Negative Pressure Pulmonary Edema in outpatient setting

[nimbus]

I usually skip the bite block and yank em when they have somewhere around .3 Mac, and pop in an oral airway if they are obstructing a little. Seems to work great, and I'm ready to transfer to stretcher as soon as drapes come down. Patients usually open their eyes while nurse is placing monitors in PACU. Not sure I see the benefit of leaving it in place if they will breathe fine without it...



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I use the soft bite block and leave the LMA in. I don't see the benefit of taking it out if they are breathing fine with it.....

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[btbam]

Laryngospasm is a result of messing with the patient during stage 2. That can occur with the LMA in or out.

Or are you really suggesting that LMAs must be removed deep?

So if you pull an LMA deep and then secretions drip onto the cords and they spasm while the patient happens to be in stage 2, would that be considered "messing with the patient"?

 

[urge]

Laryngospasm is a result of messing with the patient during stage 2. That can occur with the LMA in or out.

Or are you really suggesting that LMAs must be removed deep?

1 The consensus is that the patient bit on the LMA , thus obstructing the airway without laryngospasm. I don't think that can happen without the LMA.

2 My bias is that all LMAs should be removed deep. It's not a protected airway. But, yes, more important than that is not messing with the patient when they are light. Moving a patient is a pretty strong stimulus.

 

[Libertas]

how could you generate enough negative pressure before there would be a leak around the LMA??? sounds unlikely

 

[urge]

how could you generate enough negative pressure before there would be a leak around the LMA??? sounds unlikely

I have often thought the same thing about laryngospasm. How can a tiny tiny tiny muscle that I have never even seen drawn on anatomy books, obstruct all breathing from the diaphragm and all intercostal muscles?

 

[pgg]

So if you pull an LMA deep and then secretions drip onto the cords and they spasm while the patient happens to be in stage 2, would that be considered "messing with the patient"?

Nothing is zero risk.

But messing with the patient is the biggest risk here (it generally comes from nurses and scrub techs). Suction is important when pulling LMAs deep; I think the secretion to spasm risk is low if you clean them out and you didn't use a ketamine-sole-agent anesthetic. But regardless I don't often pull them deep because all I'm doing is trading a hands-off airway for a hands-on airway. I don't take patients to the PACU to emerge there because I don't trust PACU nurses to not mess with the patient. Deep extubations or LMA removals don't buy much in most patients - a notable exception being patients for whom perfectly smooth buck/valsalva free wakeups are essential.

1 The consensus is that the patient bit on the LMA , thus obstructing the airway without laryngospasm. I don't think that can happen without the LMA.

It should never happen with a proper bite block. With respect to the OP and anyone else this happens to, airway obstruction from biting-the-tube or biting-the-LMA episode is something I regard as a rookie mistake ... or a complacent pro mistake.

2 My bias is that all LMAs should be removed deep. It's not a protected airway. But, yes, more important than that is not messing with the patient when they are light. Moving a patient is a pretty strong stimulus.

I think when to remove an LMA is personal preference and can be done safely deep or awake. Both require certain precautions. My preference is usually awake.

 

[Ignatius J]

Nothing is zero risk.

But messing with the patient is the biggest risk here (it generally comes from nurses and scrub techs). Suction is important when pulling LMAs deep; I think the secretion to spasm risk is low if you clean them out and you didn't use a ketamine-sole-agent anesthetic. But regardless I don't often pull them deep because all I'm doing is trading a hands-off airway for a hands-on airway. I don't take patients to the PACU to emerge there because I don't trust PACU nurses to not mess with the patient. Deep extubations or LMA removals don't buy much in most patients - a notable exception being patients for whom perfectly smooth buck/valsalva free wakeups are essential.




It should never happen with a proper bite block. With respect to the OP and anyone else this happens to, airway obstruction from biting-the-tube or biting-the-LMA episode is something I regard as a rookie mistake ... or a complacent pro mistake.



I think when to remove an LMA is personal preference and can be done safely deep or awake. Both require certain precautions. My preference is usually awake.

As you say, nothing is zero risk. I had an attending in residency who was in private practice and was sued because she left a bite block in for a case. It caused tongue necrosis and subsequent swelling later on. Patient had airway obstruction and an anoxic brain injury. Because of that I am shy to use airways other than when I am inducing and emerging. In this instance, perhaps I can slide one in before turning supine as we were lateral. Kind of awkward. But point taken.

Still, wouldn't call it a "rookie mistake" or "complacent". I've seen hundreds, maybe thousands by now of LMA cases of all different experiences and never seen a bite block placed for an LMA whike the LMA was still in. Perhaps it's just different where I trained or in this region. But hell, it takes the whole mouth to pull out a properly seated LMA so I am not sure how you squeeze a bite block in and keep it there.

 

[pgg]

Not trying to offend. I hear you re: the risk pressure necrosis from bite blocks but I think the risk of a soft block carefully placed is far less than the risk of airway problems and NPPE from biting tubes, and that necrosis risk (while nonzero) isn't a good reason to not use a bite block. I don't use OP airways or anything hard for bite blocks precisely because of that pressure risk. Roll of gauze wound with tape, between the molars, tongue/lips out of the way. Bottom line, for me, tube/LMA goes in, roll of gauze follows (unless it's a planned tubed-to-the-ICU case).

I've had my share of should've-been-avoided complications, even posted them here a few times, and I'll have more. It remains my opinion that NPPE from a bitten tube is a nearly-100% avoidable complication.

 

[Random Anesthesiologist]

FYI Lasix isn't recommended for NPPE.

I was just thinking this as I was reading along. We had a case this week of NPPE, did CPAP and supportive care. Fortunately this person wasn't already really sick. One breath before laryngospasm. CXR was impressive in pacu.

 

[urge]

Bottom line, for me, tube/LMA goes in, roll of gauze follows (unless it's a planned tubed-to-the-ICU case).

Why is it that your ICU patients don't get the bite block? Aren't they going to wake up and bite the tube at some point?

 

[deleted171991]

Just use a Proseal/Supreme LMA, or an i-gel, or any LMA that has a bite block.

 

[stonemd]

Just so you dont think i am crazy:
the following is from the instructions that come with the LMA:
http://www.lmana.com/viewifu.php?ifu=15

Insert roll of gauze as bite-block (ensuring adequate thickness), and tape the device into
place, ensuring that the proximal end of the airway tube is pointing
caudally. When correctly placed, the tube should be pressed back into
the palate and posterior pharyngeal wall. When using the device, it is
important to remember to insert a bite block at the end of the
procedure.


Removal
1. The LMA™ airway, together with the recommended bite-block,
should be left in place until the return of consciousness. Oxygen
should be administered using a “T” piece system and standard
monitoring should be in place. Before attempting to remove or deflate
the device, it is essential to leave the patient completely undisturbed
until protective reflexes have fully returned. Do not remove the
device until the patient can open the mouth on command.
2. Look for the onset of swallowing which indicates reflexes are almost
restored. It is usually unnecessary to perform suction because the
correctly used LMA™ airway protects the larynx from oral secretions.
Patients will swallow secretions on removal. Suction equipment
should however be available at all times.
3. Deflate the cuff completely just prior to removal, although partial
deflation can be recommended in order to assist in the removal of
secretions.

 

[Ignatius J]

Not trying to offend. I hear you re: the risk pressure necrosis from bite blocks but I think the risk of a soft block carefully placed is far less than the risk of airway problems and NPPE from biting tubes, and that necrosis risk (while nonzero) isn't a good reason to not use a bite block. I don't use OP airways or anything hard for bite blocks precisely because of that pressure risk. Roll of gauze wound with tape, between the molars, tongue/lips out of the way. Bottom line, for me, tube/LMA goes in, roll of gauze follows (unless it's a planned tubed-to-the-ICU case).

I've had my share of should've-been-avoided complications, even posted them here a few times, and I'll have more. It remains my opinion that NPPE from a bitten tube is a nearly-100% avoidable complication.

Fair enough and good post.

 

[dhb]

Couple of points:
i never use a bite block
1.1 mac + narcs is a heavy handed anesthetic
pulling asleep awake or in between: who cares
to pull deep then switch to an oral airway is dumb as f...

a trick learned on these forums: if the patient bites on the tube/lma apply pressure to the lip/gums junction to have him open his mouth.

 

[risnwb]

Couple of points:
i never use a bite block
1.1 mac + narcs is a heavy handed anesthetic
pulling asleep awake or in between: who cares
to pull deep then switch to an oral airway is dumb as f...

a trick learned on these forums: if the patient bites on the tube/lma apply pressure to the lip/gums junction to have him open his mouth.

1) easier to let the patient take out an oral airway in pacu and honestly draws fewer sideways glances from pacu staff than an lma

2) more difficult to occlude if they bite down

3) gotta be a hell of a lot more comfortable to wake up and sit there with an oral airway In than an lma

4) why is if dumb as f...? Seems extreme. I urge you to reconsider because who cares




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[urge]

a trick learned on these forums: if the patient bites on the tube/lma apply pressure to the lip/gums junction to have him open his mouth.

Where is this? I cannot visualize.

 

[OB1🤙]

Where is this? I cannot visualize.

Lower frenulum.

 

[urge]

Lower frenulum.

What?

Is that the frenulum breve?

 

[deleted162650]

Another trick if the pt is biting on the ETT is to quickly deflate the cuff. This allows air to squeak by avoiding any significant negative pressure. Probably doesn't work as well with an LMA though. With an LMA you can try shoving it in deeper, that usually triggers a reflex to open the mouth.

 

[dhb]

I urge you to reconsider because who cares

you do

 

[dhb]

Lower frenulum.

yes

 

[Oggg]

How about getting gas off early, and shooting some prophylactic propofol around stage 2 (0.3 sevo or 1.x des)? Prevents laryngospasm and forceful biting and meanwhile pt blows of gas, with or without LMA/ETT. Makes a bite block unnecessary.
Also, you can blow off gas while in any position, lateral or prone.