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The Effect of Intubation on CPR

The debate is ongoing regarding interruption of chest compressions during CPR of cardiac arrest patients in the field. Photo Craig Jackson

Review of: Wang HE, Simeone SJ, Weaver MD, et al. Interruptions in cardiopulmonary resuscitation from paramedic endotracheal intubation. Ann of Emerg Med. 2009:54(5):645-652.

The Science
Emergency guidelines have started emphasizing continuous uninterrupted chest compressions for the treatment of cardiac arrests. Traditionally, paramedics in the U.S. almost always perform endotracheal intubation (ETI) on cardiac arrest patients. The authors of this study examined interruptions in chest compressions due to paramedic ETIs using data from the ROC study. They defined an interruption as greater than five seconds. They excluded the period of interruptions related to rhythm analysis. Of 182 arrests, 100 cardiac arrests were analyzed and found. They also found the following:

Median number of interruptions for ETI per cardiac arrest: 2 with a range of 1-9.
Median time for first ETI associated CPR interruption: 46.5 seconds with a range of 7-221 seconds.
Median time for second and subsequent intubations associated CPRF interruption: 35 seconds with a range of 21 to 58 seconds.
Average number of intubation attempts was two2 with a range of 1 to 9
Median total for all endotracheal intubations: 109.5 seconds.
This total interruption time did not change significantly when interruptions where defined as 10 seconds but decreased slightly (102 seconds) when interruptions were defined as 20 seconds.
ETI accounted for 22.8% of all CPR interruptions.

The authors conclude ETI by U.S. paramedics accounts for a significant amount of interruptions, as well as prolonged interruptions.

The Street
The authors find the results of this study on the role of intubation in prehospital airway management of cardiac arrest patients to be eyebrow-raising, but for different reasons.

Medic Marshall: I have to admit that I’m not one to jump to the laryngoscope and ET tube to manage someone’s airway. But I find this research disturbing and appalling. The statistics speak for themselves. I find them staggering. Nine intubations attempts? Or almost four minutes to intubate a patient? This is exactly why I’m a strong proponent for alternative airways, such as the King LT or Combitube. They are faster and more efficient, and can still secure the airway while minimizing interruptions. Best of all though, they can still be used with an impedance threshold device, such as the ResQPOD.

Again I feel the need to re-iterate that I m not against paramedics intubating in the field, just that it is really hard to justify when you have research like this. If your system is capable of giving their providers the experience and education to intubate proficiently, then by all means I think you should; I also think excellent clinical judgment needs to be used as well though know when to tube or not to tube.

Doc Wesley: I congratulate Dr. Wang and his colleagues for providing us even more compelling reasons to not perform ETI in the cardiac arrest victim. Research clearly shows that interruptions in chest compression greater than 10 seconds results in a significant decrease in coronary perfusion. This loss occurs not from the interruption alone but from the fact that it takes at least 30 seconds of chest compression to “re-prime” the heart.

Although many will scoff at the apparently long interruptions and multiple intubation attempts and say, “this could not happen in my system,” to them I say, “you are wrong.” This study was from multiple high-performance systems with excellent medical oversight and quality improvement.

Regions Hospital in St. Paul will soon be publishing their data, which shows that they were able to insert the King LT within one minute of patient contact without chest compression interruptions.

While there may be value for prehospital endotracheal intubation, the evidence is growing daily that for victims of cardiac arrest and multiple trauma, alternative airways used with appropriate monitoring may be more beneficial and avoid significant complications.

The goal now is to further reduce the chest compression interruptions with faster rhythm analysis and defibrillation.


  1. I personally feel that it’s is every systems fault for the unsuccessful prehospital ETI attempts. This is because not enough opportunity is provided to prehospital provider for practice their skill. Airway dummie are close to the real thing, but can’t provide difficult airway practice, and with it becoming more of a challenge to log OR time how are street providers able to get better? I cannot defend the time taken for attempts, because just by looking at a patient you should know if your are going to get the tube or not. I do not support alternative airways, because in my experience with them, they don’t work, and I have wasted more time with them than with ETI. I think less effort needs to be put into studying the benefits of prehospital ETI, and more effort put into providing field staff the opportunity to practice ETI.

  2. Here we go again, take ETI away from medics. Am I the only one who recognizes that ETI (according to this article) is still LESS then 25% of interruptions? How about patient movement? If you are on a 5 story carry down and your service does not employ the use of a lucas or the zoll CPR machine is CPR being done? No, so are we then supposed to terminate CPR on refractory V-Fib and V-Tach in those scenarios too? How about CPR preformed by a person being ineffective in the back of of an ambulance traveling at speeds over 30MPH?
    The King, LMA and Combi tube are “more efficent” than ETI? In what universe!? If you bring a patient into the ED with a King, Combi Tube or LMA the attending is pulling it ou. No conformation, no lung sounds nothing. Why? They want definitive airway management!…ETI. Now we reach the root of this argument/debate whatever you want to call it, ED attending’s NEED a certain amount of intubations in most ED’s, as well as their resident’s (in teaching hospitals). They need the tube so they don’t want US doing it.
    Medics are not with out their faults, 9 ETI attempts is AWFUL ! That is a scenario where you SHOULD HAVE sucked it up, used whatever secondary device (remember they are secondary advanced airway management devices) LMA, Combi or king, your service employs and get the patient moving! And 221 seconds of interruptions ? Did I read that right ? Thats a 4 minute interruption! You may as well have not showed up! You are not doing your patients any favors, I certainly hope those providers spent A LOT of time with their training officers and medical director afterwards. We can be our own worst enemy in these instances. Do yourselves and our profession a favor, TRAIN, make sure you maintain the basic mechanics of the skill, pay attention to what you are doing, time your ETI attempts with rythm checks if you need to stop CPR to preform ETI but if you don’t need to stop CPR for ETI…THEN DON’T!! Try it while compressions are being done…it’s not all that hard in most patients!

    Be safe Brothers and Sisters!!!

  3. We need to remember that there are two reasons to quickly control the airway in cardiac arrest: Protect it from aspiration, and delivery of ventilations to the lungs. Even the most perfect CPR loses its effectiveness if the patient’s stomach contents ends up in their lungs. I personally think the answer is not to withhold ETI, but make sure the folks in the field are well practiced and keep their skills fresh.

  4. The problem is not with the intubation but stopping CPR to intubate. Our system performs ETI while CPR is being performed. It makes the skill a little more challenging but never eliminates circulation. We have actually found that this process has improved our intubation success rate because it is more like the controlled environment of the OR. We have our medics take their time and get the tube on the first try. I believe that we scare medics to death with the whole “less than 30 seconds” per attempt. With continuous compressions for the first five minutes of the code, our medics can take as long as they need during that time. The new guidelines with minimize breaths perspective supports this method. We have also implemented automated CPR and the impedence threshold device with breaths only appropriate according to the ETCO2 readings. There is nothing wrong with Paramedics intubating, simply the rediculous way we have all been taught to do it.

  5. One of the biggest issues that is mostly ignored in the responses to this article is that in patients with sudden death [a vfib or arrest] the heart is the issue,not the lungs.These patients do not need any respiratory intervention. The oxygen saturation at the time of the arrest is normal and it takes 8 minutes for the saturation to drop to less than 70 % [while this is not normal it is adequate]. The issue is that the heart has stopped and there is NO BLOOD FLOW . We need to restore flow to the brain and the heart. Constant uninterrupted chest compression is the key. Any respiratory intervention is unnecessary.Furthermore, any attempt at bag valve mask ventilation increases intrathoracic pressure and decreases both cerebral and coronary blood flow . The experience in Arizona , Wisconsin and Kansas City [as well as our own unpublished data] showed that resuscitation rates above 40 % with witnessed shockable rhythms could be achieved. Intubation should not be allowed in the first 8 minutes after a cardiac arrest . Respiratory arrests clearly need respiratory interventions , like intubation, bag valve mask ventilations etc.

  6. Voitek Novakovski

    This is just another in a string of studies that prove that too many, prolonged attempts at ETI, and too many interruptions in CPR are detrimental to the patient. I’ve been in EMS since 1982 and a respiratory therapist since 1974. If current ACLS guidelines are followed, e.g. don’t stop CPR for more that 10 sec every 2 min when you stop to reevaluate, and don’t over-ventilate the patient, they do better. This does not mean paramedics should stop intubating! It means they need to do it right and ventilate correctly. As an RT, we don’t hesitate to intubate at codes in the hospital but we limit the time and you might get one shot (lasting not > 10sec, before the most experienced RT grabs the tube and puts it in. Then we monitor CO2 in accordance to the standards and it works. Don’t let bad technique be an excuse to stop a potentially life saving technique.

    Ski the RT/Medic BSRC, RRT, NREMTP, CCEMTP

  7. Can I ask why some services are ceasing CPR when ETI is being performed??? Our service in Perth, WA Australia, requires uninterupted CPR so we tube whilst compressions are being done, this elimniates the interruptions to CPR. We also have a standing order of 2 tube attempts per arrest, if unsuccessful then we LMA. Also we have a secondary crew at scene to assist in ETI. Also our cardiac arrest protocols (ARC) require chest compressions, defib and drug therapy coming prior to ETI (if the airway is clear and patent). So our ETI can happen in about 6-8 mins AFTER CPR, defib, drug therapy have been commenced.
    It would be nice to see a study done on the effectiveness of ETI in a cardiac arrest without stopping CPR for ETI and see what the outcomes would then be. Also as stated above maybe the person doing the study could look at the overall picture i.e. patient movement from scene to van, moving in the vans to the ED and add that into the study. Thiswould allow services too start recommending automated CPR devices and more real time training with ETI.

  8. I like a lot of the comments above; the times stated in this study are indeed appalling, and in countries (i.e. South Africa) where medical control is minimal I can guarantee you that it is just as bad if not worse. My personal take on airway management in CPR: on arrival insert an LMA (either an intubating LMA or an I-Gel), do the basics (CPR, defib, ventilations, IV/IO access, initial drug therapy) and then look at ETI. This is not a rigid approach as the need for ETI can become apparent quickly. I believe that there are two instances where ETI in cardiac arrest is mandatory: gastric reflux (actual or anticipated) or decreased lung compliance (e.g. drowning). The reason for these two instances is that the LMA does not protect against aspiration, and is incapable of producing higher airway pressures needed in decreased lung compliance. I recently read about a study that showed that ETI in cardiac arrest is harmful, possibly due to higher intrathoracic pressure causing a decreased venous return. How interesting, for the longest time we thought that the higher pressure was beneficial.

  9. And yet again, a study comes out that criticizes Pre-hospital ETI. And yet again, doctors are jumping on the “ban it” band wagon. I have seen ED physicians unable to intubate patients before with the RT stepping in to do it. So don’t automatically slam Medics.

    This particular study looked at interrupted compressions in order to intubate. How about doing a study on those services that do not interrupt compressions to ventilate! I’m not saying jump to a tube right away. Always start with the basics and get the compressions going and lasting, however, there will come a point where ETI is needed. As Nick stated above, you bring a patient into the ED with a King or Combitube in place with good chest expansion and breath sounds present, and the doctors yank it out and bag without an airway in place till THEY get to intubate (interrupting compressions as they do so). Before the powers that be decide to ban this skill, a closer look needs to happen. Not only pre-hospital but with in the ED also.

    Just my 2 cents……

  10. There are a number of reasons why ETI has it’s problems w/ many of today’s Medics. Medics are not intubating pt’s that just a few years ago, they might have. CPAP and the AHA guidelines havw had a major impact on this. Many paramedic Training Institutes no longer require their students to do ETI’s on “live pts ” during their training. In fact, many ORs do not allow medic students in to do so. So who’s fault is it then, the medic gets out into the field and can’t intubate someone while CPR is in progress( I do this) or takes 9 attempts to do so?..IMHO, it is the same medical community who is jumping on the “no ETI for Medics bandwagon”. Dr Wang’s studies are highly inaccurate. Take a good luck at the study! there is without a doubt a problem w/ Medics who do not keep their skill sets up to a proficient level. Service Medical Directors need to take this matter in hand and assure that their practioners are up to speed. Being a “nice guy” and letting your Medics slide is not helping anyone. We need to continue to provide a definitive airway, ie: endotracheal intubation, but we also need to lose the ego, and place an alternative airway when the ETI fails after the 2nd attempt. We need to practice ETI while CPR is in progress..practice is the key. SO, Physicians can HELP or they can continue on the “take away ETI” bandwagon. Which will they do? That remains to be seen.

  11. As several of you have mentioned, there is no need for ETI in the first 8min of downtime as our bodies (hemoglobin and residual lung volume) hold onto the oxygen for quite some time. We just need to get it moving with effective chest compressions. These numbers are beyond staggering, but ETI also is only 25% of the problem, so are we going to take away defib next because that caused a delay in chest compressions as well?

    My department and myself have personally had success with placement of a King as first line airway with an ITD attached, and my ego is NOT hurt when the MD/RT at the ED replace it with an ETT! Though the pt may still be coding, it is a more controlled environment where the pt can be brought to the proper height for optimized visualization of the cords, paralytics can be given, and bronchs/glidescopes are in the room for the team to use for DL of the difficult airways (which we SHOULD be able to identify prior to placing the blade on the tongue).

    Now don’t get me wrong, fully taking away ETI from paramedics WILL KILL more people then it will save. We have patients that need intubation in the field and until Star Trek is a reality and we can ‘beam’ our pts to the hospital this won’t change. It’s up to us to fight for more opportunities, get our med control to support us in this fight, convince our respective agencies to purchase tools that will better aid us in successful 1st ETI.
    My department has been given the AirTraq and we have had great success with it, it provides DL even with difficult no neck pts (because we all know everyone that arrests is a healthy grade I airway and has not eaten for 12hrs prior). There are some neighboring agencies that have purchased portable bronchs (which could help with FBO removal). The trick is finding the money (support) for tools we might only get to use a couple times a year. I agree with many of you that intubation during chest compressions is possible, it’s a skill that needs practice (like any ETI, surprise!). One of the easiest ways to combine both worlds is to train medics to insert the blade, tube in hand and THEN stop chest compressions for no more then 7seconds to place the tube between the cords in the bouncing target is daunting. And when you train on intubation mannequins, make it as difficult as possible. Put the dummy on the floor against the wall, intubate them sitting up, and tape them upside down under the table. Get creative and challenge yourself! The more bleed in training the less you sweat in combat. Be aggressive and fight for your patients and the paramedicine field as a whole. TRAIN TRAIN TRAIN, complacency will kill your patients quicker then anything they could do to themselves!


  12. Why are people ceasing CPR to perform intubation? I rarely require an interruption to allow intubation and if people practice like this, then the majority of times there will be no CPR interruption and a secure airway provided.

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