Saturday, May 31, 2008

The spiritual purpose of the intern

video: a science teacher demonstrating that potassium in water is dangerous--and to think I prescribe this stuff every day!

Interns working on our floor keep getting pages that go something like this:

"Please address chloride levels on your patients. 43770"

Various interns have done various things in response to these pages, including calling the number which is never answered.

My own response was to think, "What the hell?" The page was like an extreme version of the very common pages we get from nurses: "K is 3.5 on Mr D in 225, do you want to replete" or better yet, "Smith's Mg is 1.8, please put in order to replete". Some time ago some people showed that after heart attacks, people had fewer ventricular arrythmias when their potassium (periodic table of elements label = K) was above 4.0 (but not too high) and magnesium was above 2.0 (but not too high). Now everyone gets electrolyte repletion for K of 4, Mg of 2, even if they came in to the hospital with metastatic cancer in every part of their body except their perfectly working heart. And because a small but active fraction of nurses are more protocol-driven than thoughtful, we sometimes get paged with an urgency that seems to suggest that a K of 3.7--a perfectly normal human potassium level--represents a dire medical problem.

Anyway, looking at my "chloride levels" page, and briefly puzzled that there was yet another electrolyte page but one that didn't make any sense to me, I looked through the chloride levels on my patients. I was figuring I was going to then call a nurse and try to figure out how to explain that I wasn't going to address the chloride levels. (High or low chloride is a symptom of other things, and we don't deal with it as an isolated problem.) Then, I saw that the chloride levels in my patients were all normal. Then I realized that someone was messing with me.

It did not take long to find out that J, a resident, has been delightedly going around the floor sending these pages. "I'm teaching the interns not to be so gullible" he says, earnestly, as if genuinely imparting some kind of teaching point. (At other times, he actually is quite earnest about imparting teaching points.) "If someone believes that you have some kind of teaching point, J" I said, "that's the person who is truly gullible."

The joke page was funny because electrolyte repletion pages are a constant feature of intern life. Perhaps because it represents a simple number which can be addressed with a simple response, and because low potassium and low magnesium are quite common, electrolyte repletion becomes its own justification for nurses and interns alike. So to puzzled medical students, or to attendings who ask why we're ordering electrolytes on stable patients every day, I've taken to explaining the K-of-4-Mg-of-2 obsession by saying, "K of 4, Mg of 2 is the spiritual purpose of the intern. You can't take that away from us."

Someone recently reminded me of my first day as an intern when she described a first-day-of-internship experience identical to mine: writing an order for potassium repletion, and suddenly becoming gripped by fear. During my first K order, I realized that I was writing for potassium, and that high potassium can kill at least as surely as low potassium, so the level of potassium had to be correct. I knew in my brain that this was not a difficult goal to achieve, but in my heart, suddenly the realization struck: "I could kill someone just by putting in an order."

I'm still fearful from time to time, but it's not potassium that scares me.

Video: This demonstration shows very poor safety technique. This common chemistry teacher stunt is elemental potassium reacting with water and forming potassium hydroxide and hydrogen gas; the heat of the reaction then causes the hydrogen gas to catch on fire. You have likely already gathered that we don't prescribe elemental potassium in the hospital; potassium chloride is stable and then the chloride and potassium can each go their separate ways in the body without anything catching fire.

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