Adult LMA sizing-- suggested weights

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morepatience

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How do you size your LMAs for adult patients? I've found the LMA Unique size 5 way too big for patients even over its suggested weight, and usually use size 4 for adults, sometimes size 3.
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My understanding is that the size 3 was designed for standard adult females, the size 4 for standard adult males, and the size 5 for large males. I don't think putting a size 5 in a 5"1'/140kg female makes any sense (but I see it all the time).
 
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WholeLottaGame7 said:
My understanding is that the size 3 was designed for standard adult females, the size 4 for standard adult males, and the size 5 for large males. I don't think putting a size 5 in a 5"1'/140kg female makes any sense (but I see it all the time).
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+1. With extensive use, one can judge pretty fast not only what LMA size will fit the patient best, but also what kind. The initial learning curve can be annoying, as the OR staff watches the crazy doc trying various LMAs. 🙂
 
Kind of a judgement call. Older folks, even the skinny ones are more likely to get a larger size. The larynx keeps growing. Also, Think of those old skinny COPDers who you could slip a 9.0 ett in easily.


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I use size 5 LMAs fairly frequently. Oftentimes there are leaks with smaller sizes, and I like having enough confidence in my LMA that I can ventilate through it completely (full VCV/PCV/PC-VG) if for whatever reason I needed to.
 
NeuroSpeed said:
So please excuse the CA-1 question, but hypothetically, what if a woman had been doing fine with 3's, then one time someone managed to fit a 5 in and she did great, is she now ruined for 3's for forever?

:thinking:
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I wouldn't see why. It's not like the tissue would get overstretched and never rebound or something.
 
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You guys ever get those skinny people where you put the LMA in and you actually see the outline of it moving down their neck...? Kinda creepy.
 
Just use the Ijel LMA. 4 for most women/small men 5 for most men. The Ijel seals without a cuff takes a bit longer to seat and seal but once in place it's tolerated better then cuffed LMAs. I have not placed a cuffed LMA in months.
 
Agreed with most above. Start with a #4 on most people and you'll be fine.

LMA3 for small adults.
LMA4 for most adults.
LMA5 is huge and for people with huge throats/faces/mouths etc.
 
I avoid LMAs in fatty's, you guys do the same?
 
okayplayer said:
Still get 1/10-1/15 patients or so where I can't go get a good seal with the iGel, even trying two sizes. Oh well. The other 90-95% of the time they are incredible.
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With those patients that won't seal. Give it an extra 5 minutes the soft tissues relax on to the Igel for me it works perfectly. I have not had any seal issues.
 
narcusprince said:
Just use the Ijel LMA. 4 for most women/small men 5 for most men. The Ijel seals without a cuff takes a bit longer to seat and seal but once in place it's tolerated better then cuffed LMAs. I have not placed a cuffed LMA in months.
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Wow, you either have a really obese population, or you don't ask them about sore throat, or you do very short cases. I would say that most women are an i-gel 3 and most men an i-gel 4, once you give the gel a few minutes to warm up and expand.
 
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chocomorsel said:
Never even heard of it. Had to google it.
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It's my favorite LMA for regular/bigger people (it's not the best for small throats). I have done gynecologic procedures in BMI 45-50 women, on pressure control ventilation, with i-gel 3.
 
FFP said:
It's my favorite LMA for regular/bigger people (it's not the best for small throats). I have done gynecologic procedures in BMI 45-50 women, on pressure control ventilation, with i-gel 3.
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Why??

Have you heard about that new device for airway management they're calling an ETT?

Sounds like it would be perfect for that case you're describing.
 
fakin' the funk said:
Absurd.
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Yeah, door to procedure start in less than 10 minutes is absurd. End of procedure to PACU in 5 minutes with an awake patient is absurd. Not having to worry about ventilating/intubating potentially difficult airways, especially for short procedures, is absurd. I bet even videolaryngoscopes are absurd for you.

As I said above, there is a separate thread for LMA vs ETT.
 
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@FFP, no one is arguing against the utility or benefits of LMA's. I am arguing though that an LMA is not a great way to go for this morbidly obese pt in T-berg coupled with controlled ventilation. The pros you mention can just as easily be achieved with an ETT, and even if you're not some Jedi rockstar, there are times when safety should take precedence over slickness.

You say "not having to worry about ventilation/intubation" but what about when that precious iGel LMA doesn't seat quite right or the pt regurgitates mid case 'cuz her head is down and you've been slowly but surely puffing a little bit of air into her belly with each pressure controlled breath. Yeah you got away with it, but a solid anesthetic plan never includes "I think I can get away with . . . "
 
SaltyDog said:
@FFP, no one is arguing against the utility or benefits of LMA's. I am arguing though that an LMA is not a great way to go for this morbidly obese pt in T-berg coupled with controlled ventilation. The pros you mention can just as easily be achieved with an ETT, and even if you're not some Jedi rockstar, there are times when safety should take precedence over slickness.

You say "not having to worry about ventilation/intubation" but what about when that precious iGel LMA doesn't seat quite right or the pt regurgitates mid case 'cuz her head is down and you've been slowly but surely puffing a little bit of air into her belly with each pressure controlled breath. Yeah you got away with it, but a solid anesthetic plan never includes "I think I can get away with . . . "
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"I got away with it" many times. I didn't start doing it until I had a ton of experience with all kinds of LMAs (including how to minimize risk of aspiration). We are talking about 20-30 minute-procedures in females. Because of the gynoid pattern of obesity, most of the fat is on the lower body (pear-shaped). Also, chances of putting air in the stomach at pressures less than 15 cm H2O is very small (and I prefer PCV at smaller volumes to apnea in the obese patient - obviously PSV is the best, I was just pointing out that the i-gel 3 allowed me even to do PCV when needed). Plus they were in minimal Trendelenburg; one just needs to raise the bed to the proper height for the gynecologist. Plus I have a pretty good idea which LMA to use for a great fit for most patients. If anything, I am anal about safety; some of the CRNAs hate me for that.

Anyway, my point above was that the i-gel is a fantastic LMA, except for smaller airways (I didn't have smaller sizes than 3).
 
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You sound like you like the Igel as much as I like Suggamadex. I'm still trying to perfect that technique one of the posters here has talked about where they insert the LMA at a quarter turn into the mouth but cannot quite get that to work out. Do you just slip the Igel in the old fashioned way down the middle?
 
acidbase1 said:
I avoid LMAs in fatty's, you guys do the same?
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How fat are we talking? A lady that's a BMI 50+ with large breasts and a lot tissue on the chest? I'll avoid it. BMI 40 ish on a bottom heavy person? If the airway doesn't look too terrible, LMA is usually fine for shorter cases.
 
Brother im going to explain this once. Lube it up on the outside. Slip it in midline avoid teeth and go back deep till you hit resistance.... this may help you later in life....
 
sheeed said:
How fat are we talking? A lady that's a BMI 50+ with large breasts and a lot tissue on the chest? I'll avoid it. BMI 40 ish on a bottom heavy person? If the airway doesn't look too terrible, LMA is usually fine for shorter cases.
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I got burned yesterday using a size 5 in a giant. 350lbs, 6’4. He was fat but not morbidtly obese. Ended up ultimately throwing in a tube. Which was funny, had the glidescope, sux, and 8.5 tube ready to go. So subconsciously knew it wasn’t going to fly.

Put in a popliteal block for a 5th metatarsal amputation
 
acidbase1 said:
I got burned yesterday using a size 5 in a giant. 350lbs, 6’4. He was fat but not morbidtly obese. Ended up ultimately throwing in a tube. Which was funny, had the glidescope, sux, and 8.5 tube ready to go. So subconsciously knew it wasn’t going to fly.

Put in a popliteal block for a 5th metatarsal amputation
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That's a huge guy...I'll say most of our patients that qualify for morbid obesity are MUCH shorter. And agreed, if you had he glidescope on standby you must have thought he was a difficult airway.
 
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