Making a lecture top ten myths of anesthesia

[Robotic Wis-Hipple]

Thank you to everyone responding to this thread, I'm a resident and find it very helpful!
If you are able, could you please link an article with your comment, so that I could have it available when my attending (no doubt) chastises me for using LR with pRBC, etc.

I'd also like to know more about the usefulness of testing ventilation before paralytics are given.

Here's a thought experiment;

You push 200mg of propofol but withhold the sux/roc. Pt goes to sleep. You are asked to mask ventilate but are unable to. What is your next move outside of placing an oral airway, attempting to improve positioning, and/or two hand masking?

Do you suppose the addition of sux/roc would make what you would be attempting next more difficult or easier?

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[deleted171991]

Here's a thought experiment;

You push 200mg of propofol but withhold the sux/roc. Pt goes to sleep. You are asked to mask ventilate but are unable to. What is your next move outside of placing an oral airway, attempting to improve positioning, and/or two hand masking?

Second generation LMA (Supreme, i-gel etc.).

 

[Robotic Wis-Hipple]

Second generation LMA (Supreme, i-gel, Air-Q etc.).

lol I knew someone would drop an LMA. Still think the logic follows.

 

[deleted171991]

lol I knew someone would drop an LMA. Still think the logic follows.

True. For low-dose sux or roc with suggamadex. Otherwise one may have just burned the last bridge (which applies to high dose propofol, too). You don't really need muscle relaxant to intubate, just to keep the patient from throwing up.

And, btw, one doesn't need to push more propofol than whatever renders the patient apneic. That's less than the intubation dose. One can always push more, after one has ascertained that one can ventilate and pushed some muscle relaxant, too.

I tend to agree that, in the era of advanced supraglottic ventilation devices (and video intubation devices etc.), the chances of just pushing muscle relaxant and getting into trouble are very small. On the other hand, the muscle relaxant can help with ventilation. So I would be much more cavalier with it at a well-equipped place than at a poor community hospital.

 

[facted]

Can we get back to pre-oxygenation? How is that a myth? Pre-oxygenating a large patient with poor reserve is SUPER helpful. Pre-oxygenation = time. And time in a difficult ventilation / intubation patient can be the difference between life and death. You can't pre-oxygenate for a minute or two and get the etO2 to 80 or 90?

 

[Robotic Wis-Hipple]

True. For low-dose sux or roc with suggamadex. Otherwise you may have just burned the last bridge.

And, btw, you don't need to push more propofol than whatever renders the patient apneic. That's less than the intubation dose. You can always push more, after you've ascertained that you can ventilate and you pushed some muscle relaxant, too.

But I tend to agree that, in the era of advanced supraglottic ventilation devices, the chances of just pushing muscle relaxant and getting into trouble are very small. On the other hand, the muscle relaxant can help with ventilation.

If you think there is only one bridge you shouldn't be rendering apnea. And while I'm not arguing for super doses of propofol (like is commonly done), I'm a cardiac guy after all, I do not buy into this apnea dose but then you can't ventilate so maybe more propofol, then try other things for the sake of saving the bridge you are currently on as it burns. Minimize apnea time. Period. I argue relaxant likely gives you the best shot at that. Whether it's optimal ventilatory or intubation conditions. If you're aiming for apnea, do it. Then get the tube in. Otherwise you're only wasting FRC for the sake of dogma.

 

[deleted171991]

If you think there is only one bridge you shouldn't be rendering apnea. And while I'm not arguing for super doses of propofol (like is commonly done), I'm a cardiac guy after all, I do not buy into this apnea dose but then you can't ventilate so maybe more propofol, then try other things for the sake of saving the bridge you are currently on as it burns. Minimize apnea time. Period. I argue relaxant likely gives you the best shot at that. Whether it's optimal ventilatory or intubation conditions. If you're aiming for apnea, do it. Then get the tube in. Otherwise you're only wasting FRC for the sake of dogma.

That is a good point. But 99% of patients can be somewhat ventilated with a good LMA (not the kind you'd find in a cardiac room). Again, one can argue that the muscle relaxant will help with the ventilation, too.

Also, don't forget that difficult ventilation is a predictor of difficult intubation. At least according to academic dogma. Of course, you will argue that I could just ventilate the patient with the LMA till the muscle relaxant wears off, or I figure out a better way to intubate.

The problem is that not all places have good LMAs (or good videolaryngoscopes). In those places, inducing apnea in a potentially difficult airway is a leap of faith. Also, as usual, it is a medico-legal problem. The "expert" witness will be an academic who will argue that ventilating before muscle relaxant is the standard of care.

 

[Robotic Wis-Hipple]

And I'd argue they're wrong, just as I did on my orals. I'll relate one of your sayings here; absence of proof (ability to ventilate in suboptimal conditions) is not proof of absence.

 

[deleted171991]

And I'd argue they're wrong, just as I did on my orals. I'll relate one of your sayings here; absence of proof (ability to ventilate in suboptimal conditions) is not proof of absence.

This is one of those things about which you'll have to agree to differ with many people. Like CVP for me.

 

[Arch Guillotti]

huh?

Who preoxygenates?

 

[deleted59964]

Can we get back to pre-oxygenation? How is that a myth? Pre-oxygenating a large patient with poor reserve is SUPER helpful. Pre-oxygenation = time. And time in a difficult ventilation / intubation patient can be the difference between life and death. You can't pre-oxygenate for a minute or two and get the etO2 to 80 or 90?

just a little in joke ... nothing to see here, move along

 

[periopdoc]

Myth - CVP and PAP are useful numbers.

 

[deleted171991]

Myth - CVP and PAP are useful numbers.

PAP is useful, but only for the patient with pulmonary arterial hypertension (and/or RV failure).

 

[anbuitachi]

Nothing wrong with using hydrocortisone, but hypotension isn't caused by mineralocorticoid deficiency.

what? adrenal crisis has more than just hypotension

 

[Robotic Wis-Hipple]

Myth - CVP and PAP are useful numbers.

Whoa! I want to hear your Jedi PAP opinions. I'm guessing you're going to say keep MAP/DBP normal/high and you're good. But I'm intrigued.

 

[deleted171991]

Whoa! I want to hear your Jedi PAP opinions. I'm guessing you're going to say keep MAP/DBP normal/high and you're good. But I'm intrigued.

I think he's going to say: use your TEE.

 

[Robotic Wis-Hipple]

I think he's going to say: use your TEE.

Well that's boring. I want Jedi tricks

 

[Noyac]

!

 

[GravelRider]

what? adrenal crisis has more than just hypotension

How did we go from prophylactic stress dose steroids to adrenal insufficiency to full blown adrenal crisis?

 

[OB1🤙]

Myth - CVP and PAP are useful numbers.

Related myth: if you float a Swan, you should wedge it. And postop, the ICU should check and trend wedge pressures.

 

[Ronin786]

Desflurane can't be used to treat bronchospasm

Sevoflurane and Isoflurane create fat depots in longer cases when compared to Des.

 

[deleted171991]

Desflurane can't be used to treat bronchospasm

You must have not seen bronchospasm and coughing from des. Next time, try to induce your pedi patient with nitrous+des, and see what happens. Been there done that (by mistake).

 

[stonemd]

Give IV lidocaine before propofol to prevent pain on injection
use ETT to reduce chance of aspiration pneumonia
Laryngospasm will break with PPV/CPAP
Screening labs
MAC is safer than GA

 

[anbuitachi]

Give IV lidocaine before propofol to prevent pain on injection
use ETT to reduce chance of aspiration pneumonia
Laryngospasm will break with PPV/CPAP
Screening labs
MAC is safer than GA

I disagree with ETT. i feel like its better than unsecured airway.

 

[facted]

Give IV lidocaine before propofol to prevent pain on injection

I've had prop both ways and lido made a world of difference. Not a myth in my opinion. I personally mix it for my patients.

 

[pgg]

I've had prop both ways and lido made a world of difference. Not a myth in my opinion. I personally mix it for my patients.

It seems to work better if you mix it, vs giving the lidocaine first.

Unless you do a lidocaine Bier block first.

 

[MirrorTodd]

It seems to work better if you mix it, vs giving the lidocaine first.

Unless you do a lidocaine Bier block first.

That's how I've had it explained to me. Said you had to inject with a tourniquet up and let it sit for a good minute before letting the tourniquet down and pushing propofol. I've never actually seen anyone do that though.

 

[deleted171991]

Give IV lidocaine before propofol to prevent pain on injection

Not a legend. The key is to know HOW to give that lidocaine and propofol. I get grimacing or complaints from less than 3% of my patients. Most report feeling only warmth or nothing.

MAC is safer than GA

It is, as long as it's just minimal anxiolysis.

 

[dmk5n]

This book seems like it would be relevant.
Amazon product

ISBN-13: 978-3319431673
ISBN-10: 3319431676

You’re Wrong, I’m Right: Dueling Authors Reexamine Classic Teachings in Anesthesia 1st ed. 2017 Edition

 

[Noyac]

It seems to work better if you mix it, vs giving the lidocaine first.

Unless you do a lidocaine Bier block first.

Anesth Analg. 2003 Dec;97(6):1646-51.
Physicochemical compatibility of propofol-lidocaine mixture.
Masaki Y1, Tanaka M, Nishikawa T.
Author information

Abstract
To examine the physicochemical stability of combinations of propofol-lidocaine mixtures frequently used in clinical practice, we added lidocaine 5, 10, 20, or 40 mg to commercially available 1% propofol 20 mL. To assess chemical stability, propofol concentrations were determined by gas chromatography assay for 24 h after preparation of the mixture. In addition, scanning electron microscopy was used to determine the maximum detectable droplet size in randomly selected fields. Macroscopically, separate, colorless layers were first seen at 3 and 24 h after the addition of 40 and 20 mg of lidocaine to propofol, respectively, whereas the mixture with 5 or 10 mg of lidocaine was macroscopically stable. Propofol concentrations in the mixture with 40 mg of lidocaine decreased linearly and significantly from 4 to 24 h after preparation, whereas those combined with other lidocaine doses were unchanged compared with baseline concentrations. Scanning electron microscopy showed that droplets with diameters >or=5 microm first appeared 30 min after the addition of 40 mg of lidocaine to propofol, and the emulsion droplets were enlarged in a time- and dose-dependent fashion. Our results indicate that the addition of lidocaine to propofol results in a coalescence of oil droplets, which finally proceeds to a visible separate layer. Depending on the dose of lidocaine and the duration between its preparation and administration, this combination may pose the risk of pulmonary embolism.

IMPLICATIONS:
The addition of lidocaine to propofol results in time- and dose-dependent increases in oil droplet diameters in emulsion. This mixture is physicochemically unstable over time and may cause pulmonary embolism, depending on the dose of lidocaine.

 

[anbuitachi]

Anesth Analg. 2003 Dec;97(6):1646-51.
Physicochemical compatibility of propofol-lidocaine mixture.
Masaki Y1, Tanaka M, Nishikawa T.
Author information

Abstract
To examine the physicochemical stability of combinations of propofol-lidocaine mixtures frequently used in clinical practice, we added lidocaine 5, 10, 20, or 40 mg to commercially available 1% propofol 20 mL. To assess chemical stability, propofol concentrations were determined by gas chromatography assay for 24 h after preparation of the mixture. In addition, scanning electron microscopy was used to determine the maximum detectable droplet size in randomly selected fields. Macroscopically, separate, colorless layers were first seen at 3 and 24 h after the addition of 40 and 20 mg of lidocaine to propofol, respectively, whereas the mixture with 5 or 10 mg of lidocaine was macroscopically stable. Propofol concentrations in the mixture with 40 mg of lidocaine decreased linearly and significantly from 4 to 24 h after preparation, whereas those combined with other lidocaine doses were unchanged compared with baseline concentrations. Scanning electron microscopy showed that droplets with diameters >or=5 microm first appeared 30 min after the addition of 40 mg of lidocaine to propofol, and the emulsion droplets were enlarged in a time- and dose-dependent fashion. Our results indicate that the addition of lidocaine to propofol results in a coalescence of oil droplets, which finally proceeds to a visible separate layer. Depending on the dose of lidocaine and the duration between its preparation and administration, this combination may pose the risk of pulmonary embolism.

IMPLICATIONS:
The addition of lidocaine to propofol results in time- and dose-dependent increases in oil droplet diameters in emulsion. This mixture is physicochemically unstable over time and may cause pulmonary embolism, depending on the dose of lidocaine.

you have to mix right before giving.

And i see some people occasionally do bier block with blood cuff on stasis, in academic center of course

 

[Ronin786]

You must have not seen bronchospasm and coughing from des. Next time, try to induce your pedi patient with nitrous+des, and see what happens. Been there done that (by mistake).

Not what I said/meant. There's a propagated myth that in an intubated patient with bronchospasm you need to switch from Des to Sevo/Iso. Deepening with any agent will result in bronchodilation, a characteristic of all volatile anesthetics.


There's no denying that an inhaled induction with desflurane can precipitate bronchospasm. But when are you using an inhaled induction to treat bronchospasm?

 

[Urzuz]

I feel like a lot of the "myths" being posted here by several people are actually proven fact, but they either don't know the evidence or don't do it properly.

Something isn't a myth just because you're too lazy to do a Pubmed search on it.

 

[Ignatius J]

I am going to throw one out there that people may not like: putting Pedi patients in the "recovery" position (on their side). I never do that anymore.

I'll also throw in the myth of penecillin-cephalosporin cross-reactivity, NS instead of LR for ESRD, buretrols on kids older than 3 months, cancelling cases for uncontrolled hypertension after fiddling with their meds and them being nervous wrecks, brachial a-lines giving people "cold arms" (good journal article recently), the BIS monitor in general, the need for central lines in kidney transplants (especially given novel non-invasive CO machines), and pretty much anytime the surgeon asks us to give mannitol for something and it affecting clinical outcome. Haha, kinda shooting from the hip.

 

[Airlife91]

It seems to work better if you mix it, vs giving the lidocaine first.

Unless you do a lidocaine Bier block first.

This study supports the bier block method: "The two most efficacious interventions to reduce pain on injection of propofol were use of the antecubital vein, or pretreatment using lidocaine in conjunction with venous occlusion when the hand vein was chosen."
BMJ 2011;3421110 - http://www.bmj.com/content/342/bmj.d1110

Lidocaine-propofol admixture and lidocaine alone came in as 3rd & 4th, respectively, as most effective after the two methods mentioned above.

 

[epidural man]

fellow sdn anesthesia people,

I have a monthly lecture series I do for the group and need your assistance. I want to do a top 10 myths of anesthesia backed w research of why some things we do are inherently dumb. I have a partial list and would love to hear your input.

Red haired people have higher mac requirements
Sellick maneuver for rsi
Gravid women needs a lower does of local for sab due to smaller epidural space
Test ventilation before giving paralytics
Miller blade as your back up for dl
Colloid vs crystaloid for volume recessitation
Oj with pulp 6 hrs npo

Granted this is an abbreviated list but for an 1 hr lecture I can get thru a top ten. What else do you guys have ?

Thanks for ideas

Sdd

Many of these are not "myths" but controversial topics.

Take your fluid resuscitation choice for example. You can find plenty of evidence either way.

We had a massive transfusion protocol today in OB that I had to run help with. The patient was very tachycardic. Two bottles of 25% albumin corrected her tachycardia. I don't think 200cc's or saline would have done that (I'm just saying...it's controversial).

 

[epidural man]

You should also consider adding - stupid things people do in the OR.

Like using phenylephrine or norepinephrine in a non-weight based dosing....

Or when extubating, giving a positive pressure breath on the bag while pulling the tube (it baffles me that anyone would want to blow that snot and spit and all the SH$T into the lungs while pulling the tube...but I see it all the time)

 

[deleted162650]

25% albumin

25% really?? Or did you mean 5%?

 

[daneeka]

Or when extubating, giving a positive pressure breath on the bag while pulling the tube (it baffles me that anyone would want to blow that snot and spit and all the SH$T into the lungs while pulling the tube...but I see it all the time)

It makes more sense done properly: give a big VC breath, wait, then pull the tube during expiration. No idea if it works but at least it's easy.

 

[anbuitachi]

25% really?? Or did you mean 5%?

pretty sure he meant 25%, otherwise he wouldn't have said 200ml saline

 

[facted]

Or when extubating, giving a positive pressure breath on the bag while pulling the tube (it baffles me that anyone would want to blow that snot and spit and all the SH$T into the lungs while pulling the tube...but I see it all the time)

YES! It's great for getting a nicely extubated patient to cough all over...My residents do it all the time. Drives me up the wall.

 

[facted]

It makes more sense done properly: give a big VC breath, wait, then pull the tube during expiration. No idea if it works but at least it's easy.

Why do it at all? Not to mention usually giving a nice big breath in a spontaneously breathing patient who is on the verge of waking up is a great sure-fire way to get the patient coughing and making yourself look like a fool during extubation...

 

[facted]

Anesth Analg. 2003 Dec;97(6):1646-51.
Physicochemical compatibility of propofol-lidocaine mixture.
Masaki Y1, Tanaka M, Nishikawa T.
Author information

Abstract
To examine the physicochemical stability of combinations of propofol-lidocaine mixtures frequently used in clinical practice, we added lidocaine 5, 10, 20, or 40 mg to commercially available 1% propofol 20 mL. To assess chemical stability, propofol concentrations were determined by gas chromatography assay for 24 h after preparation of the mixture. In addition, scanning electron microscopy was used to determine the maximum detectable droplet size in randomly selected fields. Macroscopically, separate, colorless layers were first seen at 3 and 24 h after the addition of 40 and 20 mg of lidocaine to propofol, respectively, whereas the mixture with 5 or 10 mg of lidocaine was macroscopically stable. Propofol concentrations in the mixture with 40 mg of lidocaine decreased linearly and significantly from 4 to 24 h after preparation, whereas those combined with other lidocaine doses were unchanged compared with baseline concentrations. Scanning electron microscopy showed that droplets with diameters >or=5 microm first appeared 30 min after the addition of 40 mg of lidocaine to propofol, and the emulsion droplets were enlarged in a time- and dose-dependent fashion. Our results indicate that the addition of lidocaine to propofol results in a coalescence of oil droplets, which finally proceeds to a visible separate layer. Depending on the dose of lidocaine and the duration between its preparation and administration, this combination may pose the risk of pulmonary embolism.

IMPLICATIONS:
The addition of lidocaine to propofol results in time- and dose-dependent increases in oil droplet diameters in emulsion. This mixture is physicochemically unstable over time and may cause pulmonary embolism, depending on the dose of lidocaine.

I've seen this study before. I usually put some lidocaine in the prop in between cases when setting up. The last time I saw or suspected a PE soon after induction was never. Might be chemically true, but clinical significance approaches zero.

 

[vector2]

This article, Anesthesia Dogmas and Shibboleths, by Gordon published in A&A in 2012 is a must-read for all anesthesiologists

Anesthesia Dogmas and Shibboleths: Barriers to Patient Safety? Pages 1 - 6 - Text Version | FlipHTML5

 

[Robotic Wis-Hipple]

Why do it at all? Not to mention usually giving a nice big breath in a spontaneously breathing patient who is on the verge of waking up is a great sure-fire way to get the patient coughing and making yourself look like a fool during extubation...

I think this practice is based on the idea that if you give a positive pressure breath just prior to deflating the cuff exhalation will carry all the secretions sitting on top of the cuff out of the trachea.

I never bought it, that's why I just extubate without deflating the cuff. Hard to cough or laryngospasm with dislocated VC's.

 

[vector2]

Myth - CVP and PAP are useful numbers.

I've always thought MAP/PAP ratio to be helpful in quickly assessing sick vs not sick cardiac pts. Using PADs as an assessment of volume status....thats probably as questionable as using CVP.

 

[Urzuz]

Like using phenylephrine or norepinephrine in a non-weight based dosing....

And why is that stupid? Every pump we have is programmed to have phenylephrine, norepinephrine, and epinephrine infusions in mcg/min...and literally every professor I had in residency dosed it that way as well (in adults). So why is it wrong to do this again? Sounds similar to insisting on a certain type of tape for the tube or something...where multiple methods can accomplish the same goal but one is clearly "more better" and the other methods are idiotic.

 

[teeva]

Or when extubating, giving a positive pressure breath on the bag while pulling the tube

I was taught this as a resident and stopped practicing this "maneuver" as a resident. It's terrible for a smooth extubation, especially in someone who's already smoothly waking up.

IV lidocaine before propofol works, but IME only if you push lido slowly with IV dripping slowly and let it stew in the vein for 10-15 secs.

 

[dchz]

Can we get back to pre-oxygenation? How is that a myth? Pre-oxygenating a large patient with poor reserve is SUPER helpful. Pre-oxygenation = time. And time in a difficult ventilation / intubation patient can be the difference between life and death. You can't pre-oxygenate for a minute or two and get the etO2 to 80 or 90?

@facted you are getting trolled. Preoxygenation is not a myth. Speaking as a huge troll myself, you should trust your own judgement over SDN trolls.

 

[anbuitachi]

And why is that stupid? Every pump we have is programmed to have phenylephrine, norepinephrine, and epinephrine infusions in mcg/min...and literally every professor I had in residency dosed it that way as well (in adults). So why is it wrong to do this again? Sounds similar to insisting on a certain type of tape for the tube or something...where multiple methods can accomplish the same goal but one is clearly "more better" and the other methods are idiotic.

What? your pumps are mcg/min? ours are all ng/kg/min, it just feels a lot easier using weight based. it feels more error prone if you dont use weight. what is your go to starting norepi infusion dose for a 1kg patient vs a 150kg patient?