CNN article re: awareness under anesthesia

[epidural man]

no it is not my job to interpret emg on a BIS monitor...

i don't need to respond to epidural man's points. this debate isn't going to be productive.

Ah come on man. I'm not sure the purpose of this forum is to make the world more productive. I thought the purpose was exactly the opposite - to waste our time as a diversion to doing something productive.

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[BuzzPhreed]

You have to prove that BIS does not measure anesthetic depth.

The burden of proof is on the person making the positive claim. Besides did you completely skip/ignore what I posted?

I get it that you struggle to understand when a BIS is giving you useful information. I would disregard a monitor like that as well.

No, that's not it at all. The concern is that it is providing misleading information. And that it is also a distraction.

 

[pgg]

Man, for a scientist, you've got some loose logic here.

I think if you are going to hold BIS to this standard, you need to hold the SAME standard to every monitor you use, and if it hasn't been shown to improve outcomes, then to prevent yourself from being a miserable hypocrite, you need to disregard and stop using ALL monitors that don't show improved outcomes with its use. Think about the shape of the ETCO2 waveform. That waveform often contains such subtle but VERY useful information. I doubt the waveform shape has ever been documented to change outcomes - yet we rely on that rather heavily for many things.

Of course we do. Capnography is about as transparent and un-manipulated a measurement as can be, and the physics and physiology are very well understood.

So, if you won't use BIS because they have a "secret" algorithm that they won't share, then you need to apply that SAME logic and standard to EVERYTHING you use. That means you will unlikely be able to use anything electronic at your work or in your home.

Dude, you're trying too hard. These analogies suck:

Your ultrasound machine likely has secret software so the compound imaging makes things look beautiful.

Ultrasound is a straightforward measurement of anatomy that we confirm as we watch the needle move in real time. I don't think I've ever seen a good ultrasound image that I had any reason to believe didn't reflect the reality of the structure under it. Shadows and resolution/frequency/depth tradeoffs are easily understood and predictable. I don't have a bit of skepticism that a good image shown on the ultrasound isn't what's actually under the skin.

On the other hand, how do I tell the difference between a "good" 55 and a "bad" 55 on the BIS?

If you use spotify or something like it, it uses secret encryption software.

I don't use closed-source or proprietary encryption for anything for exactly this reason. The closest I come to it is using https/SSL when web browsing for shopping or banking, but those algorithms have undergone extensive peer review. Hell, I've implemented some of the common industry encryption algorithms myself in my pre-med days. Of course back then we used 3DES and not AES but I hope you get the point.

You will need to throw your phone away today. It is LOADED with secret software.

I have confidence that my phone does what I want it to do, because it, you know, works as a phone. Remember, the entire crux of this BIS debate is that many of us don't have confidence that it does what we want and expect an "anesthetic depth" monitor to do.

It's not privacy we're interested in, it's function. I don't know how Google's search engine works, but it works and I use it.

None of these companies say anything about the secrets they have created, nor apologize that you don't know what it is, or how it is done. Please apply the same standard you have for BIS to all technology around you.

This is crazy talk. It's such a bizarre argument that I really have trouble putting into words how much of a wacky, irrelevant, bizarro-world argument it is.

You're really arguing that I should hold the toaster that cooks my breakfast muffin to the same standards of quality and peer-review as a monitor used in providing anesthesia? Really? As long as the toaster doesn't burn my house (or my breakfast) I'm cool with it. I have higher standards for the stuff I use in the OR.


I'm not a BIS hater. There's something to be said for a processed EEG monitor ... it's noninvasive and may be a useful data point in cases where depth is harder to objectively measure, such as some TIVAs. I think their utility doesn't outweigh their expense, most of the time. (And I'm usually quite happy to spend tens of anesthesia dollars in the context of a hospital admission.)

 

[epidural man]

The burden of proof is on the person making the positive claim. Besides did you completely skip/ignore what I posted?



No, that's not it at all. The concern is that it is providing misleading information. And that it is also a distraction.

I didn't skip the article you posted. it shows that BIS doesn't prevent awareness. So. That isn't what BIS is useful for at all.

Also, I disagree. Most would argue that there is a very STRONG correlation between anesthetic depth and BIS number. Most would argue that if you give 10 awake people induction dose of propofol (and nothing else), that BIS numbers will decrease. That is clear as a bell for MOST people.

I would argue that the few on here that are aguing that BIS does NOT do that, should prove that - because that is against standard thought.

 

[epidural man]

Man, for a scientist, you've got some loose logic here.



Of course we do. Capnography is about as transparent and un-manipulated a measurement as can be, and the physics and physiology are very well understood.




Dude, you're trying too hard. These analogies suck:



Ultrasound is a straightforward measurement of anatomy that we confirm as we watch the needle move in real time. I don't think I've ever seen a good ultrasound image that I had any reason to believe didn't reflect the reality of the structure under it. Shadows and resolution/frequency/depth tradeoffs are easily understood and predictable. I don't have a bit of skepticism that a good image shown on the ultrasound isn't what's actually under the skin.

On the other hand, how do I tell the difference between a "good" 55 and a "bad" 55 on the BIS?



I don't use closed-source or proprietary encryption for anything for exactly this reason. The closest I come to it is using https/SSL when web browsing for shopping or banking, but those algorithms have undergone extensive peer review. Hell, I've implemented some of the common industry encryption algorithms myself in my pre-med days. Of course back then we used 3DES and not AES but I hope you get the point.



I have confidence that my phone does what I want it to do, because it, you know, works as a phone. Remember, the entire crux of this BIS debate is that many of us don't have confidence that it does what we want and expect an "anesthetic depth" monitor to do.

It's not privacy we're interested in, it's function. I don't know how Google's search engine works, but it works and I use it.



This is crazy talk. It's such a bizarre argument that I really have trouble putting into words how much of a wacky, irrelevant, bizarro-world argument it is.

You're really arguing that I should hold the toaster that cooks my breakfast muffin to the same standards of quality and peer-review as a monitor used in providing anesthesia? Really? As long as the toaster doesn't burn my house (or my breakfast) I'm cool with it. I have higher standards for the stuff I use in the OR.


I'm not a BIS hater. There's something to be said for a processed EEG monitor ... it's noninvasive and may be a useful data point in cases where depth is harder to objectively measure, such as some TIVAs. I think their utility doesn't outweigh their expense, most of the time. (And I'm usually quite happy to spend tens of anesthesia dollars in the context of a hospital admission.)

PGG...

It is NOT a bad analogy. I am asking for the same treatment of BIS as all other monitors we use. The arguement Napster is making is this

BIS sucks ALL THE TIME because on occasion it gives crappy data and isn't realiable all the time as an anesthestic depth monitor.

Fine. If you are going to make this argument, you also have to apply the same standards to all monitors we use. So, if you make this argument, I personally feel - to not be a world class hypocrit, you also have to say the same thing about all monitors. If you ever have an a-line that gives crappy, unreliable or unpredictable data - you then have to claim that a-lines are crappy ALL THE TIME and not to be used ever. I'm not sure how that is faulty logic.

Plus, I doubt you understand all the proprietary software you use on a daily basis. That seems faulty logic to me.

You tell a bad "BIS" number the same way you tell a bad CVP number, or screwy urine output, or a spurious HCT on your istat, or an illogical SPO2 number. You use all the other data you have been provided.

Again, why does BIS, out of ALL THE OTHER moniters we use have to live up to such a higher standard - such that it has to work ALL THE TIME and be reliable ALL THE TIME? So very very very strange....

Finally, you last statement about cost, etc. I agree. I rarely use BIS, but I do find it has utility. To say otherwise (as a few have done - flately said it is completely useless) is hipocritical in my mind. Same with an a-line....I rarely need it or use it, but I do sometimes. Sometimes when I do, it doesn't give me useful information. So be it. I move on.

 

[pgg]

Compared to all of our other monitors, the BIS really stands apart when it comes to a lack of transparency.

The same can be said of its marketing. Aspect has been kind of sleazy there, with FUD and especially shoddy sponsored research.

And the expensive disposable electrodes ... really, there's no reason the machine couldn't have a couple of re-usable leads that could connect to the same super cheap stickies we use for intraop ECGs. Imaging if your 3- or 5-lead ECG couldn't connect to those cheap stickers, and instead every patient needed a $16 set of disposable leads too.

Just about everything about the BIS and Aspect has annoyed me since the day they showed up in our ORs.

I guess the best I can say for it is that it's not a completely worthless monitor.

 

[BuzzPhreed]

I didn't skip the article you posted. it shows that BIS doesn't prevent awareness. So. That isn't what BIS is useful for at all.

Also, I disagree. Most would argue that there is a very STRONG correlation between anesthetic depth and BIS number. Most would argue that if you give 10 awake people induction dose of propofol (and nothing else), that BIS numbers will decrease. That is clear as a bell for MOST people.

I would argue that the few on here that are aguing that BIS does NOT do that, should prove that - because that is against standard thought.

What is the BIS useful for if it's not preventing awareness? There is absolutely horsecrap-level of proof that it actually works as a "depth of anesthesia" monitor, or that such a monitor (as it's sometimes erroneously used) even has a meaningful impact on cost or outcome in the first place.

I'm with pgg; I think your logic is a bit tortured, especially the part where you are basically asking us to prove that Santa Claus doesn't exist. Makes me believe that you don't understand the concept of "burden of proof" when someone or some entity is making a claim.

This is the key to the whole bag of marbles right here:

"Traditionally, most anaesthetic drugs were given using standard dosing guidelines without applying knowledge of their pharmacokinetics and dynamics to control their administration. Recently, improved understanding of pharmacokinetics and pharmacodynamics has permitted target controlled infusion for i.v. agents or end-tidal controlled inhaled administration for inhaled drugs."

http://bja.oxfordjournals.org/content/97/1/85.full

In other words you don't need a DoA monitor. Unless you're a hack... or a CRNA.

 

[epidural man]

..... especially the part where you are basically asking us to prove that Santa Claus doesn't exist.

I...uh....hmm....

Makes me believe that you don't understand the concept of "burden of proof" when someone or some entity is making a claim.

Like the claim that BIS is a useless monitor?

umm....uh....

 

[BuzzPhreed]

I...uh....hmm....

Like the claim that BIS is a useless monitor?

umm....uh....

Like I said already, you don't understand "burden of proof".

The claim, made by the manufacturer and certain other proponents of this device, is that the BIS is useful to assess depth of anesthesia. The data used to support that is all over the place, with most studies indicating that it is not. Therefore, the conclusion is that the data doesn't fully support the claim, therefore the BIS -- as it is being marketed -- is a useless device. That's not a claim; it's a rejection of their claim based on the evidence.

Until the makers of the BIS can definitively show that it actually does what they say it does, it is fair to draw that conclusion. There is no "burden of proof" on me or anyone else to disprove a negative, which is what you're asking. You're essentially asking me (and others) to prove that it doesn't work. That's the same as asking any of us to prove that pink unicorns don't exist. That's just not how it works. The burden of proof is on the person making the claim. Now do you see the flaw in your logic?

This is Philosophy 101 stuff, my man. And an opportunity for you to get smarter.

 

[epidural man]

Like I said already, you don't understand "burden of proof".

The claim, made by the manufacturer and certain other proponents of this device, is that the BIS is useful to assess depth of anesthesia. The data used to support that is all over the place, with most studies indicating that it is not. Therefore, the conclusion is that the data doesn't fully support the claim, therefore the BIS -- as it is being marketed -- is a useless device. That's not a claim; it's a rejection of their claim based on the evidence.

Until the makers of the BIS can definitively show that it actually does what they say it does, it is fair to draw that conclusion. There is no "burden of proof" on me or anyone else to disprove a negative, which is what you're asking. You're essentially asking me (and others) to prove that it doesn't work. That's the same as asking any of us to prove that pink unicorns don't exist. That's just not how it works. The burden of proof is on the person making the claim. Now do you see the flaw in your logic?

This is Philosophy 101 stuff, my man. And an opportunity for you to get smarter.

Okay Buzz, I concede your point, but just a couple of questions.

How to you assess for depth of anesthesia?

Also, this is the claim by Covedian

"Bispectral Index™ (BIS™) technology was the first clinically proven and commercially available direct measure of the effects of anesthetics and sedatives on the brain."

Just curious, what do you use to measure the effects of anesthetics and sedatives on the brain?

Also, you mentioned there seems to be data that supports BIS as a depth monitor is all over the place. What studies have shown that it doesn't show depth? And remember, I don't care about studies showing that it doesn't prevent awareness. I want studies that directly look at anesthetic depth and disprove that a BIS number (and bispectral index) does NOT correlate with anesthetic depth. I am unaware of those. I am excited for this education you are going to provide.

 

[BuzzPhreed]

Let me instead frame this a different way: why do you need a machine to tell you the depth of anesthesia, when that machine has never demonstrated an impact on outcome? What does it matter?

I use clinical judgment, and careful monitoring of the patient's physiologic status intraoperatively, to determine whether or not their anesthesia is adequate. I don't need another monitor to stare at. You know what? I've yet to have any patient complain to me (or anyone else) post-operatively about awareness, inadequate anesthesia, etc. in the over 10,000 anesthetics I've been involved in directly or in a supervisory role at this point in my career. The last time I used a BIS was in 2007. Guess what? My patients, when I'm in charge of the anesthesia solo, still wake up fast and comfortably. I don't need a machine to help me do that and potentially distract me from paying attention to more important things.

But, it has been an interesting concept that looked good on the drawing board. Sadly it has proved to be totally superfluous in practice. But Aspect committed to it and spent a ****-pile of money developing it. So now I think, like many other unnecessary technologies in our profession that people attempt to sell us, the BIS is nothing more than a dubious solution looking for a problem. There is no real problem to solve here... for a good clinician. And even if you're not good this is not really a solution anyway. More like a false security blanket just that can at best only corroborate something you should already know. If you need this machine to tell you that you're stepping on the gas pedal too hard, then you're probably a hack to begin with and... well... I wouldn't rely on this machine correcting your other co-requisite deficiencies as a clinician. In my opinion all it does is add cost to the anesthetic and serve as a potential distraction. But you repeat something long and often enough and people stop questioning its validity and just start to believe it has value, despite the fact that it has never been clinically validated as a "depth of anesthesia" monitor despite all the published studies.

Sorry Aspect Medical/Covidien. I know you hate guys like me. But I call bullsh*t when I see it. However, that's really your problem not mine.

 

[BuzzPhreed]

I want studies that directly look at anesthetic depth and disprove that a BIS number (and bispectral index) does NOT correlate with anesthetic depth. I am unaware of those. I am excited for this education you are going to provide.

Already posted.

Read the meta-analysis/review I linked. There is no correlation with anesthetic level and the reading on the machine in individual patients. Therefore it has no predictive value RE: what is actually "too" much anesthesia for any given patient.

Of course, this requires people to actually read and understand clinical studies, and not just the abstracts...

 

[epidural man]

(By the meta-analysis isn't science and proves nothing. I'm surprised you feel so strongly about BIS and still believe in meta-analysis)

Anyway, questions for buzz and napster.

Often when people argue, they are so worried about making their point they totally miss the point of what the other person is saying.

So, in a few sentences - what do you think I am arguing? What do you think my point is?

Here is what I understand of your arguments.

1. The BIS number has absolutely no correlation to anesthetic depth in any circumstance. Therefore, there will never be an anesthetic case where having a BIS number is useful to the anesthesiologist.

2. BIS monitoring has never shown to improve outcomes (or the majority of articles show they don't...obviously there are articles showing improvement) so because of this, the utility of BIS monitoring is zero. There is no case or situation where BiS would ever be useful.

Post what you think I am saying, then correct my statements above if I missunderstand your points.

 

[urge]

I have an anecdote equal to or maybe even better than nap$ster's.

We got a bunch of BIS monitors towards the end of my residency. Mine outside the box case was on a GA for (IDK excatly now it was 7-8 years ago at this point) a big ventral hernia repair or something. The guy's BIS was 80+ after induction and even after cranking the sevo up to 1.5 MAC and pushing propofol which only made his pressure plunge. My attending was freaking out. The guy got almost 30mg of midazolam for a slightly longer than two-hour procedure, because every time you'd give 2-3 mg, the BIS would dump down into the low 70's or upper 60's. We changed the strip, repositioned him, did just about everything. 2-3 mg of midaz and 5-10 minutes after dipping it would start to creep back up into the 80's.

That patient was supposed to go home. Spent two days in the hospital. I don't think he remembered anything for the first 24 hours.

Why people would give long acting drugs iv for a BIS number is beyond me. Just crank the gas to 3 MACs and run a pressor if you are concerned. Or just ignore it based on your own judgement. I would not expect a machine to work every single time. Especially considering that all our practices are based on 95% probability.

 

[Mman]

The BIS can provide useful information. Anybody disagreeing with that is just being stupid and/or arguing for the sake of arguing. Should it be standard of care? Of course not. Can it help you determine the level of anesthetic depth? Of course it can. That isn't saying it always can. That's like I can say that phenylephrine can help make the BP go up. Does it always? No. I've seen a patient with bad pulm HTN have their BP go down from phenylephrine. But throwing out a random example of when it doesn't work doesn't mean it can't ever be helpful.

I probably use it in about 5-10% of patients, mostly TIVAs, and it can be useful.

And if you ever had a case of intraop awareness during a TIVA and you didn't use a BIS when you had it immediately available? Well let's just say you are probably not going to have a very good defense.

I think true actual awareness probably happens about 1/10K or 1/20K cases. Pretty darn rare. Usually in life threatening emergency situations. And obviously 99% of the patients you hear talk about awareness were during a MAC or regional case where they woulda/coulda/shoulda had it explained to them that they may remember things during surgery. But I've personally met 2 patients that had real, actual intraop awareness under GA during previous surgeries. One was during an emergency CABG and the other was in a 50 kg lady that had some of the highest tolerance I've ever seen to our drugs (after 10 mg versed and 250 fentanyl she was still wide awake chatting prior to induction and took more than 200 mg propofol to go apneic).

So it happens. We don't hear about every single case of it and it is really rare so the whole "it never happened" is more luck than skill IMHO. I mean I haven't had any of my patients develop MH but that doesn't mean I'm just better at avoiding it.

 

[Mman]

Why people would give long acting drugs iv for a BIS number is beyond me. Just crank the gas to 3 MACs and run a pressor if you are concerned. Or just ignore it based on your own judgement. I would not expect a machine to work every single time. Especially considering that all our practices are based on 95% probability.

In situations where I have been using a BIS and found the number not believable I throw it in the trash can and carry on without it.

 

[jwk]

no it is not my job to interpret emg on a BIS monitor...

i don't need to respond to epidural man's points. this debate isn't going to be productive.

Don't you interpret the rhythm on your EKG monitor?

 

[nap$ter]

Don't you interpret the rhythm on your EKG monitor?

the ekg is a standard of care ASA monitor and provides useful information that guides useful interventions - all residents and physicians are taught to interpret this data.

the emg on a BIS is a non-standard of care monitor not endorsed by the ASA - interpretation of the emg from a BIS does not show up on the boards (I would have loved it if an examiner had asked me about it). BIS interpretation will never be part of my job.

it is laughable that you would compare the anesthesiologist duty of ekg interpretation to interpretation of the emg on a BIS - i am really looking forward to where you go with that one...

 

[nap$ter]

And if you ever had a case of intraop awareness during a TIVA and you didn't use a BIS when you had it immediately available? Well let's just say you are probably not going to have a very good defense.
.

This is absolute horsefeces. The studies are all above.

 

[nap$ter]

(By the meta-analysis isn't science and proves nothing. I'm surprised you feel so strongly about BIS and still believe in meta-analysis)

Anyway, questions for buzz and napster.

Often when people argue, they are so worried about making their point they totally miss the point of what the other person is saying.

So, in a few sentences - what do you think I am arguing? What do you think my point is?

Here is what I understand of your arguments.

1. The BIS number has absolutely no correlation to anesthetic depth in any circumstance. Therefore, there will never be an anesthetic case where having a BIS number is useful to the anesthesiologist.

2. BIS monitoring has never shown to improve outcomes (or the majority of articles show they don't...obviously there are articles showing improvement) so because of this, the utility of BIS monitoring is zero. There is no case or situation where BiS would ever be useful.

Post what you think I am saying, then correct my statements above if I missunderstand your points.

no thanks. not interested in discussing BIS further with you - i think both arguments have reached the end of the tracks.

more interested in why you think the statistics of meta-analysis are invalid?

 

[nap$ter]

In situations where I have been using a BIS and found the number not believable I throw it in the trash can and carry on without it.

if you must put something on the forehead let it be something useful like a cerebral oximeter.

 

[Mman]

This is absolute horsefeces. The studies are all above.

You have not provided any good study showing that BIS doesn't decrease awareness risk during TIVA. There are plenty of studies that suggest BIS isn't better than monitoring end-tidal gas concentrations. But we can't monitor end tidal propofol. When you do a TIVA with tucked arms, how do you know your IV didn't infiltrate?

 

[Mman]

if you must put something on the forehead let it be something useful like a cerebral oximeter.

I use cerebral oximeters for sitting position cases. They can be helpful. I use BIS monitors when I feel they are appropriate. They, too, can be helpful.

If you think there is never an indication to use a BIS monitor, you either don't take care of a wide array of patients and surgeries, or you are too angry about it to be rational. And keep in mind, I'm a person that rarely uses them.

 

[nap$ter]

You have not provided any good study showing that BIS doesn't decrease awareness risk during TIVA. There are plenty of studies that suggest BIS isn't better than monitoring end-tidal gas concentrations. But we can't monitor end tidal propofol. When you do a TIVA with tucked arms, how do you know your IV didn't infiltrate?

apparently you missed buzzphreed's posts and the big bis studies - here's a repeat from buzz's post:

"Traditionally, most anaesthetic drugs were given using standard dosing guidelines without applying knowledge of their pharmacokinetics and dynamics to control their administration. Recently, improved understanding of pharmacokinetics and pharmacodynamics has permitted target controlled infusion for i.v. agents or end-tidal controlled inhaled administration for inhaled drugs."

http://bja.oxfordjournals.org/content/97/1/85.full

i know my IV hasn't infiltrated because i monitor the flow (and HR, BP, patient movement, etc...) - if the drip rate of my chaser changes i investigate - the patient will not wake up before i investigate (and if arms are tucked i always have at least 2 good IV's) - and you can always give volatile in an emergency...

show me the study that shows BIS prevents awareness (or even helps in any way) when an IV infiltrates during a TIVA? i haven't seen any study demonstrating that a BIS can tell you if an IV infiltrates... remember, the burden of proof is on you.

 

[nap$ter]

I use cerebral oximeters for sitting position cases. They can be helpful. I use BIS monitors when I feel they are appropriate. They, too, can be helpful.

If you think there is never an indication to use a BIS monitor, you either don't take care of a wide array of patients and surgeries, or you are too angry about it to be rational. And keep in mind, I'm a person that rarely uses them.

why is this logical? i do not think there is ever an indication to use a BIS, and

a. i work at a regional referral center - i do take care of a wide array of patients and surgeries.

so,

b. i must be angry?

why do you think i'm angry? why do you think i'm irrational?

 

[epidural man]

no thanks. not interested in discussing BIS further with you - i think both arguments have reached the end of the tracks.

more interested in why you think the statistics of meta-analysis are invalid?

Nap,

I respect you don't want to discuss further. But I want to supplicate that you read the articles that have been referenced. First of all, there isn't a meta-analysis. It's concerning that buzz doesn't know what a meta-analysis is, but he posted a single center trial, and a review article.

I would also ask ANYONE following this thread to do the same. Please read the articles, and form thoughts from that. Here are some claims being made in this thread.

BIS does NOT measure depth of anesthesia and there are studies to prove it.
BIS has NEVER been shown to improve outcomes
BIS is useless in EVERY CASE

Read the articles that was posted to PROVE those above facts. The review article is an excellent resource. In this review article, you will find citations and a discussion that yes, BIS does measure depth of anesthesia, and yes BIS has been shown in trials to improve some outcomes in the delivery of anesthetics.

You will also find that yes, BIS does not prevent awareness. However, as I have mentioned, so what. No one is arguing that it should be used to absolutely and emphatically prevent awareness.

PGG has argued that he doesn't like BIS for several reasons. His arguments are reasonable. ASPECT has been horrible - they even tried to make BIS a standard of care. That has left a lot of us with a bad taste in our mouth for this technology. You can't argue with that.

 

[nap$ter]

Nap,

I respect you don't want to discuss further. But I want to supplicate that you read the articles that have been referenced. First of all, there isn't a meta-analysis. It's concerning that buzz doesn't know what a meta-analysis is, but he posted a single center trial, and a review article.

I would also ask ANYONE following this thread to do the same. Please read the articles, and form thoughts from that. Here are some claims being made in this thread.

BIS does NOT measure depth of anesthesia and there are studies to prove it.
BIS has NEVER been shown to improve outcomes
BIS is useless in EVERY CASE

Read the articles that was posted to PROVE those above facts. The review article is an excellent resource. In this review article, you will find citations and a discussion that yes, BIS does measure depth of anesthesia, and yes BIS has been shown in trials to improve some outcomes in the delivery of anesthetics.

You will also find that yes, BIS does not prevent awareness. However, as I have mentioned, so what. No one is arguing that it should be used to absolutely and emphatically prevent awareness.

PGG has argued that he doesn't like BIS for several reasons. His arguments are reasonable. ASPECT has been horrible - they even tried to make BIS a standard of care. That has left a lot of us with a bad taste in our mouth for this technology. You can't argue with that.

let me make the claims above specific to my views:

BIS does not provide useful information about depth of anesthesia in the real world where complicated combinations of drugs and paralytics are given to a varied patient demographic.

I disagree with the conclusions of any study I have seen that postulated an improved outcome with the use of the BIS

BIS is useless in every case.

what did you mean by this?:

"By the meta-analysis isn't science and proves nothing. I'm surprised you feel so strongly about BIS and still believe in meta-analysis)"

it sounds like you don't believe in the statistics of a meta-analysis...

 

[sevoflurane]

In reading this thread, my BIS has gone from 90 to 05.

My thoughts on it's use?

I don't use it beacuse I don't need it. Vital signs, peak preassures and knwoledge of multimodal anesthesia is sufficient for every single case I've ever done. It often does correlate with patient depth but at the same time it can certainly muddy the waters when the BIS reads 90 and you KNOW the patient is in Stage III.

I have used the BIS extensively. It may be useful for some people, but I have put it in the anesthesia trick door along side of the bullard and combitube. Of course, this is just one man's opinion.

 

[pgg]

But we can't monitor end tidal propofol.

Someday?

http://www.ncbi.nlm.nih.gov/pubmed/17413902

Heard about this in residency, but haven't heard anything since.

 

[Gern Blansten]

If y'all aren't careful, you are going to summon the ghost of aghast1 (Barry Friedberg) back into the forum. I don't think the emoticon level would be tolerable.

 

[Mman]

why is this logical? i do not think there is ever an indication to use a BIS, and

a. i work at a regional referral center - i do take care of a wide array of patients and surgeries.

so,

b. i must be angry?

why do you think i'm angry? why do you think i'm irrational?

because you are irrational in your posting

 

[pjl]

Since we are discussing this, lets talk about the utility of CVP.

I use the BIS when a patient is very worried about recall, and asks me to use it. I discuss limitations if they appear to care, which is almost never.

 

[deleted171991]

Since we are discussing this, lets talk about the utility of CVP.

It is a BIS monitor connected to a central venous line. They must share the same random number generator, just on different intervals.

 

[nap$ter]

because you are irrational in your posting

example?

i don't think i've ever said an angry or irrational thing on this forum - every view i've ever expressed has been humbly based on data or pragmatism.

 

[anes]

The only people I've seen use the BIS with regularity are the weakest anesthesiologists. The forehead is limited real estate. If I had to choose between Cerebral oximeter or BIS, guess which one would win every single time. The Cerebral oximeter.

How many of us have had a BIS reading of 80 with etSevo of 2? Which of those two numbers would you trust?

Now if you have a healthy 20 year old, with normal vital signs having appendectomy with a BIS of 20 and etSevo of 0.4% what would you do? I would increase the sevo.

I've been in both of these situations, and I'm sure if I used any of the info from the BIS, harm would have been done to the patient.

 

[nimbus]

The only people I've seen use the BIS with regularity are the weakest anesthesiologists. The forehead is limited real estate. If I had to choose between Cerebral oximeter or BIS, guess which one would win every single time. The Cerebral oximeter.

I routinely use both during carotids and pump cases. Both need to be interpreted in the context of the whole picture. I must be weak.

 

[BuzzPhreed]

I routinely use both during carotids and pump cases. Both need to be interpreted in the context of the whole picture. I must be weak.

No, you just drank too much of their corporate Kool-Aid.

http://www.ncbi.nlm.nih.gov/m/pubmed/15277912/

It didn't work or make a meaningful impact in 2004, unless you were maybe already a hack that needed a machine to tell you that you were giving too much anesthesia. What's the difference now? They've had ten years to hone their marketing skills and (for some reason) make certain people believe that this machine actually does something important when, the fact is, it has NEVER been validated as a depth of anesthesia monitor.

 

[jwk]

This is absolute horsefeces. The studies are all above.

Pray they don't call Carol Weihrer as a plaintiff's witness, complete with eye patch.

 

[jwk]

the ekg is a standard of care ASA monitor and provides useful information that guides useful interventions - all residents and physicians are taught to interpret this data.

the emg on a BIS is a non-standard of care monitor not endorsed by the ASA - interpretation of the emg from a BIS does not show up on the boards (I would have loved it if an examiner had asked me about it). BIS interpretation will never be part of my job.

it is laughable that you would compare the anesthesiologist duty of ekg interpretation to interpretation of the emg on a BIS - i am really looking forward to where you go with that one...

A cerebral oximeter is a "non-standard of care monitor not endorsed be the ASA" either, but apparently you use and interpret the data from that. For that matter, temperature monitoring is not required by the ASA for every case either, but I'll bet you use that as well.

Clearly we won't convince each other that our opinion is the correct one, and I realize there are a lot of people that think BIS is absolute garbage. Unfortunately, I think that a lot of people let their opinion of Aspect Medical and their original marketing techniques with BIS 10 or more years ago cloud or color their opinion of the device, and have never made any serious attempt at using it (or have never used it at all) and simply fall back on word-of-mouth negativity regarding the company and studies that cast it in a dubious light. I think it has it's place - you don't. We agree to disagree.

 

[anes]

I routinely use both during carotids and pump cases. Both need to be interpreted in the context of the whole picture. I must be weak.

I didn't say that only weak anesthesiologists use the BIS. I said that the only ones I've seen use it regularly are weak ( people I wouldn't trust to take care of my family).

I remember a case during fellowship. We were inducing a patient with AS. My attending insisted on using the BIS for a slow titrated induction. We induced BIS remained 70-80 for a good straight 10 min. Patient received 8 mg of midaz, 300 fent, 160 of propofol, and some agent, along with several boluses of phenylephrine. My attending finally said okay let's paralyze and intubate with the BIS still 75ish. When I asked why he insisted on using the bis for induction if he was going to ignore the number. His reply was "if it's 40 you know patient is asleep... If it's 80 then the bis is wrong".

I routinely use the Cerebral oximeter for pump cases and carotids. I would trust a Cerebral oximeter reading of 20 as something I need to act on than a bis of 2.

Let me ask you this, has the BIS provided any tangible evidence that has changed your management of a patient?

 

[epidural man]

what did you mean by this?:

"By the meta-analysis isn't science and proves nothing.

it sounds like you don't believe in the statistics of a meta-analysis...

I have several reasons to not believe meta-analysis.

First and foremost, because I do a ton of reading. Anyone (I personally feel) that reads a lot of literature will come to the very same conclusion that meta-analysis DO NOT tell the truth. One will read the articles used in the meta-analysis, deconstruct them, glean what they can from them, and then read a meta-analysis. Almost always, the meta-analysis misses the point, doesn't tell the correct story, or basically lies depending on the bias of the writers. This has happened to me time and time again. That is the first main reason.

Secondly, most societies, or standards use randomized, controlled, blinded studies as the highest quality of evidence. Meta-analysis are (almost) never in the hiarchy of quaility of evidence. (I say almost because I am sure there is someone out there that does rank it as a high quaility - but I am not aware of it). There is a reason for that. A controlled trial will always trump pooling random data that have absolutely no comparablity, but are compared anyway. The whole point of a CONTROLED trial is to control as many variable as possible to minimize the effects of bias. However, meta-analysis completely ignores this. For example, the Modified Guyatt Evidence Assesment Grid rates grades of evidence based on RCT's of good quality as highest, RCT with methodological weakness as next, then observational studies as last. Meta-analysis has no part in grading level of evidence. (Parenthetically, chochrane produces a nice check list that someone can use to grade the quality of the RCT or observational trial).

Thirdly - did I mention they lie? Take for example a recent meta-analysis by Apfel about post-dural puncture headaches. If one were to read this, the would come away thinking that leaving a spinal catheter in for 24 hrs does absolutely nothing for the headache and it was a waste of time. However, if one actually read the articles that was references on the subject in the analysis, the reader will come away with a VERY DIFFERENT opinion. How is that possible? It is in the way the question is asked. So if you ask the question, does it prevent a headache, the answer may be no and in the anaylsis, it makes the claim it is worthless. However, if you read the articles, you understand that although headache incidence might not be different, the outcomes were HUGELY different. Patients suffered WAY LESS with catheters in place. But the analysis doesn't tell you this because of the way they asked the question. It all has to do with how the writer wanted to tell the story. It's WAY better to avoid meta-analysis all together. Read the articles. Read the RCT's. Grade them based on the Cochrane scale and decide what they say.

There are other reasons....those are a few.

 

[deleted171991]

Meta-analyses are just another way to BS one's way to a paper. When one combines multiple independent studies, the probability of an error goes through the roof. One doesn't need a PhD in math to see it.

All the statistical methods use hypotheses that are almost never respected by the "researchers" who sign off on the data analysis for 90+% of the papers. Hence that p is almost never truly under 0.05, whatever they say. The more complex the study, the more worthless the conclusions.

Until we will start withdrawing academic degrees based on papers whose conclusions were proven false later (and I don't mean fraud, just the usual incompetence of resume chasers), this crap will not stop.

 

[epidural man]

A cerebral oximeter is a "non-standard of care monitor not endorsed be the ASA" either, but apparently you use and interpret the data from that. For that matter, temperature monitoring is not required by the ASA for every case either, but I'll bet you use that as well.

Clearly we won't convince each other that our opinion is the correct one, and I realize there are a lot of people that think BIS is absolute garbage. Unfortunately, I think that a lot of people let their opinion of Aspect Medical and their original marketing techniques with BIS 10 or more years ago cloud or color their opinion of the device, and have never made any serious attempt at using it (or have never used it at all) and simply fall back on word-of-mouth negativity regarding the company and studies that cast it in a dubious light. I think it has it's place - you don't. We agree to disagree.

JWK,

I totally agree with you -hence the reason I started down this path. Statements like "it's a useless monitor!", or "show me outcome studies!" are what made me think I should say something. I wonder if there is correlation between being dogmatic about something so pointless and Axis II disorders.

Also, to demand that BIS has outcome studies, but not demand the same for other monitors used seems ridiculous to me as well. It reminds me of when the FDA claimed that droperidol was causing harm and gave a black box warning without any peer-reviewed evidence of such harm - yet at the SAME TIME, zofran and others had plenty of peer-reviewed evidence of the same harm that was accused of droperidol. Yet those drugs had no such warning placed. Based on this logic and the fallacious arguements of some on this post, I recommend those peoples find a job at the FDA.

 

[Mman]

Let me ask you this, has the BIS provided any tangible evidence that has changed your management of a patient?

Yes.

 

[nimbus]

I didn't say that only weak anesthesiologists use the BIS. I said that the only ones I've seen use it regularly are weak ( people I wouldn't trust to take care of my family).

I remember a case during fellowship. We were inducing a patient with AS. My attending insisted on using the BIS for a slow titrated induction. We induced BIS remained 70-80 for a good straight 10 min. Patient received 8 mg of midaz, 300 fent, 160 of propofol, and some agent, along with several boluses of phenylephrine. My attending finally said okay let's paralyze and intubate with the BIS still 75ish. When I asked why he insisted on using the bis for induction if he was going to ignore the number. His reply was "if it's 40 you know patient is asleep... If it's 80 then the bis is wrong".

I routinely use the Cerebral oximeter for pump cases and carotids. I would trust a Cerebral oximeter reading of 20 as something I need to act on than a bis of 2.

Let me ask you this, has the BIS provided any tangible evidence that has changed your management of a patient?

More often than not the bis just serves to reassure me that the patient is anesthetized. If the bis suddenly rises during a pump run, I ask the perfusionist to confirm the vaporizer is delivering what he thinks it is delivering. That is worth it to me. If a device or technique allows me to feel less stress or anxiety during a procedure, I consider it superior and worthwhile.

 

[IlDestriero]

I haven't used the BIS in a decade.
The only time it might make me more secure in my anesthetic would be for a crash general C-section when I'm running on low agent. And it may be a false sense of security anyway.
I give them scop to make me feel better.
I used to use it all the time in residency.

 

[urge]

More often than not the bis just serves to reassure me that the patient is anesthetized. If the bis suddenly rises during a pump run, I ask the perfusionist to confirm the vaporizer is delivering what he thinks it is delivering. That is worth it to me. If a device or technique allows me to feel less stress or anxiety during a procedure, I consider it superior and worthwhile.

That's when I find it useful.

IV blowing during a TIVA or the vaporizer on the pump running dry during a case.

I don't find it very useful for regular straight forward cases, from which the naysayers are drawing their conclusions.

 

[urge]

I routinely use the Cerebral oximeter for pump cases and carotids. I would trust a Cerebral oximeter reading of 20 as something I need to act on than a bis of 2.

Let me ask you this, has the BIS provided any tangible evidence that has changed your management of a patient?

I would take the BIS any day over the cerebral oximeter.

I have seen so many pts with low numbers do just fine, and just as many pts with good numbers totally stroke out or seize.

 

[nap$ter]

I have several reasons to not believe meta-analysis.

First and foremost, because I do a ton of reading. Anyone (I personally feel) that reads a lot of literature will come to the very same conclusion that meta-analysis DO NOT tell the truth. One will read the articles used in the meta-analysis, deconstruct them, glean what they can from them, and then read a meta-analysis. Almost always, the meta-analysis misses the point, doesn't tell the correct story, or basically lies depending on the bias of the writers. This has happened to me time and time again. That is the first main reason.

Secondly, most societies, or standards use randomized, controlled, blinded studies as the highest quality of evidence. Meta-analysis are (almost) never in the hiarchy of quaility of evidence. (I say almost because I am sure there is someone out there that does rank it as a high quaility - but I am not aware of it). There is a reason for that. A controlled trial will always trump pooling random data that have absolutely no comparablity, but are compared anyway. The whole point of a CONTROLED trial is to control as many variable as possible to minimize the effects of bias. However, meta-analysis completely ignores this. For example, the Modified Guyatt Evidence Assesment Grid rates grades of evidence based on RCT's of good quality as highest, RCT with methodological weakness as next, then observational studies as last. Meta-analysis has no part in grading level of evidence. (Parenthetically, chochrane produces a nice check list that someone can use to grade the quality of the RCT or observational trial).

Thirdly - did I mention they lie? Take for example a recent meta-analysis by Apfel about post-dural puncture headaches. If one were to read this, the would come away thinking that leaving a spinal catheter in for 24 hrs does absolutely nothing for the headache and it was a waste of time. However, if one actually read the articles that was references on the subject in the analysis, the reader will come away with a VERY DIFFERENT opinion. How is that possible? It is in the way the question is asked. So if you ask the question, does it prevent a headache, the answer may be no and in the anaylsis, it makes the claim it is worthless. However, if you read the articles, you understand that although headache incidence might not be different, the outcomes were HUGELY different. Patients suffered WAY LESS with catheters in place. But the analysis doesn't tell you this because of the way they asked the question. It all has to do with how the writer wanted to tell the story. It's WAY better to avoid meta-analysis all together. Read the articles. Read the RCT's. Grade them based on the Cochrane scale and decide what they say.

There are other reasons....those are a few.

we agree - kind of.

any study involving statistics can lie - depends on what question is asked and whether analysis is appropriately applied.

however, to discount meta-analysis completely is erroneous.

pooling data from RCT's with similar enough questions/data points can increase the power of the analysis - that's the whole point of meta-analysis. it can clarify answers. it can also create lies, as can any analysis.

 

[nap$ter]

A cerebral oximeter is a "non-standard of care monitor not endorsed be the ASA" either, but apparently you use and interpret the data from that. For that matter, temperature monitoring is not required by the ASA for every case either, but I'll bet you use that as well.

Clearly we won't convince each other that our opinion is the correct one, and I realize there are a lot of people that think BIS is absolute garbage. Unfortunately, I think that a lot of people let their opinion of Aspect Medical and their original marketing techniques with BIS 10 or more years ago cloud or color their opinion of the device, and have never made any serious attempt at using it (or have never used it at all) and simply fall back on word-of-mouth negativity regarding the company and studies that cast it in a dubious light. I think it has it's place - you don't. We agree to disagree.

agreed - we do disagree.

i am still laughing at the suggestion that interpreting the emg on a BIS is as much a part of my job as interpreting the EKG... great example of logic gone askew