Endotracheal Intubation vs. King LT

[Kn.ght1]

Hi All!

I had a interesting discussion with my paramedic partner while on shift. I brought up a study about endotracheal intubation and that our protocols here are be coming more restrictive about when paramedic are allowed to intubate. She mentioned that there is more and more evidence showing that intubation increase mortality by 20% in most patients. She said that studies are showing the King LT are just as effective in maintaining a airway. I've read a couple studies that showed the disadvantages to intubation during a cardiac event and that a King LT was just as effective.

Other that not being able to deep suction a patient what does the endotracheal intubation have that King LT don't in the prehospital setting? Especially since there has been questions into the number of attempts it takes some paramedics to acquire a successful tube. Will ET tubes eventually be replaced by King LT's in the prehospital settings? What situations would a ET tube still be the golden standard in the field?

kn.ght1

[ERDoc]

I don't think you will ever see ETTs fully removed off of the ambulance, but you will see less and less use for them. An OPA or King would be fine for a cardiac arrest situation. A code is a temporary situation, it will end one way or another in a short amount of time, so why not use a temporary airway, especially when an ETT takes away from the most important part of a code, the CPR. I don't start worrying about a definitive airway until the pt has been stabilized, relatively speaking.

[systemet]

I agree that it's unacceptable to stop CPR to place an ET tube on a cardiac arrest, outside of a few select situations, e.g. copious amounts of blood in the airway, inability to ventilate by other means. I do think that it's possible to intubate (+/- a bougie) a lot of people without stopping compressions, and have done this on the last few arrests I've worked. At the same time, I think there's no shame in throwing in a King, either as a primary airway, or after taking a look and realising that this is not the airway that's going to be captured easily during CPR.

Anecdotally, I like having a good capnograph, and have had some problems with getting consistent readings on a King.

In terms of a comparison between supraglottic airways and ET tubes, I think you're got a couple of issues:

1. A supraglottic airway can fail due to glottic edema, e.g. anaphylaxis, caustic ingestion injury, inhalation burn, angioedema

2. The cuff on most supraglottic airways typically fails at fairly low pressures versus an ETT. So this might not be the best airway to use on someone who requires high peak pressures to ventilate.

3. Not everyone is going to be easy to ventilate using a supraglottic airway.

Granted, these will work for the vast majority patients. I'm looking forward to seeing some data published from studies comparing primary ETI versus primary SGA versus primary BVM. This should resolve some of the issues over which approach is best.

[mobey]

Anecdotally, I like having a good capnograph, and have had some problems with getting consistent readings on a King.

Not an anecdote at all my friend!

ETC02 has been a proven effective guide to measure quality of compressions and feasibility of positive outcome.

ETC02 has NOT proven to be accurate with King airways of LMA's.

That's enough right there for me to use Ett for cardiac arrest. That being said, I rarely need to interrupt CPR to place one.... and when I do need to, I do it when we are switching out compressors.

I really think the "problem" with intubating codes is in the intubator, not the procedure.

Is the jury still out on the whole "King airways decrease cerebral blood flow"? Haven't seen much on that in the last year....

*Does anyone else find the term "intubator" a little dirty to say?

[systemet]

Not an anecdote at all my friend!

ETC02 has been a proven effective guide to measure quality of compressions and feasibility of positive outcome.

Hi mobey! When I wrote "anecdotally", I was referring to my having better luck getting good capnographs with an ETT versus a King, more than to the utility of CO2 in predicting outcome, and assessing the effectiveness of CPR. All the best.

[mobey]

Ahh.... Gotchya

[BAYAMedic]

*Anecdote alert*

My experiences are strictly that. I have personally never used a King LT but have intercepted calls with one in place.

One was a STEMI --> witnessed VFib arrests x6 (NSR following single 300j shock) patient had failed Ett placement x2 and a King was placed. King was removed on ER arrival and replaced with ETT. Pt released Neurologically intact without deficits and came by the station 2 weeks later.

The second was a GSW to the head and after failed attempts a KING was placed. Patient was overdriving the vent and was left in place during organ harvest.

Every cardiac arrest I have been directly been involved in, have had ETT placed with one exception of a surgical Cricothyrotomy. This comes from having cut my teeth as a paramedic in a system in Washington State (that had arrest survival rates nearly mirroring King County Medic One), that utilizes a strict cardiac arrest QA/QI process, and intubation is the only advanced airway used. Kings are available but each paramedic in this system averages 15 intubations per year. Airway mannequin time is encouraged and OR time is mandatory with any multiple intubation failure. This stringent QA QI process promotes paramedic Advanced airway competency and RSI with offline protocol. We have Resuscitation University Faculty as our MPD and CPR Quality Audits, therefore any intubation attempt will be during compressions. Like I stated in the beginning this is all anecdotal but this is what I know.

Didn't the Japanese study show poorer outcomes with SGA due to Carotid/Jugular impingement from the cuff limiting Cerebro blood flow?

BAYAMedic

[chbare]

No, a Japanese study showed less favorable results in arrest patients who had advanced airways placed. Unfortunately, I believe some of the issues revolved around the fact that they used a variety of devices including EOA's?

There was a very small animal study (n=9) that indicates SGA's may decrease CBF in the arresting animals.

[systemet]

The trouble with these studies, is they're retrospective -- none were randomised to control for confounders. They weren't intended to compare ETI versus SGA versus OPA versus ApOx, for example. Instead, someone took a bunch of registry data (CARES, Hasegawa et al. -- the Japanese study wit 65K participants), or reanalysed data from a trial designed to look at another intervention (ROC-PRIMED). So, we see a significant association between OPA use and survival -- but this could simply be that patients who are resuscitated in the first few minutes of a cardiac arrest are more likely to survive and less likely to have been intubated -- so they end up biasing the basic airway group towards survival. Likewise the Japanese study showed OPA >> ETI > SGA, but this could simply be a result of longer cardiac arrests being less likely to survive and more likely to get some form of advanced airway, and the patients with multiple failed intubations, or less skilled providers, more likely to end up in the SGA group with more interruptions in CPR.

This is a fundamental limitation of this sort of study design, you can only find associations. To infer causation, you need a RCT -- I believe there's one ongoing in the UK (http://bmjopen.bmj.com/content/3/2/e002467.abstract), where you set out to randomly either intubate, place an SGA, or use an OPA (or potentially use ApOx), and then you group the patients by intent-to-treat, so if the patient gets ROSC before airway placement they're analysed as if they had been intubated, or had an SGA placed, etc.

It remains possible that the SGAs are affecting cerebral blood flow -- this seems to be the case in pigs (http://www.ncbi.nlm.nih.gov/pubmed/?term=LMA+carotid+compression) , but it's difficult to know if this happens in humans. There are two small studies showing compression of the carotids with LMA use (http://www.ncbi.nlm.nih.gov/pubmed/9466022), http://www.ncbi.nlm.nih.gov/pubmed/9303289 . But it's difficult to know if this has a clinical effect, at this point.

It will be interesting to see how this plays out.

[ERDoc]

I know evidence outweighs opinion and experience but with the number of LMAs being used in the OR, I find it hard to believe that we haven't seen a problem, assuming one exists. You would think that something like this would be pretty easy to study. I would do it in a place with high survival rates the first time around and then if there is a difference, run the study in more average areas.