Without evidence of benefit, an intervention should not be presumed to be beneficial or safe.

- Rogue Medic

Do Emergency Physicians Intubate Often Enough to Maintain Competency?

 

    There is a study of the frequency of intubation among emergency physicians in the current Annals of Emergency Medicine. This study is accompanied by a discussion, which unfortunately does not question the assumption that intubation improves outcome. There is very little evidence to suggest that intubation improves outcomes. That evidence is only using paramedics with the highest success rates – much higher than your average paramedic.

 
Greater intubation experience in paramedics is associated with improved patient outcomes2; does a similar relationship exist for emergency physicians?[1]
 


Image credit.

The unquestioned assumption is that excellent intubation performance improves outcomes, rather than that excellent intubation performance causes less harm than average intubation performance, or below average performance. We do not have any good evidence to support the wishful thinking that paramedics, or even much more experienced emergency physicians, improve outcomes by intubating patients. We just assume this, because we don’t really want to know. If we decide to be honest and actually find out the effect of intubation, how will we handle it if the results show that we are harming more patients than we are helping?

The Cardiac Arrhythmia Suppression Trial was only started because the proponents of the different antiarrhythmics (encainide, flecainide, and moricizine) wanted to prove that their drug was better than all of the rest. They even agreed to include a placebo arm, although the doctors did not like the idea of depriving patients of such beneficial treatment.

 
CONCLUSIONS: There was an excess of deaths due to arrhythmia and deaths due to shock after acute recurrent myocardial infarction in patients treated with encainide or flecainide.[2]
 

People who had frequent ectopic heart beats – PVCs (Premature Ventricular Contractions) after a heart attack were more likely to die than people who did not have frequent PVCs. The obvious solution – the equivalent of intubation and blood-letting – was to give drugs that will get rid of the PVCs. The problem is that the PVCs were not the problem. The PVCs were just a sign of the problem. The drugs made the actual problem with the heart worse, while making the heart appear to be better. The same is true of blood-letting and may be true of intubation. Abundant evidence for the obvious benefits of blood-letting are quoted in the footnotes.[3]

If intubation is harmful, do we want to know?

If intubation by the average paramedic is harmful, do we want to know?

If intubation by the average emergency physician is harmful, do we want to know?

It isn’t as if we take intubation seriously. If we did take intubation seriously, we would practice much, much more than we do. In stead, we make excuses for failing to practice something that we claim is life-saving, because we are too arrogant to admit that practice is important to develop and maintain any skill.

Practicing on even the most basic mannequin should be done before every shift, whether you are a paramedic or an emergency physician. Unless you have a 99%, or better, success rate on hundreds of patients.

Footnotes:

[1] Intubation by Emergency Physicians: How Often Is Enough?
Kerrey BT, Wang H.
Ann Emerg Med. 2019 Dec;74(6):795-796. doi: 10.1016/j.annemergmed.2019.06.022. Epub 2019 Aug 19. No abstract available.
PMID: 31439364

The article above is commentary on the article below:

Procedural Experience With Intubation: Results From a National Emergency Medicine Group.
Carlson JN, Zocchi M, Marsh K, McCoy C, Pines JM, Christensen A, Kornas R, Venkat A.
Ann Emerg Med. 2019 Dec;74(6):786-794. doi: 10.1016/j.annemergmed.2019.04.025. Epub 2019 Jun 24.
PMID: 31248674

[2] Mortality and morbidity in patients receiving encainide, flecainide, or placebo. The Cardiac Arrhythmia Suppression Trial.
Echt DS, Liebson PR, Mitchell LB, Peters RW, Obias-Manno D, Barker AH, Arensberg D, Baker A, Friedman L, Greene HL, et al.
N Engl J Med. 1991 Mar 21;324(12):781-8.
PMID: 1900101

Free Full Text from N Engl J Med.

[3] Blood-Letting
Br Med J.
1871 March 18; 1(533): 283–291.
PMCID: PMC2260507
 

Physicians observed of old, and continued to observe for many centuries, the following facts concerning blood-letting.

1. It gave relief to pain. . . . .

2. It diminished swelling. . . . .

3. It diminished local redness or congestion. . . . .

4. For a short time after bleeding, either local or general, abnormal heat was sensibly diminished.

5. After bleeding, spasms ceased, . . . .

6. If the blood could be made to run, patients were roused up suddenly from the apparent death of coma. (This was puzzling to those who regarded spasm and paralysis as opposite states; but it showed the catholic applicability of the remedy.)

7. Natural (wrongly termed ” accidental”) hacmorrhages were observed sometimes to end disease. . . . .

8. . . . venesection would cause hamorrhages to cease.
 

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Bougies and ALS Airways

ResearchBlogging.org
 

The last paper we were working on for the EMS Research Podcast was this paper on the use of a bougie in the intubation of a simulated patient with spinal immobilization.

Is BAI (Bougie-Assisted Intubation) an improvement over traditional intubation (ETI or EndoTracheal Intubation)?
 

For this study, we had three separate hypotheses: The first was that BAI would be more successful than ETI in a difficult airway scenario; the second was that BAI would take no more time to complete than ETI in a difficult airway scenario; and the third was that BAI would be perceived by providers to be as easy to perform as traditional intubation.[1]

 

1. Better.

2. As fast.

3. As east to use.

That is a lot.
 

The study was done inconjunction with an annual skills competency assessment session. Each participant was being assessed for competence in nine different out-of-hospital procedural skills, and the study involved only one of the skill stations. The participants gave written consent to participate, but they were blinded to which skill was being assessed and what data were being obtained during the study. At the ETI station, a brief explanation and demonstration of BAI was given to each participant.[1]

 

An intubation mannequin had its neck strapped down to simulate motion restriction that would be consistent from intubation attempt to intubation attempt.

 

Before and during the study, three experienced emergency physicians verified that the best obtainable view by direct laryngoscopy was a partial glottis opening of approximately 20%—equivalent to a grade III Cormack and Lehane glottic view.[1]

 


Image credit.[2]
 

Grade III is a lovely view of the epiglottis, but that is as good as it gets with Grade III. A good view of the airway is going to involve a glimpse of arytenoid. More than that is just gratuitous. As with the rest of medicine, our goal is not to do as much as possible, regardless of the harm. Our goal is to do as little as possible, realizing that doing more often means doing more harm.

Since Cormack-Lehane Grade III means that the glottis is not visible, is it appropriate to call this a Grade III glottic view?
 

The participants were not aware that they were being timed. Timing began when the laryngoscope blade entered the mouth and ended with ventilation through the ETT with the BVM (evidence of successful ventilation as determined by manikin lung inflation or evidence of failed placement as determined by manikin stomach inflation).[1]

 

I do have problems with both of these.

Timing should begin when the last ventilation is delivered, rather than when the blade enters the mouth. The patient does not care why there is a delay in oxygen delivery, only that there is a delay in oxygen delivery. If we want to use hypoxia as a guide, then hypoxia also has nothing to do with when the blade enters the mouth.

The timing should end with successful ventilation either through a properly placed tube or through the BVM after recognizing incorrect placement. They did not record times for incorrectly placed tubes, but this information is relevant when dealing with real patients.

Also, is placement as easy to identify as with Fred The Head, where the lungs are visible? A requirement for a good assessment should be a part of the study. From the end of the paper, the reference to this method being similar to what could be done with the SimMan, suggests that this is Fred, or a close relative of Fred.
 

We found this model to be an easy and inexpensive way to provide EMS personnel with a difficult airway experience without the use of a high-fidelity simulator,[1]

 

This is not a criticism of Fred the Head or SimMan. We need to pay attention to what they are there for. They are there to assist us in creating a simulation of a real world environment, not to assist us in creating scenarios that are easy to measure. Their utility is that we can do both, when we address the reality of the simulation first. Otherwise, we begin to teach bad techniques.[3]

We can use low fidelity equipment to teach people to do the right thing, but we can also use high fidelity equipment to teach people to do the wrong thing. We need to understand what we are teaching.

Should we be teaching that time is not important if we do not place the tube between the cords?
 

Upon completion of the two techniques, each participant was asked to complete a five-point Likert-style survey to assess his or her overall ease of intubation with both techniques in this particular difficult airway model.[1]

 

How did the bougie do?
 

41% rated the ease of intubation the same for the two methods (asterisked values in Table 2), 50% rated the BAI to be easier than traditional ETI, and 9% rated traditional ETI to be easier than BAI. The participants perceived the BAI to be easier than traditional ETI in this difficult airway model (Jonckheere-Terpstra exact p = 0.0006).[1]

 

It is interesting that for a supposedly very difficult intubation, 16/35 participants (just under half) rate this simulated difficult airway as easy or as very easy.

There are many possible explanations, arrogance, excellence, not really very difficult, great airway education, et cetera.
 

3. As east to use?

Yes.
 

There was no significant difference in the average time to successful intubation (20.4 seconds for BAI [standard deviation (SD) = 9.1 seconds] versus 16.7 seconds for ETI [SD = 9.6 seconds], paired t-test p = 0.102). When controlling for order of techniques attempted, the difference between the groups remained nonsignificant (p = 0.0901). The analysis was limited to the 27 participants who were successful with both methods.[1]

 

This is one of the reasons that airway management should be seen as more complicated than just in the hole/not in the hole. The subjects who were least successful had their times eliminated from this comparison of times.

Does that bias the results?

I do not see how it can be considered as anything other than introducing a bias to the results.

Time from last ventilation to first ventilation is the time that matters. Whether the ventilation is through an endotracheal tube or a BVM is not as important as the ventilations.

If the tube is placed incorrectly, the amount of time until this is recognized does matter to the patient. This is one of the reasons why we should always listen over the stomach first.[4],[5]
 

2. As fast?

They did not come up with a statistically significant difference in times, but they only compared times when the subject was successful with both methods. Since almost all of the failures were when the bougie was not used, this would seem to preferentially eliminate the worst times for the traditional intubation.

The trend was toward a difference in favor of traditional intubation, but the method of time keeping had what appears to be a strong bias built in toward whichever method had the most failures.

The most failures turned out to be with the traditional intubation.

2. As fast?

There was no statistically significant difference in what was measured, but what was measured is not what should have been measured.

Maybe faster. Maybe as fast. Maybe slower. We do not know.
 

There was significantly greater success in intubating the simulated difficult airway with BAI than with ETI (94% vs. 77%, McNemar’s exact p = 0.0313). The order of techniques attempted did not influence this conclusion.[1]

 
94% success vs. 74% success.

If we are to continue using intubation, maybe we should use bougies all of the time.
 

1. Better?

Much better.
 
 

The problem with the bougie is that it is too long to be carried by EMS without bending it. Management tends not to approve of bending equipment that is not supposed to be bent. At 2 feet long, or longer, my excuse has been that the bougie is impractical in my gear.
 


 

This is the pocket bougie by Bomimed.

That will easily fit in my airway bag, or even a cargo pocket.

I have run out of excuses for not having a bougie with me.

I do not have any financial connections with anyone manufacturing or selling bougies. I just like the way this makes it much more practical for those of us in EMS to improve our intubation first pass success rates.

Dr. Scott Weingart (EMCrit) and Dr. Minh Le Cong (PHARM) have both covered the Pocket Bougie.

EMCrit.

PHARM.

 

[youtube]WDnDjfuh1Dc[/youtube]
 

Notice that when you use a bougie, you keep the laryngoscope in place until the tube is placed. Holding the bougie with the same hand that is holding the laryngoscope makes this an easy one person procedure.

Footnotes:

[1] Comparison of bougie-assisted intubation with traditional endotracheal intubation in a simulated difficult airway.
Messa MJ, Kupas DF, Dunham DL.
Prehosp Emerg Care. 2011 Jan-Mar;15(1):30-3. doi: 10.3109/10903127.2010.519821. Epub 2010 Nov 10.
PMID: 21067319 [PubMed – indexed for MEDLINE]

[2] Rapid airway access
Sérgio L. AmantéaI; Jefferson P. PivaII; Malba Inajá RodriguesIII; Francisco BrunoIV; Pedro Celiny R. GarciaV
Print version ISSN 0021-7557
J. Pediatr. (Rio J.) vol.79 suppl.2 Porto Alegre Nov. 2003
doi: 10.1590/S0021-75572003000800002
Free Full Text Article from Jornal de Pediatria.

[3] On Combat
by Lt. Col Dave Grossman (with Loren Christensen)
Chapter Two
Whatever is drilled in during training comes out the other end in combat–no more, no less

[4] Intubation Confirmation
Fri, 25 Apr 2008
Rogue Medic
Article

[5] More Intubation Confirmation
Sun, 27 Apr 2008
Rogue Medic
Article

Messa, M., Kupas, D., & Dunham, D. (2011). Comparison of Bougie-Assisted Intubation with Traditional Endotracheal Intubation in a Simulated Difficult Airway Prehospital Emergency Care, 15 (1), 30-33 DOI: 10.3109/10903127.2010.519821

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