LMA, Who can use them?

[KSEMT122]

Here in KS I believe EMT-B's may use a LMA, however I have yet to hear of a service that carries them on the trucks here. At my service we carry ET tubes and the EOA. Maybe EMTI4NOW could answer more definately for KS since I"m having a hard time remembering. I know B's here can use the follow airway devices

OPA

NPA

EOA

EGTA

Combi-Tube

[Amhet1]

The LMA is not nearly as popular here as it is in Europe. They really made the jump from the OR to EMS in the UK (if I remember correctly).

It is true that thee is slightly less airway control with an LMA vs ET, but the simple fact is that you can drop an NG past the LMA prior to inflation and the problem is solved. The other big factor to consider is airway maintenance. Statistics available show FAR too many misplaced/displaced/bad ET placements. The LMA has less chance of being misplaced or displaced, and minimal risk of regurg if it needs to be replaced. The LMA is also completely functional with EtCO2 monitoring. It also meets all AHA guidelines for tube placement (with the obvious exception of passing the cords).

The cost argument is not a valid one. A cursory look at the web shows the cost being equal to ET tubes. The LMA does not need 2 handles and 5 blades or stylet. So the over cost of use is less with the LMA.

This is one of those cases where EMS is slow to move something to proven to be better and more beneficial. (I know, personal opinion). Look how long it took before we got some logical guidelines on backboarding.

The one other caution with the LMA is making sure your ER staff knows its an LMA..... Its really painful on the patient to remove it without deflating first.

[chbare]

Hmm, a few thoughts if I may?

First, a LMA is not a true patent airway regardless of how you spin the information. The LMA is very fickle and prone to dislodge. This can be a significant problem in the prehospital environment. Proper placement can be tricky as well.

Next, the classic LMA design will only work with low airway pressures. Have even a moderately ill patient, and that goes out the door. In reality, you go above 20 and you start ventilating the stomach. This may be different with the other designs such as the proseal. With a failed airway, I do not see my self taking time to drop an NG/OG prior to placing an LMA.

Next, remember AHA guidelines are based on people in arrest. So, no the LMA is not acceptable for airway management in all patients.

Finally, people remove the LMA while inflated. This is an acceptable technique and may prevent aspiration of upper airway secretions and matter. Howeve, the removal technique will vary according to provider and situation. In the hospital, a tube exchange and fiber optic devices may be utilized.

Take care,

chbare.

[mshow00]

In my basic class I had to test out on the LMA(King LMA for company), CT, and ETT. We dont use the the CT in our area, and the LMA(King LMA) and ETT are all advanced airways.

[Amhet1]

All very good points, chbare. Some of the information I passed on may be somewhat dated as I haven't really looked into it in a few years. My comment about deflation before extubation was based on seeing significant pharyngeal trauma induced by it on one occasion.

I agree that displacement may be an issue but I would be interested to see a comparative study between that and ET intubations in the field. I read recently that the Univ of Kansas is in the process of such a study. The results should prove interesting.

I would like to comment on one point that you make tho. It is true that there is frequently some leakage around the mask, there is minimal chance of insufflation of the stomach. Recall that the tip of the mask sits at the esophageal os. The airway itself is open to room air so most (if not all) blowby from the mask will follow the path of least resistance, ie, passed back out the oropharynx.

To support my point, I did find a study that compared the LMA (unknown model or type) to a simple face mask. This was published in the Canadian J Anes.

Gas leak and gastric insufflation during controlled ventilation: face mask versus laryngeal mask airway.

CONCLUSION: Ventilation was adequate in all patients using both techniques. Leak was pressure dependent and greater with LMA use. Most of the leak was vented to the atmosphere via the pharynx. Gastro-oesophageal insufflation was more frequent with ventilation using the face mask. LMA use with positive pressure ventilation would appear to be a better airway management method than the face mask.

This was a randomized study using 20, 25, and 30cm of pressure on a group of 60 patients with 30 getting an LMA and 30 getting a mask under general anesthesia.

Two other points I would like to make quickly. I am a proponent of the LMA because of its overall ease of use, the skill involved with placement is less than ET intubation thus making it preferable for smaller and more rural services, and less loss of technical competency when the skill is not performed frequently.

Lastly, I would like to apologize to the original poster for heading off on my little tangents. I know you were looking for services that use the LMA and instead I go off and post about actually using them instead. ET will remain the gold standard for many years to come. There have been attempts to recreate the wheel with the EOA, EGTA, PTL (Pay the lawyer), CT, and the LMA. So far, the studies show the LMA coming closest to the ET in many respects.

[Dustdevil]

The LMA is great, but none of the studies I have seen are applicable specifically to the field environment. I have never used them in the field, but I have no intention of doing so either. And yes, I have them available to me in the field. If you hang your BVM off the end of a King or secured ETT while you move your patient, you can be pretty sure the airway will still be patent when you pick the bag back up. Not so with an LMA. The placement of that thing is just too precarious for me. If I'm in the OR, or working a code in an ICU bed, and need a back-up airway, I would find the LMA to be an attractive option. But not in the field. There is simply too much potential mechanism for dislodging it. Not to mention a greater potential for aspiration and other complications found in the acute patients we manage.

[hertzvanrental]

As previousley stated it is used widely in the UK and has been for a number of years. All paramedics are trained in it's use and a lot of EMTs can use them. When moving a patient to the truck then hanging the BVM might be asking for trouble if not tied in well. But once on the truck we pop the patient on the ventilator and our hands are free. Have to watch out for pressures though. If manually ventilating then careful bagging is what is required. Wouldn't want to use one on a Asthmatic resp arrest though. Having said that I haven't done many on the road, usually get the tube or use a boogie if difficult tube. Last time I used an LMA was on a person who set fire to themselves. It provided a great airway. When I was in the OR doing my trainig I inserted about 70 compared to 31 tubes because over here anaesthetists are opting for LMAs as most people are fasted and most procedures are short in duration.

[chbare]

All very good points, chbare. Some of the information I passed on may be somewhat dated as I haven't really looked into it in a few years. My comment about deflation before extubation was based on seeing significant pharyngeal trauma induced by it on one occasion.

I agree that displacement may be an issue but I would be interested to see a comparative study between that and ET intubations in the field. I read recently that the Univ of Kansas is in the process of such a study. The results should prove interesting.

I would like to comment on one point that you make tho. It is true that there is frequently some leakage around the mask, there is minimal chance of insufflation of the stomach. Recall that the tip of the mask sits at the esophageal os. The airway itself is open to room air so most (if not all) blowby from the mask will follow the path of least resistance, ie, passed back out the oropharynx.

To support my point, I did find a study that compared the LMA (unknown model or type) to a simple face mask. This was published in the Canadian J Anes.

Gas leak and gastric insufflation during controlled ventilation: face mask versus laryngeal mask airway.

CONCLUSION: Ventilation was adequate in all patients using both techniques. Leak was pressure dependent and greater with LMA use. Most of the leak was vented to the atmosphere via the pharynx. Gastro-oesophageal insufflation was more frequent with ventilation using the face mask. LMA use with positive pressure ventilation would appear to be a better airway management method than the face mask.

This was a randomized study using 20, 25, and 30cm of pressure on a group of 60 patients with 30 getting an LMA and 30 getting a mask under general anesthesia.

Two other points I would like to make quickly. I am a proponent of the LMA because of its overall ease of use, the skill involved with placement is less than ET intubation thus making it preferable for smaller and more rural services, and less loss of technical competency when the skill is not performed frequently.

Lastly, I would like to apologize to the original poster for heading off on my little tangents. I know you were looking for services that use the LMA and instead I go off and post about actually using them instead. ET will remain the gold standard for many years to come. There have been attempts to recreate the wheel with the EOA, EGTA, PTL (Pay the lawyer), CT, and the LMA. So far, the studies show the LMA coming closest to the ET in many respects.

I think we will have to disagree on some of your points at this time. The information you provide compares the BVM to the LMA. We all know how often people correctly perform PPV with a BVM. I simply think comparing a supraglottic device to a BVM does not prove the device is a good choice in the context of our conversation. Nor does it say that gastric inflation does not occur with LMA use. I think the LMA has a place as a rescue device and it does work in the OR setting with a patient who is fasting and has had an anesthesia pre-assessment prior to the procedure. However, I am not sure this translates to the EMS environment. My thinking is much more on the lines of what Dustdevil just stated.

With that, several variations of the LMA exist. The LMA proseal and ILMA for example, may be better suited for use in the EMS role.

Take care,

chbare.

[hertzvanrental]

We use portex in the field. In hospital It was an more robust autoclavable version which I found easier inserting to the side of the mouth and giving it a twist which worked every time compared to holding it like a pen and inserting it in line with the roof of the mouth. Also used proseal and found that easier with it's introducer, I was working with one of the consultants who was to do with it's development.

[Amhet1]

"If you hang your BVM off the end of a King or secured ETT while you move your patient, you can be pretty sure the airway will still be patent when you pick the bag back up. Not so with an LMA."

Excellent point. I hadnt considered that "twist" factor.....

As far as the study I cited, it was the closest thing to support my point. I does show the minimal risk of gastric insufflation. That doesnt decrease any real risk of regurg tho. I do understand the concerns you all point out with using the LMA as a primary airway device. That said, i still have concerns with the studies Ive seen with 5-10% ET displacement/ misplacements. And as a basic, anything is better than nothing!

I would have to say it looks like we all pretty much agree that this something that need further study. Im just glad to see that Univ Kansas (as opposed to the other UK) is working on research on it! If I were really smart, Id say theres alot more we could research, but Im not so I wont!