High airway pressures

[24858]

Here's something to think about:
Starting an A/P spine today. I intubated with a fiberoptic scope just for skill upkeep. Not a difficult airway. The surgeons do the anterior lumbar surgery. We move the patient from the OR table to the stretcher. I give another 20 mg of Rocuronium Next from the stretcher we flip the patient prone back onto the OR table. I have the patient in a Shea head rest and then connect my tube back to my circuit. As I start my vent my previous tidal volumes are way down at like 200 and my peak airway pressures are 48. Patient had history of asthma. I turn off the vent turn up O2 and when I hand ventilate still have same vent issues. I ascultate the back and hear little to nothing. I call for my fiberoptic back in the room.
What do you think is happening and what would you do? The answer is to follow...

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[Idiopathic]

My differential

1. kink in the ETT
2. distal/proximal tube migration
3. acute bronchospasm
4. pneumothorax
5. intraabdominal compression

If I cant hear anything and we are able to do so, I flip back supine before doing anything else. Check ETT position and fix the kink/place bite block. Look down to the carina with your scope.

I would deepen the anesthestic with IV agent while hand ventilating...if not a mechanical problem with the tube, this is most likely a bronchospastic process, perhaps in response to a med given. If you are moving air, albuterol ten puffs, otherwise low dose epi 10-20 mcg boluses IV.

Dark horses are pneumo from possible diaphragmatic injury (I would think this extremely unlikely) or compression from acute intraabdominal process (bleed?). If you are stable after the maneuvers then proceed, otherwise, get CXR, ABG, consider checking labs.

 

[pgg]

Here's something to think about:
Starting an A/P spine today. I intubated with a fiberoptic scope just for skill upkeep. Not a difficult airway. The surgeons do the anterior lumbar surgery. We move the patient from the OR table to the stretcher. I give another 20 mg of Rocuronium Next from the stretcher we flip the patient prone back onto the OR table. I have the patient in a Shea head rest and then connect my tube back to my circuit. As I start my vent my previous tidal volumes are way down at like 200 and my peak airway pressures are 48. Patient had history of asthma. I turn off the vent turn up O2 and when I hand ventilate still have same vent issues. I ascultate the back and hear little to nothing. I call for my fiberoptic back in the room.
What do you think is happening and what would you do? The answer is to follow...

Kinked tube, mainstem after movement, positioning compression, bronchospasm, PTX.

Go back supine?

 

[Frank Rizzo]

My differential

1. kink in the ETT
2. distal/proximal tube migration
3. acute bronchospasm
4. pneumothorax
5. intraabdominal compression

Throw in compression from the fupa/panus or some sort of anaphylaxis rxn, and I think you have 99% of your likely causes covered.

I'm hoping for some crazy zebra though....

 

[Idiopathic]

Throw in compression from the fupa/panus or some sort of anaphylaxis rxn, and I think you have 99% of your likely causes covered.

I'm hoping for some crazy zebra though....

well i was considering those inclusive with #3 and #5, but yeah, I have a hard time imagining what else it could be

 

[sevoflurane]

Good differentials. I would add thick secretions in the tube or obstruction somwhere in the circuit....further down the differential.

 

[fakin' the funk]

1. kink in the ETT

Cuff herniation is another cause of this. If I had the auscultatory findings as above, I'd pass a 10fr suction catheter down the ETT next and see how far it goes.

Knowing the shape and value of the capnography while this is happening would be helpful too.

Although the OP didn't describe, if this was an anterior spine with neuromonitoring this 20mg of rocuronium might be the first time this case the patient's exposed. Was the anesthetic a little light prior to the flip?

 

[Idiopathic]

Cuff herniation is another cause of this. If I had the auscultatory findings as above, I'd pass a 10fr suction catheter down the ETT next and see how far it goes.

Knowing the shape and value of the capnography while this is happening would be helpful too.

Although the OP didn't describe, if this was an anterior spine with neuromonitoring this 20mg of rocuronium might be the first time this case the patient's exposed. Was the anesthetic a little light prior to the flip?

since its L spine its unlikely to be with MEPS, although possible.

cuff herniation would not present as high airway pressures, it would present as a leak, your bellows would fall, and you would deliver no Vt (or you would at least get no Vt back). obviously you have to consider tube problems as 1, 2 and 3 here, and you really need to flip back, unless you are supremely sure that your tube is okay. (i.e. hand ventilation results in chest rise and not extremely high PIP) in which case you could have a machine issue proximal to the tube (kinked inspiratory limb, defective y-piece). if you are prone in pins (not in this case), you could pass a scope that way, although not ideal

 

[Frank Rizzo]

Good differentials. I would add thick secretions in the tube or obstruction somwhere in the circuit....further down the differential.

including valves... had one stick a couple of weeks ago.

 

[24858]

Sorry it isn't a zebra, just wanted to get people to think up some differentials. So I did what most people said, I put on 100% O2, hand ventilated, and called for the fiberoptic. I also was ready to bring the stretcher back into the room to flip the patient supine. However I stuck my hand in the patients mouth to see if he was biting on the tube somehow and it turned out the tube was bent in the Shea headrest. I unbent the tube and problem solved. That was the first time I have ever had that happen to me.

 

[fakin' the funk]

cuff herniation would not present as high airway pressures, it would present as a leak, your bellows would fall, and you would deliver no Vt (or you would at least get no Vt back).

Righto, I mistakenly used "cuff herniation" when I meant either "eccentrically inflated cuff" or "cuff ballooned over end of ETT"

 

[Idiopathic]

Righto, I mistakenly used "cuff herniation" when I meant either "eccentrically inflated cuff" or "cuff ballooned over end of ETT"

i have never in my brief career seen the situations you describe lead to obstruction of the tube

 

[RxBoy]

Cuff herniation is another cause of this. If I had the auscultatory findings as above, I'd pass a 10fr suction catheter down the ETT next and see how far it goes.

If that patient is bronchospastic, that is a disaster waiting to happen. Same goes for advancing a fiberoptic passed the tube.

I had a patient with peaks in the 40s moving minimum air and low EtCO2 minutes after induction. Used the fiberoptic scope to verify placement, ended up stimulating the airway and caused the patients peak to climb to 50 with further fall in EtCO2 and TVs in lower 2 digits. Cranked the sevo ski high, added albuterol puffs and hand ventilated for 5 minutes until peaks and TV became acceptable. Another resident had a bronchospasm so severe he couldn't ventilate so they pushed 100 mcg of epi. Seconds later patient coded, no pulse, asystole. Pt came back with more epi within a minute (before they even started chest compressions). Extremely reactive asthmatics truly are scary, especially if EtCO2 is 0 after intubation and people waste time reintubating.

 

[Idiopathic]

thats a good anecdote, and it reinforces how careful you need to be in your thought processes.

deepening the anesthetic is my first choice in a case of suspected bronchospasm, severe or otherwise. 50-100 mg IV lidocaine and 100+ mg propofol if the hemodynamics will tolerate, this allows time to get volatile on board.

i would not have given that much epi IV for bronchospasm, I usually start at 10mcg, although i know its very difficult to dilute in a crisis. I think the 1mcg/kg dose is usually better given IM or subQ.

 

[rsgillmd]

thats a good anecdote, and it reinforces how careful you need to be in your thought processes.

deepening the anesthetic is my first choice in a case of suspected bronchospasm, severe or otherwise. 50-100 mg IV lidocaine and 100+ mg propofol if the hemodynamics will tolerate, this allows time to get volatile on board.

i would not have given that much epi IV for bronchospasm, I usually start at 10mcg, although i know its very difficult to dilute in a crisis. I think the 1mcg/kg dose is usually better given IM or subQ.

I was taught 25-50 mcg IV of Epi for adults. I've seen 25 mcg help significantly with tolerable increases in heart rate.

Certainly never hurts to go lower, like you do. You can always give more, but you can't take away what you've given.

One of my attendings during residency said he saw an MI induced after 10 or 15 mcg of Epi. I forget the exact value, but the point he was making was that even low doses can cause problems in the right patients. So I tend to reserve Epi as a last ditch effort.

 

[rsgillmd]

Good differentials. I would add thick secretions in the tube or obstruction somwhere in the circuit....further down the differential.

I second this. Have seen it happen.

 

[Idiopathic]

I was taught 25-50 mcg IV of Epi for adults. I've seen 25 mcg help significantly with tolerable increases in heart rate.

Certainly never hurts to go lower, like you do. You can always give more, but you can't take away what you've given.

One of my attendings during residency said he saw an MI induced after 10 or 15 mcg of Epi. I forget the exact value, but the point he was making was that even low doses can cause problems in the right patients. So I tend to reserve Epi as a last ditch effort.

attendings say lots of things and often misattribute causality. like, "ive seen an MI after just 100 cc of normal saline" (i didnt say the saline caused the MI)

 

[rsgillmd]

attendings say lots of things and often misattribute causality. like, "ive seen an MI after just 100 cc of normal saline" (i didnt say the saline caused the MI)

Good point.

 

[proman]

What does a Shea headrest look like?

 

[Bertelman]

What does a Shea headrest look like?

It's the square pillow with the scoop, and removable foam "T" if you are going to place them prone.

 

[fakin' the funk]

If that patient is bronchospastic, that is a disaster waiting to happen. Same goes for advancing a fiberoptic passed the tube.

So a bronchospastic patient is going to be just with some 30fr PVC pipe in their trachea, but not a 10fr suction catheter or FOB just distal to said pipe?

 

[proman]

It's the square pillow with the scoop, and removable foam "T" if you are going to place them prone.

Got a pic? I've only used a pink foam or blue/white foam pillows.

 

[pgg]

So a bronchospastic patient is going to be just with some 30fr PVC pipe in their trachea, but not a 10fr suction catheter or FOB just distal to said pipe?

Possibly

Most patients are in fact just fine with the PVC pipe in their tracheas, but if you move the tube, or pass something through it and thump the carina, coughing bucking etc are often easy to produce. Static vs moving, mid-trachea vs carina.

That said, the scope doesn't need to reach 2nd or 3rd gen bronchioles to be useful in verifying correct position of the tube; it usually won't even need to exit the tube at all, so probably no big deal.

 

[24858]

Got a pic? I've only used a pink foam or blue/white foam pillows.

Here is a picture I found

 

[lord_jeebus]

I had a similar case early as a CA-1. A patient with some sort of stage IV cancer with extensive bone mets, but who nonetheless wanted "everything done" until the end, presented with subacute lower extremity weakness which had developed over the past week or so. Neurosurgery wanted an MRI, but he was unable to lie still for it, so we did it under GA. The scan took about 2-3 hours. After the scan, the surgeons decided that they wanted to immediately proceed to decompress his spine, and I kept him tubed and sedated up to the OR.

A few minutes after turning prone, I acutely have a similar difficulty ventilating - barely able to manually deliver tidal volumes of ~150 cc. No obvious kink on quick visual inspection (we use these headrests so it's easy to see the ETT).

As we rushed the gurney back into the room and were preparing to flip him back, my attending strolls in the back door, takes a suction catheter, tells everyone to stop what they're doing, and quickly extracts a huge ball of mucus from the ETT. Instant cure.

 

[Idiopathic]

So a bronchospastic patient is going to be just with some 30fr PVC pipe in their trachea, but not a 10fr suction catheter or FOB just distal to said pipe?

the fear is you could make them worse, and if you bump the carina you possibly could. i would argue that someone who is in such bad bronchospasm that you are putting a scope down is probably not going to be worse off afterwards, especially if you are just verifying tube placement/no tracheal obstruction.

 

[Idiopathic]

while its not a peak pressure issue, we see an OG/NG passed into the trachea and placed on suction in an intubated patient probably twice a year...calls from junior residents "where are my tidal volumes going", or "why wont my bellows rise"

 

[fakin' the funk]

while its not a peak pressure issue, we see an OG/NG passed into the trachea and placed on suction in an intubated patient probably twice a year...calls from junior residents "where are my tidal volumes going", or "why wont my bellows rise"

I've wondered about what this would clinically look like if I did put the OG in the wrong hole.

Does it just sneak past the cuff and leave the cuff unharmed, or does the cuff pop/get damaged?

 

[lord_jeebus]

I've wondered about what this would clinically look like if I did put the OG in the wrong hole.

Does it just sneak past the cuff and leave the cuff unharmed, or does the cuff pop/get damaged?

I've managed to do this twice. The bellows quickly collapse after you hook up the suction, and what has happened is very obvious if you think back to what you were doing immediately prior to losing your ability to ventilate. No cuff damage.

 

[bigdan]

I've wondered about what this would clinically look like if I did put the OG in the wrong hole.

Does it just sneak past the cuff and leave the cuff unharmed, or does the cuff pop/get damaged?

Saw this once, early this year. In my case, cuff was NOT damaged, pt had decent TV EXCEPT when suction was on. Of note, we were using Isoflurane, and you could smell the Iso coming from the pt's mouth when you leaned forward to listen for a leak.

 

[Idiopathic]

yeah all of those, typically you dont notice it until you turn on the suction.

of note, ive also seen an NGT cause a pneumothorax in an intubated patient in the ICU setting and Ive seen a dobhoff make its way to the left lower lube in an intubated patient, which is probably a lot easier to do

 

[Bertelman]

I've managed to do this twice. The bellows quickly collapse after you hook up the suction, and what has happened is very obvious if you think back to what you were doing immediately prior to losing your ability to ventilate. No cuff damage.

I've done this a few times, too. My favorite was after taking over a difficult intubation. I let the initial team know it was VERY easy sliding that NG blind down the nose into the trachea, if they ever cared to intubate again.

 

[proman]

Here is a picture I found

Thanks, it's a bit different then the ones I've used.