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Intubation for Cardiac Arrest Patients

The debate over whether to intubate cardiac arrest patients remains strong. Photo Kevin Link

The debate over whether to intubate cardiac arrest patients remains strong. Photo Kevin Link

Recently, I came across a destitute colleague who had just responded to a code for a cardiac arrest. During the arrest, the patient was intubated successfully, without interruption of compressions. I was puzzled. Why was my colleague distressed? Surely, she had done her job well, securing the airway in a prompt and efficient manner.

As it turns out, another provider had questioned numerous elements of her care. First, the other provider debated whether to give a paralytic. The other provider vehemently argued that a paralytic was indicated to “best optimize the chance of success.” My colleague did not feel that a paralytic was indicated in cardiac arrest, and intubated without the use of any additional medications.

After the argument about the paralytic, the other provider then had the nerve to question whether the patient should have even been intubated at all! In point of fact, intubation in cardiac arrest is quite controversial, and my downtrodden colleague had every right to feel frustrated.

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Although endotracheal intubation has long been regarded as the “gold standard” for cardiac arrest, recent guidelines de-emphasize the procedure, especially if intubation is to be achieved at the expense of other evidence-based interventions (i.e., CPR and electrical therapy) associated with improved survival and better neurological outcomes.(1,2)

Now I will admit that when I first read this recommendation, it was difficult to digest. As a paramedic, anesthesiologist, and intensivist, I’ve never thought twice about securing an airway with an endotracheal tube during a cardiac arrest. Historically, to do otherwise would be considered malpractice! However, when one examines the recent literature, it is understandable why intubation for cardiac arrest remains a provocative topic. For starters, the reader is referred to a comprehensive and well-written review on this topic by Dr. J.V. Nable et al.(1)

Intubation has not been shown to positively impact outcomes for cardiac arrest patients, and there are several explanations for this somewhat counterintuitive finding.

First, intubation during cardiac arrest is not always straightforward, and in at least one study, 30% of patients required more than one attempt.(3)

Second, the learning curve to attain competence is steep—one study suggests up to 60 intubations are required to become proficient—and in some systems, EMS providers do not have opportunities maintain this skill.(4) As Nable et al write, “maintaining proficiency in endotracheal intubation is a significant barrier for many prehospital providers.”(1) In Wang et al, intubation success by medics was only 78%.(3)

Third, intubation is followed by positive pressure ventilation (PPV), and PPV has been shown to decrease preload, lower cardiac output, and negatively impact the effectiveness of chest compressions.(1)

Fourth, intubation may require interruption of chest compressions, and this has clearly been linked with worse outcomes.(5) For the abovementioned reasons, in some countries, such as the U.K., a case has been made for abandoning intubation altogether in cardiac arrest.(6)

Coming back to my colleague’s dilemma regarding paralysis for intubation in cardiac arrest, this is also a contentious topic. On one hand, paralysis may enhance intubating conditions and facilitate prompt control of the airway, thereby avoiding airway trauma with multiple laryngoscopic attempts, and preventing aspiration. Moreover, the most feared complication of paralysis—the “can’t intubate, can’t ventilate” scenario—is relatively rare. In one study of more than 6,000 trauma patients at our institution (University of Maryland R Adams Cowley Shock Trauma Center in Baltimore), only four patients required a surgical airway.(7)

On the other hand, the hazards of positive pressure ventilation, hyperkalemia associated with succinylcholine, and the rare instance of failed intubation in a paralyzed patient with a difficult airway, all pose an unacceptable risk/benefit in cardiac arrest. The decision to use paralytics is as difficult as deciding to intubate in cardiac arrest, and the use of these agents can only be recommended for the most highly trained providers.

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What about supraglottic airways? This class of airways includes the laryngeal mask airway (LMA), Combitube, laryngeal tube and other various proprietary devices. Although these devices do not represent a “definitive airway,” several studies have shown equivalent outcomes when these devices were compared to endotracheal intubation in cardiac arrest.(1,8) Supraglottic airways have several advantages over intubation. Learning curves are easier, the devices can be placed faster, and there may be fewer complications during device insertion.(9)

To date, no one device has been shown to be conclusively superior to another. Patients eligible for placement of a supraglottic airway require adequate mouth opening, no underlying severe lung disease (i.e., decreased lung compliance), and low risk for aspiration.(1)

At the end of the day, airway management for cardiac arrest may be achieved according to the proficiency and resources available to the provider. EMS providers should not be discouraged by the literature! Airway management is still important. In one study by Wong et al, the best short-term survival was seen in patients who had an advanced airway placed within five minutes of the arrest.(10)

Other studies have failed to show any difference between intubation and use of bag-valve mask ventilation (BVM).(11) However the airway is managed, current recommendations still emphasize the importance of providing ventilatory support during cardiac arrest.(2) In jurisdictions where intubation is used for cardiac arrest, providers should perform the procedure with “sufficient frequency to maintain competence within a highly managed system that actively monitors success rates, complications and patient outcomes.”(9)

If intubation is to be considered in cardiac arrest, it should only be attempted if:

  • The provider is proficient;
  • There are no interruptions in chest compressions; and
  • The attempt takes no more than 10 seconds.(2)

Survivors of cardiac arrest who require intensive care management will usually require definitive airway management with endotracheal intubation at some point, but early in the arrest, providers should focus on providing high-quality CPR.(12)

References
1. Nable JV, Lawner BJ, Stephens CT. Airway management in cardiac arrest. Emerg Med Clin N Am. 2012;30:77–90.

2. Neumar RW, Otto CW, Link MS. Part 8: Adult advanced cardiac life support: 2010 American Heart Association guidelines for cardiopulmonary resuscitation. Circulation. 2010;1222(183):S727–S767.

3. Wang HE, Yealy DM. How many attempts are required to accomplish out-of-hospital endotracheal intubation? Acad Emerg Med. 2006;13:373–377.

4. West MR, Jonas MM, Adams AP, et al. A new tracheal tube for difficult intubation. Br J Anaesth. 1996;76:673–679.

5. Kellum MJ, Kennedy KW, Ewy GA. Cardiocerebral resuscitation improves survival of patients with out-of-hospital cardiac arrest. Am J Med. 2006;119:335–340.

6. Deakin CD, Clarke T, Nolan J. A critical reassessment of ambulance service airway management in prehospital care: Joint Royal Colleges Ambulance Liaison Committee Airway Working Group. Emerg Med J. 2008;27:226–233.

7. Stephens CT, Kahntroff S, Dutton RP. The success of emergency endotracheal intubation in trauma patients: A 10-year experience at a major trauma center. Anesth Analg. 2009;109:866–872.

8. Kajino K, Iwami T, Ktamura T, et al. Comparison of supraglottic airway verus endotracheal intubation for the pre-hospital treatment of out-of-hospital cardiac arrest. Critical Care. 2011;15:R236.

9. Thomas MJC. Prehospital intubation in cardiac arrest: The debate continues. Resuscitation. 2011;82:367-368.

10. Wong ML, Carey S, Mader TJ, et al. Time to invasive airway placement and resuscitation outcomes after inhospital cardiopulmonary arrest. Resuscitation. 2010;81:182–186.

11. Shin SS, Ahn KO, Song KJ, et al. Out-of-hospital airway managemetn and cardiac arrest outcomes: A propensity score matched analysis. Resuscitation. 2011. Accessed 18 Feb 2012.

12. Morley PT. The key to advanced airways during cardiac arrest: Well trained and early. Critical Care. 2012;16:104.

15 comments

  1. dear all
    i am one of those who believe that sga should not be used at all during cardiac arrest. Studies such as roc primed (Aufderheide et al. NEJM 2011)and studies from japan showed a negative outcome when sga’s were used(shin etal ,Resuscitation 2012 Mar;83(3):313-9) . It might be related to the fact that when the cuff of an sga is inflated pressure is exerted on the carotid arteries(Chase et al, Segal et al, and Wang et al. Prehosp Emerg Care 2012; colbert etal CANADIAN JOURNAL OF ANESTHESIA / JOURNAL CANADIEN D’ANESTHÉSIE 1998 Volume 45, Number 1, 23-27;

    • Hello Stefan,

      What a great, thought-provoking post!

      Some studies have suggested potential adverse outcomes with supraglottic airways (SGAs), just as some have suggested problems with intubation. We know that use of a SGA reduces “no flow time” during CPR (Wiese et al., Wien Klin Wochenschr, 2008; 120(7-8)), and not every study has shown a negative association with SGA use in cardiac arrest (Kajino et al., Crit Care, 2011; 15(5)).

      The animal data, while concerning for carotid artery occlusion with SGA use, needs to be interpreted with caution. Swine airways are not the same as human airways (though as you point out, a few studies have shown compression in human volunteers–such as Colbert et al., 1998). The most recent study by Segal et al. (2012), only looked at 9 pigs, and did not measure what is perhaps the most relevant pressure–cerebral perfusion pressure. The degree of carotid artery compression also varies with each type of SGA, and we do not know how this may or may not be related to clinical outcomes in patients with out of hospital cardiac arrest.

      Finally, the study by Aufderheide et al. (2011) did not examine the effect of a SGA on outcomes; the intervention was an impedence threshold device (ITD), not an SGA, though SGAs were used in the study, and a reason why the ITD did not improve outcomes may be related to a failure to prevent airway leaks.

      Clearly there is much more work to be done in this area. If you are going to intubate, I recommend following the three conditions outlined above, as recommended by the American Heart Association.

      Thanks!

      Sam G.

  2. Why would a paralytic ever be needed on a patient in cardiac arrest??
    I have never seen any muscle tone in a patient in cardiac arrest; HR 0, RR 0, BP 0/0!

    Please explain.

    THANKS!

  3. Be aware of sga. Studies are showing low survival and neurological outcomes related to carotid artery compression. Just be aware of this fact.

  4. thx for allowing to share my opinion

  5. Aside from the question of paralytics in cardiac arrests, (do you really need an arressted patient any more flaccid?) you have to consider the extrication of the patient and the transport of the patient. Once they’re on the ER stretcher, they’re not likely to see much more movement compared to the pre-hospital phase of the call.
    If the patient can be tubed while meeting the criteria required of out-of-hospital care, then go with the gold standard.
    I find the routine of paramedics attacking each other to be more distrubing than any other process in the business. EMS will never and I mean NEVER get anywhere if the “one-upmanship”, second-guessing and backstabbing doesn’t stop! If the rest of the professions see that we don’t trust each other, why should they? Do your calls in a way that you are comfortable with, provide good patient care – and tell everyone else to “MIND YOUR OWN DAMN BUSINESS!”

    • Steve,

      I completely agree with you! Unfortunately, in both EMS and medicine in general, the coexistence of large egos can get in the way of good patient care. In this case, my colleague, who was was severely criticized as highlighted in my article, was completely correct for NOT administering paralytics, for all of the reasons that you and several others have suggested. Thanks for the comments!

      Sam G.

  6. I dont give any meds in order to intubate a pt in Cardiac Arrest. One thing I have learned in EMS is that there is no such thing…”I think I’m in” or “I think I got it” you should see something going somewhere.

    I told this to my Nurses where I work. I work in a HEMS.

    And the first time they got to tube….guess what I head? I also hear that with new medics…If you are not sure, pull it out, and Bag….period….Use a rescue device instead.

    • Alex,

      I am with you on this one, 100%. We teach all of our new residents and medics here at Shock Trauma to first, look for chest rise, then capnography (or colorimetric ETCO2 detection–which is what many of us use in the field), followed by breath sounds. There are some exciting new devices that we may eventually have to supplement our clinical exam, but for now, clinical acumen and ETCO2 detection remains the standard. Like you state, you are either “in or out.” I highlighted a great example of this in my last article for this column.

      Thank you for the post!

      V/R,

      Sam G.

  7. I am a firm believer in intubation, for cardiac arrests, or any situation where the airway needs to be controled. I don’t know why one would need paralytics during a cardiac arrest, unless, the patient had a seizure first and for some reason the jaw remains in trismus. Once the initial CPR, D-fib, IV and first round of anti arrythmics are given. Intubating allows for better ventilation and air way control. If less skilled first responders were there first, who are not as skilled with air way maintainance, doing CPR for a period of time, there are changes of gastric inflation which = vomit = aspiration.

  8. ETT is the only way to secure your airway from vomit, blood, etc. Everything else can/will allow this junk into the airway, further complicating any small chance of recovery your patient had. Intubate when you have the time, not as the first thing you do AS LONG AS you have 1) A patent airway and 2) are getting good ventilations with a BVM. Don’t interrupt compressions to intubate if at all possible.

    As for paralytics…if your patient in cardiac arrest needs to be paralyzed so you can intubate, you might want to re-think your field diagnosis of cardiac arrest.

  9. In southern Arizona for the first 8 min we do not attempt ETI. Only epi and chest compression with a non rebreather. There has been a huge jump in survival rates with this rapprochement. After the first 8 min we go to standard ACLS with intubation. Great article.

  10. I think a lot of this has to do with provider training and equipment. Video and fiber-optic laryngyscopes can help infrequent providers.

  11. In my 20 year career I’ve only ever heard someone mention a paralytic during a cardiac arrest is:

    1) when a paramedic failed to recognize rigor mortis in the jaw of the patient
    2) post cardiac arrest when the pt is starting to wake up, and being transported or transferred between facilities and a NMB agent was used post sedation to encourage proper ventilation and oxygenation.

    I’ve personally used the LMA in many of my last cardiac arrests and it has worked quite well. It was only when we had ROSC that we switched to ETI and this was only done with the most qualified personnel (2 ALS paramedics). .

  12. Great discussion, I agree that the ‘One-Upmanship’ in medicine has to disappear. Unfortunately many providers come from the ‘break em down to build em up’ mentality; this will get us no where. As for the argument that intubation should be deemphasized because “up to 60 intubations are required to gain proficiency…and manintaining proficiency is a barrier to many prehospital providers” (Nable et al.), i find that to be an invalid reason. If that were the case than we should get rid of surgical airways, IO infusions, chest decompression, or other infrequently used skills. That argument is, I feel, selfish. We know that the fewer patients who are intubated prehospital that means more ntubations for the physicians and residents, of which many hospitals have a hard time getting tubes for thir students. If we focused as much on training, mentorship, and extending skills such as RSI to medics in the field instead of sitting around beating the same old drum, perhaps we could see these ‘statisitcs’ reverse themselves. Thanks

    Jusitn Poland A.A.S., EMT-P

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