# LMA vs ET tube



## Explorer127 (Jan 10, 2010)

Just curious why in EMS we use endotracheal intubation and never use Laryngeal mask airways/other intubation techniques...


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## Shishkabob (Jan 10, 2010)

The ETT seals the trachea and as such is the 'gold standard'.  The LMA does not.  The LMA is a supraglottic device and does not prevent aspiration.


Other devices are use such as the Combi and King that are 'blind' insertion devices for use if you either can't get an ETT or don't need to go that far.


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## reaper (Jan 10, 2010)

We use LMA's,Combitubes,and King LT's in EMS. ETI is a more secure airway, so it is used often. But many still use the others, especially when intubation can not be done.


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## MrBrown (Jan 10, 2010)

We use LMA and ETT in our system.  LMA is quick and easy to insert and provides more definitive airway control than an OPA or NPA.

It is not perfect but its a good adjunct for our Ambulance Technician level providers to use.

I'd like to see us compare LMA and the King Airway.


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## Melclin (Jan 10, 2010)

They are used all over Australia. LMAs are easy to put in with minimal training leading to excellent success rates. As well as being the only 'advanced airway' available to our Basics, they form an important part of the failed intubation drill for ALS.

Also,



> In patients in whom positioning or prolonged extrication does not allow for endotracheal intubation, the LMA can be inserted and allow for successful airway management until a definitive airway can be established


(1)



They are not always successful though for a number of reasons. e.g. I was at a job once where the patients throat had been crushed, changing his anatomy somewhat - couldn't seat an LMA. ETI is the gold standard. 

This is the best breakdown of LMA info I've seen, although its getting a bit old now: http://www.ncbi.nlm.nih.gov/pubmed/11165839

(1) http://emedicine.medscape.com/article/82527-overview


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## Shishkabob (Jan 10, 2010)

There are LMAs out now that facilitate ET placement going through an already placed LMA.


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## LondonMedic (Jan 10, 2010)

Linuss said:


> The ETT seals the trachea and as such is the 'gold standard'.  The LMA does not.


ETT cuffs don't quite 'seal' the trachea, because they now have high volume low pressure cuffs it is possible for secretions or aspirate to leak past.


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## MrBrown (Jan 10, 2010)

Linuss said:


> There are LMAs out now that facilitate ET placement going through an already placed LMA.



Yep, the intubating LMA


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## Smash (Jan 10, 2010)

LondonMedic said:


> ETT cuffs don't quite 'seal' the trachea, because they now have high volume low pressure cuffs it is possible for secretions or aspirate to leak past.



Yep, it's a common myth that the airway is 'secure' or sealed with an ETT.  Care must still be taken to minimize chances of aspiration by dliligent suctioning of both the ETT and the oropharynx as well as placement of a naso/oro gastric tube early on (also helping with CPR) 

That said, ETT provides better protection than an LMA and is better suited to patient s who have high airway resistance, unusual anatomy, non fasted patients... Pretty much all of ours!

There have been a number if theadsnon this I think, try searching for them


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## VentMedic (Jan 10, 2010)

LondonMedic said:


> ETT cuffs don't quite 'seal' the trachea, because they now have high volume low pressure cuffs it is possible for secretions or aspirate to leak past.


 


Smash said:


> Yep, it's a common myth that the airway is 'secure' or sealed with an ETT. Care must still be taken to minimize chances of aspiration by dliligent suctioning of both the ETT and the oropharynx as well as placement of a naso/oro gastric tube early on (also helping with CPR)


 
It was never the purpose of the ETT to "seal" the trachea completely or the "hold" the ETT in place.  The "seal" should be just enough to prevent air from escaping to aid in ventilation.  The high volume low pressure tube has little to do with preventing the seal and is intended to prevent high pressure damage to the trachea.    In the hospital we don't use a "recipe" to fill the cuffs but rather gauge the pressure (approx 20 cmH2O) after we do a minimal leak technique to ensure just enough air is inserted and not more than necessary.  

Also, the cuff is positioned below the glottis.  Anything that passes the glottis is aspirated.  Suctioning of the oropharynx is definitely important.  However, in the hospital we will often change out the field tube for one with a subglottic suction port to minimize the risk of VAP (Ventilator Associated PNA) if the patient is going to be intubated for more than 48 hours.


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## MrBrown (Jan 10, 2010)

Perhaps I should also mention that the LMA is not designed to totally seal the esoug.....esop....esoup.....eh, the thing food goes down.

There have been one or two cases apprently of sparky providers doing the good ole ambo trick of "more is better" and over inflating the cuff thinking it will completely seal the (*gets dictionary) esophagas.

If you over inflate the cuff it can cause more air to leak out the sides and also pushes against the base of the tongue which leaves the door open for dental trauma and really SNAFUing the whole situation up.


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## LondonMedic (Jan 10, 2010)

VentMedic said:


> It was never the purpose of the ETT to "seal" the trachea completely or the "hold" the ETT in place.


I think smash and I are both well aware of this, just as we are aware that there are plenty of people outside of anaesthetics and critical care, including paramedics and EMTs, who don't understand how tubes work and what they're there for.

Although I have never used them myself, and have no particular desire to, I'm told that the old small volume high pressure cuffs _did_ provide a better seal. Is this incorrect?


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## VentMedic (Jan 10, 2010)

LondonMedic said:


> Although I have never used them myself, and have no particular desire to, I'm told that the old small volume high pressure cuffs _did_ provide a better seal. Is this incorrect?


 
They are not "old" by any means. High pressure tubes are very much still around and definitely have their applications. The armoured ETT is one of them and it can be part of the intubating LMA set. Some EMS agencies also do not use the Hi-lo tubes since they are slightly more expensive or some in EMS even believe they do form a "tighter" seal. 

You have to remember that EMS providers may only see one or two different types of ETTs unless they work IFT. There are actually many different ETTs and well over 300 different airway devices that can be used for both short and long term. 



> I think smash and I are both well aware of this, just as we are aware that there are plenty of people outside of anaesthetics and critical care, including paramedics and EMTs, who don't understand how tubes work and what they're there for.


 Don't know what either of you know or don't know. I'm just going by what I read in your posts. Don't get your panties in a knot if I expand upon your post.


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## fire_911medic (Jan 23, 2010)

Intubation is the current gold standard as it is the only thing which provides a definitive seal on the airway preventing aspiration.  The LMA actually encourages aspiration.  It seats poorly in the airway, was designed for patients that were NPO so there was no risk of vomiting, if the patients do vomit or have heavy secretions, they will become trapped within the base of the LMA and have no option but to go down into the lungs as you bag the patient (simply due to design).  If I had to pick an alternative airway of choice for me it would be the King airway as it is simple to use, a wider range of sizes (pediatric - large adult), and only one balloon to inflate.  Plus a tube can be placed down it to limit gastric insufflation (air in the belly) - a definite perk over the other airways.  Also, extremely easy to intubate around if chosen.  There is a variety of the LMA known as the intubating LMA, but those are not commonly found in prehospital environment and the LMA was designed to be an inhospital (OR) tool.  I dislike combitubes as if multiple attempts are made to place it and simply from the sheer size of the balloons inflated there is some trauma to the trachea making it more difficult to intubate around it - or in place of it.  Also, should the wrong port be inflated, then you have the same situation as a failed intubation.  The king is meant to be a simplistic airway and not go into the trachea.  The rate of failure is quite low.  There is also the S.A.L.T. airway which is supposed to allow the tube to curve more improving success rate of intubation among other toys and tools.  I'm not that familiar with it and have only utilized it in an airway class.  So my choice would be endotracheal intubation immediately followed by the king, then combitube, then LMA.  Of course, that is my manner of personal preference as that is what I am most comfortable with for the reaons listed above.  Yours may be different depending on your experiences with each.


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## Melclin (Jan 23, 2010)

fire_911medic said:


> So my choice would be endotracheal intubation immediately followed by the king, then combitube, then LMA.



Gee wouldn't the pt's throat be a bit crowded.


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## TomB (Jan 23, 2010)

fire_911medic said:


> Intubation is the current gold standard as it is the only thing which provides a definitive seal on the airway preventing aspiration.



Actually, that requires qualification. The ACLS Reference Textbook (2003) summarized the issues nicely:

"Tracheal intubation, once the "gold standard" of assisted ventilation, remains the advanced airway of choice only for experienced providers who working in programs with careful performance monitoring, defined requirements for skills maintenance (e.g., establishment of minimal number of intubations to be accomplished per year), and an atmosphere of continuing quality improvement [...] In the absence of quality improvement programs, the probability of lethal complications from tracheal intubation become unacceptably high."

How often do paramedics meet these criteria?

The "gold standard" is appropriate ventilation, however achieved.



> The LMA actually encourages aspiration.  It seats poorly in the airway, was designed for patients that were NPO so there was no risk of vomiting, if the patients do vomit or have heavy secretions, they will become trapped within the base of the LMA and have no option but to go down into the lungs as you bag the patient (simply due to design).



I've had both good and bad experiences with the LMA. For a cardiac arrest patient, if you can insert it without interrupting chest compressions it's probably not a bad choice. If you don't fill up the stomach with air using a BVM with an oral airway, it turns out the patient is less likely to vomit. 

On the other hand, the LMA doesn't work too well for a drowning victim (for example).



> If I had to pick an alternative airway of choice for me it would be the King airway as it is simple to use, a wider range of sizes (pediatric - large adult), and only one balloon to inflate.  Plus a tube can be placed down it to limit gastric insufflation (air in the belly) - a definite perk over the other airways.



I agree! I haven't used the King LT yet, but we're budgeting for it in the next fiscal year so we can use the Wake County EMS approach to cardiac arrest patients.



> Also, extremely easy to intubate around if chosen.



It is? That's a new one for me! I've seen the graphic that shows a cross-section of a patient with a King LT in place and it's hard for me to imagine how you could intubate around one. I'm not saying you're wrong, because I don't have real life experience with the device, but doesn't the proximal cuff seal off the oropharynx?



> There is a variety of the LMA known as the intubating LMA, but those are not commonly found in prehospital environment and the LMA was designed to be an inhospital (OR) tool.



I'd be interested in hearing about anyone's experience with the intubating LMA.



> I dislike combitubes as if multiple attempts are made to place it and simply from the sheer size of the balloons inflated there is some trauma to the trachea making it more difficult to intubate around it - or in place of it.  Also, should the wrong port be inflated, then you have the same situation as a failed intubation.



I've never used the combitube, but why bother intubating around it?



> The king is meant to be a simplistic airway and not go into the trachea.  The rate of failure is quite low.  There is also the S.A.L.T. airway which is supposed to allow the tube to curve more improving success rate of intubation among other toys and tools.  I'm not that familiar with it and have only utilized it in an airway class.  So my choice would be endotracheal intubation immediately followed by the king, then combitube, then LMA.



Even for the cardiac arrest patient? Why use a tracheal tube over a King LT when we know that stopping chest compressions for any reason is bad? Or would you intubate the patient without stopping compressions?



> Of course, that is my manner of personal preference as that is what I am most comfortable with for the reaons listed above.  Yours may be different depending on your experiences with each.



Fair enough!

Tom


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## fire_911medic (Jan 23, 2010)

TomB said:


> Actually, that requires qualification. The ACLS Reference Textbook (2003) summarized the issues nicely:
> 
> "Tracheal intubation, once the "gold standard" of assisted ventilation, remains the advanced airway of choice only for experienced providers who working in programs with careful performance monitoring, defined requirements for skills maintenance (e.g., establishment of minimal number of intubations to be accomplished per year), and an atmosphere of continuing quality improvement [...] In the absence of quality improvement programs, the probability of lethal complications from tracheal intubation become unacceptably high."
> 
> ...



Hope this gives you a better idea of where I'm coming from !


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## TomB (Jan 25, 2010)

fire_911medic said:


> I'll be the first to say that the intubation skills in the majority of programs are severely lacking and training maintenance programs across the nation need to be revamped not only for this, but other skills that are used less frequently. We are eager to get students experience, but once you become a licensed provider, then there isn't the same concern for keeping those skills sharp. And I'm sorry, but intubating fred the head isn't the same as people. Instead the approach that schools or CCT programs utilize of so many intubations a quarter (notice i said a quarter, not a year to prevent someone going and doing them all one day a year) is great and there's more than enough to go around.



I can't argue with that! 



fire_911medic said:


> This is one that falls back to personal experience. I'm still waiting to have a good go round with it - but the two patients I've used LMA prehospital on (we were one of the first ground programs to bring them on prehospital in the state) ended up with aspiration. Often we are getting the patient after overzealous bagging by volunteer rescue (I use the term loosely) squads which have nothing more than a CPR cert. I would have to deal with a different situation in order to give a more non biased opinion.



See, now that's a problem. It seems to me that if you're going to use an LMA (or King LT) for a cardiac arrest patient it should be used right off the bat (as opposed to using an oral airway and BVM first). Based on current evidence it seems to me that first responders would be better off placing the patient on a NRB mask and performing continous chest compressions for the first 2-minutes and then shocking. Would you be on the scene by then?



fire_911medic said:


> KEEP GOING ! It's done frequently around here. And if you are efficient, you are not stopping compressions for more than 30 seconds which about equal to you switching out an exhausted provider. Remember - I'm rural so longer transports - frequent hour plus.



I don't know, fire_911medic. 30 seconds is a really long time! Why should it take more than a few seconds to switch out the chest compression guy? I'm not one to be dramatic, but interrputing chest compressions for 30 seconds could be the difference between life and death.



fire_911medic said:


> Hope this gives you a better idea of where I'm coming from !



Absolutely! We're 90% in agreement.

Thanks,

Tom


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## EMTinNEPA (Jan 25, 2010)

At my place of employment we used to carry endotracheal tubes and combi-tubes.  However, the combi-tubes were recently phased out in favor or the King LTs (BEST DECISION EVER).  We also have nasogastric tubes to alleviate gastric distension.  According to this study, the King LT has significant accuracy and placement time advantages over ETTs or Combi-tubes.  However, as has been stated the endotracheal tube provides better protection... also, something I don't think anybody has touched on, the endotracheal tube, if correctly placed, gives us another route for certain medications, something the LMA, Combi-tube, and King LT doesn't.

Oh, and...


Melclin said:


> Gee wouldn't the pt's throat be a bit crowded.


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## fire_911medic (Jan 25, 2010)

TomB said:


> See, now that's a problem. It seems to me that if you're going to use an LMA (or King LT) for a cardiac arrest patient it should be used right off the bat (as opposed to using an oral airway and BVM first). Based on current evidence it seems to me that first responders would be better off placing the patient on a NRB mask and performing continous chest compressions for the first 2-minutes and then shocking. Would you be on the scene by then?
> 
> *No in 99% of the cases - I am in an extremely rural area and with the exception of the very rare patient that is right in town, our average response time is 30-45 min due to road conditions (extremely narrow and winding - add in weather it's even longer) which is why we do utilize either troopers stationed throughout the county (which are also trained first responders - some higher but only function to that level) and individuals with rescue squad that live through the county.  Whoever is closest responds.  The rescue squad members are first responder trained but do not carry AED (due to cost and poor response by some members it's not cost efficient to issue each their own - they do from home/work area response) Troopers then back up with the AED as there are usually some within a reasonable distance.  In this area though, King (or any substitute is not within FR skills).  Also it is a relatively poor county and at the time was lucky to have more than one medic per shift.  It's coming around staffing wise, but it's tough.  Fire is entirely volunteer so no competition there.  Bit different environment.  The two patients I referenced using an LMA on were extreme anterior and large necked that would have been challenging for any medic to have gotten and rather than waste time fishing, I utilized the LMA.*
> 
> ...



Take care and stay safe out there !


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## fire_911medic (Jan 25, 2010)

EMTinNEPA said:


> At my place of employment we used to carry endotracheal tubes and combi-tubes.  However, the combi-tubes were recently phased out in favor or the King LTs (BEST DECISION EVER).  We also have nasogastric tubes to alleviate gastric distension.  According to this study, the King LT has significant accuracy and placement time advantages over ETTs or Combi-tubes.  However, as has been stated the endotracheal tube provides better protection... also, something I don't think anybody has touched on, the endotracheal tube, if correctly placed, gives us another route for certain medications, something the LMA, Combi-tube, and King LT doesn't.



That is defintely another benefit to the King - which I believe I mentioned earlier (perhaps I didn't brain is slow today) is the ability to use an NG tube to prevent gastric distention.  I agree that the King is almost impossible to not place correctly and with the advantage of having multiple sizes (though the LMA does as well), it's going to provide better protection with less trauma if compared directly to the combi tube, though all being said, I've not seen an LMA cause much trauma at all.  But I also have quite limited experience with them as when I had the first two go badly I steered away from them and towards the King LT.  

Overal I think better assessment and early recognition of difficult airways and utilization of alternate devices like the King LT is going to help improve the situation (with the exception of excessive airway trauma which would require a more definitive airway)

Another thing to consider is with the widespread use of the IO's, meds down the tube is used less and less.  You can find a site to put an IO in almost anyone and in all honesty, I would go that route over putting meds down the tube anyday.  Remember any time meds go down the tube, you are putting on average double the dose - put enough down it while you are fishing around for a line and well, a few meds, a few rounds, and you have the potential of overloading the lungs with fluid.  Just something to consider.  It takes seconds to place an IO (especially with EZ IO) and in arrest situations, likelihood is that (with our response times) they will be peripherally clamped down and it's gonna be tough to get a line established anyway.  I'm probably going to go IO anyways.  Just another side of the fence...

Everybody take care and stay safe out there !


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## phildo (Feb 9, 2010)

Linuss said:


> There are LMAs out now that facilitate ET placement going through an already placed LMA.



Those are really expensive.  would love to have them.


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## ivanh3 (Feb 12, 2010)

The question should be decided based on patient outcomes. There is entirely to much "YMMV" in EMS already. Two recent articles suggest that the ET tube is not what it used to be. I have seen entirely too much time wasted on "gettin' the tube" during arrests. I have seen this both in the hospital and pre-hospital setting. I have literally stood at the door of the ER and watched crews still trying to intubate in the ambulance bays. Here are two recent articles about the subject. The one by Bledsoe and Gandy published in the March 2009 addition of JEMS is probably well known here. The other is an article from the AAP.

http://www.jems.com/news_and_articles/articles/jems/3403/the_disappearing_endotracheal_tube.html

http://pediatrics.aappublications.org/cgi/content/full/122/2/e294


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## rhan101277 (Feb 12, 2010)

Also LMA's tend not to stay in place as most ambulance rides are very bumpy, where as you can count on your ET tube.

Also you can't use LMA's or combitubes on pediatric patients or folks under 5 feet tall.


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## 8jimi8 (Feb 12, 2010)

rhan101277 said:


> Also LMA's tend not to stay in place as most ambulance rides are very bumpy, where as you can count on your ET tube.
> 
> Also you can't use LMA's or combitubes on pediatric patients or folks under 5 feet tall.



Don't "count" on your tube. Verify and RE-verify your placement.  The one time you don't may have been the wrong one to trust.  The ambulance IS very bumpy and ET tubes DO migrate.


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## ivanh3 (Feb 13, 2010)

rhan101277 said:


> Also LMA's tend not to stay in place as most ambulance rides are very bumpy, where as you can count on your ET tube.QUOTE]
> 
> 
> 
> ...


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## rhan101277 (Feb 14, 2010)

8jimi8 said:


> Don't "count" on your tube. Verify and RE-verify your placement.  The one time you don't may have been the wrong one to trust.  The ambulance IS very bumpy and ET tubes DO migrate.



Yeah this is good advice.  With waveform capnography monitoring, viewing chest rise and fall, hopefully when it comes my turn I can do good.  Obviously after the tube is passed and I check breath sounds, I won't be able to check them again when i am by myself in the back.  I will have to depend on my equipment and viewing chest rise/fall, condensation on the tube etc.

I would be hosed up if someone got brain damage or something because a tube became dis-lodged and I missed it.  I just need to do my best.


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## boingo (Feb 14, 2010)

I take intubated patients into the ED with the monitor.  I print out a copy of the waveform at the bedside, and hand it off and verbalize it as well.  If things change after that, the ED would be hard pressed to fault the medic, IMHO.


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## VentMedic (Feb 14, 2010)

boingo said:


> I take intubated patients into the ED with the monitor. I print out a copy of *the waveform at the bedside, and hand it off and verbalize it as well*. If things change after that, the ED would be hard pressed to fault the medic, IMHO.


 
However, what I have found is some Paramedics run their ETTs very high and even though the tip is through the cords, the cuff is above or supraglottic. The seal will be just enough where you will still get a waveform but essentially the tube is in a very unstable position. Careful documentation of placement at the cm mark must be made and what your reference point is. Hospitals will generally refer to the teeth, lip or gum line. Paramedics may refer to where they have attached it at the commercial tube holder device. The Thomas tube holder is definitely one to be careful with. The 23 cm mark at the screw may be anywhere from 19 - 21 cm at the lip and on a 5'10" pt or taller, that tube may be very close to out or the cuff may not be below the cords. It wouldn't take much more than a move from the stretcher to stretcher with the BVM still attached or head positioning to dislodge to tube to a bad position. Also, it doesn't take much of a cough for a patient to move this device as well since the straps stretch. 

http://www.armstrongmedical.com/index.cfm/go/product.detail/sec/3/ssec/16/cat/71/fam/509


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## boingo (Feb 14, 2010)

Good points.  In addition to printing off the waveform at the bedside I will report the tube depth as well, I usually reference the teeth, if not, I will specify, gums, lips, etc...I document the grade of view, number of attempts and any difficulty encountered.  I will note the airway score pre-intubation if it was performed.


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## VentMedic (Feb 14, 2010)

Those who do NTI also fall very short on some patients. A 6.0 or 6.5 tube will only be about 28 and 29 cm which might be a great depth for some orally intubated patients but even then we might be taping at the hub if that tube is used. For NTI, the cuff will more than likely be supraglottic.

It would be great if everyone was taught to score the airway for degree of difficulty before just taking a few stabs at it.


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## MedicMeJJB (Feb 14, 2010)

The point here was nailed several times.. LMAs are made for NPO patients, prior to surgeries. They are ideal for that situation, ET intubation is ideal for truly securing an airway - SO LONG AS IT IS DONE CORRECTLY! Confirmed.. Reconfirmed.. and then recomfirmed again!


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## VentMedic (Feb 14, 2010)

That does not mean you shouldn't be proficient in at least one and preferrably two alternative airways which might include the LMA.  If for some reason I could not do ETI on someone who has esophageal varices, I would be very reluctant to an alternative airway that went into the esophagus if I had to establish some type of airway to get from point A to point B.


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## MedicMeJJB (Feb 14, 2010)

Absolutely agreed. I didn't mean that ET is the only way, sorry if it came across that way. All advanced providers should be proficient and trained in several alternatives. We are currently carry the King tube and Combi tubes, also. Surgical airways cannot be forgotten. ALL starting with good, proficient BLS bagging. B)


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## phildo (Feb 14, 2010)

Something I do to mitigate tube displacement is to apply a cervical collar, and immobilize the patient on a long spineboard with headblocks prior to moving them. Really helps if you have to carry them downstairs, like I had to do last shift with a really large OD patient that I had to RSII.  I make sure to tell the ER staff that it was only to facilitate movement.


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