmonary edema (fluid overload) most likely caused by CHF. Again, great job.
ReplyDeleteWow! It is wonderful that people are still challenging established medical wisdom, in the proper manner. Running studies like this one ensure that we are still using the best available technology in medical circumstances. It is important to keep pushing society to improve conditions in all medical areas, but especially emergency care.
ReplyDelete