Common carotid artery

October 27, 2013

Steroids for cardiac arrest…really? My take on the VSE study – #FOAMed, #FOAMcc

So I’ve been asked a few times for my opinion about the VSE study in the last couple of months, so here we go.

JAMA. 2013;310(3):270-279. doi:10.1001/jama.2013.7832.

First of all, lets look at it from a theoretical perspective.  How would steroids contribute to ROSC (return of spontaneous circulation)?  Hard to believe they possibly could, given the ultra-short timeframe to ROSC – minutes mostly – and the much longer action of steroids.  However, it is quite possible – and in view of this study perhaps likely – that there is an effect on shock and RONF (return of neurological function).

Why?  Post arrest shock results in MSOF due to a cascade of inflammation resulting from the hypoxic insult. Remember that we are not designed to survive these events. Being designed to fight off moderate trauma and infection (eg being bitten by an animal or clubbed by another caveman) our physiological reaction often overshoots the mark resulting in more damage than good, as it does in sepsis (variably depending on our different geno/phenotypes).  So whether liver, kidney or brain damage, some component is not only related to pure hypoxia but also to an inflammatory cascade that has a prolonged effect. This is the same thing we are targeting with cooling, on top of a simple metabolic supply/demand issue, so in terms of biological plausibility, it makes some sense.

In the post-ROSC phase, there is always the possibility of relative adrenal insufficiency – after all, the adrenals have taken a hit as all the other organs did – so again there is biological plausibility.

There’s quite a bit of debate out there as to whether or not to apply this.  I’m pragmatic, not a purist, and my beliefs lie in evidence, biological plausibility and the risk/benefit ratio.  In this case, I think the decision is actually quite simple.  The way I see it, the steroids are harmless and probably helpful, so I have been giving solumedrol in the last few months.

If anything, I’m more concerned about the harm I may be doing with epinephrine/vasopressin, especially in terms of RONF.  I do hope an epi (various doses) vs placebo study is done, because it is difficult to withhold, knowing that there is greater immediate effect on ROSC… Hard decision as the clinician at the bedside, and hopefully this will become clearer in the near future.

For those unclear about the whole epi debate, the physiological issue is that the relationship between pressure and perfusion is represented by an inverted U curve – at very high pressures (from vasoconstriction) perfusion is decreased (think of the extremities on high dose pressers with a decent BP).  So although we may help coronary perfusion pressure and thus ROSC, end-organ damage is greater…and nothing matters much without a brain.

 

So bottom line:  I’d go ahead with the steroids, and for now the V and E, but I wouldn’t be surprised to drop or decrease those soon.

More to come on resuscitation and its future (the present for some of us…) in posts and podcasts!

Hope this helps!

Philippe

 

 

October 21, 2013

Ultrasound-guided central venous catheter insertion: standard of care or preventing procedural skills? #FOAMed, #FOAMcc

Ok, so let me preface this with the fact that I walk around with a handheld ultrasound rather than a stethoscope, and that I examine ALL patients with a focused cardiopulmonary and abdominal exam. My bias towards bedside ultrasound is ridiculously huge. I think practicing without it, once the skill is acquired, is unethical.

Having said that, I have an issue with the fact that it now seems to be “standard of care” for all lines to be ultrasound guided.

Hmm…here are the problems as I see them:

1.      I have come across junior staff intensivists who have never inserted a jugular or subclavian catheter without ultrasound, using landmark techniques. That is an utter shame and worse, a possible disaster in an instance of technology failure (ie the ultrasound is out for repair, etc…).   Intensivists who would be unable to put in a line???

2.      I have been teaching bedside ultrasound for the last 5 years, and practicing it for over a decade.  I teach ultrasound-guided line workshops. The ability to safely and properly follow a needle tip to venous puncture is an expert-level skill. I cannot count how many times a participant has sworn that his beam is right at the tip of the needle and been befuddled when I point to the blue phantom and show him how he is scanning just a bit beyond the hub and that the tip is in fact several centimetres into the blue phantom (better the phantom than the lung!).  The problem comes from a false sense of confidence and security that the procedure being “guided” provides. I’ve already seen several carotid insertions and pneumothoraces with IJ and SC guided procedures…

3.      The evidence is shabby in the following sense:  if you look at the papers comparing blind to guided, the stats on the blind procedures are not exactly very impressive to start with (time and number of attempts)… Also, did all trainees who are out there doing guided procedures receive the same training that those in the study did?  All residents with a probe are not trained/created equal, hate to break it to you…

So…what is my preference?  I spot all lines, meaning that I scan both sides of the neck for jugular size, position relative to the carotid and anomalies.  I then do the IJ line blind, unless it is particularly small or really anomalous (eg right on top of the carotid), then I would do it guided. I use ultrasound for ventilated subclavians.

In the interest of science I have timed myself and recorded stats. I can generally get a functional line (puncture to catheter insertion – not including suture time) in 60-90 seconds, with an average of about 1.1 punctures (eg 1 in 10 times I need to widthdraw and re-angle/puncture).   Obviously this comes with about 18 years of doing central lines (since I was an R1), but I know I’m not the only one out there with this type of skill – there are a lot of CC/ED/anasthesia..etc docs who can do the same.  But it does take practice.

My suggestion would be for trainees to spot the vein and keep a ready ultrasound probe (sheathed and sterile), and do a blind puncture.  If they find it on a first pass, then great. If not, then go ahead with the ultrasound (but here I would hope that they would have had some good training in guided insertion and not just that given by a senior resident who’s done all of 5 lines…).

So I think that this is yet another example of N=1, in this case the 1 being the physician rather than the patient, and I think we are in a bit of a tough spot with these recommendations, as the skills will deteriorate in time, and within a generation there will be few if any physicians well-versed in landmark insertion, which would be a shame. It has served us well in the last decades and, unlike the stethoscope, I don’t think its time has passed…

let me know what you think!

PR

ps when I have the opportunity, I will record a demo on my blind technique, for interested trainees.

Hi Philippe

just read your post on central line insertion. One of the things you mention is:

I cannot count how many times a participant has sworn that his beam is right at the tip of the needle and been befuddled when I point to the blue phantom and show him how he is scanning just a bit beyond the hub and that the tip is in fact several centimetres into the blue phantom 
 
This is one of the critical issues that we face with our hands-on intervention course…we’ve made videos, taken photos regarding ‘fanning the beam’ to keep the needle tip in view, etc … and still there are those whose spatial conception are challenged by the imaging…. many understand, but some do not ( my best guess is that it’s the narrow-window 2D image of a 3D structure that throws some people off ) 
 
Do you have any suggestions on how we can modify our approach to teaching this skill ? 
 
thanks for the great blog postings 
Chris
Tough question. The only way i get around that is one on one when a resident/student/attending is acutally rounding with me and we have time to really teach that 2d/3d relationship. You’re right some just have a hard time. Sometimes the long axis in plane works for those people, especially in subclavian access where this problem is more concerning. But its a tough issue, which i’m sure is happening everywhere.
 
Good question to ask some of the other faculty at CCUS 2014.
 
Cheers and looking forward to meeting you in a couple months!
 
Philippe