LMA time limits

[24858]

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Does anyone here have a LMA time limit? Say if you were to do a six hour case, would you use a LMA? What reason do you have to have a time limit or not have one? There are I believe two case reports of uvular/small palate ischemia with LMA usage for prolonged periods. I used to not use the LMA on cases longer than three hours but have loosened my stance on this. I just want to make sure I am not missing the boat as far as the literature is concerned.

 

[pgg]

LMAs are overrated.

I'll use them for short supine cases without muscle relaxant but that's about it. I can't think of an instance in which I'd really want to put up with one for a six hour case.

 

[Idiopathic]

my cutoff is three hours, although ive had one in for five or more. the nerve injury possibility is real, has been seen on the case report level, and is probably due to both high pressures and prolonged time. i think the safest way to do it from a legal point of view is to limit it to 3-4 hours, because, honestly, do you want to have an LMA in for 6 hours? i cant see the case where I would feel like thats a good idea.

 

[rsgillmd]

I was always taught 1.5-2 hours as a soft guideline. The theoretical concerns expressed were airway edema developing leading to LMA coming out of position, and potential for ischemia of the palate in prolonged cases.

When I was a 3rd year medical student I remember sitting at an M&M and hearing discussed that several attendings used LMAs for 3-4 hour cases. At that time I didn't question why not for longer cases.

Overall, I view an LMA as basically a fancy oral airway. If I think I need or might need a secure airway, I'll place an ETT.

Just my $0.02.

 

[proman]

I've done 6 hours. Didn't start that way, was supposed to be a 2 hour case, then 1 more hour, 1 more hour, 1 more hour, 1 more hour. I wouldn't electively place an LMA for a 6 hour case though.

 

[deleted162650]

Another concern is that pts tend to pull small tidal volumes under GA which eventually leads to atelectasis and hypoxia. Obviously more of a problem the longer the case. PSVPro/Pressure support modes help with this but not all our machines have these modes.