>S**t! I DO have to know the Frank Starling Curve

>We ran a code sim as part of class the this week and it was one of the more educational sims sessions I have done in medical school. Keep in mind, none of us have done ACLS training yet…

A guy presented with the typical story for MI and we got an EKG which showed elevations in the precordial leads. Us four students were standing around the bedside trying to remember what MONA stands for when all of a sudden the patient’s pressures stared to drop…  120…110….100…90. In a knee jerk reaction I brazenly shouted out “IV Fluids wide open!” Secretly patting myself on the back for recalling this basic principle of resuscitation, we stood back and waited for Mr. Sim to pull out of his nose dive. But the opposite occurred, he continued his systolic nose dive at an even greater slope, crasheed through 60 down through undetectable, and quickly coded. Tada! You sir, have killed your patient!

Now, this is (hopefully) something that an experienced clinician would have avoided. Given that this sim was part of our advanced physical diagnosis course, it may have behooved us to actually perform a physical exam, instead of getting all bogged down in the logistics of resuscitation. If we had, we would have heard some soggy sounding lungs. Little did we know, that the patient was was in advanced CHF when he presented.

So what happened, and what SHOULD we have done? Lets look at that bitch of an inverted U, the Frank Starling Curve.

So what happened? 
Our guy essentially presented at point 2 on the curve. Because he was in advanced CHF with tons of fluid retention, he already had an advanced LVEDP. And thus, when we gave him MORE fluid we pushed him farther to the right on the curve, which means his stroke volume  dropped even farther, and hence his pressures tanked. For a normal person, not in CHF, with dry lungs, giving them a bump of fluids, also pushes them to the right, but they are starting from point 1. So this push to the right, RAISES SV, and increases blood pressure.
When we were first considering what to do when this guy had a systolic of 90, we debated giving Nitro. Afterall, its part of MONA. But we know that generally, nitro will cause vasodilation and drop pressures. Bad idea when we were trying to raise pressure. Right? Wrong. Since our guy was at point 2 on the curve, dropping his LVEDP via nitro, would actually have been of great benefit. Drop the LVEDP, he moves to the left on the curve, meaning his SV goes up, and he starts doing better. Tada! You actually saved him this time!
Moral of the story: 1). Never forget your physical exam 2). Some of the BS stuff from from MS1 year actually does matter. 

About ER Jedi

I’m a resident doctor in Emergency Medicine and I’ve learned during the past few years that 1) I’ve had some pretty amazing experiences 2) I have a very bad short-term memory. So this blog is just a place for me to write about some of these experiences, from the ER, medical school, the wards and life in general. At least that way I’ll have some idea as to where I’ve been all this time. A scrap-book of sorts, a place to vent, organize some clinical tools and post a few good songs I’ve heard along the way.

Posted on February 5, 2011, in Emergency Medicine, Medical School, Simulation. Bookmark the permalink. 2 Comments.

  1. >Huh, GTN does some weird stuff!We've just covered MONA for MI's, I didn't realise it had more applications. I will remember this gem, when our HF case turns up :)Any idea if a diuretic is indicated in this scenario, too?

  2. >The cleaning company is called Maidsense, and their # is 267-325-6388.OMDG

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