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SCCM Pod-459: Processed EEG Monitoring in the ICU

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6/21/2022

This podcast educates clinicians on the unfamiliar parameters of processed EEG. Host Pamela M. Peeke, MD, MPH, FACP, FACSM, is joined by Meghan B. Lane-Fall, MD, MSHP, FCCM, to discuss the benefits of processed EEG for monitoring sedated mechanically ventilated patients and patients undergoing neuromuscular blockade. Dr. Lane-Fall is an associate professor of anesthesiology, critical care, and epidemiology at the University of Pennsylvania. This podcast is sponsored by Medtronic.

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Transcript:

This podcast is sponsored by Medtronic. Processed EEG is a technology that has been around for quite some time. Over the past two years, there has been a noted increase in the use of processed EEG in the ICU. Medtronic is excited to bring this podcast to you to help you learn more about the technology and how it can be used in the ICU. To learn more, please visit medtronic.com.

Dr. Peeke: Hello and welcome to the Society of Critical Care Medicine’s Critical Care podcast. I’m your host, Dr. Pam Peeke. Today, we’re going to be talking about processed EEG monitoring in the ICU. I’m joined by Dr. Meghan Lane-Fall, who is vice-chair of inclusion and diversity and equity, associate professor of anesthesiology and critical care, and associate professor of epidemiology at the University of Pennsylvania. Welcome, Dr. Lane-Fall.

Dr. Lane-Fall: Thanks so much, Dr. Peeke. It’s great to be with you.

Dr. Peeke: Wonderful. Before we start, do you have any disclosures to report?

Dr. Lane-Fall: I don’t have any financial conflicts of interest to report. I am the vice-president of the Anesthesia Patient Safety Foundation, and I’m on the board of directors for the Foundation for Anesthesia Education and Research. I also have some research grant funding from the National Institutes of Health, the Agency for Healthcare Research and Quality, the Patient-Centered Outcomes Research Institute, and the American Heart Association.

Dr. Peeke: Thank you so much. I want to go over the learning objectives. Listeners will recognize the benefits of monitoring mechanically ventilated patients with processed EEG when sedated. As well, they’ll learn about the value of monitoring patients with processed EEG who have neuromuscular blockade. Why is this podcast needed? It’s needed because patients are coming into the ICU sicker and in greater need of treatment. Successful education about the benefits of monitoring with processed EEG will help aid caregivers to provide the best care to their patients, and we’re addressing a knowledge gap that includes helping educate clinicians about the unfamiliar parameters of processed EEG. With that said, Dr. Lane-Fall, can you please define processed EEG?

Dr. Lane-Fall: Sure. I’m not a neurologist, which is probably good, because I would go into too much detail if I were. Basically, I think most folks who work in an ICU are familiar with the conventional EEG, or electroencephalogram. It’s that device that, if you put a bunch of little dots on the patient’s head and you monitor brainwaves from front to back, you get a very complicated EEG readout. For most of us, it’s pretty difficult to read. I can tell you, when I look at an EEG on one of my patients, I can tell you if they’re seizing and I can tell you if they’re in burst suppression. But beyond that, I can’t tell you much. It’s a pretty complicated tracing to read, to give you a sense of what is happening in terms of brain activity.

What a processed EEG does is distill down, or essentially collapse, all of those data into an easier-to-use format. You get a single tracing of brain activity. But more importantly, for those of us who use it in the ICU, you get a single number that’s meant to reflect a level of consciousness. That number gives you a sense of how awake your patient is. Certainly, whenever you collapse down a lot of information, you lose some granularity, so processed EEG is certainly not as precise as a full EEG. It’s not used for the same purposes. But for the purpose of letting us know how awake someone is, it’s really helpful.

Dr. Peeke: Why was this developed? What was the unmet need here?

Dr. Lane-Fall: My understanding as an anesthesiologist is that processed EEG met its heyday in the operating room. Part of the rationale behind it was to get a sense of what a patient’s level of consciousness is when they’re getting surgery. We, as anesthesiologists, use a lot of different medications, sedatives, hypnotics, to decrease consciousness, to make people unconscious for surgery. There are certain kinds of medicines, like volatile anesthetics, inhaled anesthetics, where if we give you a certain percentage of gas that you breathe in, we know with a lot of confidence that you’re going to be unconscious. It’s interestingly something that’s preserved across species. If you’re anesthetizing a fruit fly, a mouse, a monkey, or a human, if you give them a certain percentage of a given anesthetic, whether it’s sevoflurane or desflurane or something like that, you know that they’re going to be unconscious.

When it comes to the IV medicines, when it comes to propofol, when it comes to any of the benzodiazepines, when it comes to dexmedetomidine, we have no idea how much it takes to make you unconscious. There are some concepts of target-controlled infusion where you can actually measure the amount of drug in the blood and that gives you a better idea. But, at least in the United States, those aren’t in practice at all. So essentially, if you’re using IV anesthetics or sedative hypnotics, it’s a total black box and it’s an educated guess as to how much you need to give the patient for them to be unconscious.

The gap here that processed EEG fills is to tell us how active a person’s brainwaves are, which we use as a proxy for consciousness. We know that if we get to a certain number, where 100 is fully awake and 60 and below is general anesthesia, at least on one of these devices, that that patient is reliably unconscious. That’s the gap, helping us understand if that patient is actually unconscious. In the ICU, it’s been used for the same purpose, but on a different time scale, because we’re monitoring those patients for longer, but same basic idea, to let us know how unconscious someone is.

Dr. Peeke: This is amazing. This is obviously a huge problem. I’m curious if you could share with us, prior to processed EEG, was it just basically guessing? How did you know if someone is chemically paralyzed, that they’re actually awaking in pain? Prior to processed EEG, what was the standard of assessment?

Dr. Lane-Fall: There wasn’t really a standard. Yes, it was an educated guess. I would say, in practice, what we would do is monitor vital signs to give us a sense of whether someone was awake or not. Honestly, it’s a bit like reading tea leaves. It’s not reliable at all. But the thought is that if someone’s heart rate or blood pressure doesn’t change in response to a noxious stimulus, they’re probably unconscious. If everything looks stable, if they don’t start sweating, it’s sort of an absence of things, an absence of reaction to noxious stimulus gives you confidence that they’re not conscious, but it is not at all reliable.

Dr. Peeke: Gotcha. I was just thinking, as providers, taking care of patients prior to processed EEG has got to be very stressful on providers because what you don’t want to do is have someone experience pain and be unaware of that. It’s very stressful, and caregivers within the ICU obviously carry that burden. Wouldn’t you agree?

Dr. Lane-Fall: I do agree. It is and has been stressful. I think that one difference between the ICU and the operating room is that, in the operating room, often we’re using chemical paralysis, and we do that in the ICU, and we’ll get to that. But often in the OR, we’re using chemical paralysis. And we really, really don’t want people to be paralyzed. That leads to posttraumatic stress disorder, that leads to all sorts of problems down the line. In the ICU, many of our patients are not paralyzed, so even though we’re essentially using an educated guess when we’re sedating them, often we have enough ability to interact with them to say, okay, we think they’re uncomfortable. We can use the behavioral pain scale, we can use the Richmond Agitation-Sedation Scale or any of the other sedation scales to say, where are they? Because they do, at least in theory, have the ability to move. So that gives us a little bit of reassurance. But then you get to that special use case of, they’re chemically paralyzed either because they have—ARDS would be the most likely use case, but there are other reasons you might chemically paralyze someone—and then you’re back in that boat of, oh my goodness, I really hope that they’re sedated because I have no way of telling.

Dr. Peeke: Okay. You mentioned neuromuscular blockade. Let’s go there for a moment.

Dr. Lane-Fall: Yes, neuromuscular blockade, it’s interesting, and I think that people in the ICU have a good awareness of this now. There is no sedation or hypnosis or amnesia conferred by neuromuscular blockade. These medications, whether it’s cisatracurium, vecuronium, rocuronium, they just paralyze. So if you only give those meds, then you have a patient who’s awake, can feel, but cannot move. That’s the worst possible scenario. So when we think about using these paralytics, these neuromuscular blockers for clinical purposes, we also want to co-administer a sedative or hypnotic so that we can at least make sure that the patient isn’t aware and doesn’t remember.

Dr. Peeke: Okay. Very good. Now, tell us about your experience with processed EEG.

Dr. Lane-Fall: My experience with processed EEG is in both the OR and the ICU. In the OR, the way that I usually use it is I’ll put it on an awake patient and I’ll explain to them why I’m putting it on them so they know why I’m putting the sticker on their head, because that’s usually where it goes. I’ll say, I’m going to put this sticker on your head and it’s going to help me figure out how asleep you are. I can actually watch the processed EEG numbers change as that patient becomes sedated as I administer medications. I’ll see it go from the 90s, 100s, down all the way to below 60 to general anesthesia.

In the ICU, often I’m dealing with a patient who’s already sedated. If we take that use case of ARDS, acute respiratory distress syndrome, if you have someone who has acute lung injury or ARDS, they’re probably already mechanically ventilated. They’re probably already sedated and it’s gotten bad enough that you say, I need to not paralyze them. You’re already starting from a sedated baseline. We’re already deviating a little bit from the use in the OR. But then often we’ll put on the processed EEG before we paralyze to get a sense of where the patient is in terms of sedation. Sometimes their mechanics or lung mechanics or their oxygenation is bad enough that we just have to go ahead and paralyze and then put on the processed EEG. But in either event, the processed EEG is helping us understand whether that patient is adequately sedated or not. It helps us titrate our sedatives.

Dr. Peeke: How easy is it to train your team to utilize processed EEG?

Dr. Lane-Fall: I think it’s pretty easy. It’s a monitor so, just like any other monitor, it has its limitations. I think the most important thing for our team to figure out is whether the tracing is reliable or not. On the processed EEGs that we use, there’s usually some indicator of muscle activity. There’s usually some indicator of signal quality. When we’re training our team to use it, we want to make sure that they’re ensuring that there is good signal quality before they’re making clinical decisions based on the reading from the machine. We also want to make sure that there’s good contact on the skin because if the electrodes aren’t fully contacting, then your signal won’t be good. Occasionally, we’ll run into issues where somebody is really sweaty or the thing won’t stick, and we have to troubleshoot that. But for the most part, it’s pretty straightforward to use, which is good.

Dr. Peeke: Do you have good trust in the numbers you’re getting from processed EEG such that your own levels of stress decrease a bit? Based upon your experience, have you actually seen that it appears to be accurate enough that you don’t run into problems with people being awakened in pain or not adequately sedated?

Dr. Lane-Fall: It’s such a good question and there’s no gold standard here, which makes it a little hard to know exactly how good it is. In contradiction to noninvasive cardiac output monitors, the gold standard might be a pulmonary artery catheter, right? So I can check to see, is the noninvasive thing showing me the same thing as the invasive thing? In this case, the way that I will look for whether I should trust it or not will be to titrate the sedative. What I’m hoping to see is that if I lighten the sedative, if I decrease the sedative dose, the processed EEG number should go up, right? It should indicate more consciousness. And if I give more sedatives, then the processed EEG number should come down, it should indicate deeper levels of sedation. When I don’t see the numbers change in response to sedation changing, then I start to worry a little bit, can I trust this thing? But for the most part, I would say that I do see that, so I’m relatively confident that I’m seeing what I want to see in terms of an indicator of level of consciousness.

I will say that one of the really nice things about processed EEG is that it can often give us confidence to lighten sedation, because we often are really heavy-handed with the sedatives because we’re trying to make sure that patients aren’t awake. We give them a lot and sometimes they don’t need as much, so it’s nice to be able to dial back the sedative, which also means that you may not have as much hemodynamic compromise, you may not have as much residual sedative effect, and you can confidently dial that sedative back and know that they’re still unconscious. That’s a really nice benefit of processed EEG.

Dr. Peeke: That’s fantastic. How widespread is the use of processed EEG?

Dr. Lane-Fall: It’s hard to know. In our ICU, it started off in our medical ICU. I do most of my work in our surgical ICU and our trauma ICU. I remember every once in a while we’d have somebody with ARDS and we’d have to go to the medical ICU and say, can we use your thing, can we bring it over, and they’d say okay. But at some point all of our ICUs started using it because you see ARDS everywhere, especially after COVID. In our ICUs, it’s really widespread, which is great. It’s in all of our operating rooms as well. My sense is that it is picking up. But I think it tends to be institution specific. Institutions have to decide whether they’re going to use it or not. But once they do, I think it takes off pretty quickly within those institutions, because people see how useful it is.

Dr. Peeke: That’s fantastic. It’s just great to know we have a tool that is beneficial for both provider as well as patient, to say the least, because this has been a real critical unmet need for quite some time. I’m so happy to hear that you trust it enough and that the other providers you’re working with have also found great benefit to processed EEG usage. This should be very encouraging for other critical care providers as they listen to this podcast, to reach out and look into processed EEG as a new tool in the toolbox to be able to benefit patients. Would you not agree?

Dr. Lane-Fall: I think that makes sense. Yes, it’s definitely something to look into. We don’t have a great alternative to understanding depth of consciousness, so I’d say it’s a no-brainer to at least explore it a bit more to understand whether it’s something that would make sense for any group’s individual practice.

Dr. Peeke: Excellent. You have been incredibly enlightening about all things processed EEG. We have met both of our objectives. As we conclude, I’d love for you, Dr. Lane-Fall, to share perhaps your last thoughts about processed EEG as it relates to your peers out there who are curious about this and wonder what they should do next in terms of looking into this.

Dr. Lane-Fall: That’s a great point, Dr. Peeke. I think what I would encourage folks to do is to ask themselves, given their current practice, if they don’t use processed EEG, how do you know what your patient’s levels of sedation are and how are you able to assure yourselves and your patients and their families that they’re getting the care that they need and that we’re being appropriately precise in the care that we’re delivering? I don’t think that processed EEG is the right thing for every patient. But I think pulmonary artery catheters aren’t the right thing for every patient either. There are certain situations where you need to be able to more precisely determine exactly what you’re doing and why you’re doing what you’re doing. I think getting people to ask themselves, how do you do this, how do you smartly select a sedation regimen for a patient who might need chemical paralysis or might need deep sedation is really important. Then work with your team to figure out how to evaluate whether it’s something that makes sense for your organization.

Dr. Peeke: Excellent. Share with everyone your current institution where you practice.

Dr. Lane-Fall: I’m at the University of Pennsylvania in Philadelphia.

Dr. Peeke: Fantastic. So everyone knows, if someone reaches out to you, they’ll probably say, I heard you on the Society of Critical care Medicine’s Critical Care Podcast, and could you share a little bit with me? So don’t be surprised if you hear from people.

Dr. Lane-Fall: Happy to talk.

Dr. Peeke: That’s excellent. That’s what I wanted to hear more than anything else. Dr. Lane-Fall, thank you so much for being our guest expert as we talk about processed EEG monitoring in the ICU. This concludes another edition of the Critical Care Podcast. For the Critical Care Podcast, I am Dr. Pam Peeke.

This podcast is sponsored by Medtronic. Processed EEG is a technology that has been around for quite some time. Over the past two years, there has been a noted increase in the use of processed EEG in the ICU. Medtronic is excited to bring this podcast to you to help you learn more about the technology and how it can be used in the ICU. To learn more, please visit medtronic.com.

Pamela M. Peeke, MD, MPH, FSCP, FACSM is a nationally renowned physician, scientist, expert, and thought leader in the field of medicine. Dr. Peeke is a Pew Foundation Scholar in nutrition and metabolism, assistant professor of medicine at the University of Maryland, holds dual master’s degrees in public health and policy and is a fellow of both the American College of Physicians and the American College of Sports Medicine. Dr. Peeke has been named one of America’s top physicians by the Consumers Research Council of America. She is a regular in-studio medical commentator for the national networks and an acclaimed TEDx presenter and national keynote speaker. Dr. Peeke is a three-time New York Times best-selling author and is a science and health advisor for Apple.

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