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SNI, Surgical Neurology International, an Internet Journal, and SNI Digital Innovations and Learning, a video journal interactive with discussion in association with the Sub-Saharan African
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neurosurgeons
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present their monthly grand rounds of the Sub-Saharan Africa International Neurosurgery Grand Rounds on the first Sunday of every month.
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This is the 12 Sub-Saharan Africa International Neurosurgery Grand Rounds, all of which deal with global solutions to clinical challenges in neurosurgery. The moderators are Estrada Bernard and
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James Osmond in a participation with an international audience.
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In this Grand Rounds, The discussion will be about non-invasive ICP, inter cranial pressure assessment, the current evaluation of the products on the market, by Dr. Elo Ibikui and Dr. Paul Vespa.
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Dr. Vespa is the assistant dean of critical care medicine and research at the Gary L. Brendan son, family, chair and neuro critical care. He's also professor in residence of neurosurgery and
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neurology and director of the neuro critical care program at the Ronald Reagan UCLA medical center in Los Angeles.
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Dr. Elo Ibikui is a fellow in that neuro critical care division run by Dr. Vespa. at the Ronald Reagan UCLA Medical Center in Los Angeles. He is slated to be a neurocritical care fellow beginning
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in 2025 in Tanzania and Africa.
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Intercreative pressure monitoring can be done invasively or noninvasively. Today
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in most hospitals in the world, invasive and curricular catheter monitoring is impractical because of the needs for trained personnel to use it, infectious complications and high costs. Two
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noninvasive monitoring systems will be presented in this program for their ease of use, accuracy costs, low costs and widespread use potential and practicality. These presentations and discussion
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will allow the viewer to select a system of value for their circumstances. Together, both sessions are 90 minutes, the total time, each one about 45 minutes, parts one and parts two.
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Thank you, gentlemen. I don't see any ladies in the group, but I'm honored and thanks for giving me the opportunity to present. The topic for today will be the use of non-invasive ICP assessment
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It's evidence and it's use case. I have no disclosures, but I have a lot of appreciation. I would like to give a big thanks to first and foremost, Dr. Paul Vesper, right here in the middle, one
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of my mentors and big teachers, Dr. Manuel Blanco as well, another UCLA trained and UCLA faculty, and to the right is an engineering colleague of mine, Gil. has been working closely with our ICU
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team on a novel ocular ultrasound device to improve the validation and utility of the optic nerve sheet damage and the neuro-ICU. I'll discuss more about this later. This is the outline of the
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presentation by Dr. Iwikui and Vespa,
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first part of the on the history and principles of inter cranial pressure measurement with the introduction of the noninvasive optic sheath nerve diameter monitoring. It'll be about 50 minutes.
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Transcranial toplar monitoring will also be introduced and
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discussed for about three minutes as another noninvasive monitoring of inter cranial pressure, followed by neuropupillary index monitoring for 13 minutes by Dr. Vespa.
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A discussion of 22 minutes among the audience and the presenters will follow as the last part of this presentation.
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First part is on the history and principles of any cranial pressure measurement
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and the introduction of the noninvasive of the cranial pressure monitoring by optic nerve sheet diameter measuring and monitoring.
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Well, I think it would be worthwhile for the audience to give them about a two or three minutes summary of your background in your training in Ohio State and so forth and so on and what your plans to
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come to Tanzania and so forth. I think they'd be very interested to know that. Okay, yes. So
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I'm an immigrant to the US originally from Nigeria and I did most of my medical training in the Midwest, went to medical school, University of Kentucky. and completed a neurology residency at the
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Ohio State University. The last two years I've spent learning under the tutorship of Dr. Paul Vesper, Manuel Blanco, as a neuro-traumer, intensiveist fellow. I will be heading over to Tanzania
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at the Mohimbili Orthopedic Institute with the Cornell neurosurgery group under the training of Dr. Roger Hartle and Melinda Mangat to essentially help them get their neurological ICU up to par with
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their surgical side of things. I have a lot of interest in global health and I hope to model my career like you distinguished scholars in here and contribute and give back to the people of Africa
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with a focus on non-invasive tools, especially with the ultrasound machine.
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Thank you very much, terrific. Thank you. So we'll start out with the case. You know, we have a 60 year old male with a history of atrial fibrillation present after a motor vehicle collision.
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You know, CT had shows by frontal contusions and we have diffuse circle of basement. Pay attention to these labs. The INR is three platelets of 50, 000 and BUN is 80. GCS is a 225, so a total of
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nine At this point, I would like you guys to start thinking about how would you approach this patient from a diagnostic and management perspective.
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Historical evolution of the intracranial pressure monitoring. Discovery of
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CSF was first mentioned in
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1764. And then the first mention of ICP by Dr. Alexander Munro. We're all familiar with the Munro Kelly doctrine 1824 Kelly is autopsies and experiments essentially confirms and collaborates what
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Dr. Monroe mentioned about several years before. And then we have the establishment of the Monroe Kelly Doctrine that was determined in 1828. Fast forward many years to 1927 is when the first
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instance of ICP monitoring using an EVD by Dr. Addson and Dr. Leyle in 1927
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And Dr. Niels Lundberg essentially in 1960 established ICP monitoring at SAFE. Since then we've had several modifications, evolutions and improvements of the invasive and non-invasive ICP
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monitoring. Briefly, what is intracranial pressure? I don't really hope to, you know, my goal with this is not to stop and saw anyone, interlegged, but just briefly, ICP is a pulsatile
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pressure in the brain that is based on blood circulating in the brain tissue. Here, we have the Monroe-Kelly doctrine. So, in 1783, Alexander Monroe described in his observations on the structure
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and function of the nervous system, which was later supported by 1824 in Kelly
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on his observations on human cadaver. This concept explains that the human cranium has a fixed amount of space with three main components, CSF, brain tissue and blood. Now, if any space occupying
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lesion or any of these three components is increased beyond the compliance, then elevation in ICP is inevitable. Intracranial compliance, essentially, is the change in volume over the change in
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pressure. Initially, this relationship between pressure and volume is linear, but may become exponential over time. That is to say, as the volume of the ICP increases. there's a slow linear rise
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in ICP, as long as its compensatory mechanisms are in place. And these compensatory mechanisms include displacement of the CSF into a thicosac, and also the compression of the blood into the
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standable cerebrovanes. But once these mechanisms fail, then ICP can increase at an exponential rate with only small increases in volume Adding to the Monroe Kelly concept in 1960 was the Dr. Nils
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Lundberg determined that ICP monitoring with an EVD was safe. And he introduced the medical field to the concept of Lundberg AB waves, that is ICP plotted over time. And these waves represent
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prolonged periods of profoundly high ICP indicating poor brain compliance with the severe risk for further ongoing brain injury and reduced brain perfusion.
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The causes of elevated intracranial pressure can be broken down into four categories. We have the due to intracranial space occupying lesions due to increased brain volume from cytotoxic edema,
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such as from stroke, ischemia, rice syndrome, which we rarely see in the adult neurological ICU. The third component is increase in the brain and blood volume from vasogenic edema, such as from
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traumatic brain injury, meningitis, encephalitis, infections, and
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vascular pathology. And lastly is an increase in cerebral spina fluid volume, such as in hydrocephalus. Now,
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why is ICP, and why is elevated intracranial pressure bad? Well, the main negative effect of elevated intracranial pressure is death. And this is due to reduced cerebral blood flow Cerebral blood
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flow is based on cerebral perfusion pressure. Now the brain auto-regulation maintains the cerebral blood flow at a constant flow. But as you can see here with this formula, as ICP increases, the
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mean arterial pressure has to increase to ensure a constant cerebral perfusion pressure above 60 millimeters of mercury. Now mortality associated with higher ICPs, essentially an ICP of 35 is almost
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associated with 100 mortality.
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Now what are the indications for ICP monitoring? Based on the guidelines, moderate to severe
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TBI, GCS of eight or less, or evidence of brain edema or mass effect on a brain image in such as a CAT scan,
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a normal CT with a patient that has posturing, hypertension and is over 40 years of age. But honestly, this indications can be summarized Whenever there is a clinical or radiographic evidence or
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suspicion of elevated intracranial pressure with the depressed level of consciousness, I think ICP monitoring is paramount.
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But the ICP treatment guideline threshold per the Brain Trauma Foundation, we should treat ICPs above 22 millimeters of mercury. But I beg to differ, and I'm sure some of a lot of you in this
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conference this morning will agree that we might be on the treating, and we'll agree that an ICP of 10 to 15 might actually be elevated in normal individuals like yourselves and I.
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But this ICP above 22 was chosen by the Brain Trauma Foundation because the mortality treating above 22, when mortality of sustained ICP above 22 was quite high so they decided on this number.
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Now, there are several types of invasive ICP monitoring. The first we all know about is the extenoventricular catheter. This offers the utility to diagnose intracranial pressure as well as offering
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treatment through
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CSF draining. The other types of sensors is a parenchymal sensor. In our facility here at UCLA, in most places in the US, we use a device company called the Codman. This does not give us the
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opportunity to treat elevated ICP. It just lets us monitor and be aware of it. We have a new device or a relatively new device called the rheumatic, which offers ICP monitoring, brain tissue
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oxygenation monitoring, and brain temperature. And then we have these others, which I've never seen in my career, the Epiduro and the Duro monitors.
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And now the main purpose of this talk is non-invasive ICP monitoring. And I would like to draw your attention to three that have been validated and supported for clinical use. First is the object
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nursery diameter. Second is the transcranial doppler TCD, which looks at cerebral blood flow in the MCA, middle cerebral arteries, to estimate a concept known as a pulsaticity index. And I will
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emphasize on this later on And then lastly, we have the Quantitative Neurological Popular Military Index, which uses infrared technology to quantify the dilation and constriction of the eyes to
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assess pathological compression of the oculomotor parasympathetic fibers. Now these non-invasive monitors are useful in certain scenarios. So if you remember the initial patient, Vignette, with
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the BUN
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of AT, thrombocytopenia 50, 000 and Coagulopathio of INR of three. I'm quite sure that no one here is itching to place an ICP monitor or an invasive ICP monitor in this patient due to the risk of
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bleeding. Another utility of non-invasive ICP monitor and is that the cost and availability of these invasive devices are not feasible in many parts of the world, especially in Africa. And then
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there's a risk associated with invasive ICP monitor in which the non-invasives can bypass These include the risk of infection, bleeding, and also misplacement of the device in the brain.
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The pitfall, though, of non-invasive monitoring is that it's unable to provide continuous serial assessment of
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ICP and it's been plagued with poor specificity and sensitivity.
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Now, the next few slides will focus on the optic nerve sheet diameter. because it has shown the most promise and validation for use in clinical practice. In the early 90s, we were introduced to
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the optic nerve sheet diameter through Dr. Hansen and Dr. Helmke. And since then, we've had several modifications and improvements and studies validating his use in the clinical setting.
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Now, what is the optic nerve?
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Embryologically, the optic nerve starts out as an outpouching of the central nervous system with the sheath being in continuation with the dura and contains a subarachnoid space. Now, ICP
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elevations are transmitted through the subarachnoid space and will result in the tension of the optic nerve sheath. Three millimeters behind the retina where the optic nerve inserts is the largest
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diameter of the sheath and it's where the maximal distinction of the sheath happens and this has formed the basics. our measurement criteria.
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The next six to seven slides, I will briefly highlight the method of
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methodological research and the data validating the use of the ocular ultrasoundoptignerci diameter in the neurological ICU. So in
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1994, not really trying to date myself, but that was periw when I was born, Dr. Helmke and
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Dr. introduce us to the concept of ocular ultrasound and it showed that the optignerci diameter is acutely elevated after acute intracranial hypertension. I'm using a study of 16 patients with
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clinical and radiographic evidence of intracranial and intracranial pressure matched to a control of 20 patients with neurological disease without ICP elevation.
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Showed three interesting findings. One is that the optic nerve sheet diameter is increased as early as four hours after acute intracranial hypertension. Two, interestingly though, signs of
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papilladema such as an elevated optic disc was only present in three out of 16 patients. Therefore, the assessment of the optic disc, which is different than the optic nerve sheet diameter is not a
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sensitive test. And then lastly, the laterality of the injury was not correlated with laterality of the eye with a larger optic nerve sheet diameter. Yeah, hello, before you go ahead, could
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maybe you'll come to this here. Could you go back to the slide before this?
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And what's that, that shows, you're measuring this by ultrasound, is that what you're doing in your measure? What are you measuring there? No, this was a post-mortem study on 12 optic nerves of
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patients without ophthalmological pathology. And essentially what it's showing us is the anatomical underpinnings of the nerve. So, right here is, this is a cross section of the nerve And these
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trabeculae kind of connective tissue that forms the mainframe of the optic nerve. And this is what the slide is showing the anatomical histological slides of what the optic nerve sheet at cross
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sections look like. When you're measuring this with ultrasound, what are you measuring? Yeah, and I will talk about this in a few slides, but what we measure is the diameter of the anterior
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segment of the nerve. And the more about this in detail in the next few minutes. Okay, so you're gonna be measuring not only the neurological or glial components, but also the water content, is
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that correct? Essentially, what's been the
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optic nerve sheath as pressure in the brain elevates, the
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subarachnoid fluid gets transduced to the subarachnoid space in the optic nerve and the subarachnoid space, if you pay attention to the pointer will be here and this causes a distention of the nerve
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sheath itself. So we measure the diameter or the distance from two points of the nerve sheath.
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So you're, I think the terminology may be confusing and that is you measuring the optic nerve sheath or you measuring the space between the dural covering
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and they in the sub-recognized space around the nerve. Essentially, is it the thickness of the trabicula layer that you're showing in the. Yeah, so I'll just forward you to this slide quickly.
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Sure, sure. I'm just trying to understand the technology so we can comment on it. So this is the nerve itself. And this is where this hypoecholic region, right in between this green and blue line,
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is the subarichnoid space, which is essentially the sheath of the nerve. And both sides of the nerve have a sheath with a dura on the outside. So what we measure is the diameter, which is the
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green line, the diameter of the nerve.
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So it's constricted by the diameter the, the of diameter and component canal, right?
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Yeah, so as ICP increases, the CSF gets transduce into this hypochloric region in the subarachnoid space, and that causes the nerve to widen in diameter. And why is the word is then you're trying
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to get CSF into the space at the same time as fluids going into the tissue, isn't that right? Yes, sir. So what you're doing is measuring the compromise and actually the CSF space between the
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nerve and the dura, is that what you're measuring here? I'm just trying to, what are you - No, it's stretching. So as CSF pressure builds up, the sheath is collecting more CSF, the optic nerve
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sheath and the diameter between the two ends of the sheath are widening, right? Just like the ventricle is widening. And so what you can do is measure the widening of the optic nerve sheath, and
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that correlates to
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So, so the red, the red outline is the nerve, which you have there in the slide. Right. And the optic nerve sheath, which is, it says it includes the dura. What else is in there? Well, the
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yellow is the distance that you're measuring. And that's, that's the entire, that's the nerve with the nerve sheath. So you're measuring the entire diameter. What's the bony? What's the bony
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diameter? In other words, it's like the brain, Paul, it's, it's, something's got to give, right? Right, right. So we're measuring, we're measuring at a point,
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we're not, we're not, well, there may be constriction from, from the canal itself, but it turns out that it's, it's a, it's a small increase incremental increase that's on the measure, you
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know, measurement of
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two to three I mean, so it's a really small increase that you're measuring. Interesting. So the variability in the diameter of the octa canal is it's very limited is what you're saying. 'Cause if
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it was large, you would have a hard time measuring this, right?
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Mm-hmm, it's a
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qualitative measurement. It's not quantitative, right? So, I mean, once you reach that threshold, it's a qualitative measure indicating that ICP is elevated. Yeah, and this is kind of why the
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study has been plagued with low sensitivity and specificity because people measure different things and there's not been a lot of reproducibility.
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And also, we don't know exactly what number. We do have an idea of what number indicates high intracranial pressure and what number would probably indicate little interquennial pressure. but
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there's a lot of gray area there's some gray area well let's have you let's have you resume and then we it sounds like there's a lot a lot of interesting things to talk about but but continue now i
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still i still don't understand it i mean i just don't understand it is are you i'm sorry i'm sorry i straddled uh are you the
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red lines the optic nerve yes fine is the sheath you're measuring the diameter the difference between the two yeah we're measuring the diameter from point a um to point b because as icp increases um
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that fluid and edema gets transmitted through the subarachnoid space and that causes the nerve to enlarge in diameter so if there was a theoretically high icp we would expect the two the yellow lines
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to increase in diameter
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so gendered measurement includes the optic nerve is the measurement all the way across including the optic nerve and in the. the CSF space on either side of the nerve, the net of that, is that
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correct? Yes, sir. Very good. Okay. We're not measuring bones and there's no, we don't take into account the size of the optic canal, which once again, that could also be plaguing the low
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sensitivity of the study because patient population could differ.
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Okay. Okay. Go on. I still, I still don't understand it, but I.
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Okay. So, um, so I, um, I think I was. Yeah. So two years later after the, um, you know, the. The research done by Dr. Hamke and Hamskja that shows That the optic nurse sheet is increased
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as early as four hours after acute intracranial hypertension. Um, the laterality of the eye injury was no correlated with the allergy of the eye with an elevated. Um, optic nurse sheet. They
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showed anatomical underpinnings of the optic nerve and his sheath. Um, so they took 47 optic nerves post mortem and injected with gel to simulate the cerebral spina fluid under increased
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hypertension They then embedded this gel and measured the diameter of the nerve using an ultrasound. What they showed anatomically was that the anterior optic nerve, where it inserts inside the
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retina, three millimeters, was mostly narrower than the posterior optic nerve. The trabeculae were longer and wider in diameter anteriorly compared to posteriorly. The density of the nerve remains
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the same. Sunographically what they showed though was that the maximal distension of the anterior segment was 53 times greater at baseline than the posterior distension which forms the basics for
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measurement of the anterior segment of the nerve because that's where we get the maximal distension of the sheath. So in conclusion, what they showed was that pressure-induced optic nerve sheet
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diameter widening happens more dramatically and reliably in the anterior segment of the nerve. And then this optic nerve sheet diameter increase can be dependably as. and made it with low
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inter-observer differences. Therefore, this procedure is suitable for clinical use. What is that? In that slide, I'm still trying to understand let's go back through that slide. S is the, what?
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What does that represent? S is the sheath. So P is the, so this - Is S a space or is it a membrane? Yeah, S is a space that contains the sub, it's a subarachnol space containing cerebral spinal
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fluid. Okay, that's when you say optic nerve sheath. The sheath. The sheath is the black, right? That's the Dura. Yeah. So I'd say, I think you misnamed this. This should be the optic nerve
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space. So, and that, why does it become bulbous in the end? That's, is it through the bone and canal by that point? And the anterior segment? Yes. I believe so, yes. Yeah, it's. So that's
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why it's enlarged and can change and shape. Isn't that right? Yes, sir. That's why I asked all those questions before. So you're measuring the anterior portion of the optic nerve space. Yes.
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I think Paul, you should change what you talk about this. The sheath is a membrane, can't expand. The space can expand. Do you understand what I'm saying, Paul?
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Paul? Well, okay. I'm sorry, I was muted. Yeah, I do, yeah. You understand what I'm saying? The nomenclature, I'm thinking about the sheath, the nomenclature is actually you're measuring
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the space, which can be variable because the bony anatomy must not be there, if it was, it wouldn't be variable, but it can be, like the dura couldn't expand a little bit in the skull. That's
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what you're talking about. You're measuring that space, right? That's right, yes.
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Is that may help you, Paul, in terms of presenting it because I'm looking for something else. Okay, so, and you've obviously looked at a whole series of specimens and found with the normal values
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that space would be, right? Yes, yep, and the normal, and I'll talk about this later, but less than 05 centimeters should make you feel comfortable that most likely the intracranial pressure is
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not elevated. And once we start getting a both 07, we start thinking about elevated intracranial pressure. So let me ask you, I'm really sorry about it, but I think this is, I'm asking the
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fundamental questions. If you've got increased intracranial pressure, the fluid is gonna go into the nerve, the nerve will expand, so the space size, the space size, S is going to decrease, is
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that correct?
31:46
Well actually the S should be. increase, because the nerve doesn't really expand per se. What expands is the space where there's - Okay. Okay. Fair enough. Fair enough. So you have some space
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there that has some leeway, and the pressure builds up that space gets larger, right?
32:07
That must have some limits. Yes. Yes. There's a concept on compliance of the nerve and plastic degradation of that. Right. So you're into the same concept of the brain and the box, right? In
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the skull. Yes. So that makes us a very unique finding on where you can measure the inter cranial pressure. See what I'm getting to, Paul?
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Yeah, it's the convention has been to call it the nerve sheath because I think that it the whole thing expands and it expands as a function of CSF building up there and it builds up as a result of
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the, you know, elevated cranial pressure so that's why the the
32:54
concept is called the nerve sheath diameter. I got you. But yeah, the nerve is in the middle of the sheath and
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the space is actually what's expanding. Right. That's very, that's a very unique finding that's terrific. Okay
33:11
So in 1996, two years after that, they eventually translated their bench work research into the clinical setting, forming the basics for a new bedside clinical diagnostic method And so what they
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did was match 51 control subjects ages 0 to 18 without any pathology to patients. 15 patients in the ICU, same age range with clinical signs of elevated intracreenal pressure. What they found was
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between the fourth and the fifth year of life is when the optic nerve sheet diameter of children reaches the adult range.
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So essentially the optic nerve sheet becomes stable after 8, 4 or 5
34:01
So I hope you don't get tired of hearing the names. The same doctors, again, we have Dr. Hampson and Helmke, in 1997, performed another study investigating the relationship between the optic
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nerve sheet diameter and intracreenal pressure in terms of absolute changes, reversibility and saturations. They show two findings, you know, the
34:26
optic nerve sheet diameter has a saturation effect So above a threshold of 22 millimeters of mercury. There is a linear relationship between intracranial pressure and the optic nerve sheet diameter
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to the plateau of about 35 millimeters of mercury. This optic nerve sheet increase plateaus, and I think that's where the compliance of the space becomes limited to expand. And then they also show
34:53
that most of
34:57
the variability in the optic nerve sheet diameter is determined by the subarachnoid space. Let me ask you another question. These measurements are being made by ultrasound, correct? Yes,
35:00
ultrasound and. What's the accuracy of
35:08
your ultrasound? Well,
35:18
that's been an issue that's plagued the studies with a clinical utility with low sensitivity because there could be a lot of interrater variability. And I will discuss this later this later we have
35:30
two critical techniques that can increase the accuracy and give actually really good reliable numbers when done properly in the right way. Now, let's grab this slide. This slide tells really what
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we've been talking about. You reach your upper limit because it's expanded as much as you can expand. And is there any with this? Is there any measurement of the function of the optic nerve as the
35:57
pressure goes up in the optic nerve sheet in that space? Well, these were, no, they did not assess the function of the quality of the nerve.
36:09
Well, that would be important. No, no, we're not. These were mostly, this study was mostly, it was a postmortem study. Oh, okay. Okay. I'm just trying to ask questions so I understand it.
36:24
Thank you.
36:27
So transitioning to another continent, this time we go to South Africa Cape Town.
36:34
We have a group from Cape Town, Dr. Oparayaki introduced us to another concept
36:41
of the optic nerve sheath diameter known as deformability index. So this is based on the hypothesis that arterial pulsations is transmitted to the optic nerve sheath through the CSF. And these
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pulsations can be used to calculate something known as a deformability index The deformability index DI is a novel dynamic optic nerve sheath parameter. It describes the relative lateral motion of
37:08
opposite sides of the optic nerve sheath or the optic nerve space with the cardiac cycle. And what it hypothesizes is that the relative motion is non-symmetrical in states of low ICP but becomes more
37:25
symmetrical in states of high ICP that is to say if the ICP is high The sheath becomes different with the. less ability to deform, therefore high ICP will give low deformability index.
37:44
Well, wait a minute. If the ICP is already up, I won't expect the sheath, the space, the sheath, you got to change that term, the space there
37:57
to be, to, there, there's, you can't expand the space anymore, because you've already expanded it some when the pressure has gone up, right? Yes, sir. And you lose a lateral displacement or
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motion. Right.
38:12
Right And even if blood pressure goes in there, it's the same as intercranial pressure is really what you're saying, right? Yes, sir. Yeah. So you're trying to compare this to what intercranial
38:22
pressure is, saying you're measuring the same thing. Yes. Without having to drill into the hand. I gotcha. Okay.
38:33
So the same group in South Africa in 2019 showed that now combining measuring the damage of the optic nerve sheath. in combination with a dynamic displacement of the nerve, known as
38:48
a deformability index. It shows that combining both of those was significantly better than just using the optic nerve sheet diameter itself.
38:57
So Dr. Osman, thank you so much for drilling about the fundamentals of the basic science. And I think it's a point that we understand that to transition to the next part of the talk So we spend a
39:10
lot of time understanding how ICP monitoring with the optic nerve sheet diameter came into place. But what are we doing right now in clinical practice? Well, we have made several advances, but the
39:23
optic nerve sheet diameter does not replace invasive tools such as an EVD or a card man. And it's also not as used widely in most neurological ICUs even given the cost. And we think this is due to
39:37
multi-factual reasons. Most of the studies have good sensitivity, but the specificity is low. And several reasons accounting for this is that the optigner sheet diameter threshold for diagnosis of
39:50
elevated interquina pressure has differed across the different studies. So it's possible that a single universal optigner sheet diameter cutoff may not accurately detect ICP elevation in all patients
40:06
Another reason for this low specificity is that there's been a variety in the study population in terms of pathology of disease and clinical demographics.
40:20
Thirdly, there is a disease variety. The impact on the optigner sheet diameter from TBI might say have a different pathology on that from chronic hydrocephalus. And then lastly, and a very
40:33
important concept is operator the upper measure we when? measuring actually we are what So error
40:40
nerve sheath diameter. So we should actually measure the optic nerve, including the hypoechoic region, which is the space where a subarachnoid fluid flows, and the yellow line is the dura covering
40:58
that space. The red line is the nerve itself. We should be measuring three millimeters behind the insertion of the optic nerve into the retina, as the anterior optic nerve is
41:15
more pliable, and has distanced more than the posterior optic nerve.
41:22
Another technique that could help us improve the accuracy of optic nerve sheet diameter measurement is utilizing color doppler and ultrasound. And we can utilize color doppler to visualize a central
41:34
retinor artery in vein that will also now ensure you that you know that if this is a central retinor artery and vein, that this is the nerve inserted right behind the retina. And once again, you
41:46
can see the nerve, the hypoachloric region here. And then you can see the
41:54
space with the do-around the outside lining and covering the nerve. And you would measure from here to here,
42:06
Now, despite this nuances with the optigner sheet diameter, what does the current data show for use in clinical practice? A group from the University of Michigan, Ann Arbor, in collaboration with
42:20
the hospital in New Delhi, India, did a prospective analysis and 120 patients with severe
42:28
TBI. Essentially, patients were 18 years of age and enrolled within 48 hours of injury They had the presence of an intracranial invasive monitoring with a codman or an EVD to collaborate with an
42:42
optoner sheet diameter. What they showed was, for an ICP above 22 millimeters of mercury, an optoner sheet diameter of 072 centimeters had a sensitivity of 82 for detecting elevated intracranial
42:59
pressure So essentially 1 in 5 can be missed.
43:04
though the specificity of this was quite low with a negative predictive value of 98. What, the study also showed that size of papilladema, which is the optic disc elevation above four millimeters
43:20
as it inserts into the retina, had a sensitivity of 90. This is another parameter that we can now use to add to our diagnostic arsenal So with the diameter, the deformability index, and size of
43:36
papilladema with the optic disc elevation.
43:41
More on the concept of optic nerve sheet diameter and this concept of deformability index. You know, I briefly just talked about the concept. This is based on the hypothesis that the cardiac
43:52
arterial pulsations are transmitted to the optic nerve sheath. And these pulsations causes lateral displacement of the nerve sheath in different magnitudes Um, And so the higher the ICP, the
44:06
stiffer the nerve, the less magnitude for lateral displacement of the optic nerve sheath. So in summary, higher ICP, lower deformability index. Between 2020
44:20
and 2022, a study was done by a group. I believe this was in Norway that shows the diagnostic yield of using deformability index, plus the optic nerve sheath diameter to distinguish dichotomized
44:38
ICP above 15 millimeters of mercury was superior than using optic nerve sheath diameter alone. Essentially, what this is saying is that utilizing the deformability index with the optic nerve sheath
44:50
diameter increases the sensitivity and specificity of the optic nerve sheath to determine high ICP
44:60
Just a quick question, just technically speaking, how. readily is that deformability index done? How compared to the optic nerve sheath diameter, how easily can one measure the deformability
45:11
index? Yeah, so thank you Dr. Estrada. The diameter can be measured right at the bedside. You sequenced the nerve, we plot, we measure the diameter right at the bed. And
45:33
now the deformability index, we have to use a software for this. And there are two steps involved. The first step is tracking. First you, like, first you, once you collect about a 30 second
45:45
video of the optic nerve sheath on the ultrasound, we manually select two points on both sides of the optic nerve sheath. And the motion is then automatically tracked over time. And then, then
46:03
using Fourier analysis, we apply Fourier analysis to obtain frequency components of the transverse motion. So essentially I asked you a question, Dr. Estrada, you need a software to get this done.
46:14
Is that built into the equipment? No, no, not yet, no. Okay. Now what you measure at the bedside for clinical purposes now is just the optic nerve sheath diameter. So these other variables are
46:28
what needs to be developed into a clinical tool But this is, you know, early development of technology, but this is not readily available clinically. Sure, okay, okay, makes sense. Thanks,
46:39
thank you. So they, all these data points you're getting are by ultrasound, right? Yes, ultrasound collaborated in patients with an intercoinopressure monitor and with an EVD. I got all that,
46:53
but the deformability
46:56
index, which you pick two points and you, you see over time what's happened, Those are all done by ultrasound, right? That's where all ultrasound measurements are all ultrasound measurements and
47:08
what's the variability in the ultrasound measurements and and the person is taking the the readings. Well, that's why we've, we, we talked about, there's lots of variability, but I think the
47:19
issue was that we would people have done it differently and that's why this concept on actually measuring the right thing, measuring the nerve, including the subarachnoid space As well as utilizing
47:32
Doppler flow to visualize the central retinor artery and vein can improve the accuracy of the measurement. This is Doppler flow and Doppler vascular flow correlate with vision.
47:49
Not that I am aware of. Nobody studied that. I don't think they've studied it So, I mean, that's what you're trying to do is determine what their nerve function is, but you're setting that. No,
48:01
I think this is this is. apart from nerve function, this is just, you know, structure of the optic nerve sheath diameter. And I'm trying to make a correlation between what we do clinically. If
48:16
somebody comes in and we measure their ICP, and they neurologically deteriorate, it's a gross measurement because it's a combination of all kinds of things that are going on in the brain. That you
48:28
can get a correlation here, but you haven't done this with the nerve, right? Right, but there's a way to do that, actually, and we're gonna talk a little bit about the complimentary technology
48:41
in a little bit called pupilometry. But
48:55
to get back to your other question, Jim, what's the precision of the ultrasound? Precision of the ultrasound in a static probe is pretty high in terms of discussion. of millimeters and so forth.
49:07
So the resolution of the ultrasound itself is not the question. The variability that comes is by the movement of the hand. So you're holding this device
49:19
manually and a very small movement, you know, imperceptible tremor, et cetera, could make you make things change So where would they've done these measurements of the deformability index, they've
49:35
had fixed position devices so that they don't have that kind of movement. And what we're trying to get to in our patent and our development program with that, with the clinical engineer that we
49:48
guild and the team is working on a device that will
49:57
You know, reduce that kind of user variability and fix it to the. But so those are very good points. And so what, but what these,
50:07
I think in terms of the science of these papers that they, they try to control for those elements, but in practical settings. Yeah, from user to user that's a major issue and, and part of the
50:20
very variability of
50:22
how well it performs in the clinic versus true ICP monitoring is contaminated by that human error Excellent explanation. Just as inside here when I was a young resident, I was about five years ago.
50:36
I ultrasound came out to measure, you know, they were measuring if you had a subderal hematoma or not that's what it was used for And I was in the emergency room measuring and I said, gee, this
50:48
man's got a subderal hematoma. I took him up to surgery, put some pearls and emergently, and it was a gross error on my part And I certainly, I heard about that, but, uh, so, so, There is
51:03
error in the technology and there's an error in the person who's doing it. One thought, Paul, is the eye is an extremely sensitive neural structure. And just by using an eye chart, if they were
51:17
awake enough to do that, you can go and see, can you read this line here? It might give you some way to correlate it. I don't know if this is practical or not, but I'm just trying to, if you had
51:30
a correlation with eye function, it may enhance the, what you're doing.
51:38
Hold on to that thought because, you know, generally speaking, these are not, these have been done in coma patients, but hold on to that thought because I was going to show you a little bit about
51:45
pupil armature, which gets at eye function.
51:51
Good terrific idea. Okay.
51:54
Thank you. So we've mostly spent the last. half an hour talking about the optic nurse sheet diameter in patients with traumatic brain injury. What about in
52:09
subarachnoid hemorrhage? Most, a group in Norway, actually there's a recent study that was just published in neurocritical care journal in
52:16
2025. It's showing promise in this regard in utilizing optic nurse sheet to assess the intracrine impressions of arachnoid hemorrhage. In a study conducted between 2022 and 2024, 20 patients were
52:30
enrolled 18 years and older. 26 ultrasound recordings were collected serially for an average of three to five days. And what they found was quite fascinating actually that the optic nurse sheet
52:44
diameter is able to accurately discriminate dichotomized ICP above 50 millimeters of mercury, especially if the basal systems had not been surgically manipulated So in a sub-group analysis, Without
52:59
manipulation of the basal systems, for ICPs above 15 millimeters
53:06
of
53:09
mercury, there was a statistically significant increase of optic nursery diameter to a mean size of
53:12
068, 07 centimeters versus a
53:17
diameter of 06 centimeters for an ICP less than 15.
53:24
Very good, you say if the basal cisterns haven't changed, how are they gonna change? You get a, they have a lumbar puncture or something, they're not gonna, how are they gonna change? Yeah, I
53:34
think these were patients that had manipulation the cistern either through surgical intervention. Well, they've had previous surgery or something. Part of a hemichryneectomy for -
53:45
I see, okay, I got it, I got it. So the two critical points of interest was that manipulation of the basal cistern close to the perioptic cistern could potentially create a CSF diversion alters
53:58
the propagation of pressure to the optic nerve like noise space. Got it. Also, it also showed the concept that optic nerve sheet diameter in the ICP seem to have a linear relationship, except in
54:12
those with critically elevated ICP causing a cessation of cerebral blood flow known as a state of brain tamponade.
54:23
So this indicates that when arterial pulsations cesate during state of brain tamponade, this
54:30
disruption to the pulsations and the optic nerve sheet
54:35
happens. And this shows that the optic nerve sheet diameter in the space is dependent on the brain cerebral blood flow pulsation related to our concept of the deformability index.
54:48
The second will be on transcranial Doppler monitoring, which will last about three minutes
54:56
Well. Hopefully, I haven't bore the audience too much with the optic nurse sheet, but from the questions, I think everyone is quite intrigued. I wanna transition to other non-invasive ICP
55:08
monitors, and then I'll wrap up the talk and answer questions. We have what's called a transcranial doppler TCD,
55:15
and the third is a quantitative papillometer. Transcranial doppler looks at blood flow in the middle cerebral artery, primarily the first division of the middle cerebral artery, MCA, division one.
55:30
And ICP can be estimated using either of two techniques. The most common is the Gosling Pulsation Index, and there's another technique called the Cosnisca CPP Estimation. Our focus is on
55:45
Pulsatility Index. The Pulsatility Index takes into account the peak systolic volume, minus the end-ystolic volume divided by the time average peak velocity. Now, high pulsability index could
56:01
indicate or indicate in our case, distal arterial compression from elevated pressure.
56:10
So for ICP is above 22 millimeters of mercury. The pulsability index has a good sensitivity of detecting intercoronial pressure of 95, but very low specificity, about 30 And this low specificity is
56:27
because there are lots of other things that can cause high positivity index. Essentially, there are other things that can cause elevated distal arterial compression, such as atherosclerosis with
56:38
age,
56:41
distal vasospasm as well,
56:44
can cause this to be elevated, impaired auto-regulation, and other parenchymopathology without high ICP, can also cause a positivity index to be elevated.
56:55
And the third will be a neuro pupillary index monitoring given by Dr. West by that'll be 13 minutes. The third non-invasive device that we have is something called the neurological pupillometer
57:11
index. So the oculomotor nerve, coronavirus 3, its pupillary reactivity has been considered to be nature's natural ICP monitor. So one would expect that as the ICP increases the parasympathetic
57:28
fibers on the outside of the oculomotor nerve become compressed causing pupillary changes, essentially a dilated pupal that's non-reactive. Now often bedside visual assessment, which we have to do
57:43
in neurological exam in every patient, but the bedside visual assessment using the flashlight is only a qualitative assessment of this
57:54
oculomotor nerve change. and will miss subtle changes in early signs of high ICP and herniation. That's why we have this concept of the MPI, the neurological pupillary index. And what it is, it's
58:08
a quantitative assessment of the pupillary activity from exposure to infrared light to track the speed of constriction of the nerve with light exposure, following it to its size at maximal
58:23
constriction and also assessing the speed of relaxation of the nerve. A Swedish group in 2024 shows that for an MPI-gridded and 39 to exclude ICP elevation above 22 millimeters of mercury has a
58:43
negative predictive value of 97
58:48
This device is really good because. it does not require specialized technical skills and can be done by anyone at the bedside, including the nurse, the physician, medical students, trainees. So
59:02
let's tie the pieces together.
59:06
In summary, no - So Ella, let me interrupt you there for a minute
59:12
about the pupilometer. So this is a device that measures
59:20
is an automatic device, you can see there in the candle and measures the pupil response to a standardized light exposure. And the device is a commercial
59:36
device, actually out of Irvine, California, the company's out of Irvine, California. And it reproducibly gives the same sort of light stimulus to the patient. and to the eye and then measures
59:53
the reaction of the eye to that stimulation. And then generates a number basically, which is a
1:00:06
called the New York People Air Index. If you could unshare for a second, Ellen, and let me share, if you would. Yes, one second, I'm done sharing
1:00:19
This is from a talk that I gave a
1:00:22
couple of months ago. But this is the patient's being stimulated and you have a space line starting people airy size and then it constricts, the people constricts to the white and then goes back up
1:00:37
again, dilates up again. And they integrate this, there's software that's
1:00:44
integrates the rate of constriction and then dilatation again puts that together in its own process. and gives you what's called a neuro-pipillary index, which normally is around four to five range.
1:00:57
Anything greater than about 35 is considered to be normal, and below that, you would worry about problems within the nervous system. In this case, we're focusing on the suspicion of elevated
1:01:10
intracranial pressure, although there are other reasons for this people area index to be abnormal. But suffice it to say that we're looking at this in the context of ICP. You actually get a variety
1:01:23
of different variables here. And these variables have been differentially considered to be important for various other sort of
1:01:35
measures. But this is actually the variety of measures that come from the NPI.
1:01:43
And in NPI,
1:01:46
in peopleometry, this has been roughly correlated to be an indicator. of elevated ICP. The data is not as robust in terms of
1:01:59
the optic nerve ultrasound. We have less data where we have serial measures of both invasive ICP and pupalometry, although those kinds of studies have been done. And there is some correlation with
1:02:14
elevated ICP. And it turns out that some
1:02:18
of these correlate in various studies better with ICP than some other
1:02:25
parameters. And these are the three. The NPI, the percent change in the maximum constriction velocity, sometimes correlate in various studies better than others for ICP
1:02:37
control. I think this - but there are some - some -
1:02:44
there's been some correlation also between pupal size and pupillary light response as well. basically the parameter that's been
1:02:54
used. And this device is
1:02:58
relatively low cost. It's reusable between patients. Each patient gets a unique disposable plastic ring that's used just for that patient, but the actual handheld flashlight device you can take
1:03:15
from patient to patient and clean it in between and so forth So that's probably and it's very easy to use. So
1:03:25
our nurses use this relatively routinely. We're using it not only in the neuro ICU, but we're using it in other ICUs. So even nurses that are not well trained in the neuro exam and doctors that
1:03:37
well trained in the neuro exam can use this, but clearly it's something that gives you more information
1:03:46
then you get just by the simple right response and it's quantifiable. and it's trackable and is something that is, again, being considered to being a non-invasive tool. Now, Jim, you came up
1:04:01
with a really excellent observation is that, well, how about the function? No one has really combined the NPI with the ultrasound and no one's combined that in real time.
1:04:13
Repeated measures of these things. So it's kind of a very interesting and intriguing concept But these things have been used distinctly, separately from each other, really. But the pupilometry is
1:04:29
not something that has all of this air of optic nerve, ultrasound, variability, hand variability, you know, user variability between users, that type of thing. This is much more robust and
1:04:45
ready to use, I think, today in all kinds of areas. And so it's something that is probably worthwhile exploring, you know, for the group if they haven't already been using it. I think that's
1:04:58
gonna make some comments. Paul, that's very interesting. Can I ask you a question? You got a cataract? Or if I have a Suburact known hemorrhage and have blood in the vitreous, how does that
1:05:11
affect the pupilometer? It's probably gonna make it abnormal I mean, you know, they do have the
1:05:21
need. So if you have a surgical pupil, you have any kind of anterior chamber problem. Yeah, it's probably gonna make this not interpretable or differentially interpretable. So it's a good
1:05:32
question. What I like is what you've done, is you've correlated with function. The other thing is nerve transmission. I mean, you're measuring several things, compose the measurement In other
1:05:43
words, does you have a standard source? you go into the eye chamber, there's variability there, then you get a nerve impulse that's conducted and it goes through the nervous system and then it
1:05:55
comes back and then, and you get changed in the pupil size and there's a speed and time component to that. So you're measuring
1:06:05
a number of things that's very interesting. You're measuring and you're using an open path to the nervous system using a reflex arc
1:06:15
I think that's a neat idea. Yeah, yeah, the company's been very successful. I don't have any stock or anything in the company, but I know
1:06:26
the origins of this, we worked with these same people on a completely different device that was also successful. So they're very good entrepreneurs and there's a physicist who's at UC Berkeley who's
1:06:40
the backbones of this that works with them. So it's a very interesting thing They're starting to look at this, not just. or ICP, but they're starting to look at this for brain function in coma
1:06:51
patients as well. That's a completely different sort of rationale for use, but I think for
1:06:60
ICP or someone who you may think have, you know, you wanna screen out, you know, ICP issues, you know, maybe you get a scan and you don't, you can't get a repeat scan and you wanna monitor them,
1:07:12
you know, hour by hour, this allows you to monitor them And if the number remains good, you know, and good means above 35. So in this case, I think it's 39, 37,
1:07:28
NPI's. Even if they're comatose or they have a poor exam that's difficult to track, this gives you an objective number, you know, and you can ask your nurses, Hey, what's going on? And then
1:07:38
they say, Well, now the left pupil is threeand that the right pupil is 35 Well, now, you know, And you're worried, let's say you're worried about that side from a clinical perspective, you know
1:07:49
that they have a trauma on that side. Now you can, that can start, you know, helping you try to determine how to treat these patients. And you may want to, you know, think about either, you
1:08:00
know, treating them medically or considering, you know, any surgical options. So. I think that's terrific. I think, does this reflux fatigue? In other words, particularly in somebody who's
1:08:13
common toast, does that ref, I know nothing about this, but just if you repeat it, take repeated measurements. Is that a fatiguing reflex or not? No, in fact, we take it, sometimes we do that.
1:08:24
Like we'll do it twice, you know, back to back on the same eye and then we'll go to the other eye and do it back to back. And it doesn't, it doesn't really fatigue. And there's, that's another
1:08:33
question. Is there a difference between eyes? There can be, there can't, we often see asymmetries. Yeah, there's got to be. You know, all kinds of different asymmetries.
1:08:44
So what you're really doing, I mean, all of this is about can I find a non-invasive measurement that's accurate on measuring intracranial pressure? I mean, that's what all these things are because
1:08:55
the alternatives, but an ICP monitor it, which in many countries people can't afford, they can't do it, it's not practical. And in what does this supply information practically that I can use
1:09:10
between a neurologic exam in an ICP monitor? I mean, that's really what you're doing, right? Yeah, so it's a whole area that's very ripe, and I think that's what we're excited, not only
1:09:26
to study this, but we're excited about Ello's future here in the next couple of years, and collaborations, and really trying to field test some of these concepts Let me ask you this practically,
1:09:41
okay, a patient comes in. He's got a head injury, I put him in the ICU. I'm watching him for a while. I don't know if I want to put an ICP monitor and that seems to be a big step by if they're
1:09:53
going to take care of it there and I'm in a resource-limited country, it's going to get infected and people are not going to watch it and all those things that you know well about. Is this something
1:10:05
that I can use reproducibly that would - either one of these monitors, use that reproducibly that would guide clinical judgment and
1:10:13
what would
1:10:16
I find that would change my clinical management? A discussion among the presenters and the audience, international audience, will then follow, which will last about 22 minutes. It's a very good
1:10:31
discussion that's complete and answers many of your questions.
1:10:39
So, Dr. Hillel. Dr. Osman, I would transition now to really answer the question. That was a very nice segue. So tying the pieces together right now, no current noninvasive monitor can replace
1:10:51
our invasive monitors with the ventricular drain or the codman. But when used together in serial assessments to trend ICP, in addition to the clinical exam, it can be very useful. In combination,
1:11:05
when utilizing all three, the optic nerve sheet diameter, the transcranial doppler, and the neurological pupillary index, it shows a
1:11:17
high sensitivity with an area under the curve of 091, which is quite good. So three numbers I want you to remember is that if a patient, like our patient scenario, we don't place an EVD and we
1:11:31
decide to do an optic nerve sheet diameter, it's important to do this serially and trend daily if ideally, multiple times a day. an optigner sheet diameter less than 05 centimeter probably
1:11:43
indicates a normal ICP. A both 07 centimeters probably indicates a high ICP. Now, a high MPI, the pupulatory index and a low positivity index based on the transcranial Doppler blood flow is good.
1:12:04
So MPI above 39 with the positivity index less than 16 is reassuring that ICP is not elevated. While an MPI less than three with an elevated positivity index of 16 should trigger urgent evaluation
1:12:25
for elevated ICP. So to tie this together, I asked you a question, Dr. Osman. If we use the opt-igner shift diameter, I would like to see a number of less than 05 centimeters to reassure me and
1:12:36
would trend this daily If we use the Positivity Index. using the transcranial Doppler, which is less feasible in sub-Saharan Africa. But a number of less than 16 is reassuring and indicates that
1:12:51
the distal arterial vessels of the brain are not being compressed. Now the most feasible, which would be the MPI, an MPI above 39 is also reassuring So taking all these three values into account
1:13:08
can be quite useful at the bedside for SSNICP.
1:13:14
So the MPI is what Paul was talking about. That's your abbreviation for that. People are your index? Yeah. That's right. Yeah. Okay. How much the difference in cost?
1:13:27
At this stage of my career, I don't know how
1:13:31
I'd like Dr. Vadperanza I'm in, I'm in, I'm in Subseh or in Africa, I'm lucky if I can find a thousand dollars in my hospital because I've got all kinds of other things. they want to spend it on
1:13:41
which one of these devices should I buy? And the pupilometer.
1:13:47
That's going to be, that's the one that's going to be affordable right now. The one is the one you were talking about, Paul, MPI. Yeah. It may make sense to me. So so that will be your
1:13:57
transition between putting in an ICP monitor and watching the patient. It's could be easily done by a nurse You could do it repeatedly and the measurements and what's the accuracy? The IP, uh, NPI,
1:14:12
Paul is a percent at what's accuracy is going to be 90 accurate or. Oh, yeah. It's, it's even above that. Yeah. Okay. I mean, I think the encouraging thing that is, that it has a very, both
1:14:27
of those have very high negative predictive values. So you can almost with confidence say that the person doesn't have or creating a hypertension if they meet.
1:14:39
if they meet their criteria, but their positive predictive value isn't that high. So you'd be, you won't want to make an intervention based on those
1:14:52
modalities. We used to get transcranial dopplers and it
1:14:59
would be actually dependent upon the technician.
1:15:04
So your NPI would appear from what you said is not very limited technician dependency there, correct? That's correct, right. With the pupilometer in which you've got to use a human interface to
1:15:17
get the data, I'm sure it's not as high as with the NPI. Is that correct, the pupil area index? Yeah, the NPI - Oh, the optic nerve sheet diameter. The optic nerve sheet diameter is more
1:15:32
technically challenging and - Yeah, okay, so those are terrific.
1:15:38
Oh, well, am I right? Yeah, yeah, I think that's right. And I think that we're trying to bridge the gap of of
1:15:47
availability of technology. So I think that, you know, and there's other technologies as well. We haven't been able to explore all of them, but I think these are the ones that have been around
1:15:57
the longest and have a lot of promise In your, in your operation who performs the topic nerve she diameter measurement. The doctor hello is on call all 24 7 365. He has to. He sleeps next to the
1:16:15
now. Yeah, it's the, it's either the ICU fellow or the ICU attending will do it. Yeah Yeah, it's
1:16:32
a public company. It's available,
1:16:37
I think, from a cost perspective I think from a cost perspective. of its its the least costly of all of these technologies. Yeah. Well, if I'm in Sub-Saharan Africa, and I'm a relative cost of
1:16:47
the device, obviously, the NPI is going to be less than to be my gut feeling. That's right. And if that's so, I mean, it comes into the emergency room, you don't know who's going to be using it,
1:16:57
but you know that eventually they got to do ABC, and that's going to be reproducible, and you're going to get a number that's going to be reproducible, and you'll get an index of what maybe ICP is
1:17:10
there, and then you'll get it two hours later from somebody else, and three hours later from somebody else. So it has a lot of advantages, is that correct? That's correct. I imagine that with
1:17:22
limited resources, if you do have ICP monitor capacity, but it's limited, you can use these tools to determine whether to implement ICP monitoring Right. That's right. Yeah. Strata, we've got
1:17:38
25 people here, which is good considering the subject here, which is more research or interest. Alvin, are you still on the call?
1:17:50
Alvin Do, or Sam?
1:17:54
Which of the sounds? Sam,
1:17:59
what do you think about this, Sam? Yes, this is a very fascinating, I must say, we will be looking forward to this sort of experience. Over the years, we venture into ICP monitoring that it
1:18:14
collapsed because of cost implications. And in fact, one location, one of the companies said, no, they can't operate our system because they don't have experience to service the system. And they
1:18:27
refuse to allow us upgrade from an older version of their system as you can monitor it. And the recent eventual went into day. The cost was so excessive. It's not the cost of buying the equipment,
1:18:42
but the cost passed to the patients. It was unaffordable. So we had to put a hook to it. So we're looking forward to this development. And I think it's what, but it led to the CD, sorry, the
1:18:55
MPI.
1:18:57
I think it's also attractive. And we need to need information, please, to follow up on it. Thank you. Okay, terrific So if you had somebody to spend in your hospital,
1:19:10
most practical would be the MPI. Am I guessing right or wrong, Sam? Yes, it looks, you must have put it by the moment, yes. And can you see how it could apply in different locations? It could
1:19:22
be a practical device. It would be worth its investment.
1:19:27
I believe so. It sounds like it's going to be an attractive investment Oh, okay. I wish you a good question. And you give us an idea how much does it cost? That's a rough idea.
1:19:44
I don't, I don't know that they answered. We asked that question. Yes. How much would the, you know, is there a cost for that MPI think? Yes. Yeah, there is, I'm not exactly sure what it is,
1:19:56
but, you know, I think it's - It's at1, 000. It's1, 000. I don't, I'm not
1:20:03
sure, you know, it's something you buy once and then, you know, the annual cost is not that much, right? They're using it in many countries across the world, so. Okay, now you mentioned a
1:20:16
device that had to be placed over the patient's eye. So is that a disposable
1:20:26
device? There's a little plastic ring that's disposable that's used just by the person themselves, yeah. So that would - Yeah So you would have to have ample supply of. Yeah, there's a lot. Yeah,
1:20:38
that's right. Yeah. Yeah. What about the other people in the audience, Dr. Ibi and Dr. Oakley and Dr. Wheatie. Anybody else want to ask some questions about this?
1:20:54
Let me go back to Sam. Sam, how would you see
1:20:58
application of any of this technology, specifically the NPI, and how would you see it being implemented where you are?
1:21:12
I think I would like to get one, at least one or two to see how it works out
1:21:18
The attraction is that not only doctors, but nurses can handle it. That makes it very attractive, in fact. And it's not invasive, so there is no question of renewable or something. So I think
1:21:33
it's worth trying. Personally, I'm very, very impressed with that. I would like to go venture into it, believe me, as soon as possible If I can get, if I can get information on how to the
1:21:47
company to approach.
1:21:50
concerned and immediately after the structure, if I can get information on the company to operate for this facility. All good questions. Okay, we can get that information to you. There's a hand
1:22:01
raised, Dr. Aqwee, please go ahead.
1:22:06
Yes, thank you very much for the presentation. Quite interesting. Another of our novel approaches have been developed for this non-invasive and ICP monitoring. I recall once in time, there was
1:22:18
this issue of tympanic membrane displacement, which took place on, I think, around 2014, 2015, somebody was studying it in Japan. I don't know the present, I didn't talk about that, tympanic
1:22:30
membrane displacement. It's another novel method of non-invasive ICP monitoring. I don't know whether it's that it's not quite relevant now, it didn't mention it at all. The name, since it's just
1:22:44
for monitoring, what's a non-invasive parameter, I see that just for monitoring, at what threshold do you consider intervention? but that's my challenge. At what threshold do you consider
1:22:53
surgical intervention? Because mainly in TBI patients, the aim of monitoring is to know when you're in surgical, perhaps. So what threshold do you consider for interventions? I know you're not
1:23:02
using the invasive parameters. Thank you. Yeah, good question. I think we haven't seen the tympanic membrane be propagated much. The
1:23:17
other device that's out there
1:23:20
is a
1:23:22
skull motion device that's called brain for care. And this is a device that comes from South America, which is a device that can measure distensibility of the skull. And it measures the ICP
1:23:38
waveform and is
1:23:40
something that's being explored as well, a little bit less data than what we just showed you So I think, you know, but I'm not familiar with the tympanic membrane data or have seen it much in
1:23:54
recent times.
1:23:56
What are the parameters for intervention? I think
1:24:01
if you have an optic nerve sheath that is 06 centimeters or greater, then you need to have some kind of intervention, either medical treatment or if you were considering surgery, that might be the
1:24:15
indicator for considering to go in to the operating room. The NPI generally is something where you have to be concerned if it's less than 35. I don't think there's an absolute number there that is
1:24:30
as strong as the optic nerve sheath number in terms of when to intervene.
1:24:37
I think all of these, and then the transcranial Doppler, greater than 16, again, as a concern, and some, you need some kind of intervention, maybe not surgery, and maybe not surgery for any of
1:24:52
these, but I think you have to then put together what the clinical situation is, you know? I think if you're sitting on, let's say you know that someone has a, a parentable contusion, hematoma,
1:25:07
and you're worried about, well, do they need an operation or not? And they're, you know, their exam is poor, but you're not quite convinced I think that's where you can put that information
1:25:17
together with these critical values of the optic nerve sheath or the NPI to make a decision, as a general example. You need the serial measurement, which would really be helpful, right? Right,
1:25:29
right, right. And if it's, yeah, and that's the other point is that if it's going down, if it's deteriorating, then that's another indication that then you, whatever you're doing medically in
1:25:41
treating the patient isn't working and you may need to consider surgery. There's a comment from Joseph who was on his phone, said he still looked for experience for us in Uganda. The NPI was tried
1:25:55
through aid from Duke in 2023, but it was not adopted because of the costs and maintenance. Is that a problem that's been addressed since that time?
1:26:08
Do you know that, Paul? Well, if the cause of maintenance included the disposable device for each patient. I don't know. It's a good question. You raised that earlier. Yeah, don't, not don't
1:26:21
know. You know, there is some cost associated. These are.
1:26:26
Obviously these, these are devices like any device they can, you know, break down or need treatment, but we've had pretty good performance with them You know, they, they, they plug into the
1:26:36
wall and, um, but they're not, they're not zero cost and that's, that's, that's obviously an issue. You know,
1:26:46
Sam, Sam, this might be something where you got a few selected places. We're going to go to the companies. They give us a few selected places. I'd say three places around Africa and, and let
1:26:58
people try it and report their experience. They could report it on these meetings and so forth And it would help everybody else out because Everybody can't afford to try it out, but it might also
1:27:09
help the company. Is that an idea that would be reasonable, Paul and Sam?
1:27:16
I think it's also attractive, man. If I didn't know there are some centers I was using it already in Africa, it'd be nice to have their contact so that we can reach out to them. And no, yes, yes,
1:27:28
yes. You know, our experience in other areas,
1:27:34
not necessarily with NPI or anything like that, but with other devices or other concepts
1:27:46
like this, has been to engage in a financial evaluation, a clinical and a financial evaluation, and engage with the
1:27:55
country's leadership, the health system's payer's leadership to really understand this We've seen that happen where things are costly, but if you demonstrate that you can actually be cost effective
1:28:10
overall, then there's buy-in
1:28:15
to pay for technology. And so it may be something that is, you know, more comprehensive approach is needed. But yeah, I think there are
1:28:27
organizations, foundations and
1:28:32
philanthropists that are very interested in advancing care in diverse areas across the world and
1:28:43
limited resource areas across the world. And, you know, working
1:28:49
to sort of get a package, you may be able to get something like this sponsored where at least the startup evaluation and proof of concept can be paid for by, you know, a donation or something like
1:29:01
that. Perfect. Strata's going in two weeks two and a two and a half weeks. So maybe he can connect with with you or or L. Oh and
1:29:14
and we may stop in in Nigeria and And so forth and it could talk to some people about it. Would that be feasible, Ostrata? Could you do that? I'm
1:29:26
gonna be in Ghana for for a week. So I could see about the coronavirus. Well, I had a question for you. So you will be in Tanzania And you
1:29:40
hoping to to implement the optic nurse you diameter technology Now what what do you think I'm sure you will be training people and what do you anticipate would be the time needed to get Efficiency as
1:29:57
you as you train people in this product with the product, you know, I would say using the right techniques actually using color Doppler and, you know, showing measuring the right parameters a
1:30:12
couple months.
1:30:15
Yeah, well, any other questions from the audience?
1:30:22
I appreciate you, you see anybody in the hands up?
1:30:26
Doctor, can I, yes. Yes, yes I want just to thank Dr. Paul Wester to ask, accept to give this talk, arrange this with his fellow, but there is one thing I am asking him, if there is a way
1:30:40
that these young people from Africa to rotate in your ICU one or two weeks only, to get the latest for the treatment of the TBI and other care of the neurosurgery patient, because most of the care
1:30:56
of neurosurgery is the care they do it in the ICU. Technique, yes, you have to know all the latest techniques. But if there is a way to arrange for them to rotate with you, in one or two weeks to
1:31:09
get the exposure to the latest, that's the problem we have in neurosurgery. There are a lot of new things coming and to adapt it to advance the care of the patient. I really appreciate you, you
1:31:23
can look into that so they have an opportunity to contact you to rotate over there one or two weeks at UCL That's my request from that. That's a really good idea and I think we can certainly look
1:31:36
into it.
1:31:39
Well, thank you very much. That's terrific. Okay, Strata, I think Paul, if we can have you and
1:31:50
I'll come back. I think one of the questions we'd like to ask is what, because this is a common problem in Africa is traumatic brain injury and and ask you what is new and what's new and what's
1:32:03
practical and what there should be any change in what we do, our pattern of activity. Would you be willing to do that? Yeah, sure, absolutely. Aloth, thank you, congratulations to you, just a
1:32:17
terrific job and admire you're going to Tanzania and trying to work with the group and set this up. I think it'd be just outstanding. If we can help you in any way, we'd be happy to do that. Thank
1:32:29
you Yeah, and let's stay in contact. I think we might have some common interests and I'd be willing to help you with what you want to accomplish. Again, thank you, Dr. Vespa and Dr. Ebeekwie.
1:32:43
This has been a very informative, very stimulating conversation. And I hope we'll have further discussions about this. Maybe a strata of thank, both Paul and
1:32:55
Elkin give you their email address or their WhatsApp And the contact information that others around the call can do that. Okay. Absolutely. Yeah. All right. Thank you. Thanks everybody. Have a
1:33:12
good rest of the day. Thank you. Thank you. Okay.
1:33:18
These are the references for these two talks. Take a screenshot for your record so you can preserve it for future use and reference
1:33:32
This is the first set of eight references on the first talk on the optic inertia monitoring
1:33:46
And this is the second set of references on that same subject Change.
1:33:55
For the NPI monitor, the non-invasive ICP assessment, this is a common reference which should lead you to other sources of information.
1:34:10
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1:34:14
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