Aspect Medical

[cfdavid]

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Stock's down 35% due to NEJM-published study. See their website.

What's ETAG?? I don't get NEJM.

http://www.aspectms.com/

Thoughts on the study for those that have read it? Could someone post the text to the NEJM study?

 

[fakin' the funk]

Background
Awareness during anesthesia is a serious complication with potential long-term psychological consequences. Use of the bispectral index (BIS), developed from a processed electroencephalogram, has been reported to decrease the incidence of anesthesia awareness when the BIS value is maintained below 60. In this trial, we sought to determine whether a BIS-based protocol is better than a protocol based on a measurement of end-tidal anesthetic gas (ETAG) for decreasing anesthesia awareness in patients at high risk for this complication.
Methods
We randomly assigned 2000 patients to BIS-guided anesthesia (target BIS range, 40 to 60) or ETAG-guided anesthesia (target ETAG range, 0.7 to 1.3 minimum alveolar concentration [MAC]). Postoperatively, patients were assessed for anesthesia awareness at three intervals (0 to 24 hours, 24 to 72 hours, and 30 days after extubation).
Results
We assessed 967 and 974 patients from the BIS and ETAG groups, respectively. Two cases of definite anesthesia awareness occurred in each group (absolute difference, 0%; 95% confidence interval [CI], −0.56 to 0.57%). The BIS value was greater than 60 in one case of definite anesthesia awareness, and the ETAG concentrations were less than 0.7 MAC in three cases. For all patients, the mean (±SD) time-averaged ETAG concentration was 0.81±0.25 MAC in the BIS group and 0.82±0.23 MAC in the ETAG group (P = 0.10; 95% CI for the difference between the BIS and ETAG groups, −0.04 to 0.01 MAC).
Conclusions
We did not reproduce the results of previous studies that reported a lower incidence of anesthesia awareness with BIS monitoring, and the use of the BIS protocol was not associated with reduced administration of volatile anesthetic gases. Anesthesia awareness occurred even when BIS values and ETAG concentrations were within the target ranges. Our findings do not support routine BIS monitoring as part of standard practice.

 

[urge]

NEW YORK (AP) - Aspect Medical Systems Inc. shares dropped to a four-year low Thursday after a study challenged the effectiveness of Aspect's Bispectral Index, which helps surgeons monitor patients under anesthesia.

http://news.moneycentral.msn.com/ticker/article.aspx?Feed=AP&Date=20080313&ID=8332717&Symbol=ASPM


WTF!!!!

 

[New2Midwest]

Go WashU! How many other anesthesia departments out there with a published study in NEJM?

 

[jwk]

Stock's down 35% due to NEJM-published study. See their website.

What's ETAG?? I don't get NEJM.

http://www.aspectms.com/

Thoughts on the study for those that have read it? Could someone post the text to the NEJM study?

End Tidal AGent

 

[toughlife]

NEW YORK (AP) - Aspect Medical Systems Inc. shares dropped to a four-year low Thursday after a study challenged the effectiveness of Aspect's Bispectral Index, which helps surgeons monitor patients under anesthesia.

http://news.moneycentral.msn.com/ticker/article.aspx?Feed=AP&Date=20080313&ID=8332717&Symbol=ASPM


WTF!!!!

It helps surgeons? 🙄 Man is the world out there pretty ignorant about anesthesiology.

 

[Planktonmd]

It helps surgeons? 🙄 Man is the world out there pretty ignorant about anesthesiology.

Yes, The world is absolutely ignorant about anesthesiology and 99 % of the population, including many people we interact with daily like OR nurses and surgeons, have zero idea about what we do.

 

[coprolalia]

Where's aghast1 when you need him?

🙂😀😎😱👍😍

-copro

 

[jwk]

Leaving feelings about Aspect aside, does anyone else think this is not that great a study?

 

[Bertelman]

Leaving feelings about Aspect aside, does anyone else think this is not that great a study?

When I read the abstract, I thought the folks at WASHU had some balls. I was hoping they would blind the anesthesiologist to MAC and make them rely on BIS scores.

That wasn't quite the case, and in the discussion they suggest many of the providers just did what they would have done regardless of BIS number, aside from making the alarms on the machines shut up.

In the end, the avg ETAG was equal for both groups, as was the BIS. That doesn't necessarily tell me BIS is useless, but it certainly isn't decreasing use of agent.

I think the only way to do the study is to convert ETAG and BIS to an equal scale, and provide that value to the provider without revealing whether it is BIS- or ETAG-derived. I'd like to see an IRB approve that.

You'll also probably need more than 2k procedures.

 

[dhb]

2 cases of awareness per 950 anesthetic 😱 it's a joke right? but the BIS is too so i guess it's fitting

 

[pjm]

It helps surgeons? 🙄 Man is the world out there pretty ignorant about anesthesiology.

My understanding is that Aspect upset anesthesiologists because they marketed to surgeons and patients. Patients went to surgeons, who went to the anesthesia guys and said "My patient demands this box so you have to set it up."

This leads surgeons to pop out press releases like this one:
http://www.prnewsnow.com/Public_Release/Surgery/180939.html

"Safety has no substitute. Before going into surgery, most patients usually ask two questions. They want to know will I be asleep during surgery and are you going to wake me up," says Dr. Daniel Man (www.drman.com), board certified plastic surgeon in Boca Raton, Florida. Now, thanks to a revolutionary device that monitors brain activity during surgery, Dr. Man and anesthesiologist Dr. Roger Gorman have an extra added margin of safety."

 

[fakin' the funk]

I think the only way to do the study is to convert ETAG and BIS to an equal scale, and provide that value to the provider without revealing whether it is BIS- or ETAG-derived. I'd like to see an IRB approve that.

Like you said, a study where they blind the anesthesiologist to the dose of a lethal drug and have them give it based on an invalid monitor, that's the kind of study that we even have IRBs for.

You'll also probably need more than 2k procedures.

Why?

 

[Bertelman]

I don't think 2,000 cases is sufficient to capture enough awareness episodes to really compare. I think you could poll many hospitals, and wouldn't find a single case of awareness in 2,000.

 

[Jeff05]

the most compelling study on awareness quotes an incidence of about
1:14,500.
the NEJM study is grossly underpowered to distinguish between bis and non-bis groups.
i'm shocked it was published.

 

[Bertelman]

the most compelling study on awareness quotes an incidence of about
1:14,500.
the NEJM study is grossly underpowered to distinguish between bis and non-bis groups.
i'm shocked it was published.

The media seem to have gotten hot on "breaking" medical news, like how lowering your cholesterol leads to more heart attacks.

Sometimes I wonder if certain journals publish certain studies knowing they will make headlines in the health section. Or in this case, the financial section.

 

[luversed]

There are more than a few reasons to believe this study is of dubious value.

1) The population group is not really "high risk"... The study's inclusion criteria to be 'at risk of awareness' are very liberal, especially the minor criteria. This was probably not a patient sample that was at significant risk of awareness. Specifically, table 1 shows the following inclusion characteristics: 44% of patients were on beta-blocker, 50% had moderate limited exercise tolerance, and 44% had obesity (each of these are a minor inclusion criteria).

So to expect 1% awareness seems odd. It is no wonder they ended up with 0.2% awareness, the group was more representative of the general population, which people beleive to have a 2 per 1000 ratio of awareness.

2) They did not share the drug mix, so no way to know if the BIS group received similar mix drugs as the ETAG group. So comparing MAC is not as relevant if we don't know the mix of drugs. Also they did not indicate if they used versed.

Also, it seems like they overdosed their patients...which would explain why you had less awareness. It is no doubt that overdosing would lead to less awareness.


3) Look at the cases of awareness cited for both groups. They have absolutely NO idea when the awareness happened. In a couple instances they said awareness was for the ENTIRE CASE! Also, for patient A-4, they don't even have consistent BIS DATA!! How could this be included as a case of awareness due to BIS when it clearly demonstrates a failure on the part of the anesthesia team?

4) They rarely adhered to their stated protocols. Only 26% of the time for the ETAG protocol. So is this really a legitimate alternative to reduce awareness??


I am frankly shocked that the NEJM would allow a study like this to enter their journal. Seems like there might have been some backroom dealings to get it in.

 

[Pilot Doc]

the most compelling study on awareness quotes an incidence of about
1:14,500.
the NEJM study is grossly underpowered to distinguish between bis and non-bis groups.
i'm shocked it was published.

A larger multi-center trial by the same group is in the works. That said, I think this is a useful contribution to the literature as a counterpoint to some of the original Aspect supported trials.

As for the 2 in 1000 incidence, the study was done in high risk groups - my understanding is that the incidence in their population is in line with prior studies. They also interviewed every patient 3 times and many of the cases were caught at the 30 day interview. Many of the cases are of a type that probably wouldn't be reported by the patient themselves - e.g someone having a memory of briefly hearing voices but having no pain.

 

[militarymd]

There are more than a few reasons to believe this study is of dubious value.

1) The population group is not really "high risk"... The study's inclusion criteria to be 'at risk of awareness' are very liberal, especially the minor criteria. This was probably not a patient sample that was at significant risk of awareness. Specifically, table 1 shows the following inclusion characteristics: 44% of patients were on beta-blocker, 50% had moderate limited exercise tolerance, and 44% had obesity (each of these are a minor inclusion criteria).

So to expect 1% awareness seems odd. It is no wonder they ended up with 0.2% awareness, the group was more representative of the general population, which people beleive to have a 2 per 1000 ratio of awareness.

2) They did not share the drug mix, so no way to know if the BIS group received similar mix drugs as the ETAG group. So comparing MAC is not as relevant if we don't know the mix of drugs. Also they did not indicate if they used versed.

Also, it seems like they overdosed their patients...which would explain why you had less awareness. It is no doubt that overdosing would lead to less awareness.


3) Look at the cases of awareness cited for both groups. They have absolutely NO idea when the awareness happened. In a couple instances they said awareness was for the ENTIRE CASE! Also, for patient A-4, they don't even have consistent BIS DATA!! How could this be included as a case of awareness due to BIS when it clearly demonstrates a failure on the part of the anesthesia team?

4) They rarely adhered to their stated protocols. Only 26% of the time for the ETAG protocol. So is this really a legitimate alternative to reduce awareness??


I am frankly shocked that the NEJM would allow a study like this to enter their journal. Seems like there might have been some backroom dealings to get it in.

so.....what do you do for Aspect?

 

[Planktonmd]

The study might not be perfect but it definitely makes more sense than a number based on a secret algorithm to predict the unpredictable!
Finally someone has the spine to respond to these jokers with science superior to the pseudo science they have been using for years to shove their random number generator (BIS monitor) down our throat.

 

[urge]

There are more than a few reasons to believe this study is of dubious value.

1) The population group is not really "high risk"... The study's inclusion criteria to be 'at risk of awareness' are very liberal, especially the minor criteria. This was probably not a patient sample that was at significant risk of awareness. Specifically, table 1 shows the following inclusion characteristics: 44% of patients were on beta-blocker, 50% had moderate limited exercise tolerance, and 44% had obesity (each of these are a minor inclusion criteria).

So to expect 1% awareness seems odd. It is no wonder they ended up with 0.2% awareness, the group was more representative of the general population, which people beleive to have a 2 per 1000 ratio of awareness.

2) They did not share the drug mix, so no way to know if the BIS group received similar mix drugs as the ETAG group. So comparing MAC is not as relevant if we don't know the mix of drugs. Also they did not indicate if they used versed.

Also, it seems like they overdosed their patients...which would explain why you had less awareness. It is no doubt that overdosing would lead to less awareness.


3) Look at the cases of awareness cited for both groups. They have absolutely NO idea when the awareness happened. In a couple instances they said awareness was for the ENTIRE CASE! Also, for patient A-4, they don't even have consistent BIS DATA!! How could this be included as a case of awareness due to BIS when it clearly demonstrates a failure on the part of the anesthesia team?

4) They rarely adhered to their stated protocols. Only 26% of the time for the ETAG protocol. So is this really a legitimate alternative to reduce awareness??


I am frankly shocked that the NEJM would allow a study like this to enter their journal. Seems like there might have been some backroom dealings to get it in.

I think you are missing the point of the paper. The BIS was marketed as a reliable device to help you to dose a light anesthetic safely, thus avoiding awareness. The meat of this data is that it didn't really make a difference in the anesthetic (2000 pts I think is enough for this) and it wasn't that reliable(I concede the study is not that powerful here, but who cares, if you are going to dose them the same way in the end?). Is it missing data regarding the drugs used on both groups? Yes. I'm sure they can pull it back and analyze it. They might get 2 papers out of the same study.

Bottom line is that the anesthetic was not different form usual. How is the BIS helping you then?

 

[coprolalia]

so.....what do you do for Aspect?

Who knows? But, s/he apparently loves midazolam.

Smells like a cameo appearance of aghast1. 😍👍😀🙂😛

-copro

 

[fakin' the funk]

the most compelling study on awareness quotes an incidence of about 1:14,500. the NEJM study is grossly underpowered to distinguish between bis and non-bis groups. i'm shocked it was published.

1:14500 in an unselected group? What about a group at high risk for awareness? Are you saying that their sample size calculation (detailed in the Methods section) was complete BS?

I'm harping on this because "Not enough patients" seems to be the easiest, laziest, and most common criticism leveled at any study. Journal club after journal club is hampered by "Well, it was a good study, and they showed a significant and clinically important result - but there weren't enough patients!" which shows a complete lack of understanding of how/why studies use the # of patients that they do.

So, it's one thing to disagree with their awareness estimates for the ETAG and BIS groups, or "Fisher's exact test" 🙂confused🙂, or the values they used for beta or alpha, but it's another just to lob "Not enough patients" at every study that comes down the pike.

 

[Jeff05]

if i flip a coin 5 times and 4 out of 5 it lands on heads - do i assume that the probability of heads is 80%?! in order for this to approach a certain normal distribution there MUST be a minimum N...

and in order to see differences between two groups there MUST be adequate power, otherwise, you may as well GUESS whether to accept or reject Ho.


you mentioned :"Well, it was a good study, and they showed a significant and clinically important result - but there weren't enough patients!"

that's the whole point!!! you can't show any significant and clinically important results in a grossly underpowered study.

 

[Bertelman]

1:14500 in an unselected group? What about a group at high risk for awareness? Are you saying that their sample size calculation (detailed in the Methods section) was complete BS?

I'm harping on this because "Not enough patients" seems to be the easiest, laziest, and most common criticism leveled at any study. Journal club after journal club is hampered by "Well, it was a good study, and they showed a significant and clinically important result - but there weren't enough patients!" which shows a complete lack of understanding of how/why studies use the # of patients that they do.

So, it's one thing to disagree with their awareness estimates for the ETAG and BIS groups, or "Fisher's exact test" 🙂confused🙂, or the values they used for beta or alpha, but it's another just to lob "Not enough patients" at every study that comes down the pike.

I don't think you've been to enough journal clubs to accurately report this.

😛

 

[fakin' the funk]

that's the whole point!!! you can't show any significant and clinically important results in a grossly underpowered study.

I understand. My point was, how do you know any given study is grossly underpowered? You evaluate the figures they cite in the methods section and either you agree with them or not. Waving your hands and saying "it's underpowered" is poor form and not constructive when evaluating a study.

 

[Jeff05]

to be able to tell if a study is underpowered is statistics 101...

as far as this study is concerned, lets focus on the detectable difference...

"The anticipated incidence of anesthesia awareness was 1% for the
ETAG group, on the basis of the incidence rates
reported for patients at high risk for anesthesia
awareness,3-5 and 0.1% for the BIS group, on the
basis of previous studies.3,21 A total of 940 patients
would be required in each group to detect
this 0.9% difference with a one-tailed alpha of
0.05 and a power of 80% with the use of Fisher’s
exact test."

The incidence of intraoperative awareness in the large sample of patients from a regional medical center undergoing general anesthesia was 0.0068%, or 1 per 14,560 patients, substantially less than that reported in the recent
literature. (Anesthesiology 2007; 106:269–74). Reviewing the NEJM sample, it does not strike me as a HIGH RISK sample they make it out to be (due to inclusion of patients with 2 minor criteria).

In effect, the detectable difference should not be the 0.9% they conveniently quoted (by incorrectly including non-high risk patients into high risk group), but 0.09% (0.1%-0.0068%) - which is a 10 fold difference!!! Assuming a geometric relationship they would need 10,000 patient in EACH group to discern a difference at 95% confidence (80% power).

at the end of the day it's up to you. if the study is up to YOUR standards - because YOU will be the one treating patients, go with it. i think you will understand this, and become more critical of published material, once you actually have your own patients.

 

[coprolalia]

In effect, the detectable difference should not be the 0.9% they conveniently quoted (by incorrectly including non-high risk patients into high risk group), but 0.09% (0.1%-0.0068%) - which is a 10 fold difference!!! Assuming a geometric relationship they would need 10,000 patient in EACH group to discern a difference at 95% confidence (80% power).

That may be for detecting awareness. But, that's kind of a moot point and not how the study was powered, and the groups were balanced. It was powered to detect a difference between targeted BIS versus end-tidal gas concentration with awareness being a surrogate endpoint to detect a difference in anesthetic regimen guided either by BIS or ETAG. There were only four cases (out of 2000 patients) of awareness, and it was independent of the BIS number. You don't need a large "N" in such a statistical study, as it was adequately powered to detect a difference in anesthetic regimen. Likewise, the study clearly showed the BIS made no difference in the anesthetics given, which was the point. If anything, it proves that you are at a risk for awarness if you generally fall below 0.7 MAC during a case. Small, but significant risk.

-copro

 

[luversed]

That may be for detecting awareness. But, that's kind of a moot point and not how the study was powered, and the groups were balanced. It was powered to detect a difference between targeted BIS versus end-tidal gas concentration with awareness being a surrogate endpoint to detect a difference in anesthetic regimen guided either by BIS or ETAG. There were only four cases (out of 2000 patients) of awareness, and it was independent of the BIS number. You don't need a large "N" in such a statistical study, as it was adequately powered to detect a difference in anesthetic regimen. Likewise, the study clearly showed the BIS made no difference in the anesthetics given, which was the point. If anything, it proves that you are at a risk for awarness if you generally fall below 0.7 MAC during a case. Small, but significant risk.

-copro

One point to keep in mind is that the doctors in this study could only stay within the ETAG-guided range 26% of the time! (And they could only stay in the BIS-targeted range 45% of the time.) It seems more likely that what they did was disregard the ETAG alarm and BIS alarm and just dose the patients up to 80 MAC regardless of BIS or ETAG. It doesnt seem like the doctors in this study were instructed how to properly adhere to either protocol (BIS nor ETAG).

This is but one of several problems (as cited in previous posts) with this study. I think that before we accept their conclusions we should question the problems with this study.

And for that matter, we should also question the problems with the B-Aware study published in 2004, and all the other BIS studies that conclude that BIS is a useful tool for preventing awareness, reducing dosage, and improving other clinical endpoints....before we accept the conclusions. I am certain there are problems with those studies as well (no study is perfect).

The discussion here should be all about the science. In the end, our goal is to do what is BEST for the patients. If patients are HARMED by using BIS as another tool, then we should not use it!! I do not think anyone (even the BIS haters) has ever argued that using BIS hurts the patient...

If there are benefits to patients for using BIS, then we as doctors should be open to embracing the technology. (With respect to COST BENEFIT ANALYSIS...leave that up to the hospital to negotiate!)

Clearly you can put me in the Pro-BIS camp, but being in that camp should not invalidate my questions and thoughts. I am not trying to persuade anyone here with rhetoric, rather I feel it is good to have an open discussion about the science itself. Each of you will look at the facts and come to your own conclusion.

End of the day...when you're out there with your patients...you should look to do what you feel is best for your patient. If you don't think BIS helps, then don't use it!

I encourage you to read here how one doctor uses BIS for more than awareness. http://mkeamy.typepad.com/anesthesiacaucus/2007/11/i-use-the-bis-m.html

 

[coprolalia]

I encourage you to read here how one doctor uses BIS for more than awareness.

Who's writing your paychecks? Seriously.

-copro

 

[epidural man]

thanks for the discussion. After reading all the posts and links, I have decided I should use the BIS more. It made me aware of some things I hadn't read yet, like the Cochrane review.

I understand why people hate Aspect, but it is strange that anesthesiologists don't want to use the BIS. It certainly doesn't hurt you if you use it as an additional monitor. I wish other processed EEG monitoring, like GE's entropy stuff was more available.

I'm a little suprised however, that INVOS isn't used more often. I have used cerebral oximetry a bunch and I think it is the coolest monitor ever invented. You can fit both a BIS and INVOS sticky on the head - now that is a cool anesthestic.

Nonetheless, there are a lot of cool things used, or could be used but we ignore them completely. There is a lot of great data in many different papers to show that peripheral venous pressure works just as well as central venous pressure monitoring, yet I bet most of ya all have never done it, and if you mention it to your attending they will laugh and scorn at you. There is great data to show that if you mix in CO2 with your inspired gas at the end of the case and increase minute ventilation (to keep ETCO2 normal), you can shave large amounts of minutes off your wakeup, but I don't think ANYONE is doing that. UVA has published some great data on using lidocaine infusions to cut down on post op pain and opioid use. Ever done that? I've mentioned before the articles that show ketamine before incision and infused through the case can reduce opioid use and hyperesthesia and pain around the incision 6 MONTHS after surgery - yet how many of us use ketamine routinely on surgery where the skin is cut (ie..almost every case). TEG is the most useful little piece of equipment and has shown time and time again to unequivically change important clinical decisions (and save a ton of money), yet most institutions rarely use it, if they even have a machine. The platelet mapping function of TEG is really pretty cool. The reagents are expensive though.

 

[Bertelman]

It certainly doesn't hurt you if you use it as an additional monitor.

It might if that monitor doesn't provide consistent data or change clinical outcomes. Or possibly raises the estimated cost of healthcare by 360,000,000.

 

[epidural man]

It might if that monitor doesn't provide consistent data or change clinical outcomes. Or possibly raises the estimated cost of healthcare by 360,000,000.

You are absolutely right. So the question is, does it not provide consistent data? Does it raise cost by whatever number you wrote? I don't care about clinical outcomes. We still use PA caths and I agree with using it in certain cases despite their increase in mortality with use, so this really isn't a great point.

Let me ask you this? Does an a-line provide consistent data? How about your EKG? How about any of the other monitor you use? None of them do, yet you don't have people arguing not to use an a-line because sometimes they don't work. My point is that I find it strange that we have a monitor that gives useful information that is simple to use and for some reason, many anesthesiologists get severe nausea when they are asked to consider using it.

 

[Bertelman]

My point is that I find it strange that we have a monitor that gives useful information that is simple to use and for some reason, many anesthesiologists get severe nausea when they are asked to consider using it.

It seems this reaction may be related to the approach companies have adopted when a new technology or medication is introduced. Published studies are supported by the device or drug company. Negative studies are suppressed. Drugs and devices are marketed directly to consumers, bypassing the traditional mechanism of approving new theories through a peer-reviewed process.

I'm not saying I'll never use a BIS. But allow me the right to bristle when a patient asks if I will use that "new monitor I saw on 20/20 that prevents me from waking up during surgery."

 

[coprolalia]

It made me aware of some things I hadn't read yet, like the Cochrane review.

Don't base your clinical decisions on what's put out by the Cochrane database. It's a bad methodology for determining cause/effect relationships overall. Metanalyses and pooled studies are no substitute for rigorous, blinded individual studies.

-copro

 

[epidural man]

Published studies are supported by the device or drug company. Negative studies are suppressed.

This is true, but it isn't because the resident (that worked his *** off to get some funds from a company after he wrote a protocol, then spent hours re-writing something because the ******ed IRB says this and that - and then after all that the study turns out to be negative...) wants to suppress it. He/she would love to publish the negative study. Your name on a paper, negative or positive is the same really. The real people to blame for not publishing negative studies are the journal editors. They reject negative studies (it would seem) at a much higher frequency then the people who spent three years of their life trying to do something cool would want.
Correct me if I'm wrong, but if sonosite gives you money to do a study, I don't think they have say whether or not you can publish your results.

Personally, that is why I prefer A & A over Anesthesiology. I don't think they publish many negative studies. It makes me suspicious. It was just pointed out to me that RAPM is the same way....hardly (if ever) publishing negative studies.

 

[Bertelman]

Correct me if I'm wrong, but if sonosite gives you money to do a study, I don't think they have say whether or not you can publish your results.

Depends on how much money they are giving you. When you start reaching the level of multi-center studies that tend to make a bigger clinical statement, those studies aren't paid for with grants. They are funded solely on the backs of the drug companies pushing to market.

You might have a few hot-shot names in the authorship, but the statisticians, etc. are owned by the drug companies. The data is owned by the drug companies. They can choose to suppress what they wish. Hence we now have clinical trial registration.

 

[gtb]

so.....what do you do for Aspect?

Good call on luversed's post and the seemingly direct link to Aspect. It just had the sound of a sale's rep chatting with surgeons in OR.

One thing that Aspect (??? Iuversed ???) could do, if they truly believe in their system, is reveal the actual algorithms used to arrive at the final BIS number. There are many electrical engineers, physicists, and mathematicians that now work as anesthesiologists. I even know of a few MD/PhD folks with their PhD in engineering. Publish the algorithm, and let it get independently evaluated and verified. Until then, how can I argue with those individuals who claim it is nothing more than a random number generator.

 

[urge]

I understand why people hate Aspect, but it is strange that anesthesiologists don't want to use the BIS. It certainly doesn't hurt you if you use it as an additional monitor. I wish other processed EEG monitoring, like GE's entropy stuff was more available.

For me it's just a matter of trust. Can I trust the BIS enough to run the pt at 0.4 MAC, 0.2 MAC? Never! Will Aspect go to court with me and pay for an awareness settlement since I was following their device? Doubt it! What if I'm at 2 MAC and the BIS is reading 75, do you think I'll go to 3 MAC? Crazy! Do you think a BIS 0f 40-60 gives me a sense of security? No! Then, how is it helping me? Why would I routinely use something I cannot trust?

 

[coprolalia]

For me it's just a matter of trust. Can I trust the BIS enough to run the pt at 0.4 MAC, 0.2 MAC? Never! Will Aspect go to court with me and pay for an awareness settlement since I was following their device? Doubt it! What if I'm at 2 MAC and the BIS is reading 75, do you think I'll go to 3 MAC? Crazy! Do you think a BIS 0f 40-60 gives me a sense of security? No! Then, how is it helping me? Why would I routinely use something I cannot trust?

Exactly, urge! I've been in the situation where you're at 1.5 MAC and the BIS is still reading 75-80. Patient's BP was in the toilet too. I even re-applied a new strip. I asked the patient afterwards, and he didn't remember a damn thing.

You get in the situation where you are treating a number and being distracted from other things. BIS is just a distractor most of the time. And, this study proves that it doesn't change the anesthetic.

-copro

 

[swpm]

One thing that Aspect (??? Iuversed ???) could do, if they truly believe in their system, is reveal the actual algorithms used to arrive at the final BIS number. There are many electrical engineers, physicists, and mathematicians that now work as anesthesiologists. I even know of a few MD/PhD folks with their PhD in engineering. Publish the algorithm, and let it get independently evaluated and verified. Until then, how can I argue with those individuals who claim it is nothing more than a random number generator.

There's no room for a device like the BIS in a world that values evidence based medicine and peer review. Secrets, proprietary magical algorithms, bold claims, and appeals to fear and emotion are the domain of snake oil salesmen.

I don't understand why our profession tolerates all of these from Aspect.

 

[luversed]

There's no room for a device like the BIS in a world that values evidence based medicine and peer review. Secrets, proprietary magical algorithms, bold claims, and appeals to fear and emotion are the domain of snake oil salesmen.

I don't understand why our profession tolerates all of these from Aspect.

I do not work for Aspect, nor have I ever received a payment of any kind from the company. I do not know what is in their proprietary algorithim.

However, I think it is absurd to say it is a "random number generator." Look at the 100s of studys have been done using the BIS...don't you think by now they would be able to PROVE it is a random number generator?

Also, you should know that your Pulse-Oximeter has all kinds of proprietary algorithims in it as well, just ask Nelcor!!

No one here is trying to force BIS or any other technology onto your practice. This forum is about sharing benefits, dispelling myths, refuting poor studies, and increasing the collective knowledge so that each of us can become more aware and make the best decision for our patients.

BIS has limitations, no one is disputing that fact. The question is, can we understand the limitations. Check out Dahaba study which focuses on some limitations of BIS. http://www.ncbi.nlm.nih.gov/pubmed/16115989

The question is, is there still value in having this tool (even if you don't know exactly how it works) in your tool box?

For example, in TIVA cases, many doctors feel there is no alternative tool to BIS in helping them titrate the anesthetic, improve outcomes, and prevent awareness as a side benefit.

(Even in the flawed (my opinion) NEJM study...they say that BIS is useful for TIVA cases...)

 

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My favorite BIS study was from late 2005 or early 2006 in A&A or Anesthesiology. They put 2 BIS probes on the same patient to see if it correlated. It didn't. One was reading 30's while the other was reading 70's. isn't the BIS a fantastic device?