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Evaluation of Fever in the ICU Patient
14 Plays2 years ago
In this episode, we discuss the evaluation of fever in the adult ICU patient. We discuss updates from the recently published Society of Critical Care Medicine and Infectious Diseases Society of America clinical guidelines. My guest is Dr. Andre Kalil, a critical care and infectious disease physician. Dr. Kalil is a Professor in the Division of Infectious Disease and Director of Transplant Infectious Disease at the University of Nebraska Medical Center (UNMC). A renowned clinician, educator, and researcher, Dr. Kalil has received many distinctions, including the 2021 Scientist Laureate Award at UNMC. Dr. Kalil is an author of the 2023 Society of Critical Care Medicine and The Infectious Disease Society of America Guidelines for Evaluating New Fever in Adult Patients in the ICU.
Additional Resources:
Society of Critical Care Medicine and the Infectious Diseases Society of America guidelines for Evaluation New Fever in Adult Patients in the ICU. Crit Care Medicine 2023.
https://pubmed.ncbi.nlm.nih.gov/37902340/
Executive Summary: Guidelines for Evaluating New Fever in Adult Patients in the ICU. Crit Care Medicine 2023.
https://pubmed.ncbi.nlm.nih.gov/37902339/
Guidelines for the evaluation of new fever in critically ill adult patients: 2008 Update. Crit Care Medicine 2008/
https://pubmed.ncbi.nlm.nih.gov/18379262/
Books mentioned in this episode:
Splendid Solution: Jonas Salk and the Conquest of Polio. By Jeffrey Kluger
https://www.amazon.com/Splendid-Solution-Jonas-Conquest-Polio/dp/0425205703/ref=tmm_pap_swatch_0?_encoding=UTF8&qid=1702571365&sr=8-2
Recommended
Transcript
Introduction to Critical Matters Podcast
00:00:06
Speaker
Welcome to Critical Matters, a sound podcast covering a broad range of topics related to the practice of intensive care medicine.
00:00:14
Speaker
Sound provides comprehensive critical care programs to hospitals across the country.
00:00:19
Speaker
To learn more about our programs and career opportunities, visit www.soundphysicians.com.
Evaluating Fever in ICU Patients
00:00:26
Speaker
And now your host, Dr. Sergio Zanotti.
00:00:32
Speaker
Fever occurs frequently in ICU patients.
00:00:35
Speaker
It is often an indicator of infection, but can have multiple non-infection causes in critically ill patients.
00:00:40
Speaker
In today's episode of the podcast, we will discuss the evaluation of new fever in the ICU adult patient.
00:00:46
Speaker
Our guest is Dr. Andre Khalil, a critical care and infectious disease
Guest Introduction: Dr. Andre Khalil
00:00:50
Speaker
physician.
00:00:50
Speaker
Dr. Khalil is professor in the Division of Infectious Disease and director of Transplant Infectious Disease at the University of Nebraska Medical Center.
00:00:58
Speaker
A renowned clinician, educator, and researcher, Dr. Kali has received multiple distinctions, including the 2021 Scientist Laureate Award at UNMC.
00:01:07
Speaker
Dr. Kali is an author of multiple peer-reviewed publications and is one of the co-authors of the 2023 Society of Critical Care Medicine and the Infectious Disease Society of America Guidelines for Evaluating New Fever in Adult Patients in the ICU.
Relevance of Fever Understanding in ICU
00:01:22
Speaker
Andrei, welcome to the podcast.
00:01:25
Speaker
Thanks so much, Sergio.
00:01:26
Speaker
Really a pleasure to be here.
00:01:27
Speaker
So I would like to start with asking you, why should critical care clinicians care about this clinical guideline or this topic of new fever in the ICU?
00:01:36
Speaker
Yeah, so very important question.
00:01:38
Speaker
The fever is really something that we deal pretty much every day in the ICU.
00:01:45
Speaker
And there are so many causes of fever that it becomes sometimes critical.
00:01:52
Speaker
quite complex and difficult to discern the reason for the fever and some of the reasons can be quite severe, quite serious, some of the reasons quite mild, some of the reasons can be just secondary to the natural history of some surgical procedure, but the reality is
00:02:10
Speaker
It is critical for us at the bedside to really understand the reason for the fever because that can be something quite relevant for the management and the treatment of the patient.
00:02:23
Speaker
Perfect.
00:02:24
Speaker
And I know that, as we mentioned in the intro, you've been part of the 2023 clinical guidelines, which were an update of 2008.
Defining Fever in ICU Context
00:02:31
Speaker
And I really focused on adult patients who are not immunocompromised, although I would imagine that a lot of the discussion also applies to immunocompromised patients, but that's a little bit out of the scope.
00:02:45
Speaker
But what I wanted to ask you to start the discussion is, how did you define in the guidelines fever in the ICU patient?
00:02:54
Speaker
So, you know, the definition that we use on the guideline was the temperature of 38.3 Celsius in the ICU.
00:03:03
Speaker
that that's pretty much kind of the number that has been used in a large um you know in a large historical cohorts and uh population studies uh trials but but we in the first you know in the first paragraph of this fever section of guideline we we spend a little more time trying to explain to the reader that there are nuances on this and this is really really important because
00:03:33
Speaker
As a clinician, I cannot really wait for a specific cutoff to define fever in a good number of my patients.
00:03:40
Speaker
I'll give an example.
00:03:43
Speaker
If you have a patient that is, let's say, 25 years old with meningitis, likely you're going to see a very brisk fever in
00:03:55
Speaker
in these patients, they usually have a pretty robust immunological system, inflammatory reaction, and you're going to see fever quite high, quite fast.
00:04:07
Speaker
But on the other side, if you have a patient in ICU that is, you know, 80 years old, let's say, even with meningitis, let's use the same syndrome, right, the same infectious process, it's very unlikely that the patient is going to have the same risk response as the 25-year-old, and it may take longer for the patient to develop fever, and the patient may not even develop significant fever.
00:04:31
Speaker
So the point here is that
00:04:33
Speaker
you know while we we do use the 38-3 as the usual uh fever cut off uh it you really have to individualize to your patient i'll give another example i have um a substantial number of immunocompromised patients uh solid organ transplant patients bone marrow transplant patients in which they they chronically take medications that that make the fever spike much more difficult to happen
00:05:01
Speaker
And a lot of times they know their baseline temperatures.
00:05:04
Speaker
One of the things we talked in the guideline is that if the patients already know where they live in terms of range of temperatures, that can be very helpful because sometimes just one degree above whatever baseline they live can be something quite substantial and can be defined as fever.
00:05:20
Speaker
So really try to avoid fixed cutoffs and
00:05:27
Speaker
individualize the temperature according to your patient's age, patient comorbidities, patient medications, because that's going to be way more meaningful for you to define fever than using, you know, one size fits all for, you know, certain numbers.
00:05:42
Speaker
So that's kind of the latitude that we provide in the guideline.
00:05:46
Speaker
Perfect.
00:05:46
Speaker
And I think like all guidelines, right, they're anchors, they're frameworks for us to organize our approach.
00:05:52
Speaker
But at the end of the day, we have to think of the individual patient in front of us and use our clinician hat and also understand that sometimes there are subtleties that are unique to the clinical situation that we are dealing with.
Non-Infectious Causes of Fever
00:06:06
Speaker
The second question I wanted to follow up that was, obviously, when we think of fever, most clinicians immediately jump into the thought of an infection.
00:06:17
Speaker
But in the ICU patient, there are many non-infections causes of fevers.
00:06:21
Speaker
Could you just give us maybe a quick commentary, Andre, on some of the most relevant ones that we should at least keep in the back of our mind when we're evaluating new fever in the ICU?
00:06:31
Speaker
Absolutely, Sergio.
00:06:32
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So the...
00:06:34
Speaker
You know, we tend to, when we're in medical school and in training, there is a tendency for all of us to associate fever with infection.
00:06:44
Speaker
It's almost like a knee reflex.
00:06:46
Speaker
But the reality is there are many, many causes of fever in the ICU that are not related to infection.
00:06:54
Speaker
And this is not just semantics or just like, oh, you know, just a little bit of a differential diagnosis.
00:06:59
Speaker
It is critical because some of these causes of fever actually demand, you know, a whole different diagnostic and treatment approach that can actually impact in the outcome of the patient.
00:07:12
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For instance,
00:07:13
Speaker
you can be admitted to the ICU with fever of a clear source, and it turns out that the patient, for instance, has a massive myocardial infarction.
00:07:24
Speaker
It takes a little bit sometimes for the diagnosis to be made, but you can have fever simply from the fact that the patient is getting a myocardial infarction.
00:07:35
Speaker
Sometimes patients have adrenal insufficiency that were not diagnosed before the patient comes to the ICU, and adrenal insufficiency itself
00:07:44
Speaker
We require, you know, steroids and other treatments that, you know, actually, in order to be treated, in order not only to, you know, bring the fever down, but in order to be treated.
00:07:55
Speaker
And the same with MI.
00:07:56
Speaker
I mean, you're going to treat MI with thrombolytics, whatever needs to be done.
00:08:00
Speaker
It's not going to be antibiotics.
00:08:01
Speaker
The same way patients, I mean, we see commonly patients with pancreatitis.
00:08:04
Speaker
We are a referral center for patients.
00:08:07
Speaker
liver transplant and a lot of times patients have chronic pancreatitis and sometimes end up even with a pancreatic transplantation as well and this itself can cause significant fever and sometimes it's very difficult to distinguish fever from a just an acute pancreatitis on top of chronic pancreatitis with let's say with necrotizing pancreatitis for instance another situation that's very common in the ICU
00:08:34
Speaker
We are a referral center for oncology patients and bone marrow patients, and sometimes you see patients with a tumor lysis syndrome, patients with transplant rejection, and all these things that we approach in a guideline are really important syndromic process that can cause substantial fever, can simulate infectious process, but actually require a whole different treatment approach.
00:09:02
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So,
00:09:03
Speaker
To look for non-infectious scars of fever is really important because that can change the management dramatically in order to know exactly what the patient needs.
00:09:14
Speaker
So when we see these patients at the bedside, you have to have your mind pretty open to both infectious and non-infectious sources of fever.
00:09:24
Speaker
Perfect.
Methods for Measuring Body Temperature
00:09:25
Speaker
How would you recommend or how do the guidelines recommend that we measure body temperature in critically ill patients?
00:09:33
Speaker
That was something that really took a substantial amount of time and discussion among the guideline members because it is really important to define how can we do this in a way that can be more systematic, it can be more practical, and can be available as well in the ICU.
00:09:56
Speaker
It turns out that we don't have any of the usual traditional methods that can
00:10:06
Speaker
can prove to be superior to the more rigorous methods that we've used in the past, and we don't use so much in the ICU, but that we've used in the past, for instance, with the pulmonary catheter, with bladder catheter, with esophageal probes.
00:10:21
Speaker
So all this, you know, both the bladder catheter and esophageal probes that still we have available in the ICU, so we don't use so much more of the PA catheters as we used in the past, but these really bring a much more reliable measurement of the central temperature.
00:10:35
Speaker
however um not every issue is going to have catheters uh you know probes and and and even less isofageal probes so the reality is that if by any chance the patient is does not have any kind of this more rigorous uh kind of methods then um you know the next step in terms of measuring temperature will be rectal and oral temperatures
00:11:03
Speaker
And even though both rectal and oral temperatures are not also that simple because it really, each one has its barriers.
00:11:12
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Let's say, you know, oral, if the patient's intubated or having issues related to the uropharyngeal area.
00:11:21
Speaker
And so, but we found looking into the oral evidence that rectal and oral temperatures are...
00:11:29
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more reliable than tympanic and some of these skin probes and temporal probes and so forth.
00:11:37
Speaker
So it seems that they just become a little more reliable in terms of measuring every day.
00:11:45
Speaker
The tympanic temperatures that also are used frequently
00:11:50
Speaker
in different places requires way more maintenance calibration and and actually can end up with the one to two degrees uh you know wrong uh temperature in terms of either upper or lower temperatures so the point is the reason why we didn't recommend timpanics because it seems to be way more variable and less predictable than rectal and oral temperature so
00:12:15
Speaker
That's why we, at the end, look into all the evidence.
00:12:20
Speaker
We believe that in the absence of a esophageal or bladder probe, the most reliable sites to measure are going to be oral and rectal.
00:12:32
Speaker
And this is important because whatever method you choose in the ICU,
00:12:36
Speaker
You want to make sure that you have a consistent approach, meaning that you don't want to use one method here, one method there, one method one day, one method the other day, because that's going to really make the comparison very hard.
00:12:48
Speaker
I mean, when you change the method, you change the variability.
00:12:52
Speaker
Once you change the variability, you may end up with taking action.
00:12:57
Speaker
when actually all you're seeing is the variability between the methods.
00:13:00
Speaker
So whatever method you choose, try to make sure that you have that consistently used in your ICU.
00:13:07
Speaker
And I think it's always interesting, right, like how for anything we do in medicine, there are layers of evidence and maybe not the perfect evidence, but there's always a lot to be learned.
00:13:16
Speaker
And
00:13:17
Speaker
You mentioned tympanic and maybe skin temperature, which unfortunately, because they're practical, have become widespread throughout ICUs in the country.
00:13:26
Speaker
But yet those are the least accurate, right?
00:13:29
Speaker
And I think it's important for our clinicians to understand what the evidence says regarding temperature measurement.
00:13:37
Speaker
Very important, Serge.
00:13:38
Speaker
Actually, you know, sometimes what's the most practical is not the most accurate.
00:13:43
Speaker
And this is one good example.
Empirical Antimicrobial Therapy Guidance
00:13:45
Speaker
So every time I'm on call, Andre, I will go, almost every single time I'm on call, I get a call from a nurse for a patient who has fever asking for treatment.
00:13:57
Speaker
What is the current recommendation based on the available evidence in terms of treating fever itself with antipyretic medications?
00:14:05
Speaker
So a very important question, Sergio.
00:14:09
Speaker
Generally speaking, let's say, let me divide this
00:14:15
Speaker
answer in two factors.
00:14:17
Speaker
One, if it is infection related, let's say if you think that the fever is infection related, most of the time, the vast majority of the time, fever is really a part of the immunological response to the infection.
00:14:31
Speaker
Actually, fever tends to increase the recruitment of lymphocytes, T cells, B cells, and it's part of how we defend ourselves against the infection.
00:14:41
Speaker
So,
00:14:42
Speaker
You know, low-grade fever, actually, it's something that very likely can be beneficial in most of the infectious process.
00:14:49
Speaker
The problem is when the fever starts to get to a level where it can compromise the immunodynamics of the patient.
00:14:57
Speaker
So, you know, if you're talking, let's say, in a non-infectious process, like a malignant hyperthermia,
00:15:03
Speaker
or a patient with some kind of neurological disorder that can, in which the fever can trigger seizures or something, you know, of that complexity.
00:15:12
Speaker
So these are situations where maybe, you know, it's not unreasonable for us to have a lower threshold to use antipyretics, but the guideline is,
00:15:21
Speaker
looking for most of the reasons that that cause fever and the ICU does not suggest the immediate treatment with any anti-thermic approach including antipyretics just because most of the times they will not be beneficial including patients with sepsis there were
00:15:39
Speaker
several sepsis clinical trials done in the past in the last couple of decades, working for the use of antipyretics as potentially something that could benefit the outcome and survival of these patients and didn't do anything.
00:15:53
Speaker
Actually, there are animal studies showing that actually, a brigade in the fever can potentially even be harmful.
00:16:01
Speaker
So the point is, there is really no data of benefits.
00:16:05
Speaker
There is data showing no benefits actually given antipyretics as a general rule.
00:16:11
Speaker
So I think to make the answer quite objective is that we do not recommend as a general approach the use of antipyretics, but in special situations in which
00:16:21
Speaker
the temperature can really be detrimental to the patient either because of the level of the temperature or because of the underlying disease like a neurological disease or some some a patient let's say in post cardiac arrest and situation that temperature can be detrimental then there's a situation that it is okay to use antibiotics so i think we give a little bit of this latitude to the clinician but in general uh it will not be very useful
00:16:46
Speaker
And I think that's an important point because another commonly, I think, utilized treatment in the ICU that really has no evidence and we've been just doing it because that's what we've been doing for a long time.
00:16:59
Speaker
So I think having that pause to think about it is really indicated and the situation probably will help.
00:17:07
Speaker
Just, I mean, at a very superficial level, Andre, this was not a focus of the guidelines, and then we'll go into the further evaluation, but any general comments on your standards and ID, a physician on empiric, antimicrobial, antifungal, antiviral therapy in the ICU?
00:17:25
Speaker
Obviously, like you mentioned at the beginning, not all fever is infectious, but if it is infectious and the patient's sick, probably getting the right treatment soon is very important.
00:17:36
Speaker
Yes.
00:17:37
Speaker
So one of the things that really, in my practice, I emphasize very much all my trainees and colleagues is that if I do believe that by my initial clinical assessment, the cause of the fever is infectious, it is especially if the patient is critically ill in the ICU,
00:17:59
Speaker
times of essence absolutely times of essence and and and i i believe that there's nothing uh nothing wrong and nothing risky about actually starting antimicrobials according to the history and physical examination if if you have a a good suspicion of infectious process causing the fever so i think this is really important because
00:18:24
Speaker
In the worst case scenario, if your clinical judgment is wrong and turns out that patient does not have infectious process, you can always stop antibiotics in the next 24 hours.
00:18:34
Speaker
You don't need to keep giving this for a long time.
00:18:37
Speaker
But if you are right and if your suspicion of infection is high and you're right, you really may end up not only improving the treatment of your patient, but you may end up improving the chances of surviving that.
00:18:52
Speaker
from this infection because there is plenty of data showing that in patients that are really critically ill, sick, not to infection, they can benefit from the early administration of antibiotics, especially in patients that are in septic shock.
00:19:09
Speaker
But the point is, you know, sometimes it's very hard to distinguish which patients will benefit more or less.
00:19:15
Speaker
I'll give an example.
00:19:17
Speaker
some patients that are quite immunocompromised, let's say patients that are taking, let's say, tacrolimus, myphrodic and steroids for use from a solid organ transplant.
00:19:30
Speaker
A lot of times these patients will come without a lot of symptoms of infection, but you're already in all the patients, you're already
00:19:38
Speaker
know the history of this patient's the history of infection a patient is probably having like let's say a recurrent infection of let's say a pneumonia or a uti or something that you already know the likelihood that this patient is is developing a substantial infection but the patient is not showing you know like the over clinical signs and symptoms this is the type of patient that start antibiotics early
00:20:01
Speaker
is going to be critical because these patients will crash and burn very fast if you do not start antibiotics on time especially because they're already very immune compromised so the point is again you know we have to individualize situation we have to be aggressive about starting antibiotics when they have a suspicion and we have to be aggressive about stopping antibiotics when the patient does not have infection so
00:20:25
Speaker
In my own practice, yes, if I have somebody in the ICU critically with fever and I do have a suspicion of infection, I will start empirical antibiotics until I get a better understanding of both the diagnosis and the natural history of the situation.
00:20:41
Speaker
Perfect.
00:20:42
Speaker
Let's talk about imaging studies and critically ill patients with new fever.
00:20:46
Speaker
How would you approach a patient who's been in the ICU, now has a fever?
00:20:50
Speaker
What are the imaging tests that you would order?
00:20:53
Speaker
How would you think about it?
00:20:54
Speaker
And what do the guidelines recommend?
Imaging Studies Recommendations
00:20:57
Speaker
So the guideline recommends chest X-ray as a kind of a general rule for patients with fibromyalgia and I think is reasonable because, you know, with a plain chest X-ray, you can catch the beginning of pneumonia, you can catch pleural effusions, you can catch abscess, you can catch pneumothoriasis.
00:21:16
Speaker
I mean, so many things you can diagnose with a very simple and quick image like a chest X-ray.
00:21:22
Speaker
So I think it's just reasonable to believe that
00:21:25
Speaker
chest x-rays should be part of your uh initial approach especially when you know you're just kind of first seeing the patient so i think it's very reasonable it's available it's uh it's safe you know you don't need to get the patient out of the issue they usually can do at the bedside uh so i think that's that's something that i think is quite reasonable that the guideline recommends a general now all the other image all the other image tests will depend on the history and physical examination let me give an example
00:21:55
Speaker
We suggest the addition, let's say, of ultrasounds, either, you know, either POCUS or formal ultrasounds, when there are indication of a focus of infection.
00:22:10
Speaker
For instance, if you have somebody with a
00:22:13
Speaker
abdominal pain or transaminases, elevation of transaminases, or bilirubin, or Ocfrost, or suspicion of cholecystitis, or suspicion of appendicitis.
00:22:24
Speaker
When you have somebody that really has clinical symptoms that suggest abdominal sores of the fever and potentially the sepsis, then
00:22:37
Speaker
This is a situation where images definitely can benefit to understand, you know, what is the extent of the infection and what needs to be done in terms of drainage or surgery.
00:22:48
Speaker
So that's when we recommend a
00:22:52
Speaker
the addition of ultrasounds and the addition of CT scans depends again depend on each situation I think the bedside ultrasound can be quite useful just because it is it is usually if it is available in the ICU it's right there you don't need to transport the patient to a CT scan in another part of the hospital it's less radiation so it's there's a lot of benefits of doing the bedside ultrasound and I think can be quite useful but but we do not recommend
00:23:21
Speaker
just as a, you know, doing just for doing just in case if you don't know where the fever is coming from.
00:23:28
Speaker
The guidelines recommend that you have to really have some indication that of the focus of the infection in order to maximize the yield
00:23:38
Speaker
of the ultrasound i mean i mean and you think about this is like almost every test that we do in the icu you know you have to have a little bit of a prior correct you have to have a little bit of a clinical suspicion of of the focus in order to do certain tests and and and the image is the same uh if you have um if you have a suspicion of a
00:24:00
Speaker
let's say of a respiratory infection uh and and by chest x-rays or by clinical symptoms you can go ahead and do a a bad side ultrasound of the lungs lung ultrasound you can look for brainchymal change you can look for a plurifusion so forth and it can be useful it can definitely be very useful to understand the extent of the infection of the lungs
00:24:22
Speaker
But again, the same story, what's your prior, what's your clinical suspicion?
00:24:26
Speaker
We always go back to the history and physical examination to delineate which tests are going to have the higher probability to help you to define what's happening with the patient.
00:24:37
Speaker
So we talk about bedside ultrasounds, we talked about form ultrasounds, we talked about CT scans of the chest, CT scans of the abdomen and pelvis.
00:24:48
Speaker
And when, exceptionally, again, I say exceptionally because even in my practices, rarely I would need to do that.
00:24:55
Speaker
If you reach a point where you really are struggling to find the source after, you know, extensive examination and imaging, including CT scans, potentially you can think about doing PET scans.
00:25:11
Speaker
Again, I don't think that
00:25:13
Speaker
We should be recommending PET scans as a routine in any ways and in form because it is a test that will only be helpful in very, very exceptional situations.
00:25:26
Speaker
The vast majority of the situations in the ICU will be able to make the diagnosis by clinical examination and by traditional image like x-rays, CT scans and ultrasounds.
00:25:36
Speaker
But when you're really against the wall in the situation where you don't know
00:25:41
Speaker
what's happening and you cannot find the source we recommend the PET scan as a potential tool to find you know the focus of the infection because it's a situation that really becomes quite frustrating after two days of investigation and in which the patient does not have a diagnosis but again I emphasize that this will be more the exception than the rule
00:26:11
Speaker
Perfect.
00:26:11
Speaker
And I've been in practice for many years.
00:26:14
Speaker
I'm sure I've had a couple of patients had PET scans, but I never ordered it myself.
00:26:17
Speaker
So I'm sure that by that time, I would hope that our critical care colleagues are brainstorming with our ID colleagues at the bedside, right?
00:26:26
Speaker
Right.
00:26:28
Speaker
Exactly right.
00:26:29
Speaker
I like the word brainstorming.
00:26:31
Speaker
Yeah.
Blood Cultures Collection Guidelines
00:26:33
Speaker
So let's talk about blood cultures in the critically ill patient with fever.
00:26:36
Speaker
First, if you could just tell us what the current recommendation is in terms of how many blood cultures, how much blood and the timing of that.
00:26:44
Speaker
And then I would like to hear your comments on what do we do or don't do when there's a central venous catheter in place.
00:26:51
Speaker
Yeah, Sergio, this is really important because I've had a few messages from friends and calls from friends after the deadline was published about this as well.
00:27:00
Speaker
And as you know, through the years, you know, most hospitals and ICUs learn to minimize the kind of the
00:27:13
Speaker
you know, the kind of the systematic collection of central line cultures for any reason, because, you know, at the end, when you see a lot of studies have shown the amount of blood cultures contamination from central lines, and sometimes people end up getting over-treated with unnecessary antibiotics, and
00:27:32
Speaker
So, you know, a lot of places now have rules and electronic records, basically.
00:27:40
Speaker
When you order these cultures, a lot of places automatically go to peripheral cultures to avoid the collection of central lines.
00:27:47
Speaker
And the idea here is to minimize the contamination.
00:27:50
Speaker
So this is, you know, I understand why this has been done.
00:27:54
Speaker
in many, many places as part of controlling the unnecessary use of antibiotics for contaminated cultures.
00:28:02
Speaker
But I wanted people to understand that our guideline is dealing with a different patient population.
00:28:06
Speaker
This is not everyone in the hospital that is, you know, is not very ill or has some fever or has a reason to have a culture.
00:28:14
Speaker
This is a patient that is critically ill, requires an ICU bed,
00:28:20
Speaker
has fever, and this is really important because this is not the same as a patient that's in the ward, very stable, that still has other reasons to have fever or infection.
00:28:35
Speaker
So in a patient that is in the ICU, is critically ill, has fever, and if the patient has a central line and you don't know the reason why the patient has a fever,
00:28:47
Speaker
that's a situation where you have to you have to you know literally sit with the your whole team sit with the nurses and the clinicians and the trainees everyone said listen this is a situation where i need a collection of blood from the central line and i need a collection of blood from the peripheral from a peripheral vein i need both at the same time because i want to know if by any chance the cause of this fever is kind
00:29:16
Speaker
coming from a central line infection.
00:29:19
Speaker
This is really, really important because a lot of our patients in the ICU, not only sometimes they have lines placed in the ICU, but sometimes they have lines placed outside the ICU for a long time.
00:29:31
Speaker
I have patients come to the ICU with
00:29:33
Speaker
you know, dialysis catheters with central line catheters for other reasons.
00:29:37
Speaker
They're getting fusion chemotherapy, and a lot of times they have these lines for weeks, sometimes for months, for a long time, sometimes they're in the wards for a few weeks.
00:29:45
Speaker
So the fact that the patient has a central line, the fact that you don't know what's causing a fever should be a big trigger for you to say, you know what, I have to collect blood from the central line and from the peripheral veins, because that's going to give you a sense of what's happening.
00:30:00
Speaker
The reason why we do that is because
00:30:03
Speaker
We already know that if you have a differential time of two hours or more between the culture positive in the peripheral vein versus the culture positive in the central line, that's going to be highly indicated that the patient has a central line infection and likely the central line will eventually have to be removed, especially if the patient is getting cracoling.
00:30:26
Speaker
So this is really important.
00:30:29
Speaker
The other thing I want to mention, Sergei, is that if you're going to collect blood from the central line, the guideline recommends at least two lumens, two lumens from the central line.
00:30:39
Speaker
A lot of the central lines have two lumens, three lumens or more.
00:30:43
Speaker
And the reason why is because if you collect at least from two lumens, you're going to increase the yield.
00:30:49
Speaker
of catching an infection that is contaminating or infecting the scatter.
00:30:55
Speaker
So it is important to make sure that you get this procedure done.
00:31:00
Speaker
The last thing I want to mention about the blood cultures that's important is the yield of the blood cultures, whatever blood cultures you do, whatever place you do, is very, very proportionally related to the amount of blood that's collected.
00:31:15
Speaker
So if the amount of bloods collected is too small, you may end up with a false negative blood cloture when the patient is really getting septic and bacteremic.
00:31:24
Speaker
So you don't want to get into the situation.
00:31:25
Speaker
You really want to catch these bugs if they are in the bloodstream.
00:31:28
Speaker
So you want to at least put the minimum of 10 mLs in each bottle of these blood clotures.
00:31:33
Speaker
The way the guideline recommends is that you can collect...
00:31:38
Speaker
uh two bottles of for aerobic culture one bottle for neurobiotic culture so three bottles for each site let's say two bottles from for the central line three bottles for the peripheral vein culture and it's going to be 10 ml in each it's going to be about a total of 60 mls this is really important because if you if you skimp in the in the amount of blood you're collecting you may end up with a false negative culture that can be quite detrimental to the approach to the treatment approach to the patients so these are kind of the uh
00:32:08
Speaker
the general approach that the guidelines recommend for these blood cultures.
00:32:13
Speaker
And like you mentioned, I think this is an important aspect of care for practical reasons, but also with our emphasis on trying to reduce catheter-associated bloodstream infections, I think people have sometimes gone too far in terms of not checking cultures.
00:32:30
Speaker
And when the clinical situation merits, we should do what's best for the patient.
00:32:35
Speaker
And understanding where that infection is coming from obviously is very, very important.
00:32:40
Speaker
And I think that time to positivity is something that people need to take into account and make sure that, like you mentioned, Andre, that we are measuring from more than one lumen in the central line when suspected and getting also a peripheral one at the same time and using that time to positivity to try to figure out if it's the central line or not.
Urine Cultures Collection Recommendations
00:33:00
Speaker
And then, Sergio, if you allow me, just one thing that I want to re-emphasize.
00:33:04
Speaker
I'm sure that all of us working at SU, we've read the sepsis guidelines and other guidelines, but just emphasize again and repeat again that
00:33:13
Speaker
Ideally, these cultures should be collected right before the antibiotics are being started.
00:33:19
Speaker
So you don't want to delay for any minutes the administration of antibiotics.
00:33:23
Speaker
But we all know it takes time between putting the order again, the pharmacy to mix the antibiotics and bring to the ICU.
00:33:30
Speaker
That's the time to do blood cultures.
00:33:32
Speaker
The yield of getting a blood culture positive will be tremendously increased if they are collected before the initiation of antibiotics.
00:33:39
Speaker
So that's something that should be a really big effort in all ICUs.
00:33:43
Speaker
Perfect.
00:33:44
Speaker
On the same note, I guess, similar dynamic, when and how should we get urine cultures?
00:33:52
Speaker
Yeah, that really becomes a little more complex than blood cultures because the problem with the urine cultures is that they tend to really, you know, be a little more difficult to really interpret because there is a...
00:34:08
Speaker
a very common process for contamination of urine, especially in the ICU, because a lot of patients are going to be human-animally unstable, requiring folic catheters, and it becomes very difficult sometimes to collect a specimen, a urinary specimen, that can provide a reliable result.
00:34:28
Speaker
So the recommendation that we make in the guidelines is that
00:34:34
Speaker
uh the urine really has to have uh you know pyuria the patient has to have symptoms uh and and the collection has to be really as as sterile as possible and and that includes
00:34:47
Speaker
patients that already have a folic catheter and in the vast majority of the time is when patients develop fever in the ICU they already have a folic catheter either because before they came to the ICU or a few days before you are seeing a patient and if the folic catheter is really sitting there you basically the way that you want to do if you really are concerned about the urinary infection
00:35:12
Speaker
you're going to have to remove this folic catheter, put another folic catheter if the patient really needs, and collect urine from a fresh catheter.
00:35:20
Speaker
This is going to really make your collection much more reliable.
00:35:26
Speaker
and much more informative in terms of what to do with these results.
00:35:32
Speaker
If the patient has any history of UTIs, any history of lithiasis, hydronephrosis, pyelonephritis, anything that's suggestive of UTI, and now you're collecting a sterile urine with a pyuria,
00:35:49
Speaker
that's going to be a urine that really is going to go for culture, for urine cultures, and is going to have a good yield to bring pathogens that need to be treated.
00:35:59
Speaker
So the key point is,
00:36:01
Speaker
we recommend not collecting urine from patients that already have any urinary catheter in place because at that point, when the catheter is staying there, the chances of contaminations are too high and you may end up treating the patient for a culture positive that has nothing to do with the fever, has nothing to do with what's happening.
00:36:23
Speaker
You may end up exposing a patient to unnecessary antibiotics when the patient needs another treatment approach.
00:36:28
Speaker
So this is...
00:36:30
Speaker
This is something that we emphasize very much in the guideline.
00:36:34
Speaker
Perfect.
Viral Pathogens Testing Guidelines
00:36:35
Speaker
And as we move forward, what would be the recommendation on testing for viral pathogens?
00:36:41
Speaker
Obviously, we're in the winter, respiratory season's around.
00:36:47
Speaker
Coming out of COVID-19 pandemic, COVID's still around.
00:36:50
Speaker
I have definitely diagnosed COVID in some of my patients in the ICU after several days.
00:36:54
Speaker
But what's the current recommendation on viral pathogens?
00:36:58
Speaker
So they are quite useful in general because, you know, both the nasal swab and the pneumonia panel from the sputum, both of them, they add a little bit of different information, but complementary information.
00:37:11
Speaker
So for either patients that are intubated or not intubated, if you have...
00:37:17
Speaker
a patient with respiratory symptoms, signs and symptoms, definitely it's something quite useful to do because you can not only diagnose a potential pathogen that is causing the symptoms, but also you can define if the patient's going to need antibiotics or not, correct?
00:37:37
Speaker
So, for instance,
00:37:39
Speaker
You know, I see now, just the last few weeks, I was in service, I've seen patients with, in the ICU with the Vinovirus, Perinfluenza 1, Perinfluenza 3, Metanomavirus, RSV.
00:37:49
Speaker
I mean, I've seen almost all respiratory viruses in the last few weeks, and the winter is just beginning.
00:37:57
Speaker
So these are really important because some of these viruses have specific antiviral treatment, some don't.
00:38:04
Speaker
And knowing which virus are infecting the patient, bringing the patient in ICU, are going to be really important because that's going to change our management.
00:38:11
Speaker
The other thing that I want to mention, Serge, that's very important is not only it's very easy and you're going to have the results in one or two hours, but also it's very important to...
00:38:22
Speaker
to not forget that patients can have a positive, you know, viral pathogen, you know, in a panel, and the patient could have also a bacterial pathogen that, I'll give an example, I...
00:38:39
Speaker
I have a patient that last week, that the patient had a rhinovirus, and it turned out that the patient, the panel just showed rhinovirus, and the patient is quite ill, developed respiratory failure, ended up needing to be intubated, and it turns out that after the intubation with the tracheaspirate,
00:39:03
Speaker
the pneumonia panel showed a staphylococcus aureus and the coach also showed a staphylococcus aureus.
00:39:08
Speaker
So the point is when the patient was being seen outside the hospital, it was all rhinovirus infection, came here to the hospital, was diagnosed with rhinovirus infection, progressed to a bacterial infection and ended up with a staphylococcus pneumonia.
00:39:23
Speaker
So why this is important is because the
00:39:27
Speaker
We cannot forget that a lot of times in the ICU, we're going to see patients with co-infections.
00:39:33
Speaker
They don't need to be even immunocompromised.
00:39:34
Speaker
They can be immunocompromised or not, but about, you know, up to a third of the patients that have CAP, they have co-infections with, you know, between virus and bacteria.
00:39:44
Speaker
So that's something that I want to make sure that people understand.
00:39:47
Speaker
The panel is going to be very important to define what kind of pathogens are potentially causing infection, but the panel will not define the entire history.
00:39:59
Speaker
is progressing, if the patient has a viral pathogen that is progressing to a worse disease, it could be progression from the viral disease, like COVID, could be a progression to a severe COVID, but could be a progression to a bacterial infection as well.
00:40:11
Speaker
So it's very important to keep that kind of diagnostic approach always up 24-7 to make sure that you understand if the progression of respiratory failure is secondary to the natural history of the virus or it is secondary to a
00:40:28
Speaker
post-viral bacterial infection.
00:40:30
Speaker
All these things have to be evaluated day by day on real time to our patients.
00:40:36
Speaker
Perfect.
Role of Biomarkers in Infection Assessment
00:40:37
Speaker
And what about in closing the role of rapid biomarker tests like PCT and CRP?
00:40:45
Speaker
So PCT and CRP, the way the guideline dealt with was the following.
00:40:51
Speaker
We recommend that if you have a low probability of infection based on your history and physical examination, you just kind of don't know what's happening, you don't find what's happening, but patients still have fever in the ICU,
00:41:08
Speaker
it is reasonable to check either ProCal or CRP, either one or both, whatever you have in your hospital.
00:41:16
Speaker
Each hospital has different laboratory measurements, but it's reasonable because you're a little bit lost in what's happening.
00:41:23
Speaker
The patient's having fever.
00:41:26
Speaker
to do these biomarkers.
00:41:27
Speaker
One is because if the biomarker comes quite elevated, it really is going to trigger you a more aggressive approach looking for infection, looking for what's happening with this patient, because even though the history and physical are not that impressive, now you end up, let's say, with a very high risk
00:41:50
Speaker
PCT or CRP that's going to trigger you to think okay am I missing something what's happening here the other reason for doing that is because you know once you get to biomarkers and a lot of times when you get called to these patients the patient's already getting a couple of antibiotics let's say it turns out that the PCT and the CRP are you know normal like zero zero five whatever level whatever whatever normal is in your lab it's really normal there's nothing you repeat next day still normal
00:42:16
Speaker
So, you know, now you start to see that you don't find a focus of infection, the patient's doing well, and the biomarkers are completely normal, even, you know, when you measure sequentially.
00:42:27
Speaker
Well, that's a situation where you can say, well, you know what, I think it's time to de-escalate antibiotics because I'm not seeing an infection source of fever.
00:42:34
Speaker
So these are the kind of the situations where the biomarkers can help.
00:42:39
Speaker
But I think really important, Sergio, that I want to mention here too, that we...
00:42:44
Speaker
we discussed as well in the HAPFAP guideline in the past, is that these biomarkers, they alone, they are not sufficient to rule out infection.
00:42:55
Speaker
Let me tell you one example.
00:42:56
Speaker
You have somebody with a high suspicion of infection.
00:43:00
Speaker
This is what the guideline says.
00:43:01
Speaker
This guideline says, let's say you have somebody with a high suspicion of infection.
00:43:04
Speaker
You really think the patient has infection causing a fever.
00:43:07
Speaker
If the ProCal or the CRP becomes normal,
00:43:10
Speaker
really, it should not change your management.
00:43:13
Speaker
The biomarker being normal initially should not change your management.
00:43:17
Speaker
Meaning that if you think the patient has an infection causing a fever and a critically ill situation, you give the antibiotics, you treat the patient independent of these biomarkers because the biomarkers
00:43:29
Speaker
can take a while sometimes to go up, sometimes they don't work very much.
00:43:32
Speaker
So the point is, they are not good for you to really rule out the infection, but they are good for you to understand what's happening with the patient in terms of a need for antibiotics in the next couple of days.
00:43:42
Speaker
They can help you to complement when you have a low suspicion and you don't know what's happening with the patient, but they rule along
00:43:50
Speaker
never be decisive about what needs to be done.
00:43:53
Speaker
Remember, biomarkers are only complementary and you have to take with a grain of salt because, again, your clinical assessment, your physical examination will be critical.
00:44:04
Speaker
And if you have a high suspicion of infection, these biomarkers are not going to be very useful because you already know that patient has infection.
00:44:09
Speaker
There's nothing that you're going to gain at that point in terms of diagnostics.
00:44:12
Speaker
That's why we do not recommend biomarkers for patients that you already know that have infection source for the fever.
00:44:19
Speaker
And I think it's very similar to how you might use D-dimers in the ED to rule out low suspicion PE, but it's not something very useful when you have a high suspicion.
00:44:31
Speaker
And I think it, like you mentioned, probabilities-based theorem applies everywhere in medicine, and using that appropriately is very important.
00:44:42
Speaker
Andrรฉ, really a lot of very, I think, practical, evidence-based pearls here that apply to daily situations in our ICU.
00:44:52
Speaker
So almost every day, I would imagine, at every one of our ICUs, there's somebody with a fever.
00:44:57
Speaker
And how to...
00:45:00
Speaker
follow up on that, how to approach those patients, I think is very important.
00:45:04
Speaker
These guidelines are a great tool for our clinicians, and we'll link them, obviously, in the previous guidelines in the show notes.
00:45:12
Speaker
As we close, Andre, we like to tap into the wisdom of our guests outside of the clinical topic with a couple of questions.
00:45:19
Speaker
Would that be okay?
00:45:20
Speaker
Absolutely.
00:45:21
Speaker
So the first question relates to books.
00:45:23
Speaker
Are there any books that have influenced you significantly or that you have gifted often to others?
00:45:30
Speaker
So there's so many books.
00:45:31
Speaker
It's a tough question always, Sergio, because, you know, we like so many different things.
00:45:36
Speaker
But I would say that there's one book that really was very impactful to me many years ago.
00:45:44
Speaker
It's already a little old, like in early 2000, but it's just absolutely fantastic book.
00:45:49
Speaker
It's a book titled Splendid Solution.
00:45:53
Speaker
by Jeffrey Kluger.
00:45:55
Speaker
Basically, the book is about Jonas Salk and the conquest of polio.
00:45:59
Speaker
And the reason why this book is so phenomenal to me is because it shows the struggles and the barriers and all the efforts that Jonas Salk went through to develop the polio vaccine.
00:46:16
Speaker
And this is really remarkable because we are talking about 1950s,
00:46:21
Speaker
And everything you're going to read in this book is applicable to 2023.
00:46:26
Speaker
Basically, Jonas Salk believed that the vaccine he developed was an inactivated polyvacin really would be effective.
00:46:34
Speaker
And he went against a lot of people that thought that this vaccine wouldn't work or potentially could be even harmful.
00:46:41
Speaker
And why this is important?
00:46:42
Speaker
Because Jonas Salk being in the middle of a horrendous
00:46:46
Speaker
polio epidemic in the US, was able to do a clinical trial that had hidden placebo arm that changed the history of the world.
00:46:58
Speaker
Jonas Salk clinical trial, it was a randomized trial that really changed everything that we do today.
00:47:06
Speaker
I mean, without the polio trial, unlikely we would be developing so fast what happened during the COVID pandemic with the new vaccines.
00:47:16
Speaker
vaccine trials require randomization, vaccine trials require placebo, and that's really what was done in the 1950s.
00:47:23
Speaker
It was basically the very first vaccine trial done with so much rigor.
00:47:29
Speaker
And that book, to me, is a book that should be probably part of medical school's curriculum all over the world.
00:47:37
Speaker
Excellent.
00:47:38
Speaker
And I think, like you said, very timely to what we've lived recently, but also good science, right?
00:47:44
Speaker
It transcends the years.
00:47:46
Speaker
And when you said it's an old book, you reminded me of my grandfather who instilled, I mean, a love to read in myself.
00:47:54
Speaker
And he would always tell me that old books are good because only the good ones get to be old, right?
00:47:59
Speaker
So he would say that in Italian, but I think that that is very true.
00:48:04
Speaker
Yeah.
00:48:07
Speaker
So the second question is something that you believe to be true in medicine or life that most other people don't believe or don't act like they believe.
00:48:16
Speaker
That's, that's, that's great, Serge.
00:48:17
Speaker
So what I would say is that, um,
00:48:20
Speaker
you know, I proud myself to being really, you know, a clinician that really does everything possible and possible for my patients.
00:48:30
Speaker
I really, you know, I just love being at a bedside and seeing my patients improving.
00:48:37
Speaker
And I think that's the lesson that I've
00:48:40
Speaker
learned through all these years is that being humble is really critical for us.
00:48:45
Speaker
What I mean being humble is we have to understand our limitations.
00:48:49
Speaker
We have to accept our limitations.
00:48:51
Speaker
We have to accept the uncertainty of medicine.
00:48:55
Speaker
If you do not accept the uncertainty, likely you're going to end up not really treating well your patients.
00:49:03
Speaker
And the reason why I say that is because the moment that we accept our limitations, the moment we accept that medicine has uncertainty, we have to deal with uncertainty.
00:49:14
Speaker
You're going to look for the best that can be done for your patient.
00:49:17
Speaker
You're going to still be thinking, what else can I do to improve the care of my patient?
00:49:22
Speaker
And the guidelines, like clinical trials, all they do is they minimize the uncertainty of the medical knowledge, the medical evidence correct.
00:49:30
Speaker
So what the guidelines do is they minimize uncertainty, but they don't remove the uncertainty.
00:49:34
Speaker
The same with clinical trials.
00:49:35
Speaker
So our job at the bedside...
00:49:38
Speaker
is to translate what we see in the randomized trials, what we see in the guidelines to our patients.
00:49:43
Speaker
In order to make this translation, in order to apply this evidence, we have to understand the uncertainty, we have to understand the limitations of the data, we have to understand the limitations that we have at the bedside, and really invest in trying to really discover and
00:50:00
Speaker
and improve the care for our patients by accepting that uncertainty exists and that's part of how we can really do better at the bedside.
00:50:10
Speaker
So I think being humble and understanding that we have much to improve, much to do for our patients is critical for us to really do better at the bedside.
00:50:21
Speaker
Andre, I think that's a perfect place to stop.
00:50:24
Speaker
I really want to thank you for sharing your expertise and your time with us and for being part of these guidelines that, like you said, are important in decreasing the uncertainty at the bedside.
00:50:34
Speaker
But I agree 100%.
00:50:37
Speaker
Humility is probably the number one attribute that a scientist and a physician should have at the bedside.
00:50:46
Speaker
Thanks so much for this great conversation, Sarge, and congratulations on the podcast.
00:50:50
Speaker
I really enjoyed it very much.
00:50:52
Speaker
Thank you.
00:50:54
Speaker
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00:50:58
Speaker
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00:51:04
Speaker
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00:51:08
Speaker
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