Clinical scenario

[dhb]

Had this case the other day and the nephrectomy case made me want to share this.

GETA for a small palatine tumor removal.
Easy tube everything fine. I step out to get something and the nurse calls me because the patient desats to 74. She was at 98 just a minute ago. Pulse ox wave is very good nothing weird on the vent capnography at 22.
What do you do?

---

Members don't see this ad.

 

[Planktonmd]

Had this case the other day and the nephrectomy case made me want to share this.

GETA for a small palatine tumor removal.
Easy tube everything fine. I step out to get something and the nurse calls me because the patient desats to 74. She was at 98 just a minute ago. Pulse ox wave is very good nothing weird on the vent capnography at 22.
What do you do?

Had the surgery started or not yet?

 

[Chloroform4Life]

Check vital signs: EKG, BP. Switch to manual vent 100% O2. Feel compliance of lungs. Listen to breath sounds. Check circuit and ett for kink and migration. Ddx includes mainstem intubation, bronchospasm, inadequate fio2 2/2 machine malfunction, the unlikely PE, ptx from bleb rupture, mucous plug. My ddx is broad since I don't know much else about the patient or situation other than what you told me. If everything else appears stable and normal, it could be ambient light causing false reading. This can occur even with normal tracing. Would cover up the finger.

 

[WholeLottaGame7]

Why was the EtCO2 22? PE?

Without that information, my question would be was the surgeon injecting dye for any reason?

 

[Laryngophed]

How much blue stuff do you find on the luer-lock port?

 

[dhb]

Surgery had already started the case lasted probably 40min and this was half way in.
No dye. Why was the CO2 22 well that's part of the clinical scenario.

Check vital signs: EKG, BP. Switch to manual vent 100% O2. Feel compliance of lungs. Listen to breath sounds. Check circuit and ett for kink and migration. Ddx includes mainstem intubation, bronchospasm, inadequate fio2 2/2 machine malfunction, the unlikely PE, ptx from bleb rupture, mucous plug. My ddx is broad since I don't know much else about the patient or situation other than what you told me. If everything else appears stable and normal, it could be ambient light causing false reading. This can occur even with normal tracing. Would cover up the finger.

Vitals normal, lung compliance normal didn't listen to lungs because under the drapes and fixed the problem rapidly. Nothing abnormal about the ventilation except for the Et CO2 so no disconnection or kinking. Finger was not exposed to ambient light.

 

[deleted171991]

So this was not iatrogenic?

 

[dhb]

Well it was iatrogenic in the sense that it wouldn't have happened if the patient hadn't undergone a procedure under GA

Keep in mind the surgeon is working in the patients mouth. What is your first move?

 

[deleted171991]

Well it was iatrogenic in the sense that it wouldn't have happened if the patient hadn't undergone a procedure under GA

I mean that it was not hyperventilation by nurse or that somebody forgot to inflate the cuff, or cut the balloon tubing by mistake.

Anyway, to me, this is the case when I go down on the airway and circuit from wall connections to pleura and thoracic wall, trying to figure out where the problem is.

It sounds like it was something that would be obvious immediately, so I am curious.

 

[Chloroform4Life]

It was a PE. You injected some TPA as soon as you saw the decrease in etco2 and problem was fixed. Right?

 

[deleted171991]

It was a PE. You injected some TPA as soon as you saw the decrease in etco2 and problem was fixed. Right?

You forgot the Fogarty.

 

[dhb]

Horses not zebras. But i though about the PE too thinking $hit but i figured i'd try something less drastic first. Hypoxia with low CO2 reading but normal vitals and normal vent parameters was screaming mainstem intubation. So i pulled the tube out 1cm or so and voila sats went back to 100 in a hurry.
So the surgeon probably pushed the tube down just enough to get it in the right main.
This shows you that a patient that is ventilated on 2 lobes even if not a pulmonary cripple will desat so don't trust those people saying oh but we do OLV all the time and patient do fine or oh this little PTX wouldn't cause hypoxemia etc..
Also when you see a good reading on the pulse ox (especially with an abnormal capnography) don't distrust it and go spend 10min fiddling with the probe : changing fingers covering the probe etc while the patients brain is toasting.

 

[deleted171991]

Horses not zebras. But i though about the PE too thinking $hit but i figured i'd try something less drastic first. Hypoxia with low CO2 reading but normal vitals and normal vent parameters was screaming mainstem intubation. So i pulled the tube out 1cm or so and voila sats went back to 100 in a hurry.
So the surgeon probably pushed the tube down just enough to get it in the right main.
This shows you that a patient that is ventilated on 2 lobes even if not a pulmonary cripple will desat so don't trust those people saying oh but we do OLV all the time and patient do fine or oh this little PTX wouldn't cause hypoxemia etc..
Also when you see a good reading on the pulse ox (especially with an abnormal capnography) don't distrust it and go spend 10min fiddling with the probe : changing fingers covering the probe etc while the patients brain is toasting.

That's what @Chloroform4Life said above. Your answer to him suggested it was not the case.

 

[dhb]

He mentionned it as part of his differential dx i didn't say it wasn't the case

 

[Robotic Wis-Hipple]

Unless on PCV you'd expect to see increased peak pressures/vent alarms (unless hands on provider turned them off...). Also, not sure how mainstem intubation explains the decrease in EtCO2 as it's not a dead space problem.

 

[Chloroform4Life]

He mentionned it as part of his differential dx i didn't say it wasn't the case

I think you saying lung compliance normal threw us off. If it was mainstem, lung compliance would be decreased. I.e. you would need a higher pressure to obtain that same previous total volume.

 

[Noyac]

Unless on PCV you'd expect to see increased peak pressures/vent alarms (unless hands on provider turned them off...). Also, not sure how mainstem intubation explains the decrease in EtCO2 as it's not a dead space problem.

You are new here I see. I think you are referring to the nurse in the case when you say "provider". But in case you are not, may I ask that you don't use that term when talking about physicians? It makes my skin crawl.

 

[Robotic Wis-Hipple]

You are new here I see. I think you are referring to the nurse in the case when you say "provider". But in case you are not, may I ask that you don't use that term when talking about physicians? It makes my skin crawl.

If I was trying to say physician I'd have said MDA...... (J/k).

 

[dhb]

I think you saying lung compliance normal threw us off. If it was mainstem, lung compliance would be decreased. I.e. you would need a higher pressure to obtain that same previous total volume.

Well maybe there was a difference but small enough not to be noted. Since we now use smaller tidal volumes (i was probably at 450ml) you won't necessarily see a big difference in compliance.

 

[WholeLottaGame7]

Fair enough, but the other point remains. Mainstemming the tube doesn't result in an immediate 50% reduction in EtCO2.

 

[Orin]

This shows you that a patient that is ventilated on 2 lobes even if not a pulmonary cripple will desat so don't trust those people saying oh but we do OLV all the time and patient do fine or oh this little PTX wouldn't cause hypoxemia etc..

Hmm, how is OLV and mainstemming different again?

My thoughts are that the physiology of hypoxemia in the setting of a mainstem and a PTX are a bit different. External pressure in the thoracic cavity would decrease both blood flow and diffusion area of the ventilated lung, kinda like a mucus plug or anything else would, while a mainstem would just cause lack of diffusion space with perfused hypoxemic tissue. The different effects on V/Q and HPV here would probably better explain the rapidity to hypoxemia I would think?

Not sure though, where are the CT guys?

 

[Chloroform4Life]

Hmm, how is OLV and mainstemming different again?

My thoughts are that the physiology of hypoxemia in the setting of a mainstem and a PTX are a bit different. External pressure in the thoracic cavity would decrease both blood flow and diffusion area of the ventilated lung, kinda like a mucus plug or anything else would, while a mainstem would just cause lack of diffusion space with perfused hypoxemic tissue. The different effects on V/Q and HPV here would probably better explain the rapidity to hypoxemia I would think?

Not sure though, where are the CT guys?

I think one of the main differences between OLV and mainsteming is patient positioning. It may explain why OLV is usually tolerated better than inadvertent mainsteming.

With OLV, the ventilated lung is often the dependent lung in lateral decubitus. Gravity would thus pull most of the blood flow to the ventilated lung. Hypoxic pulmonary vasoconstriction of the nonventilated lungs will further help increase blood flow to the dependent lung. Gravity and HPV together can significantly reduce the shunting that you may otherwise see. In the supine patient, you get HPV with mainsteming but no gravity helping you. I think gravity is very important in the pulmonary circulation because it is a low pressure system and thus can easily be impacted by gravity's force.

 

[deleted59964]

change in compliance on 1 lung is subtle
fiO2 would be key info in this case

 

[dhb]

Fair enough, but the other point remains. Mainstemming the tube doesn't result in an immediate 50% reduction in EtCO2.

Well it did in this case although not 50% probably 32 to 22.
I usually run FiO2 on the high side so probably 0.6 to 0.7

 

[nimbus]

I think one of the main differences between OLV and mainsteming is patient positioning. It may explain why OLV is usually tolerated better than inadvertent mainsteming.

With OLV, the ventilated lung is often the dependent lung in lateral decubitus. Gravity would thus pull most of the blood flow to the ventilated lung. Hypoxic pulmonary vasoconstriction of the nonventilated lungs will further help increase blood flow to the dependent lung. Gravity and HPV together can significantly reduce the shunting that you may otherwise see. In the supine patient, you get HPV with mainsteming but no gravity helping you. I think gravity is very important in the pulmonary circulation because it is a low pressure system and thus can easily be impacted by gravity's force.

I see this all the time. We do a ton of supine OLV for CABG with bilateral IMA and it is much less well tolerated than lateral decubitus with ventilation of the dependent lung. If you throw in a nitroglycerin infusion, it's even worse because ntg inhibits HPV.

 

[deleted162650]

I see this all the time. We do a ton of supine OLV for CABG with bilateral IMA and it is much less well tolerated than lateral decubitus with ventilation of the dependent lung. If you throw in a nitroglycerin infusion, it's even worse because ntg inhibits HPV.

Do you guys see many sternal wound healing problems w/ bilateral IMA's?

 

[Mman]

What do you do?

make sure not to document anywhere that you left the room with a patient under anesthesia

 

[nimbus]

Do you guys see many sternal wound healing problems w/ bilateral IMA's?

Rarely. Even in diabetics.

 

[dhb]

make sure not to document anywhere that you left the room with a patient under anesthesia

I have yet to meet a European anesthesiologist that never leaves his room...

 

[deleted171991]

I have yet to meet a European anesthesiologist that never leaves his room...

And they don't wear masks, and don't necessarily change circuits between patients, afaik.

 

[Chloroform4Life]

I hear our European colleagues also eat and drink in the OR.

 

[Mman]

I have yet to meet a European anesthesiologist that never leaves his room...

doesn't seem relevant to our litigious country and/or written standards of care

 

[Ezekiel2517]

So I guess this pt could never have OLV with a properly placed DLT since she'd have severe hypoxia. I wonder how all the thoracic pts I put on one lung don't have hypoxic brain injury when they wake up.

 

[nimbus]

And they don't wear masks, and don't necessarily change circuits between patients, afaik.

I hear our European colleagues also eat and drink in the OR.

And their infection rates are probably no different than ours.

 

[nimbus]

So I guess this pt could never have OLV with a properly placed DLT since she'd have severe hypoxia. I wonder how all the thoracic pts I put on one lung don't have hypoxic brain injury when they wake up.

She'd be lateral which reduces shunting. And she may need cpap or O2 insufflation on the down lung which you can't do with a main stemmed single lumen tube.

 

[dhb]

I hear our European colleagues also eat and drink in the OR.

Well it's not because you can't that we don't.
And no i don't change the circuit between patients.

 

[Planktonmd]

Well it's not because you can't that we don't.
And no i don't change the circuit between patients.

Changing the circuits between patients is a money maker for those who make the circuits but makes little sense!
We change the circuit but the internal plumbing of the machine and the valves are never changed or cleaned and the CO2 absorber is used for many patients until it's exhausted!
Someone decided it should be done (probably a nurse with a clip board) and now it's the standard of care!

 

[pgg]

Some places I work, there's just a disposable filter at the Y that gets changed between patients. Most places are happy to waste the money to replace it all.

It's #142 on the list of "dumb things we do because a nurse at CMS or JC thought it was a good idea" ...