LMA vs ET tube

[Explorer127]

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

 

[Shishkabob]

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.

 

[reaper]

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.

 

[MrBrown]

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.

 

[Melclin]

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

 

[Shishkabob]

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

 

[LondonMedic]

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.

 

[MrBrown]

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

Yep, the intubating LMA

 

[Smash]

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

 

[VentMedic]

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)

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.

 

[MrBrown]

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.

 

[LondonMedic]

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?

 

[VentMedic]

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.

 

[fire_911medic]

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.

 

[Melclin]

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.

 

[TomB]

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

 

[fire_911medic]

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.

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'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).

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.

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.

LOVE THEM !



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?

Deflate your cuff slightly - gives better results


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

I wasn't impressed. I think the S.A.L.T does a better job and is more cost efficient prehospital.

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

Makes life easier if you've had an overzealous basic that shoved it down or took a few tries to place it. Again, deflate your cuff just a touch to make things easier, but if they're really caused trauma to the area, then you're gonna have a more definitive airway and there's only one hole to shoot for if they've made a real mess. Personally I can't stand combi tubes - but again, that's just me. Also - longer transports (as we do) mean your patient's gonna be on a vent, not bagged and I'd rather have an ET tube.

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?

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.

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

 

[TomB]

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!

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?

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.

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

Absolutely! We're 90% in agreement.

Thanks,

Tom

 

[EMTinNEPA]

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...

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

 

[fire_911medic]

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.


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.

True, but considering the above factors I referenced I don't see it being that large of a difference. ETI is the gold standard, and I've matured alot as a medic and come a long way (as has the department) from where I was. We also have alot more tools to utilize assisting with difficult airways and if I suspect it's going to take multiple attempts or longer time, I'm going to go with an additional tool or use a King over anything else - you are very right in that time is tissue - both heart and brain. I'm very curious to see where the ice/cooling blanket studies lead us.

I think we're both on the same track of wanting what is definitely best for the patient and them having the best possible outcome. Whatever I can do to improve that outcome I will - throw pride aside, it's not about me, it's about the patient. Any and all input is welcomed here ! I think we just come from a little bit different sides of the fence and I think that influences how one thinks as a medic. With all that being said - that's why I'm interested in seeing rural and urban based studies, not just one sided. What's good for one side, isn't always as good for the other.

Take care and stay safe out there !