Probably a dumb question...

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CodeBlu

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So, lately I've seen a lot of mastectomies/lumpectomies done under GA with LMA. Usually only given 1-2 of midaz and 150-300 mcg of fentanyl, and propofol titrated to effect.

Instead of switching on the ventilator they let the patient go apneic and manually ventilate until they start breathing again...

What I've been trying to figure out... is why?

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Basic anesthesia question 101. Have you ready any textbooks or even an introductory text on the effects of anesthesia?


Yes, of course. I get the whole not wanting to ventilate the esophagus with too high of a pressure. But, what I don't understand is, that if the patient is breathing and generating their own airway pressure, aren't they still going to get some air into their esophagus?
 
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So, lately I've seen a lot of mastectomies/lumpectomies done under GA with LMA. Usually only given 1-2 of midaz and 150-300 mcg of fentanyl, and propofol titrated to effect.

Instead of switching on the ventilator they let the patient go apneic and manually ventilate until they start breathing again...

What I've been trying to figure out... is why?

100 ways to safely do a case.

Nothing wrong with putting a person with an LMA on the ventilator. Lots of us do it all the time. Nothing wrong with manually ventilating either, but I'd rather put that hand to work charting or better yet, nothing at all.

Giving a LMA'd patient so much opiate that they go apneic in the first place isn't my style.

That's a lot of up-front fentanyl for those cases too, also not my style.


Why don't you ask the person doing the case why they do what they're doing? Surely they'd tell you.
 
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Yes, of course. I get the whole not wanting to ventilate the esophagus with too high of a pressure. But, what I don't understand is, that if the patient is breathing and generating their own airway pressure, aren't they still going to get some air into their esophagus?

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3155144/

As long as the positive pressure is kept below 20 cmh2o the gastric insufflation should be minimal to none.
 
So, lately I've seen a lot of mastectomies/lumpectomies done under GA with LMA. Usually only given 1-2 of midaz and 150-300 mcg of fentanyl, and propofol titrated to effect.

Instead of switching on the ventilator they let the patient go apneic and manually ventilate until they start breathing again...

What I've been trying to figure out... is why?
Now try to figure out why this is a pretty bad idea at the beginning of a case, especially with an LMA in place. (I also agree that it's a ton of opiates upfront, which increases the risk of nausea for an already nauseating surgery.)

Doing a case under spontaneous ventilation is typical CRNA style, by the way.
 
Now try to figure out why this is a pretty bad idea at the beginning of a case, especially with an LMA in place. (I also agree that it's a ton of opiates upfront, which increases the risk of nausea for an already nauseating surgery.)

Doing a case under spontaneous ventilation is typical CRNA style, by the way.

Are you talking about only spontaneous or does SIMV also fit into that style. I love SIMV and probably use it in >75% of the cases I do.
 
Doing a case under spontaneous ventilation is typical CRNA style, by the way.

Why? I like patients spontaneous any time I have the option. Sometimes I even draw up my Glyco and neo in the SAME syringe! And I'm not a CRNA.
 
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Why? I like patients spontaneous any time I have the option. Sometimes I even draw up my Glyco and neo in the SAME syringe! And I'm not a CRNA.

LMA- Spontaneous respirations with a little PS and PEEP. This diminishes reduction in preload compared to SIMV which leads to better hemodynamics. In addition, it is easier to run a patient lighter (less volatile agent) and titrate opioids with spontaneous ventilation compared to SIMV which again leads to better hemodynamics.

ASA4 patients tolerate GAs better (IMHO) with LMAs combined with Spontaneous respirations.
 
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LMA- Spontaneous respirations with a little PS and PEEP. This diminishes reduction in preload compared to SIMV which leads to better hemodynamics. In addition, it is easier to run a patient lighter (less volatile agent) and titrate opioids with spontaneous ventilation compared to SIMV which again leads to better hemodynamics.

ASA4 patients tolerate GAs better (IMHO) with LMAs combined with Spontaneous respirations.
I emphasized the difference. PSV is not SV, and I was talking about (unsupported) SV. Hunting for spontaneous ventilations, at any price, regardless of anesthetic depth and EtCO2, and running the entire case without pressure support, are typically CRNA-ish, in my experience. I am talking about LMA cases, to be more precise.

If the patient is not breathing, I use pressure control post-induction. I get good respiratory volumes, a well-controlled anesthetic level, with low inspiratory pressures and little cardiovascular impact. Especially pre-incision, until I reach a proper anesthetic depth, PCV is better than PSV for me. Not only that, but PCV allows overbreathing, hence I can look for spontaneous breathing (without bucking) and switch to PSV when I feel we are in calm waters. By the way, kazuma, I used to be a big SIMV fan until I discovered the much more natural PCV (look at their flow curves and compare both to negative pressure spontaneous breathing).

Of course, if I get spontaneous breathing after induction, it makes me happy and I run PSV at a level that provides good tidal volumes and ventilation. I will go up to 10-15 cmH20, if needed, as if I was running PCV, to keep the patient deep and prevent atelectasis. But I don't go hunting for spontaneous ventilations at any price, especially pre-incision. That's recipe for laryngospasm and possibly recall, on incision. Later during the surgery, it can be recipe for significant respiratory acidosis. (Have you never walked in on a CRNA running the patient at EtCO2 of 60-70 and 1.5 MAC, waiting for him to start breathing? They just don't feel comfortable blowing off the gas and waking up the patient on controlled ventilation.)

Getting the patient breathing spontaneously is the best way to a fast extubation at the end of the case, but not "at any price".

Of course, there is an art to using the right amount of propofol that allows rapid recovery of spontaneous breathing, right after LMA placement. That's not what I was criticizing here.
 
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Making the patient go apneic from a narcotic bolus and then hand ventilating is..... RIDICULOUS!
 
I like it when my crnas use the vent, at least then i know that the pressure used is low, lol. Too many times i find people hand banging with an LMA and using Pressure greater than 20 but then are scared to put on PCV of 10. I always point it out and always get a glazed over look in reply. This is usually my old CRNAs


What i don't like to see with LMAs is an ETCO2 of 60-70 on some old person cardiac/COPD cripple with half hearted attempts at hand ventilation. Nice way to induce arrest, been there a couple times over my career with CRNAs
 
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Propofol is easy. They resume SV quickly and there is prep time when I give a little narcotic/ketamine/mag b4 incision while bringing in some volatile in the background.
 
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Most CRNAs are taught that an LMA is a contraindication to mechanical ventilation.
There is nothing you can do to make them unlearn this crap.
And a contraindication to muscle relaxation.

God, when CRNAs become independent, I hope we get a versed shortage!
 
Getting the patient breathing spontaneously is the best way to a fast extubation at the end of the case
I think controlled ventilation with higher MV to blow off gas is usually better. About the only time I make any attempt to get a patient breathing spontaneously is when I'm planning for a deep extubation, which I don't often do. People breathe just fine when they wake up, assuming you don't overnarc them.

That said, if the patient makes respiratory efforts I'm usually happy to let them breathe with some PS.

Splitting hairs. I just don't get the infatuation with spontaneous ventilation pre-emergence. I don't even find it an especially useful way to estimate post-wakeup pain and narcotic requirements.
 
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And a contraindication to muscle relaxation.

God, when CRNAs become independent, I hope we get a versed shortage!

I sort of wish we had a Versed shortage right now. Most overused drug in our world. Maybe if there was a shortage people would give some actual thought to when it's needed.
 
To be clear, I was referring to using SIMV most of my cases with ETT's. I was asking if FFP views SIMV in the same light as SV.

For LMA's I either use PS10 /PEEP 5 or SV. I've used paralytic for brief paralysis with an LMA in the past with an old school attending in a non-abdominal case (with pressure support of 10 and a rate).
 
To be clear, I was referring to using SIMV most of my cases with ETT's. I was asking if FFP views SIMV in the same light as SV.
My answer is the same.

I used to use SIMV pre-emergence. Now I am a big-time PCV fan, with maybe some PSV once the patient starts breathing. Much like pgg's approach. Both for LMA and ETT.

One of my very smart attendings told me during residency: "Have you ever seen an awake patient who's not breathing? No? Then concentrate on blowing off the gas and waking them up at a decent EtCO2, not on getting them breathe spontaneously. While there is still gas on board, they might or might not breathe at an EtCO2 of less than 50, but they will once the gas is gone and they wake up. Plus you can blow away the gas faster with controlled ventilation."

Truer words have never been spoken. The same attending hates SIMV with a vengeance (not that I agree 100%). :)
 
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...if the patient is breathing and generating their own airway pressure, aren't they still going to get some air into their esophagus?

Good discussion, but just to add to what I think the question originally asks, the crux of this is negative vs positive pressure ventilation.

When the patient is breathing, they are using their respiratory muscles to sucking air through the LMA. Spontaneous unassisted ventilation should have negligible esophageal insufflation.

When you are bagging or the ventilator is supplying air, even assisted, positive pressure is generated at the LMA that will travel down both the esophagus and the trachea. The amount going to down each path would depend on resistance and pressure.

Now if we were using the old iron lung to ventilate, that'd be different.
 
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Quick related question on LMA: if we have a supraglottic airway and a spontaneously breathing/ assisted patient, do we need to apply PEEP? Don't they have physiologic PEEP from their own vocal cord?
 
Quick related question on LMA: if we have a supraglottic airway and a spontaneously breathing/ assisted patient, do we need to apply PEEP? Don't they have physiologic PEEP from their own vocal cord?

I'll usually close the APL to about 3-5 when I have a patient SV with LMA, or set the machine to the same when using PS with LMA. My rationale is that although they have that physiologic PEEP you speak of, they also have some non-physiologic changes and risk of atelectasis just from general anesthesia. I don't see any reason not to use that small amount of PEEP in them.

Always PEEP to 5 with healthy GETAs ... sometimes more or less for the non healthy GETAs.
 
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I invite your input and suggestions on a case . It was interesting episode. It was an argument which ensued between CRNA and an attending in the hospital. The argument was about , how CRNA want to proceed with application of lidocaine paste 2%-4% on the cuff of ET tube. His argument was based on the article in AANA , that application of 2-4% lidocaine paste improved the extubation times. The anesthesia attending was against it , his ground was that the chances of aspiration post operatively will be high , as lidocaine paste will numb the trachea. CRNA claimed that aspiration risk is not much as , he is going to apply it on cuff and as it a paste and it will anesthetize only smaller subglottic region. He went ahead did the case anyhow with lidocaine paste not jelly.

Attending tried to talk him with his suggestion, that it should done only on specific asthmatic cases or non obese elective patients with no GERD.

Your suggestions
 
I invite your input and suggestions on a case . It was interesting episode. It was an argument which ensued between CRNA and an attending in the hospital. The argument was about , how CRNA want to proceed with application of lidocaine paste 2%-4% on the cuff of ET tube. His argument was based on the article in AANA , that application of 2-4% lidocaine paste improved the extubation times. The anesthesia attending was against it , his ground was that the chances of aspiration post operatively will be high , as lidocaine paste will numb the trachea. CRNA claimed that aspiration risk is not much as , he is going to apply it on cuff and as it a paste and it will anesthetize only smaller subglottic region. He went ahead did the case anyhow with lidocaine paste not jelly.

Attending tried to talk him with his suggestion, that it should done only on specific asthmatic cases or non obese elective patients with no GERD.

Your suggestions
Although I agree that the nurse should not ignore what the physician asked him/her to do, that physician is really wasting his time and energy on something really silly and not worth the argument.
In order to work well as a team there should be mutual respect and everyone should realize that there are several ways to do everything in anesthesia.
 
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You have to pick your battles. This doesn't sound like one to take to the mat.
However if I set a plan and a CRNA intentionally and electively deviated from that, and it was something I felt significant, I would absolutely escalate things. We are a nice practice in a nice location and many many more CRNAs want a job here than can get one. If someone is not on board with the way we work, it's not the place for them anyway.
 
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Although I agree that the nurse should not ignore what the physician asked him/her to do, that physician is really wasting his time and energy on something really silly and not worth the argument.
In order to work well as a team there should be mutual respect and everyone should realize that there are several ways to do everything in anesthesia.
That might be right, but when I am legally supposed to supervise your work, you don't get the final decision, just the right to have an input.

It's a completely different story that a wise person won't get caught in disagreements over minor stuff, but it's the intention that matters. And here, the intention was to override the physician's decision, just because the CRNA knows she can get away with it. And that's the sad part that says a lot about how things are in anesthesia today.

Now suppose that the patient had aspirated, the anesthesiologist would have been liable for way more than the CRNA. Why? Because unless s/he had witnesses, it would have been a he said, she said situation.
 
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But my question or query is regarding the article that CRNA was mentioning about in AANA. I looked for the article. Could not locate due to busy day. I will try later.
But my question is, does lidocaine paste of 2-4% really improves the extubation time and also does not increase the chances of aspiration postoperatively.
 
Improve extubation time? I think that's crazy talk. They're not applying the lidocaine paste to the patients cerebral cortex. They might argue that LTA might allow them to run less gas at the end of the case because the tube is well tolerated, and that might speed emergence.

Topical local anesthetic to the trachea helps patients tolerate the tube better, provided the case is short enough to fall within its duration of action. It may reduce coughing or bucking at emergence, which may be especially desirable for certain cases.

As for aspiration risk ... insofar as coughing is one of several airway protection reflexes, sure, the risk is probably above baseline. But significantly so? I doubt it. An awake patient's gag reflex and ability to spit out puke aren't dependent on sensation in the trachea.
 
Most CRNAs are taught that an LMA is a contraindication to mechanical ventilation.
There is nothing you can do to make them unlearn this crap.

the problem might be the teacher not the student
 
I work in a place where CRNA's are independant - they stand on their own decisions - so I have no idea how it is to supervise in a situation like this.

If a resident goes againts my advice, I have lots of ways to deal with that. My favorite is to kick them out of the room and tell them maybe they should go study the rest of the day - in fact, go home. But you couldn't do that with a cRNA.

So, could you document on the chart - as the MD, that this was your recommendation and the CRNA blantantly disregarded the direction? Would that help you as the suprivising physician? You can't FORCE the CRNA to do what you want - and if you are suprivising other rooms, you can't tell them to leave and you do it.
 
I invite your input and suggestions on a case . It was interesting episode. It was an argument which ensued between CRNA and an attending in the hospital. The argument was about , how CRNA want to proceed with application of lidocaine paste 2%-4% on the cuff of ET tube. His argument was based on the article in AANA , that application of 2-4% lidocaine paste improved the extubation times. The anesthesia attending was against it , his ground was that the chances of aspiration post operatively will be high , as lidocaine paste will numb the trachea. CRNA claimed that aspiration risk is not much as , he is going to apply it on cuff and as it a paste and it will anesthetize only smaller subglottic region. He went ahead did the case anyhow with lidocaine paste not jelly.

Attending tried to talk him with his suggestion, that it should done only on specific asthmatic cases or non obese elective patients with no GERD.

Your suggestions

This CRNA needs to reread the article. (http://www.aana.com/newsandjournal/Documents/topical-lidocaine-0412-p99-104.pdf). It says the exact opposite: "The use of LTA 360 kits with induction of general anesthesia for patients undergoing carotid endarterectomy may lengthen extubation times by nearly 2 minutes."
 
My answer is the same.

I used to use SIMV pre-emergence. Now I am a big-time PCV fan, with maybe some PSV once the patient starts breathing. Much like pgg's approach. Both for LMA and ETT.

One of my very smart attendings told me during residency: "Have you ever seen an awake patient who's not breathing? No? Then concentrate on blowing off the gas and waking them up at a decent EtCO2, not on getting them breathe spontaneously. While there is still gas on board, they might or might not breathe at an EtCO2 of less than 50, but they will once the gas is gone and they wake up. Plus you can blow away the gas faster with controlled ventilation."

Truer words have never been spoken. The same attending hates SIMV with a vengeance (not that I agree 100%). :)

What about SIMV-PC? wouldn't that offer you the best of both worlds?
 
So, could you document on the chart - as the MD, that this was your recommendation and the CRNA blantantly disregarded the direction? Would that help you as the suprivising physician?

No. Medico-legally speaking, chart wars are about the worst thing you can do.
 
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Pressure controlled ventilation-volume "guarantee" on GE
Vol AF mode on Drager
Both are same, use pressure control ventilation and calculate pressure based on tidal volume. You set TV, machine figures out required pressure.
 
I invite your input and suggestions on a case . It was interesting episode. It was an argument which ensued between CRNA and an attending in the hospital. The argument was about , how CRNA want to proceed with application of lidocaine paste 2%-4% on the cuff of ET tube. His argument was based on the article in AANA , that application of 2-4% lidocaine paste improved the extubation times. The anesthesia attending was against it , his ground was that the chances of aspiration post operatively will be high , as lidocaine paste will numb the trachea. CRNA claimed that aspiration risk is not much as , he is going to apply it on cuff and as it a paste and it will anesthetize only smaller subglottic region. He went ahead did the case anyhow with lidocaine paste not jelly.

Attending tried to talk him with his suggestion, that it should done only on specific asthmatic cases or non obese elective patients with no GERD.

Your suggestions

By lidocaine paste are we talking about lidocaine ointment?

I would not let anyone put oil into anyone's trachea.
 
Pressure controlled ventilation-volume "guarantee" on GE
Vol AF mode on Drager
Both are same, use pressure control ventilation and calculate pressure based on tidal volume. You set TV, machine figures out required pressure.
Yeah, we've talked recently about it. That's my preferred version. I just don't have VG on my current machines.

There is no such thing as SIMV-PC, AFAIK. Because PCV behaves like SIMV by default (allows overbreathing without bucking, even if differently).
 
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SIMV-PC just means that the mechanical breaths delivered would be via a pressure control rather than volume control mechanism. I've seen it on some of my ICU ventilators in my unit as a fellow. Default in that mode is otherwise a volume breath.

I hardly ever use SIMV though, unless I have a bad COPDer who is severely hyperventilating and flow-trapping as a result. But usually I'll solve that with some sedation if I don't think they'll liberate from the vent any time soon. One of my attendings absolutely forbids it's use though. I do like pressure control volume targeted though in most of my ICU patients. I'd apply it to the OR too if the machines had it.
 
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