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Neuroprognostication after Cardiac Arrest
9 Plays6 years ago
The advent of targeted temperature management has changed how we treat anoxic brain damage post cardiac arrest. In this episode of Critical Matters, we dive into the challenges and existing evidence regarding neuroprognostication in cardiac arrest survivors.
Our guest is Fred Rincon, MD. Dr. Rincon is Associate Professor of Neurology and Neurological Surgery at Thomas Jefferson University in Philadelphia, PA. He is board certified in internal medicine and critical care (ABIM), neurology (ABPN), vascular neurology (ABPN), and neurocritical care (UCNS).
Additional Resources
- Practice Guidelines on reducing brain injury following cardiopulmonary resuscitation. These guidelines are published by the American Academy of Neurology and endorsed by the Neurocritical Care Society.
Additional Resources:
Practice Guidelines on reducing brain injury following cardiopulmonary resuscitation. These guidelines are published by the American Academy of Neurology and endorsed by the Neurocritical Care Society. Click here to read.
Recommended
Transcript
Introduction to Critical Matters Podcast
00:00:09
Speaker
Welcome to Critical Matters, a sound critical care podcast covering a broad range of topics related to the practice of intensive care medicine.
00:00:17
Speaker
And now, your host, Dr. Sergio Zanotti.
Guest Introduction: Dr. Fred Rincon
00:00:22
Speaker
Today we have a very interesting topic which relates to neurological prognostication after cardiac arrest.
00:00:30
Speaker
And I'm very honored and pleased to have as our guest, Dr. Fred Rincon, who's Associate Professor of Neurology and Neurological Surgery at Thomas Jefferson University and a neurointensivist of the Division of Neurotrauma and Critical Care, Department of Neurological Surgery.
00:00:46
Speaker
Fred, I think, is not only a dear friend, but perhaps one of the most qualified people to talk about this topic.
00:00:53
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Fred has done extensive training and is board certified in internal medicine and critical care medicine through the American Board of Internal Medicine in neurology, vascular neurology, and neurocritical care.
00:01:06
Speaker
In addition, he has a master's in public health and bioethics and is a fellow of the American College of Physicians, the American College of Chest Physicians, and the American Heart Association and a member of several critical care and neurocritical care societies.
00:01:21
Speaker
I am very
00:01:22
Speaker
Honored and happy to have a good friend on the podcast today.
00:01:27
Speaker
Welcome, Fred.
00:01:27
Speaker
Thank you, Sergio.
00:01:29
Speaker
Thank you for having me here.
Anoxic Brain Injury and Patient Recovery
00:01:31
Speaker
So I think that this is obviously a topic that is dear to your heart, and you've seen both sides of the coin, both as your critical care internal medicine training, but also your neurology and neurocritical care training.
00:01:44
Speaker
And I think that ultimately, it's also an area that has evolved significantly in the last decade.
00:01:51
Speaker
So as all of us are aware, the outcomes of patients who suffer out of hospital and in hospital cardiac arrest are still devastating.
00:02:02
Speaker
And even though we call it cardiac arrest, the true issue is anoxic brain injury.
00:02:07
Speaker
And that's what ultimately determines how these patients who survive do in terms of returning to a meaningful life.
00:02:15
Speaker
So Fred, as we start exploring and diving into how do we most accurately
00:02:21
Speaker
predict or tell families what to expect from a neurological standpoint after a loved one has undergone or had a cardiac
Advancements in Resuscitation Medicine
00:02:29
Speaker
arrest.
00:02:29
Speaker
I would like to just ask you in general terms, where do you stand today in terms of targeted temper management and therapeutic hypothermia?
00:02:37
Speaker
What are you doing in your practice for a patient who has a V-fib arrest out of the hospital, is brought to the hospital, and after return circulation is not waking up or is comatose?
00:02:49
Speaker
Sergio, I think that I agree with you in everything that you mentioned before is a devastating condition and at the end of the day, what matters is how you would survive or how would the patient survive.
00:03:00
Speaker
At the end of the day, it's really how much brain injury the patient sustained.
00:03:05
Speaker
So when I deal with these patients in my practice, the first thing that I keep in mind is probably not to rush to conclusions too early in the onset of the disease.
00:03:16
Speaker
So the first message would be,
00:03:18
Speaker
wait, really don't try to prognosticate early on and the reason for that is because of the advances in resuscitation medicine that have not happened only in the intensive care unit or pre-hospital level.
00:03:33
Speaker
So the pre-hospital level we have better access to AED, CPR, bystander CPR because of all the campaigns that have happened in terms of
00:03:43
Speaker
bystander education.
00:03:45
Speaker
We have better technologies now.
00:03:46
Speaker
AEDs are primarily the ones that probably are saving a lot of lives.
00:03:50
Speaker
And then the access to the chain of survival that we all learned when we were taking our ACLS.
00:03:54
Speaker
So all those variables have contributed to a change in the outcome of this condition.
00:03:59
Speaker
So many patients are surviving now more after they arrive to the hospital after cardiac arrest.
00:04:05
Speaker
And the second thing are the advances in critical care, as you mentioned.
00:04:08
Speaker
Primarily,
00:04:10
Speaker
a neuroprotective strategies that were tested in clinical trials recently and that have demonstrated improvement in survival and functional outcome, primarily temperature management.
Hypothermia and Neuro-Prognosis
00:04:21
Speaker
So because of all of that, right, you have to consider that prior reports, prior studies that have shown different proportions of prognosis may have changed after all of the implementation of these technologies.
00:04:36
Speaker
Hypothermia and temperature management
00:04:40
Speaker
changed radically the way that we approach this and we have learned over the last 10 years after the clinical trials were reported and after we started implementing hypothermia post-cardiac arrest is that we probably need to be a little bit more conservative in terms of approaching neuro-prognosis.
00:04:58
Speaker
So that would be sort of like the first thing that I would emphasize to all of the intensives and all of the providers that deal with this condition
00:05:07
Speaker
today.
00:05:08
Speaker
Excellent.
00:05:08
Speaker
So I think that as a here very actionable and very powerful messages number one is
00:05:14
Speaker
Clearly, we have strategies now that help protect the brain and can mitigate the effects of anoxic brain injury after cardiac arrest.
00:05:23
Speaker
And that is, like you mentioned, the targeted temperature management.
00:05:26
Speaker
That will be maybe the topic of another podcast, diving into the specifics of where the literature stands there.
00:05:33
Speaker
But obviously, doing that for the right patient makes a difference.
00:05:36
Speaker
And I hear loud and clear your message, Fred, that especially because of this and because
00:05:42
Speaker
hypothermia or targeted temperature management has changed the natural course of anoxic brain injury after these types of insults, we have to be very careful how we utilize certain tools and when we utilize these tools to prognosticate neurological recovery.
00:05:59
Speaker
So with those two very, I think, strong messages, let's dive into some of the specific aspects and tools that we utilize or have available for establishing a neurological prognosis
00:06:10
Speaker
after a cardiac arrest, and then maybe at the end, discuss what a reasonable general approach would be based on the available literature and based on your opinion.
Diagnostic Tools Post-Rewarming
00:06:20
Speaker
So Fred, I would like to ask you, traditionally, we've always started with a physical exam.
00:06:26
Speaker
And tell me a little bit about what are physical findings that may be useful in terms of determining prognosis in patients who suffer a cardiac arrest and how you would use them.
00:06:40
Speaker
Yeah, so the first thing that I will look into is post-cardiac arrest to assess if the patient is a candidate for temperature management right.
00:06:50
Speaker
Is to see how good they are at post-cardiac arrest immediately after the resuscitation period because you know that one of the requirements is that the patient needs to remain in a comethode state in order to
00:07:01
Speaker
you know, be eligible for temperature management.
00:07:04
Speaker
So if the patient is waking up immediately after the cardiac arrest, starts to open the eyes and point commands and localizing, probably you have to reconsider how aggressive you want to be in terms of temperature management for that particular patient.
00:07:18
Speaker
For the patient that remains in a comatous state and that you are actually indicating the use of temperature management, then
00:07:26
Speaker
while you wait for the standard period, which is usually 24 hours, and then the rewarming period, the physical exam is the strongest predictor, believe it or not, of neurological recovery.
00:07:39
Speaker
This has been tested recently, Dave Greer, when he was at the university, at Yale University, I'm sorry.
00:07:48
Speaker
He really did the original studies done in the 1980s with a better cohort and in the area of hypothermia.
00:07:55
Speaker
What he found was that, for example, the pupillary reflexes and the motor exam were strong predictors of prognosis.
00:08:03
Speaker
That means that if you still have pupillary reflexes after rewarming, and if you are localizing, not having posturing or abnormal responses to painfully stimulation, and those are the ones that we call either flexion or extension posturing, if you don't have those and if you're localizing and you're doing spontaneous movements that look like meaningful,
00:08:25
Speaker
probably your prognosis is gonna be good.
00:08:29
Speaker
So those are the things that I am always looking when I'm examining these patients post-rewarming, and we will talk a little bit about that later, what's the right timing to do it.
00:08:37
Speaker
But the pupillary reflexes and the motor exam are the stronger predictors.
00:08:43
Speaker
So I think that if I get this right, Fred, clearly immediately after having returned to spontaneous circulation, before we do any interventions,
00:08:52
Speaker
If somebody's following commands, that tells you that probably is not the best candidate, but other findings in that immediate post-arrest situation are usually not very helpful.
00:09:02
Speaker
Correct?
00:09:02
Speaker
That's correct.
00:09:04
Speaker
And once we do the rewarming or we treat them with targeted temperature management for 24 hours and then we do the rewarming, that's when certain physical findings, like you said, the lack of pulmonary reaction or the response to motor stimuli can be useful.
00:09:19
Speaker
But as you said, there's also a timeframe in which the absence of these findings becomes more powerful.
00:09:26
Speaker
And I guess we'll touch about that a little bit later, but that is very, very important.
00:09:29
Speaker
I think again,
00:09:31
Speaker
We'll talk about other aspects or tools, but emphasizing what you just said, that the power of the physical exam, when the right findings are found at the right timing after rewarming, are still, I mean, very, very important for us to remember in our clinical practice.
00:09:49
Speaker
So quick comment on biochemical tests.
00:09:53
Speaker
Are there any biochemical tests that are in any views?
00:09:57
Speaker
I've always read about neurospecific enolase as one example, NSC, but to be honest, I don't use it in my practice.
00:10:03
Speaker
It's not available in my hospital.
00:10:04
Speaker
That's something that I think in a lot of the hospitals that we practice, we use routinely.
00:10:08
Speaker
Can you make some comments on that, Fred?
00:10:10
Speaker
Yes.
00:10:11
Speaker
So the biomarkers are sort of like the new key on the block, you can call it that way, in terms of neuroprognostication.
00:10:19
Speaker
They provide some power in terms of prognosis.
00:10:25
Speaker
And in my mind, the power when you be in conjunction with something else in what I call the multimodality neuro prognostication scheme.
00:10:35
Speaker
But biomarkers on their own, when you use it alone, don't provide that much of discrimination in terms of
00:10:42
Speaker
of prediction because there are many false positives.
00:10:45
Speaker
So you have to be careful when you're using biomarkers.
00:10:48
Speaker
It's important to emphasize that the recent cardiac arrest clinical trial by Nicholas Nielsen didn't use biomarkers for neuro prognostication.
00:10:58
Speaker
The only thing that they used actually was the clinical exam and electrophysiological testing for neuro prognostication.
00:11:07
Speaker
You have to be a little bit careful.
00:11:08
Speaker
They collected a lot of data, a lot of papers from that particular study that have shown that if you use any combination may guide you in terms of providing a likelihood of good or bad outcome.
00:11:23
Speaker
So I will be careful.
00:11:25
Speaker
The MOSES study one is the NSE.
00:11:28
Speaker
You mentioned it already, the neuronal specific analyze.
00:11:31
Speaker
and that has a discriminative power.
00:11:33
Speaker
There are some levels that can be used as cut-ups.
00:11:36
Speaker
I think the one that is generally accepted is 30 or 33 picograms per deciliter.
00:11:44
Speaker
And this is the one that when you have it, right, you can actually predict a poor outcome.
00:11:50
Speaker
I've been fooled before by this, and I could tell you that
00:11:54
Speaker
I became more humble in terms of how I interpret this stuff.
00:11:57
Speaker
So just to give you an example, I had a patient that had a level of 17, came in poor shape, we cooled him, and I signed out the patient to my colleague.
00:12:07
Speaker
I said, this guy's never going to recover.
00:12:09
Speaker
I gave my spiel to the family, and then I left, and then a week later, I came back to the intensive care unit, and the guy's watching TV.
00:12:18
Speaker
And I felt a little amazed about the outcome, but you have to be careful with this thing.
00:12:26
Speaker
You have to be a little bit more conservative and use it with other modalities.
00:12:30
Speaker
Excellent.
00:12:31
Speaker
And I think that it speaks to something that we'll probably readdress and a recurrent topic, which is that a lot of the testing done pre-hypothermia
00:12:43
Speaker
shows that these tools do not perform the same way once we apply hypothermia.
00:12:49
Speaker
So the cutoff of 33 picograms has been very publicized pre-hypothermia, but maybe it's not as predictive when you undergo temperature management post-cardic arrest.
00:13:04
Speaker
You're right.
00:13:05
Speaker
So I think that another area that I think is a lot of interest for us and something that our critical care colleagues do not manage, obviously, as frequently or as well as our neurocritical care or our neurology colleagues are the electrophysiological
EEG and SSEP in Prognostication
00:13:19
Speaker
studies.
00:13:19
Speaker
And to that point specifically, the utilization of either somatosensory evoked potentials
00:13:26
Speaker
or more commonly in a lot of the hospitals where some critical care physicians practice is the use of EEG.
00:13:35
Speaker
Could you comment on both of these and how you see them?
00:13:41
Speaker
Yes, so electrophysiological studies, like you mentioned,
00:13:46
Speaker
evoked potentials, somatosensory evoked potentials on the EE are very powerful.
00:13:50
Speaker
But the timing is the most important thing.
00:13:53
Speaker
So very early on, they have very low sensitivity and you get a lot of false positives for the somatosensory evoked potentials.
00:14:04
Speaker
When using clinical trials, it seems that the best performance is usually after 72 hours post cardiac arrest and probably a little bit later after the re-warming is when I would start using them.
00:14:15
Speaker
I would start probably thinking about SSCPs and analyzing the EEG at around five, seven days post cardiac arrest, which is what we discussed before probably 72 hours after the re-warming.
00:14:29
Speaker
And the reason for this is that if you go into the literature, there are a lot of case reports where you get shut down of the SSCPs initially, right?
00:14:35
Speaker
But as you said before, hypothermia has changed that.
00:14:38
Speaker
So the way that I see it is that hypothermia is sort of like this neuroprotectant.
00:14:42
Speaker
It's sort of like shutting down the fire, right, that occurs initially with this reperfusion.
00:14:47
Speaker
And it's keeping the neurons in this sort of like sleeping mode, hibernating mode, and preserving them for survival.
00:14:54
Speaker
So if you get the SSCPs, you're not going to see anything.
00:14:57
Speaker
And SSCPs are just,
00:14:59
Speaker
a way to determining if there is a connection between a peripheral nerve, usually the median nerve, and the cerebral cortex.
00:15:06
Speaker
And the waveforms that you see indicate at what level you see the connection.
00:15:11
Speaker
The waveform that we usually follow is the N27, and that's usually an analysis of the
00:15:19
Speaker
function of the thalamocortical projection.
00:15:21
Speaker
So by not having that signal, you are assuming that there is a diffuse injury of thalamocortical projections that at the end of the day are the ones that regulate arousal and awakening.
00:15:35
Speaker
So that's how you use SDS, but as I mentioned before, if you do it too early, you're going to get a lot of false positives.
00:15:44
Speaker
In terms of EEG, it's a little bit more complex,
00:15:47
Speaker
even more powerful because now you have a way to look at the whole brain and the waveform activity.
00:15:56
Speaker
And the most important thing is really to look at the background or the rhythm of that EEG and see if there is reactivity when you are stimulating the patient.
00:16:08
Speaker
That's a powerful predictor of good outcome.
00:16:12
Speaker
If you see a change,
00:16:14
Speaker
which is consistent with the clinical, I mean during the clinical exam stimulation.
00:16:20
Speaker
So just to give you an example, so you have a patient that has a flat EEG or is diffusely slow, you start examining him, he starts opening the eyes, he starts responding to you, and then you see a pick up in the rhythm in the EEG, that's a good sign.
00:16:33
Speaker
So in that sense, this technology enables you, right, to take a look at the patient's
00:16:41
Speaker
And not just on a cross-sectional way, but actually in a dynamic way.
00:16:46
Speaker
You're examining and seeing what's going on in the brain.
00:16:48
Speaker
So that's why it's so powerful.
00:16:50
Speaker
So I guess, Fred, reiterating, it sounds like the SSEPs, when done in conjunction with other findings,
00:17:01
Speaker
at the right timing can add to a lot, especially when they're absent.
00:17:05
Speaker
And there's other signs that suggest severe anoxic damage, but they have to be done at 72 hours or later after re-warming.
00:17:12
Speaker
And it sounds like with the EEG, what is probably good or powerful is the ability to elicit reactivity in the background activity.
00:17:21
Speaker
And that probably requires a more involved EEG, not just sending a tech recorded EEG and then be reported by somebody later on, but more of a specific, the intensivist asking for an EEG for cardiac arrest, anoxic damage evaluation, looking to see if there's any reactivity to stimulize.
00:17:41
Speaker
Is that correct?
00:17:44
Speaker
Yes.
00:17:46
Speaker
And to tell you the truth, you know, I could tell you this even though I could get in trouble with my epilepsy colleagues, right?
00:17:52
Speaker
We always like that type of fact.
00:17:58
Speaker
But you don't need to be an epileptologist to look for reactivity.
00:18:02
Speaker
It's very simple.
00:18:03
Speaker
You can learn this in five minutes at one of the workshops, in one of the society meetings.
00:18:10
Speaker
If you see a workshop on an EG after cardiac arrest and you want to learn something about it, you could learn how to stimulate a patient and look at reactivity.
00:18:20
Speaker
It's a very simple process.
00:18:21
Speaker
It doesn't require a lot of analysis or training.
00:18:25
Speaker
So, since we're on the topic of EEG, I would like you to maybe once and for all clarify to all my colleagues the difference and the implications in that difference between a myoclonic jerk and a myoclonic status EEG pattern after cardiac arrest.
00:18:46
Speaker
Yeah, so myoclonic jerks are just muscular jerks and they're called myoclonic because they are usually originated in the muscle.
00:18:55
Speaker
Most of the myoclonals that you see in postpartic arrest patients do not originate or you cannot, you know, for whatever reason, you cannot pick them up originating from the cortex.
00:19:07
Speaker
So, you know, most of the myoclonals that you see are usually what we call subcortical.
00:19:11
Speaker
They originate in subcortical networks, even the spinal cord.
00:19:16
Speaker
And that's the main difference.
00:19:17
Speaker
It's called myoclonic.
00:19:19
Speaker
It's because of the pattern of the spike that you see in the EEG.
00:19:23
Speaker
It's usually a huge spike with very long amp, I'm sorry, big amplitude.
00:19:31
Speaker
And the difference between that and myoclonic status is that sometimes you can get those waveforms originating in the cortex, and they have that at the same amplitude, and they're big, right?
00:19:43
Speaker
But when you pick them up and they are consistent,
00:19:46
Speaker
and they evolve and you don't or you cannot treat them with conventional therapy.
00:19:53
Speaker
That's what we call the myoclonic status or like syndrome.
00:19:58
Speaker
And in the 1990s there were a couple of papers saying that if you had that, it was a game over postcardiocardia and everyone sort of like learn that and that's how I was taught for example in my
00:20:14
Speaker
residency that if I saw myoclonic status that was the end.
00:20:18
Speaker
But what you mentioned at the beginning hypothermia has changed, right, the natural course of this disease and now we have learned that if we treat aggressively, not just myoclonic status but any other type of status that you see post-cardiac arrest, patients can actually survive and do well.
00:20:36
Speaker
So the aggressiveness of the therapy for myoclonic or any other type of status
00:20:43
Speaker
should be in accordance with the aggressiveness of cooling.
00:20:47
Speaker
So if you are submitting somebody to cooling, right, and it's awakening, it's awakening, and now in the EEG, you're seeing my client status, you know, most of us would favor a trial of intervention before, you know, concluding that the outcome is going to be poor.
00:21:03
Speaker
So that's what I do in clinical practice.
00:21:05
Speaker
I'm aggressive, you know, treating these patterns in the EEG, and, you know,
00:21:10
Speaker
A couple of papers published recently have shown that if you treat them, that patients could do well.
00:21:15
Speaker
So my question also regarding the myoclonic jerks, I think that often clinicians see myoclonic activity externally, like the muscular jerks, and immediately say this patient has a horrible prognosis.
00:21:29
Speaker
And that has not been shown, right?
00:21:31
Speaker
On the other hand, if you find the myoclonic activity,
00:21:34
Speaker
status on the EEG, especially when it's refractory, that is associated with the worst prognosis.
00:21:39
Speaker
Is that correct?
00:21:43
Speaker
Well, the classic myoclonus that you see, you know, I don't think it's associated with that much of poor prognosis anymore after hypothermia.
00:21:57
Speaker
And if you're not seeing
00:21:59
Speaker
myoclonus or myoclonic status in the EEG even less.
00:22:04
Speaker
The problem is really the myoclonic status is the one that I would be concerned about because if you don't treat, right, then of course the patient is going to do poorly.
00:22:14
Speaker
So that's the problem with this issue, right, is that if you don't look for it, then you will never know.
00:22:23
Speaker
And in my mind, right, if your institution doesn't have access to continuous EEG,
00:22:29
Speaker
You should be able to either consider, you know, transmit a patient and see, you know, if another institution can deal with it because you're right.
00:22:39
Speaker
I don't think that's, you know, after hypothermia, I don't think it's associated with poor prognosis anymore.
00:22:46
Speaker
The most important thing is that if you diagnose it, you provide a trial of intervention.
00:22:53
Speaker
Excellent.
Imaging in Neuro-Prognostication
00:22:54
Speaker
And I think that moving along with other tools, obviously a very commonly utilized tool is neuroimaging, and either in the form of CT scans or MRIs, which as we all know from ordering them after severe anoxic injuries can sometimes be read as
00:23:12
Speaker
significant patterns that suggest anoxic damage, but we've also seen normal CTs or almost normal CTs in patients who never wake up.
00:23:21
Speaker
So what's the role of imaging in neuroprognostication after cardiac arrest?
00:23:26
Speaker
That's an excellent question, Sergio, and the data is even less convincing that it has enough discriminating power to
00:23:35
Speaker
to predict outcome on their own.
00:23:38
Speaker
So for imaging, we have conventional computerized tomography, CAT scans, and then we have magnetic resonance.
00:23:47
Speaker
So we have MRIs to sort of help us or aid us in terms of assessing the degree of brain injury.
00:23:54
Speaker
But to tell you the truth, right, when you use them as a single, you can call it biomarkers as well, because when you use them as a single biomarker, right,
00:24:05
Speaker
they don't have that much of discrimination.
00:24:07
Speaker
I've seen people that look very bad on MRI and then eventually they wake up and that tells you about the sensitivity and specificity of this testing.
00:24:18
Speaker
The timing is another very important thing.
00:24:20
Speaker
If you do it too early, you might not see a lot of damage and you may conclude that the patient
00:24:27
Speaker
has not sustained damage and the reason is because you probably did not wait enough time to pick it up.
00:24:36
Speaker
So I usually wait about five, seven days to even consider using a test unless I'm concerned about sero-ledema and intracranial hypertension.
00:24:49
Speaker
So there are some
00:24:53
Speaker
variables in the patient characteristics that may indicate which patients may be at higher risk of developing, for example, cerule edema.
00:25:02
Speaker
At the end of the day, the cause of death in these patients is neurological, is a neurological cause.
00:25:08
Speaker
It's usually cerule edema leading to herniation.
00:25:11
Speaker
So younger people, you know, prolonged return to spontaneous circulation are the ones that are probably at higher risk
00:25:21
Speaker
to develop significance really.
00:25:23
Speaker
But I usually wait for the MRI.
00:25:25
Speaker
The MRI is sort of like the one tool that I know researchers are concentrating on right now.
00:25:33
Speaker
And there are specific things on the MRI that they are looking for.
00:25:39
Speaker
you know the burden of anoxia the burden of diffusion weighted lesions for example volumetric analysis you know sort of like track recognition meaning tensor analysis in the MRI are the tools which are very advanced tools in MRI that they are using to determine promosives I think that those are more specific
00:26:00
Speaker
but I don't think they are ready for critical use.
00:26:04
Speaker
So, you know, you have to be careful with how you interpret that as well.
00:26:08
Speaker
So this is what I'm saying, using a multi-modality approach is a better way to go.
00:26:14
Speaker
Excellent.
00:26:14
Speaker
So I guess really it's just a piece of the puzzle, but you could have a normal
00:26:20
Speaker
or almost normal CT scan and never wake up.
00:26:22
Speaker
Or you could have some signs that suggest anoxic damage and still recover.
00:26:26
Speaker
So I think that not enough to just hang our hat on that imaging, but obviously it's something that very commonly patient families are requesting and they believe that the CT scan or the MRI will really give us a lot of information.
00:26:43
Speaker
So, go ahead.
00:26:44
Speaker
And it does.
00:26:45
Speaker
I mean, sometimes patients have combination of injuries.
00:26:49
Speaker
I mean, you know, sometimes patients have hemorrhages, you know, or something happens during the cardiac arrest that you don't know.
00:27:00
Speaker
Some people fall, and then eventually they have some additional injury.
00:27:04
Speaker
You know, people can have strokes or could have embolism, right, resuscitation that
00:27:12
Speaker
that if you see them in CAT scan or MRI can give you more ideas in terms of how to think about the prognosis form.
00:27:22
Speaker
Because if you have a cardiac arrest but then on top of that, you have bilateral MCA strokes for whatever reason,
00:27:32
Speaker
you know embolism or hyperperfusion because you were in shock for so many hours right then you know that adds to the prognosis you have to be a little bit more careful in terms of interpreting additional findings not just anoxia.
00:27:52
Speaker
Excellent.
00:27:53
Speaker
So I think that kind of as we're trying to close the loop, let's talk a little bit about the timing of neuroprognostication.
00:28:00
Speaker
And I think that you mentioned earlier, Fred, that immediately after a cardiac arrest, it's really hard to make any prognosis, right?
00:28:09
Speaker
If we decide we're going to treat these patients aggressively, we should undergo therapeutic hypothermia or targeted temperature management.
00:28:16
Speaker
complete the 24 hours at the specified target, rewarm them, and once they're back to normal thermia, let's call that time zero, what happens after that?
00:28:27
Speaker
How would you handle the timing of your neuroprognostication?
00:28:31
Speaker
Yeah, so this is a great question.
00:28:32
Speaker
So I usually put a paper from the University of Pennsylvania by Ben Avella and David Gajewski where they actually looked at
00:28:43
Speaker
the notes, right, that neurologists wrote in patients after cardiac arrest and you see all the sort of like super early or ultra early assessment of prognosis and, you know, when you read the paper they quote, for prognosis, you know, devastating disease,
00:29:01
Speaker
unlikely to record so I you know if if if the listeners want to remember only one thing after this podcast is that you really have to be more conservative in terms of prognosticating and don't
00:29:16
Speaker
rush to judgment, right, and write these comments in your notes so early because, I mean, more likely you will be wrong.
00:29:24
Speaker
And this is why I said at the beginning, you know, I've been humble before about this condition.
00:29:29
Speaker
So, you know, the clearest and more, the strongest evidence, right, that you have to wait to do an accurate assessment is the Nicholas Nielsen study that basically rewarm and then
00:29:46
Speaker
kept on neurothermia for 72 hours and then waited a period of almost 72 hours to assess for neurological prognosis.
00:29:56
Speaker
So that's like the best evidence and thus like the standard, right, is to wait at least 72 hours post rewarming to start considering any neurocognostication.
00:30:09
Speaker
And it's an important message that you need to convey to the families because families want to know upfront, right,
00:30:15
Speaker
What's the likelihood of survival?
00:30:17
Speaker
What's the likelihood of recovery?
00:30:19
Speaker
This patient is very hard to determine in the era of hypothermia if you have exposed the patient to cooling.
00:30:26
Speaker
So the message is probably wait 72 hours post-neuromathermia to start looking at all of these biomarkers.
00:30:35
Speaker
And by the way, they take a while to come back.
00:30:37
Speaker
So using an NSE, if you have availability like we do at my institution, it takes about 72 hours to come back.
00:30:44
Speaker
So it gives you a lot of time to see, you know, before you conclude anything, how the patient is doing on a clinical basis, right?
00:30:55
Speaker
And it enables you to get an MRI or SSCPs or a continuous EEG within that timeframe.
00:31:00
Speaker
So, yeah.
00:31:02
Speaker
And I think that along those lines, what I always say is that it,
00:31:07
Speaker
If you have a patient who clearly has advanced directives or comorbidities or situations that you truly believe are a horrible prognosis to begin with, I think it makes sense not to do critical care, period.
00:31:21
Speaker
So you wouldn't put them on a ventilator.
00:31:23
Speaker
You wouldn't take them to the cath lab.
00:31:24
Speaker
You wouldn't admit into the ICU.
00:31:26
Speaker
You wouldn't do the hypothermia.
00:31:28
Speaker
But short of that, if you're intubating people, calling cardiology, you should protect the brain.
00:31:34
Speaker
and you should give people a chance to recover.
00:31:36
Speaker
So it sounds like the most important take home message is that after the hypothermia, you've got to rewarm them.
00:31:43
Speaker
And from that rewarming, the clock starts, zero, wait 72 hours of good support, and then start implementing these tools.
00:31:52
Speaker
And as you gather information after the 72 hours of rewarming, you are probably in a better position to share with the family what is the most likely outcome based on that information.
00:32:02
Speaker
Is that correct?
00:32:03
Speaker
Yeah, so I agree.
00:32:04
Speaker
I think that's a great approach.
00:32:05
Speaker
I think that waiting, it's probably the best thing to do.
00:32:10
Speaker
And in your practice, Fred, what are the tools that you use on a regular basis in terms of your multimodality neuroevaluation for these patients?
Practical Tools for Neuroevaluation
00:32:22
Speaker
So as I said at the beginning, the clinical exam, right, that's very important.
00:32:27
Speaker
Second thing that I use is
00:32:30
Speaker
Continuous EEG.
00:32:32
Speaker
All of these patients in our institution are monitored by continuous EEG.
00:32:36
Speaker
And you would ask me why, and the reason is because if they're in a coma, right, there's no way of knowing what's going on in the brain.
00:32:43
Speaker
And by the way, the most critical part of the temperature management is the rewarming phase.
00:32:49
Speaker
And I know that you said you're going to have an additional podcast, and I think that for that podcast, you need to concentrate on the rewarming phase.
00:32:56
Speaker
With continuous EEG, you could see changes
00:32:59
Speaker
in the electrophysiology that could indicate, for example, worsening cerebral edema and risk of herniation.
00:33:06
Speaker
And that, in our protocol, right, indicates that you need to go back and recool the patient.
00:33:12
Speaker
So if you see changes in the amplitude of the EEG, for example, while you're re-warming, we will come back and keep the patient cool for an additional day until we can start the re-warming phase again.
00:33:25
Speaker
Those tools are so powerful, not just for prognosis but also for clinical management at the bedside.
00:33:30
Speaker
So that's the second tool that I use.
00:33:31
Speaker
The third tool is SSCPs.
00:33:35
Speaker
I do it usually 72 hours post-route warming.
00:33:40
Speaker
And then finally, the NLAs.
00:33:43
Speaker
I usually send the NLAs at the third day post-cardiac arrest.
00:33:46
Speaker
I don't do it immediately.
00:33:47
Speaker
I wait day number three and then I send the NLAs.
00:33:51
Speaker
And then finally, MRI, but more
00:33:55
Speaker
to give me an idea if there's any additional injury because I've seen bad MRIs that actually don't translate into a poor outcome, right?
00:34:05
Speaker
So what the MRI tells me is more of, you know, is the patient going to have a lot of cognitive impairment, for example, you know?
00:34:15
Speaker
Or did the patient have a dissection and now he has a stroke in the posterior circulation?
00:34:19
Speaker
Did dissection occur before, cardiac arrest, CPR, you know, that sort of thing.
00:34:24
Speaker
And does the patient need additional treatment for it?
00:34:26
Speaker
You name it aspirin or anicoagulation.
00:34:31
Speaker
So those four tools are the ones that I use in my clinical practice.
00:34:37
Speaker
Excellent.
00:34:38
Speaker
Well, I think that we definitely enjoyed talking with you, Fred, about a topic specifically about the neuroprognostication.
00:34:45
Speaker
I know that the Neurocritical Care Society and the American Academy of Neurology are working on the
00:34:54
Speaker
hypothermia or neuroprotective guidelines, and they'll be cooking up soon.
00:34:58
Speaker
So we'll probably have you back to talk in more details about targeted temperature management.
00:35:04
Speaker
But as we close, I would like to first thank you for your generosity with your time and your knowledge.
00:35:11
Speaker
It's always a pleasure to talk with you.
00:35:13
Speaker
And I'm sure that we'll talk again shortly.
00:35:16
Speaker
But I also, since in critical matters, we really try to cover all aspects of practicing critical care, would like to close with a couple of questions that are a little bit off the topic, but I think super relevant to what we do as physicians, to what we do as providers in the world of critical care.
00:35:34
Speaker
Would that be okay?
00:35:36
Speaker
Yes.
00:35:37
Speaker
So the first question I have for you and a lot of our friends and a lot of our listeners know that I'm an avid reader and always interesting and picking up new things to read or to gift.
00:35:49
Speaker
Is there a book or books that have influenced you the most or what book in particular have you gifted the most to others?
00:35:58
Speaker
So I have gifted a lot of books before and and and you know, so like a
00:36:08
Speaker
books that I've read when I was in high school and when I was younger.
00:36:12
Speaker
But one of the books that have actually influenced me a lot, and this is recently because I became a bioethicist recently, is Meditations by Marcus Aurelius.
00:36:26
Speaker
And it's like an excellent book if you're dealing with
00:36:30
Speaker
a lot of problems in life and critical care is just about problems, right?
Influence of 'Meditations' on Critical Care
00:36:35
Speaker
So, you know, I find it, you know, inspiring in terms of, you know, telling me
00:36:42
Speaker
how to react in critical conditions or in environments that have a lot of conflict, right?
00:36:49
Speaker
So if I were to gift a book to a friend or something, it would probably be Meditations from Marcus Aurelius.
00:36:56
Speaker
Excellent choice.
00:36:58
Speaker
And I think that it just speaks
00:37:00
Speaker
friends think alike it's one of my favorite books I have several copies in my house and who've stayed in my house as guests usually go with one of these some of them enjoy it some of them say not for me but I do agree with you I think that philosophy applies to what we do so powerfully is a great guide in terms of how to deal with adversity but more importantly
00:37:22
Speaker
which I think is important for critical care practitioners, it really talks about how to be humble and how to really focus on the things that we can control.
00:37:31
Speaker
And I think that that's a great, a great, a great book.
00:37:35
Speaker
Another question.
00:37:37
Speaker
Is there anything that or what do you believe to be true in medicine or in life that many people or most people around you don't believe in?
00:37:44
Speaker
Yeah.
00:37:47
Speaker
You know, I think that I've been humbled by my profession a lot and that when I became a physician, right, I became a physician to help and to restore, to prolong life.
00:38:02
Speaker
And I think most people believe, right, that we're immortal sometimes and that there is no end.
00:38:10
Speaker
And in my mind, I think we have to understand that
00:38:14
Speaker
There's always a beginning and there's always an end and both are physiological processes.
00:38:20
Speaker
Of course some have better impact in your mood and in your state of happiness, right?
00:38:28
Speaker
But I don't think a lot of people understand that there's an end to everything.
00:38:36
Speaker
Sometimes even colleagues, physicians, providers, understand that sometimes when the end is coming you have to probably
00:38:44
Speaker
stop what you're doing.
00:38:46
Speaker
And that's the part that I think is very hard to acknowledge, right?
00:38:51
Speaker
That life ends.
00:38:52
Speaker
Yep.
00:38:53
Speaker
I think that's a great point.
00:38:55
Speaker
I think that actually your friend Marcos Aurelius and the Stoics talked about memento mori, remember you will die.
00:39:03
Speaker
And I think that as a way of
00:39:05
Speaker
guiding what we do every day with the precious time we have, I think it's very valuable, but also something that we should share.
00:39:13
Speaker
And when we talk with our patients, I think is very, very valuable.
00:39:17
Speaker
So that's a great point.
00:39:19
Speaker
And I think that you're absolutely right.
Ethics of Life-Sustaining Treatments
00:39:21
Speaker
And the last question, Fred, is, is there anything in particular that you would want every intensivist in sound critical care to know?
00:39:34
Speaker
It's sort of like along the same lines that we've been discussing Sergio, is to understand, and I say this from an ethical perspective, you know, ethically and morally, it's okay to stop, it's okay to consider stopping life-sustaining therapies when you think that they are not doing any good and actually harming the patient.
00:39:58
Speaker
I think that as intensive as, you know, as I said, you know, one reason why I went to medicine
00:40:03
Speaker
was to help and prolong life and all that stuff and it was sort of like ingrained in my life.
00:40:07
Speaker
Then when I went into critical care, I suddenly realized that I was actually living in a life or death environment and sometimes I needed to make decisions to allow that normal process of death to happen.
00:40:20
Speaker
And you know, it takes a lot of courage to recognize when you need to stop something.
00:40:25
Speaker
But at the end of the day, you know,
00:40:27
Speaker
The intensivist is the skipper.
00:40:29
Speaker
The intensivist is the captain of that team.
00:40:32
Speaker
And in that sense, there's a lot of responsibility for a critical care doctor, right, to guide the team in a way that is in the best interest for the patient.
00:40:42
Speaker
And understanding that sometimes stopping is probably the best way to go.
00:40:48
Speaker
So I would like everyone to understand that concept as well.
00:40:51
Speaker
Most of us do it, and I'm glad.
00:40:55
Speaker
And if everyone that is listening understand it, then I'm happy.
00:40:58
Speaker
Excellent.
00:40:59
Speaker
Well, Fred, again, a pleasure, a treat for me to talk with you about these topics.
00:41:03
Speaker
We will have to revisit some of these topics and go deeper in some specifics regarding targeted temperature management.
00:41:12
Speaker
Always a pleasure.
00:41:13
Speaker
Thank you so much for your time and your generosity, and I look forward to talking with you again soon.
00:41:19
Speaker
Thank you, Sergio.
00:41:19
Speaker
Thank you.
00:41:22
Speaker
Thanks again for listening to Critical Matters.
00:41:24
Speaker
Make sure to subscribe to this podcast on iTunes or Google Play.