Depth of anesthesia monitoring with Prof. Blobner | ESAIC 2023

Desiree Chappell: Well, hello and welcome to Top Med Talk. We are at Euroanesthesia 2023, the annual meeting of the European Society of Anesthesiology and Intensive Care. I'm Desiree Chappell, your host. Here today with a little treat for a new voice here on Top Med Talk, Andy Cumpstey. Andy, thank you so much for joining us.

Andy Cumpstey: Great to be here. Thanks, Desiree.

Desiree Chappell: Yeah. You're filling in for Monty. Big shoes to fill, I know.

Andy Cumpstey: Big shoes to fill.

Desiree Chappell: Yeah.

Andy Cumpstey: No pressure.

Desiree Chappell: No pressure at all. Monty is presenting during a session today. So, Andy and I are here on the GE HealthCare booth. We just wanted to give a big shout out to GE HealthCare for supporting Top Med Talk. Top Med Talk is free, open access medical education to the world, and we could not do it without our sponsors, so we wanted to thank them. Andy, a great meeting so far.

Andy Cumpstey: Fantastic meeting. We get excitement around the whole exhibition hall, isn't there? It's brilliant. Really exciting.

Desiree Chappell: It really is. And the sun is shining outside.

Andy Cumpstey:  Always sunny up here in Scotland, Desiree. Always sunny up here in Scotland.

Desiree Chappell: Absolutely. Well, in true Top Med Talk fashion, we're having great conversations here at the meeting in the exhibit hall. You can hear lots of the buzz around that Andy was talking about. You'll also be able to hear the barista that is positioned just so well right next to the Top Med Talk pop-up studio. So, you're going to hear all those things. So, we really are here in person. But I'm just so delighted today to introduce our next guest, Professor Manfred Blobner. Professor, it's so wonderful to meet you. Thank you so much for sitting down with us here on Top Med Talk.

Prof. Manfred Blobner: Thank you very much for inviting me to the talk.

Desiree Chappell: Yes, well, please do tell us a little bit more about yourself.

Prof. Manfred Blobner: Yes, since many years, much too long, an anesthesiologist in Munich at Technical University of Munich Medical School. Last years, I did some work on big data. Since we have that big data in anesthesia available for calculations, because I'm very interested in math points. So, yeah, I was for about 16 years vice Director of the Department of Anesthesiology. And for five years, I'm doing research as a primary task.

Desiree Chappell: Oh, interesting. So, looking at big data, big data points, what part of anesthesia and what data points are you looking at?

Prof. Manfred Blobner: So, my first interest is actually in data that show us that patients are adequately anesthetized. In former times, we did it always by measuring blood pressure or heart rate or related parameters. But I think that's very indirect. So, I'm really interested if we are able, on a practical base, to do monitoring of depth of anesthesia and depths of neuromuscular block on an actual routine base, that means in every patient. We did it in that department in the time when I was in charge, and we do it again still. That's the time. So, we have many data from which we can learn what works well so far and what has to be improved.

Desiree Chappell: So, you know, as a nurse anesthetist myself ,and Andy as an anesthesiologist, accustomed to using different types of technology in the OR for depth of anesthesia?

Andy Cumpstey: We've got a whole range of different technologies available, but it'd be interesting to get your opinion on which those technologies you think we should be using.

Prof. Manfred Blobner: Depth of anesthesia can be monitored by, let me say, any processed EEG monitoring, that's the best what can have. So independently, if you're using the BIS system or the entropy system, which is developed primarily by GE, gives us a good estimate about depth of anesthesia. It's not the truth itself. So, there must be some mistakes also. But it's at least the best what's available. Again, in my department where I'm working, it's absolutely mandatory to use one of these tool systems in a patient who is set on loss of consciousness. There's no way out not to do it.

Desiree Chappell: So, it would be for all surgical patients?

Prof. Manfred Blobner: Every patient that is anesthetized.

Desiree Chappell: Interesting. Regardless of TIVA versus inhalation versus...

Prof. Manfred Blobner: For me, that's not a big difference.

Desiree Chappell:  It doesn't matter.

Prof. Manfred Blobner: I'm doing one day in the week doing anesthesia. So, to be in practice doesn't matter what the nurse has prepared. It's a big difference. So, I can't find the difference between inhalation anesthesia or total intravenous in terms of outcome that's constructed by whoever. So, whatever is done, one thing is clear. We must measure depth of anesthesia.

Desiree Chappell: Yeah. Interesting. Andy, do you use process EEG for all patients?

Andy Cumpstey: Well, in the department I work in, we have some people who are very big advocates of using it. And I've also got some colleagues who are quite cynical about using it. And it's interesting you mentioned up outcome there as TIVA versus volatile anesthesia. But, I mean, what's the evidence that we should be using adequate anesthesia monitoring depth anesthesia monitoring in terms of outcomes, does it change our outcome?

Prof. Manfred Blobner: That's hard to explain because the study must have been done and it can't be done anymore in the department I'm working. Because this is hard, you can go for a step wedge model, for example, but not in a department in which people are used to do anesthesia. Basically, when you're using such an entropy or BIS monitor and we deal with since more than 15 years. So, there is no anesthesiologist that is trained to do it without. 
So, it's an unfair comparison. What I can tell you. I'm also working in University of Ulm in the anesthesia department one day a week, and they don't do that on a regular basis. And when we did studies, neuromuscular monitoring study, I think we will come to that later. What I saw is when I brought the machine with these depths of anesthesia monitoring for research purposes, and regular anesthesiologists did anesthesia and we did monitoring for the neuros malfunction. But as I'm also not used to do anesthesia without my brain function monitoring, I saw that they had a high rate of burst depression, and they were very astonished. Simply using that changes the way anesthesia is performed.

Prof. Manfred Blobner: There is no outcome study in my point. But you never will give a drug for controlling blood pressure but not measuring blood pressure, but anesthesiologists used to do anesthesia without measuring depths of anesthesia. It's for me not understandable.

Desiree Chappell: Yeah, but thinking that blood pressure may be an indication of depth of anesthesia, probably that's not the right answer, right?

Prof. Manfred Blobner: It's indirect, by the way. It's more indirect than a processed EEG. It's also indirect. But direct you must ask patients: are you aware or not? It's clear, it has many advantages. My point is you don't do too deep anesthesia, right? Because it's not possible to see on a clinical base if a patient that has a normal blood pressure is in a state of burst suppression. And we know that this is outcome relevant. So that's the first thing.

The second thing is why giving a drug in an inadequate dose, every drug has effects and side effects and it's so simply to know that side effects are more likely if you overdose a drug. So, what the hell brings us to do anesthesia without measuring depths of anesthesia with the best available system? They're far away from saying this is ideal, it must be further developed, it must be possible to be paid. If this census cost 20 euro, it's too expensive for a regular hospital. So that funds such a situation. Andy that you have just described that some do it, you got a change in technique when you do it on a regular basis.

Andy Cumpstey: First up, and it's interesting you mentioned cost as one potential, I'm going to say excuse or reason people choose not to use it. But are there any other potential reasons or disadvantages to using it that people may be concerned about or any risks to using it at all?

Prof. Manfred Blobner: Obviously we have different systems. When as a chair in Germany you say you have to do it in each patient, it is done. So that's simple. Normally that is today called leadership. I'm not sure if that's leadership, but that's the case in our department. It was a clear message. If your patient is anesthetized, you have to do that and if you don't do it, you have to have hard arguments. And when starting that, hard arguments came up. But then you have to convince them. But you only have to convince those people who are older than 50. The others are doing it.

Andy Cumpstey: That's it. You said I've always been trained. This is how we do it; this is how we use it. But it's interesting that as you say that change in practice, that's coming through.

Prof. Manfred Blobner: That's the point. Is it risky? I have never seen a risk by this depth of anesthesia monitoring. What I saw is definitely that there is a cost risk. Again, a time part of speaking with the producer, of course.

Andy Cumpstey: This is how we do it; this is how we use it. But it's interesting that, as you say, that change in practice that's coming through.

Prof. Manfred Blobner: That's the point. Is it risky? I have never seen a risk by this depth of anesthesia monitoring. What I saw is definitely that there is a cost risk. Again, part of speaking with the producer.

Desiree Chappell: Just to kind of get technical for just a moment. Because this is something in my department, we're having discussions about using process EEG. We use it a lot, we do a lot of TIVA, so that was our entry into saying we need to do depth of anesthesia monitoring, at least for these patients, and we do a lot. So, there's been adoption of that. But we also are doing multimodal analgesia techniques and incorporating things such as ketamine and MDA receptors. So how does that affect and have you seen that have a major effect on how patients are treated using processed EEG?

Prof. Manfred Blobner: We use processed EEG also when we are using ketamine, by the way, we do not use it very frequently. So again, what I said before we started that I do not see major differences in the way you're doing anesthesia in terms of outcome. A little bit more pressure up with a little bit more pressure down, as long as it is in a normal range, that's important. If you're using Sevoflurane or Desflurane, it's more an environmental question than the question related to the patients.

If you do gas anesthesia, whatever, and you do it too deep, then it's a problem. If you don't do it too deep, it's not a problem. If you do TIVA, you must more paralyze the patient that's known. There are good studies that show that that you have to give more neuromuscular blocking agents. That's also not a problem. If you monitor it, it's clear you have both things in balance. You can control both things. That's easy. It's more to control what you are doing than the available drugs. Then the drugs are more than ideal.

Desiree Chappell: It's another tool in your toolkit. I do use it. I'm a doctor of that. You spoke about neuromuscular blocking, and I know that's something that you're also passionate about. Tell us a little bit more about, I know that there's been some new guidelines that have been put out by the ASA in America for neuromuscular blockade monitoring and things like that, and there's Sugammadex and other alternative medications to reverse. So, let's talk a little bit more about it.

Prof. Manfred Blobner: Interesting point. I've done research for my lifetime in that field. I'm very happy that there are guidelines. It's amazing that we had the American and the European at the same moment. The first question is why do we have it in 2023 and not in 2010?

Desiree Chappell: Good question.

Prof. Manfred Blobner: A simple answer. In 2010 all the necessary knowledge was on the table. But there is no solution outside recommending Sugammadex on a more frequent base. Everything else would be not based on data. So, the community had to answer the question can we strongly recommend a drug that costs 80 euro or dollar per patient? And the answer was no, we can't. It's of such a high economical point that all the recommendations from a clinical point of view can't be completed from the systems.

Prof. Manfred Blobner: So, in Europe it's now over. MSD will lose the patent rights on the 27th or 29th July in Europe. So that means on the 1 August is available and it will change doing anesthesia in Europe, I'm sure, because there is no need to deepen up anesthesia in order to avoid a neuromuscular block. And there are some studies, I'm not completely prepared for that session, so I can't tell you so I can tell you the name of the authors and they showed that introducing neuromuscular monitoring plus Sugammadex or the base free available base, the blocks became deeper, giving incremental dose of Rocuronium becomes later, closer to the end of anesthesia. But the depth of anesthesia is not so deep.

Prof. Manfred Blobner: If you don't measure depth of anesthesia with an Entropy or BIS, then the risk for awareness will increase. And if you give very close to the end of anesthesia a neuromuscular blocking agent, you must give really enough reversal agents yeah, and you must be sure that there is a complete recovery, and you should measure the next 10-15 minutes in order to see deepening the block again. Maybe it's recurrization, or at least it's something kind of rebound. And the likelihood for rebound is in clear linear relation to the complete dose of Rocuronium irrespectively if you give Sugammadex. We have Sugammadex for 15 years in Europe, but we don't have enough knowledge about deepening the block, reducing the depths of anesthesia, in many, many cases on a regular basis. I think it's very important that neuromuscular monitoring is also carried out the whole period, not only the last five minutes, in order to see how much dose was necessary to follow the track, to see what and then give the right dose and not stop monitoring when the first 90% value is here. That's the most important problem and especially I've seen it with my friends in US very frequently, that tough 90, stop monitoring, even if they do it.

Desiree Chappell: I was just going to ask, let's talk about monitoring. I'm assuming at your shop in Munich that everyone has neuromuscular monitoring from flash to bang, right? And what type of monitoring are you using and how is that used?

Prof. Manfred Blobner: It's simply dependent on the monitoring system you have. If you have a monitoring system like Philips or GE, I think Mindray also that have modules for neuromuscular monitoring, you will take that. So in one hospital I'm working on a regular base, we have a GE monitoring and there we have the GE module and that allows us to do electromyography and kinomyography in the other hospital they have a Phillips monitoring there, only you have to use the old Tofwatch system which is integrated as a module. So, if this available, you should take that what is available.

Desiree Chappell: So, I have the old twitch monitor.

Prof. Manfred Blobner: And you don't measure quantitatively.

Desiree Chappell: No, I know. And that happens in the US.

Prof. Manfred Blobner: I'm very, very worried about.

Desiree Chappell: You know, how does one build a case for us to talk to our hospital partners, to build a case for how do we integrate and bring in neuromonitoring?

Prof. Manfred Blobner: From my personal experience, it's simply a leadership decision. So we decided that using neuromuscular blocking agent is mandatory to be monitored quantitatively and it was a cheap solution in GE because we only had to buy a new module the module and the module, irrespectively if it costs 2000 or 10,000 euro it's an inversion for one time and you can use it ten years. So, on a regular basis we use simply ECG electrodes to stimulate and as the KMG is much easier to apply, this is a 95% use and only those who are interested, use the real very much better EMG system, it's the same in all.

Prof. Manfred Blobner: So that's a single question you must pay for the modules and that's it. The question is different. The EMG is better than all mechanic systems, but it's only better if it is used correctly. And to apply five or four electrodes is a hard job for training. So normal initiatives are doing always mistakes in that case. So, the solution is the single use device that includes all. Maybe it's a next important step like this given now in the market, but they will have between 15 and 20 euro for devices, now we are again in the price question. I think in UK it's similar to Germany: 15 euro per case increases the budget by a half million in a normal hospital. And half million euro must be discussed.

Andy Cumpstey: So, on top of that, there's the training cost as well. As you mentioned, it's not just buying the modules.

Desiree Chappell: How is that going to help improve outcomes? What are we most concerned about if we're not doing neural blockade monitoring and not using depth of anesthesia monitor?

Prof. Manfred Blobner: You simply do not the best kind of anesthesia if you don't do that. And the question is, can the best way to do anesthesia improve outcome based on data of the last 20 years and continuous monitoring and PDMS during the last ten years? It's hard to define the effect on better anesthesia and outcome. I think one of the major problems in the hospital I'm talking about, we had neuromuscular monitoring and we had depth of anesthesia monitoring, as mentioned many times in our talk. So, I don't have a comparator and doing it in that way, I can't see major effects of anesthesia on outcome. What we see is that long phases of deep blood pressure have outcome effect, but not outcome related to mortality or need of intensive care. It's more like clavin dindoclass. Two, these problems are less frequent if you take care for a higher blood pressure, which by the way is easier if you don't do too deep. But I do not have comparators, but in a hospital that is well organized does have that.

Desiree Chappell: And we have talked a lot about that on Top Med Talk about using depth of anesthesia to actually help as a tool for better hemodynamic management, not having someone so deep, avoiding hypotension, things like that. I think too, when it comes to inadequate reversal, inadequate recovery from neuromuscular blockade is a real problem. We know that that's a real problem.

Prof. Manfred Blobner: Yes, that is a real problem, but I was responsible for that popular study. It was 250,000 patients in Europe in 2016 we published in Lancer Respiratory Medicine. And unfortunately, we could not show that doing anesthesia in the right way improves pulmonary outcome. And finally, the most important effect in the model, in the statistical model was the hospital. And so, I'm coming back to what I said just now. A well-organized hospital takes care of measuring depth of anesthesia, depth of neuromuscular block recovery, doses the drugs. On a routine base, in an adequate range, have a well-organized PACU, has a well-organized preparation and so all these parts are part of a bundle.

Prof. Manfred Blobner: It's really hard to find out if one of these many factors is able to improve anesthesia by itself,

Desiree Chappell: Which is a silver bullet.

Desiree Chappell: Professor, thank you so much for sitting down with us on Top Med Talk. We really do appreciate it. Great conversation. Hopefully we can have you back again sometime soon.

Prof. Manfred Blobner: It was a pleasure sticking with you.

Desiree Chappell: All right. And thank you for listening to Top Med Talk. You know, you can find us at topmedtalk.com. You can find great conversations like this on our social media platforms: twitter, LinkedIn, Facebook, we are there. Thanks so much for listening. We'll catch you on the next one. Cheers.

 

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