Thank you very much. Thanks for the opportunity. And, I mean, to start with, you can tell the experts say how complex it is. So what is a simple clinician going to say afterwards? This was an opportunity to talk to you and realize how difficult it is to identify the tests. And perhaps the CBC is still the most important test that we understand at least. I don't have any disclosures except for the fact that I'm a pure clinician. So bear with me. I'm trying to understand what these scientists do. The goals of this presentation is to truly come up with some tests that we can decipher at the bedside and apply logically, understanding that the critically ill patients pose a lot of challenges to apply to precision medicine that we are interested in these days. And how does a clinician interpret these tests is a very big problem. The three eras of critical care have been nicely identified recently. We had our foundation people who got us into describe the first cases of ARDS. Then the clinical trials people who helped us define the syndromes that are most problematic for us, namely ARDS and sepsis. And nowadays we are in the precision era where we have to come up with personalized medicine in order to treat everybody based on the pathology or the pathophysiology that they are encountering. And just to illustrate as an example what sepsis does to people, since sepsis is though referred to as an infectious disease, but in reality it is an immunologic disorder triggered by a certain infection, the different mechanisms by which pathology has been identified in different sectors and different labs basically. You talk about different cell abnormalities, immunoglobulin level abnormalities, the tremendous neutrophil dysfunction, the states of immune suppression and pro-inflammation. And all of that comes to you at the bedside and one is supposed to figure it out. In sepsis three definition, people talked about it being a life-threatening, order dysfunction disease secondary to a dysregulated host immune response. But we never measure the immune response at the bedside. So there's a big gap between what the definition and what we do at the bedside. And in reality we look at simple stuff. We look at the source of infection. We look at the vital signs and then organ dysfunction with SOFA and it's crucial to be timely in defining what to treat. All what we do has low sensitivity basically and poor specificity even unless you have cultures that tell you this is the infection. Even when you treat the infection, you're not necessarily in control of the immune dysfunction that has occurred at the bedside. So let's go back to the CBC. It's a very important tool that we use all the time. But the majority of us only look at the white count and perhaps the bands and the percentage of the neutrophils. But there's a lot of information in the CBC itself, the basic characters of it. And mind you that the current hematology analyzers and they're based on flow cytometric advances are able to give you a lot of information about the cell population itself. Like you can get data regarding the volumes, the granularity of different cells. And there is some data to say that if you were to look at these in real time, you may come up with an accurate diagnosis of an actively infected individual who's tending to go towards aseptic syndrome. And one of the biggest problems that we have nowadays, there's a lot of people who order the CBC without a differential. And that in particular may be a big problem. The one thing that one has to know that like when somebody is horribly ill and the neutrophils are rising, often the lymphocytes that are responsible for our adaptive immunity are going down. And the further down they go, the worse the outcome is and has been reported in several series actually before. I borrowed this from one of the symposium that I attended, not to scare anybody, but just to tell you about all the biomarkers that have been reported in this immunologic disease. These biomarkers are studied one at a time or perhaps two at a time, and they will add to how people identify things and trying to come up with treatments modalities. But you can tell it's impossible for a clinician sitting at the bedside to integrate all this data at once. It's just impossible. The three ones that are predominantly used currently are the C-reactive protein, the procalcitonin, and interleukin 6. Although the C-reactive protein has been there for a long time, it is the most nonspecific biomarker that people can get. And its value is not necessarily correlating with the critical outcome. Procalcitonin is a little bit different because as I show you soon, it really carries some benefit. And interleukin 6 is trying to find its way. All the others have been used in different kinds of studies, but in reality have not made it to the clinical arena yet. Every time you want to use a biomarker, one has to figure out what the kinetics of it, and as you can tell, each one of them has a different pattern. The cytokines tend to be very rapid, and they tend to be, if you're measuring them later, you may miss the opportunity, and in reality, you don't know what they are at the time that you get it, and there's no value in serial measurements in clinical medicine. In research or trials, it's a different story because we're trying to understand it. Procalcitonin, in particular, its onset starts within three to four hours, and it peaks in about eight to 12 hours, and its half-life, 24. And it can be delayed a little bit in sepsis. But more importantly, and I will focus a little bit about procalcitonin, just because it gained its say in the ICU predominantly. As you know, it's a precursor of calcitonin. Under normal conditions, it's only expressed in the thyroid and the lung neuroendocrine cells, but in disease categories, after being induced by a microbial infection, particularly with bacterial infections, there's a tremendous increase in gene expression in several of the organs. When it was applied in sepsis, it has a pretty good sensitivity and much less specificity, but it was pretty good, really. It has three values for us. The first value is the rate of its decline tends to be associated with better outcomes. So for the patients who start with high calcitonin levels who drop by more than 80% by the fourth day, they tend to do better than the ones who don't. So that's one hint that we can use it in either for those people who don't drop, that maybe we need to reexamine what we're doing at the bedside in regards to perhaps the source of infection, the type of infection, or even the presence of occult areas that need to be drained. It also has played a major role in antimicrobial stewardship. When applied, when one looks at it serially over time with adequate decline and devise a protocol for the institution that you're in, you'll be able to cut back on the use of antibiotics without any poor impact on outcome. And this is what we did over there at the UH. We kind of created based on the literature that we know is you study the patient, figure out the conditions that may interfere with procalcitonin, and if it's present, we'll decide that, you know, procalcitonin is not going to be helpful here in antimicrobial stewardship. But if none of the conditions are, then we look at the second level in 48 hours, and according to the finding, proceed with stopping antibiotics or not, depending on the value that we get. This is a quality improvement process that we tend to use, and actually the majority of institutions do, every time a new test has developed. The new stuff that's coming on board, which is very, not only very interesting, but it's probably going to change things, is the development of RNA gene expression arrays. The first one that got FDA approved is Cepticide Rapid. It is a blood test that you do that will give you a result within 60 minutes telling you what kind of process, whether the patient is septic or has just inflammation based on a SERS, quote, unquote, SERS. When it's applied in some clinical medicine through some, in several centers, the area under the curve as a diagnostic test came back at .85, which is really very good, but the standard was still having three people review it, review that the patients were septic or not. So as a diagnostic test, it was, it acted very well. And in reality, when you compare it to lactate alone versus procalcitonin alone versus the entire combination of this Cepticide with the clinical diagnosis, procalcitonin and lactate, it did the best. In other words, when you have more information applied at the same time in an integrated fashion, you will come with a more accurate diagnosis. And that's what we really want to know. And if we come up with an accurate diagnosis, actually this is also how it fared with, the kind of the way it comes about, it comes about as a scoring system. And then the score is divided into four different bands where the band four is sepsis for sure, band one is SERS for sure, particularly on a continuum. There is still some areas in it that are gray zone, but in reality, it has a pretty good negative predictive value. Which will help you stop antibiotics earlier on. A similar technology but using a different kind of gene array, it's with something, I don't know what they're going to end up with a name for it, but it's currently in development. They used like 29 messenger RNAs in the body. And when it was compared to other tools that they were using in a surgical center, 200 surgical patients, it's referred to as the IMX. It did exactly the same as procalcitonin but was superior to interleukin 6 and the total Y blood cell count. They applied it in another context through the ER having a different patient population and did pretty well relatively. However, all of these tests when applied have to be applied in a timely fashion. Like it cannot be 24 hours after the diagnosis of sepsis because I do believe they will lose their value. Great, we made the diagnosis and we're taking care of patients and whatever, but we still have a group of patients that are not going to do well and we want to go succumb to their disease. And this is very similar to the previously noted slide. And to me at least, the one that's very promising is try to identify the cells that are working and how are they working. And that's through the, it's not really new, it's an enzyme linked immune absorbent spot that's currently being applied to address the number and function of lymphocytes that are present in somebody. So if you go back to the CBC and you find the lymphocytes are dropping, it's worthwhile studying them a little bit further through this ELE-SPOT kind of technology. A drop of blood goes on a plate that is already treated and each dot that you see here represents a functioning cell and the size of the drop that you see would represent the amount of cytokine that it produces. And when you have something like this, you will also be able to stimulate it and figure out if you can make its function better. And this technology can, I mean I shouldn't say easily, but can potentially be used to determine the accuracy, the accurate treatment modality that should be given for one patient at a time. This was studied earlier and our own Dr. Remy here applied it in COVID times where he has a control of a healthy person up there and the patient with COVID. And you remember, if you remember during COVID, one of the poor prognostic values was a drop in lymphocyte count. Lymphopenia was associated with poor outcomes. And when you have patients like this, you can see how much their cells are exhausted and the concept of immune exhaustion comes about. And in those people, whenever that's the case, death becomes a must. To take home message is, and perhaps it's a frustration from a clinician, there is so much data coming at us, very high output biologic data, some from proteins, some from RNA, some from the emerging technology that we have with the different devices, as well as the immune system. And we are supposed to be humans at the bedside integrating all this data together. And that's going to be impossible. So the ask and the point is we should, the scientists and the clinicians should be more integrated in order to understand the flow at the bedside and the flow of the science. Until we do that, it's going to still be very confusing, not only in the lab, but also at the bedside. With that, I end and thank you very much.

interpreting tests

sepsis measurement

complete blood count

biomarkers in sepsis diagnosis

newer technologies