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September 11, 2012

(Landmark vs US) vs (DL vs VL)


This is adapted from an email I sent to Minh Le Cong.

Haney Mallemat recently hosted a number of us what will hopefully be the first in a long series of international EMCC real-time discussions, with participants including Haney, Scott Weingart, Rob Bryant, Jeremy Faust, Steve Caroll, myselfLaleh Gharahbaghian, and of course, the ubiquitous Minh Le Cong. (video of the discussion should hopefully be up at some point)

Two related topics came up:
  1. Is DL dead? 
  2. Is ultrasound necessary for IJ & femoral lines?
It is not lost on me that these are very similar questions, and I come down on different sides with each.* I want to explain why I see 2 very similar situations and come to 2 different conclusions.

With respect to ultrasound for IJ & femoral lines, I think that it is clear that the landmarks are simply not reliable. I don't have hard references (although people who taught me assure me they exist) but the Sinai US guru Bret Nelson loves to take junior residents, show them the nice "NAVEL" shot and then scan up and down and show how the anatomy changes -- the relationship between the femoral artery and vein is much more complex, variable, and dangerous. I have done this on nearly every femoral line I have done** and it is shocking. Similarly, Scott Weingart has shown data on the IJ similarly just not being reliably related to the carotid.

I think Marik is possibly (probably?) correct and in the era of monitoring CLAB, space-suit CVC placement, and DVT prophylaxis, the infection & DVT rates might be less of a problem.

But the placement issues -- bleeding, neck hematoma, RP hemorrhage, pseudoaneurysm, fistula, or just not being able to place the line -- do still exist.

Plus, IJs and femoral veins both collapse during most cases of hypotension, making blind placement even more difficult. In cardiac arrest, the femoral vein might have the pulse.

Further, once you get over the learning hump (maybe 5 lines in someone who is remotely savvy?) I think that it is easier AND faster to place the lines under US.

And lastly, Scott Weingart puts it very well today: people don't immediately die if I can't get the line in (unlike failed airways).

With central lines, the blind approach works very well most of the time. However, Marty Tobin put it very well:
But here’s the rub. The challenge of clinical medicine is not about taking care of the great majority of patients who do well irrespective of the methods employed by their physicians. Instead, the goal is to take feasible steps that have a high likelihood of circumventing a catastrophe in a small number of instances....Taking simple steps to prevent infrequent occurrences that lead to a clinical catastrophe should dictate the practice of medicine, rather than employing approaches that are convenient to physicians and successful in most patients. (PulmCCM; emphasis mine)
Compare with DL vs VL. As I mentioned during the discussion, the key points are that DL skills are translatable to VL; VL is easily defeated by a speck of blood, vomit, or mucus; equipment issues (ie what happens when your Glidescope blades are all getting strerilized?); and I had one more that I don't recall now. VL will get us the view in a higher percentage of cases (although you may not always be able to deliver the tube) but DL isn't as far behind as landmark lines are behind US lines. The gap is very different.

And I agree that the combo VL/DL devices are very different than the angulated devices, and allow for training of both juniors and skill maintenance over time. During my chief year I think I used the CMAC on nearly every tube but never looked at the screen unless I ran into trouble***

Lastly, Minh made a great but ultimately flawed analogy that I cannot let stand:
Giving someone a Glidescope doesn't make them a great intubator; it's not like how giving someone a lightsaber makes them a Jedi. - MLC (paraphrased
While the lightsaber is the weapon of the Jedi, it is not the source of the Jedi's power. For whatever reason, some people are just force sensitive (to varying degrees) and may be trained to hone those skills. (I do not believe the prequels to be canonical so we can ignore the microbiologic explanation of force sensitivity.)

Giving a monkey a McGRATH MAC doesn't make him an anesthesiologist, just as Luke didn't become a Jedi the moment Obi-Wan handed him his father's lightsaber.



*I do not want to simply explain myself out of some Jungian desire to resolve my cognitive dissonance (in fact, I don't even think Jung had anything to do with cognitive dissonance and simply used him here because he's the psychology giant whose name I know aside from Freud. Wikipedia states that Festinger coined the term) or some sort of unresolved father-issues. 

**both of them

***the jokes pretty much write themselves

2 comments:

  1. I might be showing my age, but if I had only one minute to get a line, I'd chose a subclavian (either infra- or supraclavicular) approach (Crit Care Med 2002 Vol. 30, No. 2). Despite protests to the contrary, ultrasound has not been proven to be definitively helpful in the subclavian approach.

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    1. Thanks for the comment! I agree that SC *may* be faster in some situations, particularly in hypotensive/hypovolemic patients, and doesn't necessitate US (although I'm looking forward to playing with US in SC when I get the chance, see http://ultrarounds.com/Ultrarounds/Subclavian_Ultrasound.html as well as my posts: Questions, Answers, and Q&A with Haney on SCUS, all from August 2012).
      It was no accident that the above discussion doesn't address SC!

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