Anesthesia Awareness

[coasterbrain86]

---

Members don't see this ad.

Interesting article:

http://www.theatlantic.com/magazine/archive/2013/01/awakening/309188/

 

[doctor712]

Authors opening sentence is SO weak. Anesthesia wasn't introduced in 1846, not even close, Ether (one type of inhalational anesthetic) specifically, was displayed publicly - in the US - for the first time in 1846. Big difference.

Having a hard time getting past that first sentence... 😛 afraid the rest probably won't be much better...

D712

 

[Idiopathic]

Authors opening sentence is SO weak. Anesthesia wasn't introduced in 1846, not even close, Ether (one type of inhalational anesthetic) specifically, was displayed publicly - in the US - for the first time in 1846. Big difference.

Having a hard time getting past that first sentence... 😛 afraid the rest probably won't be much better...

D712

you can argue the semantics if you wish, but when do you think modern day anesthesia was introduced if not with the first public display of ether for a surgical procedure?

 

[doctor712]

you can argue the semantics if you wish, but when do you think modern day anesthesia was introduced if not with the first public display of ether for a surgical procedure?

What you wrote is 1000 times better worded than what the author wrote. Frankly, it's the Atlantic, a nice magazine, well written. I just have a hard time opening an article and reading about Anesthesia being introduced in 1846... To someone who has no idea what that year means, it's just misleading. What does introduced mean, I mean, you know what I mean?

You are accurate, in fact, of course. Etherdome...Morton, Wells, Crawford Long down in GA, the whole timeframe is spot on. The author, who has editors, fact checkers and the like, really phrased it poorly, that's all I'm mentioning. Left out modern day, and surgical, and public, and all that... haha.

Semantics matter...when writing. 😀 At least to this writer. The author makes no mention of modern day, inhalational, surgical, public display, etc. Just says anesthesia was introduced in 1846, kind of short shrift for an opening sentence, no? It would be fine in Marie Claire, just have higher standards for the Atlantic. Is the statement accurate to a reader visiting from France or the UK?

Not gonna end the world, just sayin'.

D712

 

[BLADEMDA]

Interesting article:

http://www.theatlantic.com/magazine/archive/2013/01/awakening/309188/

Anesthesia awareness under GA is less than 1% and usually around 0.25% or less with a solid protocol in place.

http://www.ncbi.nlm.nih.gov/pubmed/21848460


http://www.ncbi.nlm.nih.gov/pubmed/22990178



A total of 19 cases of definite or possible intraoperative awareness (0.66%) occurred in the BIS group, as compared with 8 (0.28%) in the ETAC group (a difference of 0.38 percentage points; 95% CI, 0.03 to 0.74; P=0.99), with the superiority of the BIS protocol again not demonstrated. There was no difference between the groups with respect to the amount of anesthesia administered or the rate of major postoperative adverse outcomes.

 

[fakin' the funk]

Anesthesia awareness under GA is less than 1% and usually around 0.25% or less with a solid protocol in place.

While you're technically correct, let's put a finer point on your mindless copy-pasting, Blade.

The BAG-RECALL study you linked to specifically goes after high-risk patients and still finds a rate of recall of 0.07% in patients whose end-tidal anesthetic concentration was monitored (e.g., what most of us do). That's 0.07%. In a high risk population. What do you think our "all-comers" rate of recall is? Do we as anesthesiologists even need to talk about this topic? Does anyone think that intraoperative recall or awareness, aside from catastrophic practitioner errors (e.g. treating movement with muscle relaxants, not recognizing an empty vaporizer, treating tachycardia with beta-blockers), is an important issue in anesthesiology?

 

[pgg]

While you're technically correct, let's put a finer point on your mindless copy-pasting, Blade.

The BAG-RECALL study you linked to specifically goes after high-risk patients and still finds a rate of recall of 0.07% in patients whose end-tidal anesthetic concentration was monitored (e.g., what most of us do). That's 0.07%. In a high risk population. What do you think our "all-comers" rate of recall is? Do we as anesthesiologists even need to talk about this topic?

When a patient tells me they were "aware" during a past anesthetic, I assume they misunderstood the intent of a local/MAC.

I have yet to encounter a credible patient with an awareness under GA story.

Does anyone think that intraoperative recall or awareness, aside from catastrophic practitioner errors (e.g. treating movement with muscle relaxants, not recognizing an empty vaporizer, treating tachycardia with beta-blockers), is an important issue in anesthesiology?

It's not an uncommon fear held by patients. If patients bring it up, part of good anesthesia / consent / compassion is to reassure and educate them.

Beyond that, no, I don't think it's an important issue.

I don't mention recall in my routine GA consent, but I always specifically mention it, in a reassuring way, as an expected consequence of sedation, regional, local, MAC type cases. I don't do cardiac these days but I would mention it to those patients since they're in a higher risk group.

 

[Idiopathic]

What you wrote is 1000 times better worded than what the author wrote. Frankly, it's the Atlantic, a nice magazine, well written. I just have a hard time opening an article and reading about Anesthesia being introduced in 1846... To someone who has no idea what that year means, it's just misleading. What does introduced mean, I mean, you know what I mean?

You are accurate, in fact, of course. Etherdome...Morton, Wells, Crawford Long down in GA, the whole timeframe is spot on. The author, who has editors, fact checkers and the like, really phrased it poorly, that's all I'm mentioning. Left out modern day, and surgical, and public, and all that... haha.

Semantics matter...when writing. 😀 At least to this writer. The author makes no mention of modern day, inhalational, surgical, public display, etc. Just says anesthesia was introduced in 1846, kind of short shrift for an opening sentence, no? It would be fine in Marie Claire, just have higher standards for the Atlantic. Is the statement accurate to a reader visiting from France or the UK?

Not gonna end the world, just sayin'.

D712

Do you have a different suggestion for when anesthesia was introduced?

 

[jwk]

While you're technically correct, let's put a finer point on your mindless copy-pasting, Blade.

The BAG-RECALL study you linked to specifically goes after high-risk patients and still finds a rate of recall of 0.07% in patients whose end-tidal anesthetic concentration was monitored (e.g., what most of us do). That's 0.07%. In a high risk population. What do you think our "all-comers" rate of recall is? Do we as anesthesiologists even need to talk about this topic? Does anyone think that intraoperative recall or awareness, aside from catastrophic practitioner errors (e.g. treating movement with muscle relaxants, not recognizing an empty vaporizer, treating tachycardia with beta-blockers), is an important issue in anesthesiology?

Bingo. I have no doubt that 99% of "anesthesia awareness" happens either through practitioner error/drug diversion, or with critically ill patients where there is simply a high but acceptable risk of it happening.

These figures of 1/1000 awareness or even higher are BS. Dr. Peter Sebel, one of the paid BIS gurus, used to toss this figure around. There was a letter to the editor in the ASA Newsletter directed to Dr. Sebel that suggested that if his incidence of anesthesia awareness was actually 1/1000 that he needed to go back and relearn how to do anesthesia.

That being said, I'm a BIS fan. I wasn't for a long time - but after using it for several years now, there clearly is something to it. It's a single tool among many that we use to form an opinion in our mind that our patients are adequately anesthetized. ETAC is the same, but using 1.4 MAC on every patient isn't possible, so you have to have other data points that you can pool together to make that opinion. Each little piece of info, taken together, allows you to proceed with confidence that your patient is indeed asleep and unaware.

 

[BLADEMDA]

Bingo. I have no doubt that 99% of "anesthesia awareness" happens either through practitioner error/drug diversion, or with critically ill patients where there is simply a high but acceptable risk of it happening.

These figures of 1/1000 awareness or even higher are BS. Dr. Peter Sebel, one of the paid BIS gurus, used to toss this figure around. There was a letter to the editor in the ASA Newsletter directed to Dr. Sebel that suggested that if his incidence of anesthesia awareness was actually 1/1000 that he needed to go back and relearn how to do anesthesia.

That being said, I'm a BIS fan. I wasn't for a long time - but after using it for several years now, there clearly is something to it. It's a single tool among many that we use to form an opinion in our mind that our patients are adequately anesthetized. ETAC is the same, but using 1.4 MAC on every patient isn't possible, so you have to have other data points that you can pool together to make that opinion. Each little piece of info, taken together, allows you to proceed with confidence that your patient is indeed asleep and unaware.

BIS is only needed when ET Anesthetic gases are below 0.7 MAC or as an addditional tool to reassure your most anxious patients. If you want to run your patients "light" on vapor then BIS may be a good idea.

I have many BIS monitors available at all times and at any point suring the day less than 10% are being used. That said, I don't mind if a provider decides to place a BIS.

 

[Idiopathic]

as long as you know that your BIS wont prevent awareness we dont care what you do with it

 

[doctor712]

Do you have a different suggestion for when anesthesia was introduced?

Modern day?

Public?

Ancient?

American?

Worldwide?

In developed countries?

What kind of anesthesia do you mean? Ether from a vial or Curare amongst natives in South America? Introduced to who? Indians? Americans? The French?

It's just poorly written, don't you agree? (seriously, do you think it's good writing?)

Had the author added "modern day" to anesthesia, with perhaps "public" than I would agree 100%. Had the author tried to define "introduced" at all, or better, I would be ok with that too. It's just not good writing. Again, not a biggie.

Authors' first sentence: "Since its introduction in 1846, anesthesia has allowed for medical miracles..." (also weird to open up with a possessive pronoun before even using the noun, but I don't mind a little style...)
My revised first sentence: "Since anesthesia's first public demonstration in Mass. General's Etherdome, 1846,... bla bla bla". Or "Since anesthesia was first introduced to the US public in 1846..." (more passive, but doable).

But saying anesthesia was utterly introduced (to the world? to 4 surgeons in Crawford Long's lab - btw, long prior to 1846 -- ?) at large, I dunno, not sure I'd go for that. Crawford Long might argue with it too, no? 😉

It's an interesting topic for me, the history. As I'm using some of it in a script currently.

D712

 

[itwasalladream]

The all-comers rate for awareness in the 2012 Anesthesiology study was about 0.1% with their protocols in place. (~21000 cases). Why is that rate BS? It's also helpful to know at what point awareness was counted - i.e. does a patient who remembers the ETT being in for a short while before or after the surgery count as awareness in these studies? Might explain a higher rate than we'd otherwise guess.

The same study did find, on post-hoc analysis admittedly, a significant difference between BIS and routine care, which is what we all actually do. Who follows the gas protocols set forth in any of these studies? Of course we monitor it, but almost no one sets end tidal agent alarms (much less gets paged when ETAC is low) where I'm at.

I also thought it was interesting that 50% of the awareness cases in the BIS group did not have any sustained values above 60 during their case.

 

[Arch Guillotti]

Each little piece of info, taken together, allows you to proceed with confidence that your patient is indeed asleep and unaware.

So do you think that the BIS helps to decrease intraoperative awareness?

 

[jwk]

So do you think that the BIS helps to decrease intraoperative awareness?

That's not really what I'm using it for per se. I think of it more as a monitor to help guide the depth of anesthesia, not really awareness. I don't try and run patients as light as I can and keep the BIS value in the mid 50's. However, I don't run 1.4 MAC of gas and watch the BIS stay down in the 20's either. Clearly it has some value and the numbers mean something. Put it on an awake patient and it's 95-100. Give them a stick of propofol and the value plummets. That seems pretty obvious to me. And I don't use it on every case, but I am more likely to use it on spines and older/sicker patients in particular. But I've been doing this long enough I don't depend on it alone to control my actions, just as I generally don't depend on any monitor by itself to dictate what I do.

Again, it's one tool of many that we use. Put it all together with HR, BP, SaO2, EtCO2, and checking twitches as needed, and you have a pretty good idea of where your patient is on the anesthesia spectrum.

I think BIS is also a somewhat intuitive guide to cerebral perfusion. Doing shoulders in a beach chair position (one of the stupidest and most dangerous things we do IMHO) is a good example. Surgeons want lower BP's to help them control bleeding (remember, blood exists to perfuse the bones), but we all know about decreased cerebral perfusion in the sitting position as well. So - if my patient has a NIBP of 110/70 and the BIS is 40, I'm reasonably comfortable that the brain is being perfused. That same BP with a BIS of 10 is going to cause me more concern.

 

[Ignatius J]

Count me as someone who thinks the BIS is a gimmick. Too high of a possibility for false negatives and positives for me to think it should alter the standard of care. I think it's something you can bill for too, no? We have it as a box you can check on our billing sheet at my institution. Why drive up costs of an already daunting anesthesia bill for something that has not definitively shown that it is efficacious enough to alter the standard of care?

 

[dhb]

Question for the frequent BIS users: how often are you surprised by the BIS reading in respect of the anesthetic you are performing?

 

[jwk]

Count me as someone who thinks the BIS is a gimmick. Too high of a possibility for false negatives and positives for me to think it should alter the standard of care. I think it's something you can bill for too, no? We have it as a box you can check on our billing sheet at my institution. Why drive up costs of an already daunting anesthesia bill for something that has not definitively shown that it is efficacious enough to alter the standard of care?

We don't bill extra for it and most insurance companies wouldn't pay for it if you did.

As far as "false negatives and positives", it's more a matter of being familiar with the monitor and it's limitations. EMG interference frequently causes an increase in the number. It doesn't mean your patient is approaching consciousness, but it may be a good indicator you need to give something else to decrease muscle tone if you still need relaxation. Again, it's a tool, one of many we use. As with many things, treat the cause of the problem, not the number on the monitor. I see PACU nurses panic all the time when they see an SaO2 of 60, yet there is no waveform on the monitor and the patient is chatting away. Ah, yes, the probe is lying in the bed, not on the patient's finger.

 

[Ignatius J]

We don't bill extra for it and most insurance companies wouldn't pay for it if you did.

As far as "false negatives and positives", it's more a matter of being familiar with the monitor and it's limitations. EMG interference frequently causes an increase in the number. It doesn't mean your patient is approaching consciousness, but it may be a good indicator you need to give something else to decrease muscle tone if you still need relaxation. Again, it's a tool, one of many we use. As with many things, treat the cause of the problem, not the number on the monitor. I see PACU nurses panic all the time when they see an SaO2 of 60, yet there is no waveform on the monitor and the patient is chatting away. Ah, yes, the probe is lying in the bed, not on the patient's finger.

I think the difference is that when used properly, the pulse oximeter is vital. When a BIS is used properly, there are limitations per many studies.

 

[BLADEMDA]

That's not really what I'm using it for per se. I think of it more as a monitor to help guide the depth of anesthesia, not really awareness. I don't try and run patients as light as I can and keep the BIS value in the mid 50's. However, I don't run 1.4 MAC of gas and watch the BIS stay down in the 20's either. Clearly it has some value and the numbers mean something. Put it on an awake patient and it's 95-100. Give them a stick of propofol and the value plummets. That seems pretty obvious to me. And I don't use it on every case, but I am more likely to use it on spines and older/sicker patients in particular. But I've been doing this long enough I don't depend on it alone to control my actions, just as I generally don't depend on any monitor by itself to dictate what I do.

Again, it's one tool of many that we use. Put it all together with HR, BP, SaO2, EtCO2, and checking twitches as needed, and you have a pretty good idea of where your patient is on the anesthesia spectrum.

I think BIS is also a somewhat intuitive guide to cerebral perfusion. Doing shoulders in a beach chair position (one of the stupidest and most dangerous things we do IMHO) is a good example. Surgeons want lower BP's to help them control bleeding (remember, blood exists to perfuse the bones), but we all know about decreased cerebral perfusion in the sitting position as well. So - if my patient has a NIBP of 110/70 and the BIS is 40, I'm reasonably comfortable that the brain is being perfused. That same BP with a BIS of 10 is going to cause me more concern.

JWK,

BIS is a fine tool; but, for beach chair I think the cerebral oximeters are a better monitor for brain perfusion.

http://www.ncbi.nlm.nih.gov/pubmed/19490464


http://www.apsf.org/newsletters/html/2009/spring/04_cereboximetry.htm

 

[jwk]

JWK,

BIS is a fine tool; but, for beach chair I think the cerebral oximeters are a better monitor for brain perfusion.

http://www.ncbi.nlm.nih.gov/pubmed/19490464


http://www.apsf.org/newsletters/html/2009/spring/04_cereboximetry.htm

If we had them, I'd use them. 🙂

 

[jwk]

I think the difference is that when used properly, the pulse oximeter is vital. .

Since I did anesthesia before pulse oximetry was available, I could debate that point. 🙂

 

[Dejavu]

Since I did anesthesia before pulse oximetry was available, I could debate that point. 🙂

Ah, the good old days.

But I have to admit, with all the monitors like pulse ox and etco2, it has been a while since you've heard the surgeon say "The blood is kinda dark down here."

🙂

 

[jwk]

Ah, the good old days.

But I have to admit, with all the monitors like pulse ox and etco2, it has been a while since you've heard the surgeon say "The blood is kinda dark down here."

🙂

Ah yes, actual clinical signs rather than numbers. 😉

 

[Dejavu]

Ah yes, actual clinical signs rather than numbers. 😉

I work in a teaching institution and always find it funny that when you ask a new anesthesia provider if the pt is breathing they will look at the etco2 curve on the monitor to see. Ask an old guy like us and we will look at the bag first, works every time.

Heck, I'm even old enough to look at the chest and put my hand over the pt's mouth to feel for air movement. Can't do that with gloves on though, another bad habit from the old days I guess. I can't hardly start an IV with gloves on, you get no feel for entering the vessel.

I am such a fossil.

 

[Idiopathic]

I work in a teaching institution and always find it funny that when you ask a new anesthesia provider if the pt is breathing they will look at the etco2 curve on the monitor to see. Ask an old guy like us and we will look at the bag first, works every time.

doesnt work on my anesthesia machines unless they are off the vent, but i know what you mean. Im pretty recently done and I always put my wrist/forearm over the mouth to assess for air movement (with gloved hands)

 

[jetproppilot]

BIS is only needed when ET Anesthetic gases are below 0.7 MAC or as an addditional tool to reassure your most anxious patients. If you want to run your patients "light" on vapor then BIS may be a good idea.

I have many BIS monitors available at all times and at any point suring the day less than 10% are being used. That said, I don't mind if a provider decides to place a BIS.

That's a shame, dude.

I won't ever tout BIS as a recall eliminator.

I WILL tout it as another great adjunct in our armamentarium,

enabling the clinician to run a

TIGHTER ANESTHETIC.

Every GA at my professional crib is done with BIS.

Our wakeups

ARE AMAZING.

You can continue to doubt, Blade.

I'm convinced of BIS efficacy and I've been convinced for a long time now.

You are selling yourself, your practice, and your patients

SHORT.

I wish you could come work with me for JUST ONE DAY and see what I'm talking about.

 

[dhb]

Question for the frequent BIS users: how often are you surprised by the BIS reading in respect of the anesthetic you are performing?

Anyone??

 

[Dejavu]

doesnt work on my anesthesia machines unless they are off the vent, but i know what you mean. Im pretty recently done and I always put my wrist/forearm over the mouth to assess for air movement (with gloved hands)

Very nice. I guess there is hope for the future🙂

 

[etudiante04]

The article is interesting, but I find this discussion even more enlightening. I am learning a lot. Perhaps intraoperative awareness is not is worrisome as some think it is. But there are some surgical populations at higher risk (cardiac, OB, maybe even children?), so the depth of anesthesia should be even more tightly monitored for those patients.

 

[Idiopathic]

The article is interesting, but I find this discussion even more enlightening. I am learning a lot. Perhaps intraoperative awareness is not is worrisome as some think it is. But there are some surgical populations at higher risk (cardiac, OB, maybe even children?), so the depth of anesthesia should be even more tightly monitored for those patients.

there is a reason why the high risk groups are high risk and it isnt because they arent being tightly monitored.

 

[Mman]

Our wakeups

ARE AMAZING.

Our wakeups without a BIS are equally amazing. To me it's main use is in TIVA cases when there is no endtidal to monitor. Or high risk cases like emergency c-sections, etc. ASA 1 having a lap chole? It adds essentially zero value to the case and does add some cost.

 

[Mman]

there is a reason why the high risk groups are high risk and it isnt because they arent being tightly monitored.

🙂

Yeah, it's more like you are choosing between making sure they are anesthetized and making sure they are alive. Sometimes the line is much finer than others and I'd always rather have the patient complain of awareness than their family deal with a funeral.

 

[etudiante04]

Makes sense. Thanks for sharing your thought process.

 

[imfrankie]

That's a shame, dude.

I won't ever tout BIS as a recall eliminator.

I WILL tout it as another great adjunct in our armamentarium,

enabling the clinician to run a

TIGHTER ANESTHETIC.

Every GA at my professional crib is done with BIS.

Our wakeups

ARE AMAZING.

You can continue to doubt, Blade.

I'm convinced of BIS efficacy and I've been convinced for a long time now.

You are selling yourself, your practice, and your patients

SHORT.

I wish you could come work with me for JUST ONE DAY and see what I'm talking about.

Didn't know wake-ups were anything but amazing.

 

[jetproppilot]

Our wakeups without a BIS are equally amazing. To me it's main use is in TIVA cases when there is no endtidal to monitor. Or high risk cases like emergency c-sections, etc. ASA 1 having a lap chole? It adds essentially zero value to the case and does add some cost.

I humbly disagree.
Most anesthetics are deeper than needed.

 

[jwk]

I humbly disagree.
Most anesthetics are deeper than needed.

Absolutely agree.

 

[jwk]

Didn't know wake-ups were anything but amazing.

Ain't that the truth? It's my favorite part of the whole thing! We poison these people, bring them to the edge, yank them back, and they wake up and go home. It's a beautiful thing!

 

[Mman]

I humbly disagree.
Most anesthetics are deeper than needed.

Based on what criteria? Because I'd argue that if you use a BIS to run an anesthetic lighter than you otherwise would you are actually increasing your risk of awareness.

 

[jwk]

Based on what criteria? Because I'd argue that if you use a BIS to run an anesthetic lighter than you otherwise would you are actually increasing your risk of awareness.

Before BIS, you really had no way of determining objectively what was "light" and what was not. Anyone who tries to run their case and keep the BIS just under 60 is not playing smart, but running it 40-50 is perfectly reasonable and there is virtually zero chance of "awareness". Running a BIS of 30 or below is pointless - you're either too deep or have circulation/perfusion issues. It makes no sense to me to run a case at 1.4 MAC if the BIS is 20.