Lung Ultrasound Day for Internists 2015: ASMIQ/CCUS, Montreal, May 29th 2015.

In collaboration with the Quebec Association of Internal Medicine Specialists (ASMIQ), and featuring none other than Dr. Daniel Lichtenstein (the original pioneer of bedside ultrasound and the first to truly do and develop lung ultrasound), we’ve put together a really good day of lectures and workshops. As a bonus, my good friend Dr. Haney Mallemat (@criticalcarenow) will be giving us a hand with workshops and maybe even a special lecture! Take a look:

ASMIQ 2015 Lung US Program

This takes place in Montreal, at Santa Cabrini Hospital, and places are limited, so anyone interested should register promptly at http://www.asmiq.org.

Do note that most lectures will be in french!

thanks,

 

Philippe

The Great Septic Debate: Science vs Science (Part 1), by Dr. Lawrence Lynn and Dr. Steven Q. Simpson, #FOAMed, #FOAMcc

So after I put up Lawrence’s comment as a standalone post, a rapid-fire exchange began between him and Dr. Steven Q. Simpson, who is another one of these really bright guys I’ve had the pleasure of interacting with on the FOAMsphere.  I thoroughly enjoyed their debate and most definitely think there is a lot to gain from listening to both of their points of view. So if anyone missed it, go back to my last post a few days ago and catch Lawrence’s opening punch, and without further a due,  here is Steven’s counter:

These arguments are well intentioned, but they are, in my opinion, off the mark on a couple of levels.

First, the “N of 1” notion. If this were REALLY true, then we could toss out the collective knowledge of patient care that we have garnered through a lifetime of our own experience, not to mention the experience of others. Why would I use antibiotics in THIS infected patient if the experience of “most” patients is of no use to me or my patient? You may protest that this isn’t what was meant by the proposition. The collective experience of “most” patients with antibiotics seems too obvious for us to ignore. And the notion is too compelling – if you can kill bacteria in “most” patients, why not in this one?

Yes, this feels to you as a reductio ad absurdum argument. But I say this – if the “N of 1” argument has legs, then it should stand up across the board, for all clinical circumstances – or, at least for most. I can easily dream up an infinite number of clinical circumstances where this “each patient is an individual and will behave differently from most patients” argument falls down. So can you. Frankly, the entire argument isn’t even actually trying to achieve N=1. Do you not seek to define a phenotype, so that those with that phenotype will be treated in one way or another? Everyone? Or only some? Why define a phenotype, unless those who have it can be expected to behave in one way or another with some form of treatment? Why have the biological sciences at all, if we cannot from them derive some truths that are universal?

We will use antibiotics in this patient precisely because science tells us that a combination of them is highly likely to kill some combination of bacteria, and because the collective experience of the literature, our teachers, and ourselves tells us that this patient stands a high likelihood of responding like “most” patients. In truth, I typically see the “N of 1” argument trotted out when the arguer simply doesn’t like the opposing argument, which is illustrated by your post. In this case, the opposing argument is that the currently accepted definition of sepsis has substantive meaning, and that it is something more than a guess.

Ok, gotta chime in. The N=1 is, to me, undeniable and cannot be circumvented. Although I understand the necessity for trials, the data cannot be blindly extrapolated to all patients, but rather should represent a step forward, a proof of concept perhaps, another little brick in our understanding. The issue is just at which level one is looking. I fail to see how one has to throw away any accumulated knowledge – if anything some of that knowledge should point to N=1 cases rather than away from it.  How can we on one hand acknowledge the vast variation of organ functions, system responses, etc, and imagine that one shoe could fit all in the best possible fashion?  Antibiotics? No argument at that level, but the N=1 may apply at the level of the dose. We routinely give the same dose to a range of patients, some of which we weight base, some we base on creatinine, but a fair bit of evidence has come around recently to suggest that, paticularly in young and (previously) healthy patients, they may have increased clearance in certain phases of sepsis and that if we were to look at serum levels, we are actually under-dosing.  Serum level-based dosing is coming. But ceftriaxone 1g q24h for everyone may not be best for all, even if it is best for most, and waayy better than no ceftriaxone at all. A great lecture by Jeff Lipman on ICN can be found here:  http://intensivecarenetwork.com/pharmacokinetics-critically-ill/

The author who calls our working definitions of sepsis, severe sepsis, and septic shock a “guess” simply does not have a long enough memory. I, myself, have vivid memories of the patient who set my career on a whole different path, the patient for whom I first asked myself, “Does this man have sepsis?” It was October of my internship, 1983, and I was called to the CCU to evaluate a man who was febrile, tachycardic, tachypneic, and with altered mental status. It was the CCU, so I first checked physical exam, EKG, and cardiac enzymes. Nothing. I called my supervising resident to come, and I asked him, “Do you think this is sepsis?” To which he replied, “I don’t know, maybe, what makes you say that?” I didn’t have a real answer, but it didn’t take long in the library for me to figure out that no one else did, either. The best definitions of the time suggested a need for demonstrated bacteremia. That seemed a bit wrong to me, because it seemed silly to wait for 24 hours or more to prove that before initiating treatment. Luckily for me, it also seemed wrong to a man who had previously been an assistant professor at my own institution (the University of Kansas), Roger Bone. It seems that, beginning in the late 1970’s, while working at KU, he had proposed a syndromic definition of the condition and had set about determining whether his definition had some validity. In 1983 he had not published that, yet. But, by the time I was his fellow at Rush he had evaluated his definitions, risk-stratified patients according to them, and used them to study therapeutic strategies. It was on the basis of his investigations that the critical care community found our current working definitions to be preferable to older definitions and published them in 1992.

“Not enough”, you may say. Roger would agree with you, and so do I. Even in the late 1980’s he was looking for better ways to characterize patients with severe sepsis, and so were those of us who worked with him. The initial segment of my academic career was spent in characterizing the TNF response to gram negative and gram positive bacteria and in determining whether patients’ responses could be phenotyped on that basis. Were he alive now, Roger would applaud any and all attempts to better stratify on his definitions, or even to replace them. As long as the replacements are characterized, tested, and demonstrated to have meaning and efficacy. Until now, there are few phenotypes characterized, and none has jumped the hurdles of prospective efficacy testing. Many involve laboratory testing that is simply not available to the average intensivist. Ideas abound, and attempts to test them abound. Your post sounds as if there are no attempts being made to replace what we have, but the attempts are there. They just haven’t jumped all the hurdles, yet. I agree, though, we must keep trying.

I want to take a moment to mock myself. One of the reasons I deplored rheumatology as a specialty during my residency was the absolute reliance on syndromic definitions. But it wasn’t just that. It seems that a rheumatologist can just set aside whatever portion of the definition that he or she doesn’t like. ANA negative lupus? What are you talking about? Either it is or it isn’t caused by antibodies to DNA, right? Or, if the syndrome “overlaps” we have mixed connective tissue disease. Yes, they have made some progress through the years. We know that this or that antibody is “more likely” to be associated with this or that disease. Or this or that gene mutation. But we are rather mushy all around in our definitions of diseases as syndromes. Sound at all familiar? It is beyond me why it drives me crazy in rheumatology, but in critical care I have some equanimity about it. Perhaps it is because it all plays out much faster in the ICU. I don’t know.

Meanwhile, if you think that where we are with diagnosing severe sepsis now is a guess, then you have not been out of your ivory tower in awhile. I have spent the better part of the last decade attempting to teach people in hospitals across the nation, but especially in my own state, that these definitions have some meaning. Teaching them that one does not have to wait until shock is present to get aggressive. Coercing them to collect data on whether they are recognizing, whether they are treating, whether they are effecting better outcomes. I can assure you that the data collected show this: without organized efforts they do not recognize, nor treat aggressively, while with organized efforts they recognize better, treat better, and save more lives. In my own institution, the mortality rate for severe sepsis, which sat at 49% in 2004, was down to 9% in 2014. With effort, with constant training, and with vigilance. All while using the SAME “guess” at diagnosis. Meanwhile, it remains a hard sell to hospitals across the nation. Do not believe for an instant that what you know about sepsis translates to the average hospital in this nation or this continent. Yet, they grasp at every argument made by academic skeptics who rail against the “confines of a bad definition” and “the limits placed on us by protocols” to illustrate why they don’t need any particular efforts in their own locale.

The people who will achieve recognition at the upcoming SCCM meeting have understood something that is missing from the arguments in your blog post – that the perfect is the enemy of the good. Had they pitched in trying to find a perfect phenotype to attack, they may have been successful by now. I doubt it, because they have, in fact, continued the search for better phenotypes, along with their current treatment endeavors. But even if they had found the perfect phenotype after all these years, they would have left tens, if not hundreds of thousands of patients dying. Since we are, after all, in the business of saving lives, we must not allow the search for the perfect phenotype to be at odds with our best possible use of what we currently know. What if the American people had said to Henry Ford, “We don’t want your stupid black Tin Lizzy. When you’ve got air conditioning, quadrophonic sound, heated seats, rear cameras, adjustable wipers – hell, when you’ve got a car that will drive itself – then come back and talk to us. We don’t want anything, until we’ve got everything”? What would we be driving now? Horses? Who knows? Our current diagnostic criteria and therapeutic approaches may be Tin Lizzies, but they are helping to save lives far better than the previous horses. And, by the way, the ideas promoted by these people are only just now seeping into the establishment. It is actually the establishment that has resisted most the idea that we should make hay with what we have, rather than watching septic people die while we work on finding just the right phenotype.

Ok, gotta give a thumbs up for Steven here, I think this is a great point. The quest for perfection, in science as much as in life, is an antidote for happiness, or good, in most cases, and that those things which are discovered along the way which are good should not be discarded because they are not perfect.  They should represent something to use until something better comes along, and often we may need that footing to get to the next level. There is in my mind absolutely no doubt that EGDT and the Surviving Sepsis Campaign has saved lives, both by detection/awareness and by promoting some therapy and vigilance. This is a massive accomplishment, period.

Another stop for self mockery. I’d be wealthy man if I had a nickel for every time someone heard me say, “If we’d spent the billions of dollars that have been used to set up an organ procurement system and improving allograft transplants on actually developing artificial organs, we’d have had them by now, and all of this other stuff would go by the wayside.” I guess we all have our axes to grind, eh?

We all dream of a day when a stat test can give us the phenotype/genotype information to individually tailor our treatment. Many people, including myself, are constantly evaluating how to get us there. But it serves no purpose to denigrate the activities of the realists, also including myself, who take the very best info we currently have and attempt every day to make the very most of it.

Steven Q Simpson.

Well, it didn’t stop there: Lawrence replies…

You make many excellent points in your courageous defense of present sepsis science. No one else has the courage to defend it. I respect much of what you have said and no one can argue that the SSC and individuals like you have made a important difference. Those of you who have dedicated your lives to improving sepsis awareness warrant tremendous respect.

However, it is clear you misunderstand. We are not critical of the sepsis awareness efforts, nor do we doubt that this has had a positive impact.. This is about science, not paternal expediency. Perhaps it was expedient in the past to control the science but now it is time to do real science, studying real “true states”, and generating real statistics.

Our problem is not with SSC public health efforts, we applaud them. Our problem is with confusing the simple guesses of the 1980s for the “true state” of sepsis and septic shock and applying statistics and drawing broad conclusions about “sepsis” when the results really only relate to a group defined by the guess and not a specific clinical condition.. That is pathologic science which has not, and will not, render reproducible results.

You say the sepsis criteria were derived from data? Where is that published? Was a band count of 10, a HR of 100-10, and a SBP of 100-10 and a RR of 2 times 10 derived from data? The first step to reform of sepsis science is to present the data so we can examine its validity or to admit, in open forum, that they were guessed.

This is also about transparency of clinical trails. In the discussion section of any trial, the important limitations of the trial should be identified. Yet, in not a single sepsis trial in 25 years was the limitation of using guessed criteria (or simple static thresholds for a dynamic relational condition) as the “true state” mentioned. Nor was it mentioned that a different set of guessed criteria might have rendered different results for the trial. Whether that ubiquitous omission, which pervades the entire standard science of sepsis, is due to expediency or because the researchers have fooled themselves into believing their own guesses were gold standards is impossible to tell.

We also fool students when we give too much decision weight to static thresholds and this can cause harm. A patient with a WBC of 11, 9% bands, and a platelet count of 120 may be profoundly ill. with advanced sepsis. Static thresholds can provide a false sense of security. When such data fragments are promulgated from a central authority to ne trusted and relied upon for critical decision making and applied without an understanding of the physiology and the dynamic relational patterns of unexpected death, this may harm as many patients as are helped.

This is discussed in http://www.ncbi.nlm.nih.gov/pubmed/21314935
This article shows how well meaning, paternal oversimplification can be a pitfall.

Here is a solution:

First: SCCM needs a formal declaration of Glasnost. Allow scientist to openly call for reform of sepsis science without begin labeled as “academic skeptics” for not promulgating the failing dogma. Why do you think everyone stays silent, the young academics cannot risk being called an “academic skeptic” by the thought leaders. You make my point when you attempt to bring that hammer down on me in the end of your argument..

It is ironic to be called an “academic skeptic” by those who, argue for “science” as a function of paternal and utilitarian pragmatism . Using guesses as the true state because it is perceived as pragmatic is not academic, its pathologic science (as described by Langmuir) and generally occurs because good scientists have fooled themselves or are acting under social forces and political expediency..

Here I have to speak to all the young readers. Do not be afraid to be called an academic skeptic or “denier”.. Do not be afraid to speak out against dogma. Popper identifies volitional falsification as a manifestation of a true scientist and so it is. However, Kuhn points out that thought leaders will not abandon their dogma despite falsification.. He points out that that is where Popper’s idealized concept (of science as progressing though events of falsification) fails. Thought leaders will ignore results which falsify their own dogma (even on the 25th anniversary of the failed dogma).

As a matter of fact, be afraid of accomplishing nothing if you are not willing to take risk and speak up and challenge your mentors at the most fundamental level. If he or she does not like that, find a new mentor. Remember that when the dogma fails, and a the scientific paradigm shifts, the thought leaders will scurry to the new paradigm with the same zeal which they employed to protect the old one.

Second: Continue the sepsis awareness process . (Do not worry, Glasnost will not derail those efforts.) Provide awareness along with more advanced education about the dynamic relational patterns of the lab and vitals in sepsis (Teach nurses the type I pattern of death rather than placing reliance on a WBC of 12). For example we should teach that the WBC often falls to normal in sepsis after it rises and that while WBC is useful, reliance on any WBC or band threshold is a pitfall.

Third: Determine the phenotypes of sepsis with a large clinical trail which collects all the data. What are the different dynamic relational patterns of sepsis. These are the signatures of the different phenotypes of sepsis. The sub sets of the patterns of sepsis death.

This, to me, is huge. This is the era of big data, and we need to have huge amounts of it to pore through and begin to see patterns and associations that were not necessarily (and arbitrarily) pre-determined.  One of these, for instance, that (due to the difficulty in obtaining the data) is never taken into account is the phase of sepsis. No patient presents at Time 0.  They have all waited a variable amount of time, and their individual rate of progression through the stages likely varies. Hence, treatment may vary also. Degree of capillary leak? This in turn may depend on the particular pattern of an individual (eg IL’s and TNF etc) to a particular bacteria. We do not all react the same way to antigens do we?  I don’t have a problem with peanut butter or shellfish. Some people seem to. It’s all immune-mediated.  There are countless amounts of these possibilities which only big data will bring out. Back to you, Lawrence. 

I respect your response. None of the thought leaders dare enter the social media when their fundamental dogma is questioned. They stay where they can close discussion. However youhad the courage to read my article and publically challenge the premise. I am very thankful that there are courageous men and women like you out there passionate about saving lives and advancing science.

I would be happy to continue this discussion in open forum here. Bring reinforcements, the heavy hitters of the old guard. I am ready to be shown that I am wrong in public and that sepsis science does not need to be reformed. No more paternal control of thought.. Glasnost.

And to all the readers,… unless I am proven wrong, in one voice, call for glasnost and reform of sepsis science at the upcoming SCCM.

I don’t think the thought leaders will be doing any more defending. I’m still hoping they do.

To all the young scientists, I wanted to illustrate the objective, very real, and instant results of paternal control of sepsis science which goes beyond SVcO2 and protocols. See the ambitious study linked below. This type of research occurs when researchers rely on the fundamentals of the past (which they should be able to rely on) and no one is told (perhaps for paternal reasons as cited in the earlier comment) that the sepsis criteria were simply guessed. We have already indicated that the ARISE team was almost certainly not told that the standard sepsis “true state” for research was guessed and not derived from data.

Note this linked massive genome-wide study attempting to match the guessed unified phenotype of sepsis to actual SNPs. The genetic information is real but the unified sepsis phenotype is a guess so, of course, the findings are minimal.

This is why we cannot have a situation where we suppress dissent to produce a picture of solid science for the purpose of moving government and hospital administrators toward a well intentioned goal. This may seem like a good idea and may even be beneficial for a while. The problem is that many researchers do not get the memo. They don’t know sepsis science is paternally pathological. They think it is real (fundamentals based on solid data) so they waste time and dreams researching a “true state” which is not based in science. We cannot afford to waste research in the interest of maintaining the appearance of lack of dissent.

http://www.ncbi.nlm.nih.gov/pubmed/25533491

Most Respectfully

Lawrence Lynn

Well, that rebuttal was not to go unnoticed.  

A steadfast insistence that present sepsis science isn’t really science does not constitute an argument. I see from the hyperlink you include that you are definitely interested in genomic, possibly proteomic explanations for the syndrome. The particular article is, indeed, science, but in what way is it usable for patients? There is no scenario in which the information in it helps me to either diagnose a septic patient or treat them. Unless that science is pursued much, much farther. This reminds me of one of my favorite quotes: “We have not succeeded in answering all our problems. The answers we have found only serve to raise a whole set of new questions. In some ways we feel we are as confused as ever, but we believe we are confused on a higher level and about more important things.” That didn’t originate with sepsis, nor even with medicine, but a careful look will, I think, reveal that the thought applies. It also reminds me of where my own career in sepsis research began, investigating the role of TNF alpha in the pathophysiology of sepsis. The observations are still pertinent, but they have not helped me or anyone else to save lives. Observational associations will not help us, unless they are turned into real diagnostic tests or adequate targets for intervention.

I definitely agree with Steven here in terms of the need for practical application, and about the escalating confusion, but as physicians, we have to be comfortable with knowing that we are not practicing perfect medicine any more than our predecessors.  Better, but not perfect, and we have to accept this uncertainty as we slowly get more and more answers. Yet at the same time we are bound to do the best we can for our patients and keep a pragmatic, practical approach. Not easy.

I feel as if you are tilting at windmills when you attack the “old guard”, whoever that is. There is no such thing as paternal control of science, although I will grant you that the history of science is full of attempts at control. Science always wins. Along those lines, I am personally acquainted with the principals of the Surviving Sepsis Campaign and I know all of them to be encouraging of new science, not suppressive of it. The campaign, itself, has changed its recommendations based on new evidence. The members of the campaign are intellectually honest. Period. They would never suppress evidence, nor try to hold down good science. I am convinced that you are mistaken on that account.

Something else is troubling me about your argument. I don’t think anyone believes that the combination of infection, SIRS, and organ dysfunction is some sort of a complete descriptor of the state of sepsis. In reality it is, as Roger Bone described it, a syndrome that is recognizable to human beings who, as of yet, do not have x-ray vision or chemical sensors built in. So far, we don’t have even the tricorder. Roger recognized the syndrome not by guessing, but by careful observation of the patients he cared for (much like your observations about WBC). He did clinical studies to validate his observations and show that the syndrome was associated with a mortality consequence. It will, by the way, always be true that even when we have “the” stat lab test for sepsis, human beings in the form of physicians will need to recognize the need for sending it. And it will still be true that the sooner treatment is initiated, the more likely a patient will be to survive. Unless we develop the diagnostic tricorder, we are always going to need to initiate treatment based on data that we derive from physical examination.

The tricorder may not be as far away as we might think, Steven, there is data out there for early detection of sepsis using EKG data in kids (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2933427/), and the era of wearable tech is just beginning. 

All of that in no way negates your argument that more and better understanding of the pathophysiology of sepsis, its genomics, its proteomics, its epiphenomena is necessary and desirable. The steps you propose are the steps we need. So do it.

Now Lawrence did have a few more things to add…

We do not say the sepsis science is not “science”. We say that it is pathological science. Langmuir describes “pathologic science” as a science advanced by a group of often brilliant scientists who use the scientific method BUT make a fundamental mistake which they do not recognize. They are encouraged by threshold interactions which carries the enthusiasm forward with many papers often for decades. Eventually the “dramatic” results of earlier trials prove NON-REPRODUCIBLE. The number of disciples falls off and eventually the mistake is discovered and the science disappears. We are simply disclosing the mistake and explaining WHY the trials have failed. We are calling for transparency and are not attacking anyone.

Sepsis science is a classic example of Langmuir’s “pathologic science” . The sepsis criteria were considered the STANDARD for defining the “true state” in all sepsis research and this was the mistake in the scientific method which absolutely requires a VALIDATED “true state”. Even accepting your arguments that the sepsis criteria comprise an choice by someone brilliant like Rodger Bone, who we all respected, this does not change anything. Best guessing is best guessing no matter who does it. In Rodger’s days the “true state” of sepsis was thought to represent a “unified phenotype of sepsis” but we now know that a unified phenotype of sepsis may not even exist. All the large RCT trails using the unified phenotype as defined by the guessed “true state” have proven non-reproducible.

It is as if we are in the 1950s trying to figure how to treat “growths” on the body and we defined a expert guessed set of criteria for a unified phenotype of a growth or “neoplasm” and then treated all of neoplasm by the same protocol and had some initial encouraging results due to fortuitous patient mix and threshold interactions. In the end additional research using the unified phenotype would be non reproducible.

This is why the genomic wide investigation or any other investigation using an expert guess as the “true state” fails. I simply cited that genomic article to show why ALL research efforts based on pathologic science fail and how this is a waste perpetuated by lack of transparency.

We are working to define the actual phenotypes of sepsis. This education is simply to open minds.

It is said that failure to intubate the trachea occurs due to failure to recognize that one has not intubated the trachea. So it is that failure to recognize that sepsis science is pathologic prevent resources from moving the science from its failed position of generating non reproducible results.

I want to thank you for engaging in defense of sepsis science. This kind of dialog is what the young researchers need to see. If you do not think they are afraid, you are wrong. One young scientist recently told me that the old guard is just going to have to retire before the science can move on. They have careers, they know the politics of academia and… they are afraid.

If you desire to assure they will not be afraid, even if you do not call for reform, please join us and call for transparency. Let the limitations and origins of using simple threshold criteria for a complex dynamic relational condition be widely promulgated. I have confidence that once we set them free of the sepsis dogma and the grants can flow to fund a new direction for sepsis research, this new generation of young scientists will deliver the breakthroughs we have witnessed in so many other fields of science.

To further explain for the young docs who may think they can rely on thought leaders without examining the fundamentals for themselves:

A contemporary example of “pathologic science” was the science of peptic ulcer disease in the 1980s. This is before most readers time but Dr. Simpson will remember it well. Here brilliant scientists (almost all of them) “knew” that peptic ulcer disease comprised a single unified phenotype fundamentally caused by hydrogen ions. They performed massive research directed toward that perceived phenotype and at times, it worked. This went on for decades and seemed irrefutable given that in some settings excess hydrogen ion (e.g. Zollinger-Ellison syndrome) was the fundamental cause of peptic ulcers. They resisted the argument that there was another phenotype which was caused by bacteria. Eventually they could not hold. No one believes in the acid theory of peptic ulcer disease anymore but a zealous “acid theory denier” could find him or herself quite lonely and isolated in academia the early 1980s. This is what Dr. Kuhn says WILL happen and not even Dr. Kuhn knew how to prevent it.

The thought leaders don’t have to reform sepsis science, they just have to formally promulgate that just maybe it should be FUNDAMENTALLY reformed. However this must be described by the leaders as a potential fundamental reform not a new consensus for a new set of thresholds. Then the gates will open for the young docs with fresh ideas.

The thought leaders have accomplished so much and have saved so many lives. That legacy will not be lost. There is no downside. Join us, and call for reform or at least suggest that formal consideration fundamental might be a good idea.

Now after reading this, if you reread the linked article below, you will see that it is not an attack on thought leaders but rather it is simple a story of good science on its normal path full of deviations on its way toward truth. It is a story which is repeated over and over by ALL of US as we try to solve the worlds problems.

http://www.ncbi.nlm.nih.gov/pubmed/24383420

One final point. Although I am not familiar with your specific TNF alpha study, I will provide an explanation as to why all those biomarker trials failed.

Your study probably used the sepsis/septic shock criteria as a unified phenotype defining the “true state”. In hundreds of biomarker trials that has never been reproducible in over 2 decades.

TNF, IL6,. Procalcitonin, CRP, may each be useful for some phenotypes but since there is no unifying phenotype of sepsis they do not work well for that. One cannot identify a biomarker for a condition which does not exist or exists only in the minds of a thought leader group and their disciples.

This exposes another consequence of pathologic science. Industry realizes the science is sick and stops funding trials. This is the case today.

I have provided a plausible and well reasoned but politically unpalatable explanation as to why your studies and all the other biomarker studies failed. They all had a common fundamental flaw which rendered the science pathologic ( i e they all used of a guessed unified phenotype which does not exist as a standard for statistical analysis.)

So, I feel sorry for you just as I do for the ARISE team. You were probably unknowingly researching the 1980s unified phenotype of the sepsis dogma and no one can be successful doing that. This is hardly your fault. Everyone believed in the universal phenotype of sepsis in those days.

Of course we know better now . We are trying to generate epiphanies among excellent researchers like you which will open minds. We are trying to keep the young from following their well meaning mentors into the cul de sac.

We are at a dead end with industry pulling out and gov. grants still chasing the dogma (Paternal control of the science as a function of funding) . Yet shaking off the dogma we have learned much and future is very bright.

If you collected enough timed data on each case and get IRB approval we could re study your data to see if TNF proves useful certain phenotypes of sepsis within your subject group. We could do this for all biomarker trials and even ARISE if they collected enough timed relational data to characterize the phenotypes.

Anyone reading this, let me know if you have the data and desire to restudy your data against a wide range of dynamic relational sepsis phenotypes. We can provide funding for that effort.

I want to applaud again the courage of Dr. Simpson. We have reached out to many other sepsis thought leaders for over a year and they decline to defend their science. Perhaps they remain silent hoping for salvation as a function some miracle. Perhaps they are so convinced that they do not see the need to defend their dogma. More likely they are afraid. Subconsciously they must know there is no intellectual defense beyond the pragmatic arguments made by Dr. Simpson. No one is doubting that they are honest and not true believers of their own dogma.

I will leave you with a quote from Karl Popper who died 3 years after the sepsis dogma were promulgated.

“Normal science, in Kuhn’s sense exists. It is the activity of the non-revolutionary or more precisely, the not-so-critical professional: of the science student who accepts the ruling of the dogma of the day… In my view the ‘normal’ scientist is a person we ought to feel sorry for… He has been taught in a dogmatic spirit: he is a victim of indoctrination. I can only say that I see a very great danger in it and in the possibility of its becoming normal.”

Send links to these blog posts to the sepsis thought leaders and sepsis grant reviews and those who participated in ARISE, Process, and Promise. The fundamental flaw common in these studies will not be corrected (or reasonably masked) by a metanalysis which of course comprises the desperate new hope of present sepsis science.

As true believers we cannot expect the thought leaders to even see the need to defend their dogma but perhaps Karl Popper’s words will make them realize that they should be calling for consideration of reform of sepsis science as a matter of course, all the time, if only to avoid the risk of becoming “normal scientists”.

Most Respectfully,

Lawrence Lynn

Wow. So I think the real winner of this debate is in fact the reader, especially the young ones who can go on to carry the torch. In my opinion this fascinating debate between two experienced academics and clinicians, is really just about perspective. In actual fact, I’m fairly certain they both would treat the same septic patient in a similar fashion, with some fluids, antibiotics and vasopressors, but what we are talking about extends to the future of sepsis care, where both points of view are in fact necessary, the open-thought, “revolutionary” approach of Lawrence, as well as the practical one based on still-imperfect state of knowledge defended by Steven.   I do think that some of Lawrence’s rhetoric is likely a cause of inflammation and perhaps the cause would be best served by more “political” terminology, but my blog being the furthest thing from politically correct, it fits in well here. In his defence, he does acknowledge the immense contribution to the science from those he also takes a jab at. I think it is also a function of “the system” of institutions, journals and associations which inadvertently creates some of this paternalism, rather than it being really promulgated by the “thought leaders” themselves.  Having had the occasion  to interact with some of them myself, they are not all closed minded and religious – in fact, I find more of your “run-of-the-mill” intensivists to have that zealous follower’s attitude of not questioning what so-and-so says, whereas so-and-so himself is more likely to openly admit that hey, they weren’t sure if this was the best target/therapy/etc… but hey, gotta try something and see what happens.  So I hope this debate can help open a few minds, raise a few questions and provide some solid med-tertainment. 

Thank you and accolades to both Dr. Lynn and Dr. Simpson.

 

Cheers

 

Philippe

Post-Arrest BP Study by Young et al (Resuscitation) – interesting & important, but not yet an N=1 answer! #FOAMed, #FOAMcc

Happy New Year to all!

So trying to catch up on some reading, here is an interesting paper I came across. Young et al did a retrospective study on post-arrest BP, in an attempt to answer the very pertinent and important question as to whether or not a higher MAP may confer better neurological recovery, which is a very sensical hypothesis. After all, a brain with potential swelling, both of tissue and endothelium, may “need” a higher BP. Some societies have advocated for a higher MAP than is usually targeted (i.e. 65) and in studies this has been anywhere from 60 to 100. In their particular institution (Vanderbilt) the protocol aimed for 80-90.

Here it is:

Young et al RESUS

So what did they find?

Basically, they were unable to demonstrate that a higher MAP – in this case defined as achieving 80 mmhm – improved anything, with a follow up to 3 months. There was also no increased mortality related to the use of vasopressors.

So, why might this be? Well, I think there are a couple of important principles to review, especially for the novices reading this.

1. Pressure does not equal flow. The relationship between pressure and flow is a complex one and depends on the interaction between the pump (CO) and the circuit resistance (SVR). Pressure rises when resistance is increased, output is increased, or both. If resistance is increased without increasing output – or by a disproportionate increase in resistance vs output, flow decreases. The effect of vasopressors such as norepinephrine is complex, with both vasoconstriction and increased cardiac output (both via beta stimulation and via increased venous return), and depends on volume status, alpha sensitivity and the recruitable cardiac reserve.

So…? This means that on the surface, a BP number tells you little about flow. The same MAP may represent a highly vasoconstrictor, low-flow state, or a normal flow state. Obviously, a certain minimum pressure is required, to drive the flow from artery down thru the capillaries, but what that number is is unclear. So when looking at any study using simply MAP without another assessment of flow, one cannot draw a conclusion that improving hemodynamics may not help the situation.  How does one assess this – in all likelihood  an integrated approach using ultrasound (volume status, cardiac function), tissue saturation (cerebral/somatic oximetry) and possibly other technologies, including simple physical exam looking at skin mottling.  This type of information could categorize patients into flow categories and make results much more interesting and applicable.

Note that this isn’t really criticism on the authors – it would be impossible to do this on a retrospective study, but simply food for thought for further studies to come.

2. The N=1 principle: remember that we are never treating hundreds of patients at once, and we do not have to decide what is best for most (which is what an RCT generally answers) but what is best for the one patient we are treating.  Hence, looking at any one patient and saying that the target BP should be 65 vs 80 based on this study is incorrect.  What we should be saying is that aiming for a higher MAP may not be necessary if we feel that the patient is well perfused at 65. How each of us figures that out will depend on individual skills and available technologies, but to simply aim for 65 without further thought and assessment is relinquishing your MD in favour of the printed word, essentially what any paper protocol could do.

In the next post I’ll discuss the use of tissue oximetry and how it can be used as part of a strategy to optimize vasopressor use and MAP targets.

 

Thanks and love to hear your opinions!

 

Oh, and don’t forget to register for CCUS 2015 at http://www.ccusinstitute.org, and for more info at http://wp.me/p1avUV-bh.  In those couple of days, Paul Marik, Scott Weingart (@emcrit), Josh Farkas (@pulmcrit), and a bunch of other totally amazing speakers will be talking about this stuff, and more!

Philippe

Cool stuff coming in 2015!

I gotta give a shout out to the #FOAMed world.  The last year and a half has been really stimulating, learning from and exchanging with an amazing cohort of peers, all striving towards self-improvement and saving a few extra lives. I’m also really thankful for all those who take a few minutes of their busy days to read or listen to some of the stuff I spew out, and truly appreciate comments and discussion.

Undeniably #FOAMed has made me a better doc, both from the standpoint of learning and inspiration, which is really the fuel behind continuing education. I’ve been involved in organizing events, and in fact, doing so, and the interaction with both the faculty and the participants has been, in and of itself, of immense worth in terms of motivation and a feeling of kinship to a like-minded group, which I think is very important to practicing physicians.

As a consequence of some of these #FOAMed introductions, some good things are in the planning stages for 2015.

Winter: check out BEEM january 26-28 out in Vancouver BC – I can’t make that but really wish I could.

Spring: Two really interesting events in collaboration with l’ASMIQ (Association des Specialistes en Medicine Interne du Quebec – Quebec internists), one being a half day on Shock & Resus (may 30th), and a full day on Lung Ultrasound (may 29th) featuring the grandfather of it all, guru Dr. Daniel Lichtenstein, the one who invented it (well…discovered it, technically). Both take place in Montreal. (Technically this is for ASMIQ members but if anyone is interested, let me know and I’ll see what I can do!)

Of course, CCUS 2015 takes place may 1-3 in Montreal. Can’t miss that. Register at http://www.ccusinstitute.org.

Summer? I’m not running anything, but definitely going to SMACC Chicago. Just go. ‘Nuff said. http://www.smacc.net.au.

Fall: Ken Milne (@TheSGEM) and I will be planning a really cool day combining a critical appraisal workshop and a review of acute care highlights, taking place in Montreal in the fall. Ken will teach us how to learn while being skeptical, and participants should leave with an important skill as well as a headful of practical knowledge. We don’t have a title for this yet but I’ll be sure to let you know! In the meantime be sure to check out Ken’s awesome stuff at http://www.thesgem.com. He keeps it real.

SGEM Ken

 

I’ve also been asked to organize an Ultrasound Simulation Workshop (we are doing an EchoSchockSim in CCUS 2015), which may also happen towards the end of the year.

 

conferences 2015

Ok, so that was just a bit of an update on what’s up in the next year. Hope to meet some of you at these events, do come and say hi!

cheers

 

Philippe

Venous Hypertension: The Under-Appreciated Enemy Part 2: Discussion with Jon-Emile

So I posted about this a few weeks ago, and the discussion it brought up with Jon-Emile (www.heart-lung.org) turned out to be way better than the original post, and I just wanted to make sure everyone interested got to see it, so here we go (part 1 is here, for those who didn’t come across it: http://wp.me/p1avUV-bJ):

Jon-Emile

 

Jon-Emile: This is a great topic for review Philippe!

I have come across this problem, certainly on more than one occasion. I was first introduced to the idea of renal venous pressure and renal hemodynamics as a house-officer at Bellevue Hospital in New York. Dr. Jerome Lowenstein published work on this phenomenon as it pertained to ‘Minimal Change Syndrome.” He used to ‘wedge’ the renal vein and measure renal interstitial pressure in these patients and measured the response to diuresis. It was very enlightening and made me feel more comfortable given more diuretics in such patients. [Am J Med. 1981 Feb;70(2):227-33. Renal failure in minimal change nephrotic syndrome].

I am also glad that you bring up the cranial vault in this discussion, because I have often wondered if the encapsulated kidneys behave in a similar way. That is, as renal interstitial volume increases from edema, if there is some point on their compliance curve [like the cranium] where there is a very marked increase in renal interstitial pressure? I have found a few articles which loosely address this idea, but would be interested if anyone else knew of some. In such a situation, there would be a ‘vascular waterfall’ effect within the kidneys whereby the interstitial pressure supersedes the renal venous pressure [like West Zone II in the lungs]; then, renal blood flow would be driven by a gradient between MAP and renal interstitial pressure [not renal venous pressure]. I know of one paper that addresses this physiology in dogs, and finds the vascular ‘choke point’ to be in the renal venous system and not Bowman’s space.

What’s even more interesting, is that when renal interstitial pressure is elevated is that the kidney behaves in a sodium avid state [i.e. urine electrolytes will appear ‘pre-renal’] and this physiology has been known for at least a century!

Lancet. 1988 May 7;1(8593):1033-5. Raised venous pressure: a direct cause of renal sodium retention in oedema?

There is no good explanation as to why this occurs, but one I read is that the high renal interstitial pressure tends to collapse the afferent arteriole and the decrease in afferent arteriole trans-mural pressure which facilitates renin secretion [just like low blood pressure would]; but that would require a fairly high renal interstitial pressure unless the MAP was concomitantly low.

Again, what I must caution [and I’ve been personally wrong about this] is the reflex to give diuretics when seeing a ‘plump IVC’. When I was treating a woman with mild collagen-vascular-related pulmonary arterial hypertension, community-acquired pneumonia with a parapneumonic effusion and new acute renal failure, I assessed her IVC with ultrasound. It was plump an unvarying. I lobbied the nephrologist to try diruesis based on the aforementioned reasoning, but was very wrong. Her kidneys took a hit with lasix. What got her kidneys better was rehydration. In the end, what happened was her mild PAH raised her venous pressure and the hypoxemic vaso-constrction from her new pnuemonia only made that worse. Her right heart pressures, venous pressure and probably renal venous pressure were undoubtedly high. But I didn’t take into consideration her whole picture. She had a bad infection, had large insensible losses and had not been eating and drinking. She was hypovolemic, no doubt, despite her high right heart pressures. Fortunately, her pneumonia resolved and fluids brought her kidneys back to baseline.

Thanks again for another thought-provoking topic

 

Me: Great points as usual Jon, and your last one brings up a bit of a concern I have always had. To play devil’s advocate, one could argue that it may have been resolution of the pneumonia and its metabolic sequelae and possibly other treatment that resulted in improvement of her renal failure, rather than the fluid, no? Did her hypoxia resolution decrease PAP back to normal – with IVC dynamics restoring – and relief of renal congestion, and improvement “despite” fluid?

To me, fluid administration must – at least transiently – increase CO to have any effect on the perfusion side. To do so, my understanding is that it has to go from right to left. Because of the pericardium and interdependence, if RAP exceeds LVEDP, we will start to impair LV preload, which sets up the vicious cycle of a shrinking LV and growing RV. If we can’s increase our RT heart output, obviously our LV CO headed to the kidneys can’t increase either. Hence the assumption would have to be that somehow this additional fluid can – by increasing RV preload (without increasing RV size and further impinging LV?) – help overcome elevated PAP and increase right to left flow. To me, hard to believe without a pericardiectomy (on a short time frame, naturally). Hence I struggle with understanding how a really plump IVC with little variation (if significant pleural pressure variation is occurring) can really still need fluid.

I’d really, really like to get your comments on this. I’ve had a number of conversations about this with people – some of them pretty bright – but none satisfying. Am hoping you can point out my flawed thinking.

 

Jon-Emile: Philippe, you ask very good questions. Your first point is quite valid. I think we have a bias of assigning meaning to a particular intervention because we think that particular intervention will work. For the patient I treated, we administered multiple drugs [oxygen, antibiotics, bronchodilators, we may have even given a dose of steroids] and yet I assign meaning to the fluids given. I think in all patients with complex hemodynamics that there are multiple co-varying interventions that all [hopefully] push the patient in the right direction – making it quite hard to grant significance to one in particular. Yet in the patient I treated, the timing with respect to creatinine change and urine output made it very hard to argue in favor of diuresis. We were checking her creatinine fairly regularly as she was in step-down and we were concerned about the trajectory of her illness. With lasix, her creatinine jumped abruptly on the following chemistry while with fluids, creatinine dropped and her urine output really picked up.

Which brings me to Ulrich’s point. It is well-taken and I hope to have a pulmccm post on this shortly. While the CVP does not have any correlation with volume status or volume responsiveness as you point out, the physiology of the CVP can help explain confusing echocardiographic findings.

All a plump, unvarying IVC with spontaneous inspiration means [if you believe the Guyton, or Magder approach] is that the IVC transmural pressure is remaining on the flat portion of its compliance curve during inspiration.

Click to access cc11824.pdf

In other words, the IVC is at such high volume [on the flat portion] that lowering its transmural pressure [lowering the CVP, raising the intra-abdominal pressure or both] does not cause it to shrink in volume.

The question then becomes why is the IVC in this state? And a great analysis to this question is to consider the determinants of great vein volume [which really is a question of great vein/right atrial pressure or the CVP – which is related to volume by compliance].

There are two primary processes which will raise great vein volume and these flow from the Guyton Diagram 1. excessive venous return 2. poor cardiac function or a combination thereof [its really just inflow versus outflow]. Volume status plays one part of venous return, so certainly, if someone is hugely fluid overloaded, their venous return will be enhanced and this will favour a high great vein volume and high great vein pressure, BUT this will be mediated by cardiac function because if the heart can eject the large venous return it is receiving, then the great vein pressure and volume won’t change or may be low. Conversely, if cardiac function is poor, a patient could have a low venous return [e.g. be hypovolemic or euvolemic] and still have a high great vein volume and pressure – simply, because the heart can’t expel from the thorax what little venous return it receives. Importantly, poor cardiac function can mean almost anything [valve dysfunction, tachycardia with arrhythmia, high afterload, poor contractility, etc.].

To me, the above is the true value of thinking about Guyton and the CVP, so when I approach a patient, I try to think about what their venous return curve looks like [by a clinical exam] and I use a TTE to actually see what their heart function looks like [and to me this is the true power of ICU TTE]. The above also explains why CVP simply cannot be a marker of volume status.

In the patient I was treating, her history and physical really suggested poor venous return [she was clearly with a pneumonia, hadn’t been eating and was euvolemic to dry on examination] yet her great vein volume was high on TTE which meant that her cardiac function was most likely poor [on the Guyton Diagram her low venous return curve would be intersecting a very low, flattened cardiac function curve such that shifts with intra-thoracic pressure would not change right heart pressure at all].

But why was her heart function poor? Why could her right heart not eject what little inflow it was receiving? It was probably a combination of things. The pneumonia probably increased right heart afterload which caused some TR, she was tachycardic so wasn’t getting optimal filling time, she was septic with perhaps some underlying cardiomyopathy, perhaps her diastolic blood pressure was lower than normal [she was an elderly lady with likely stiff arteries] and she wasn’t perfusing her right coronary artery well and was suffering from relative ishcemia] it’s certainly is a lot of hand-waving, but all taken together perhaps plausible.

The antibiotics improved her lung function as did the bronchodilators which lowered pulmonary vascular resistance which improved right heart forward flow, maybe the inhaled beta-agonists increased her contractility, maybe the oxygen also lowered her pulmonary vascular resistance, maybe the steroids sensitized her to catechols and this raised her blood pressure and coronary perfusion pressure which improved her right heart function, but also maybe the fluids? Empirically, and in retrospect, venodilating her with lasix probably really lowered her venous return and this crashed what little cardiac reserve she had. It was improving her venous return with fluids that helped.

Sorry if this post is getting too long …

In terms of ventricular interdependence [an excellent, under-appreciated point in the ICU] I think that you have to be very careful extrapolating whether or not this effect is present from an IVC examination. In a classic paper [that caused much consternation at the time] Pinsky found that right atrial pressure was completely uncoupled from right ventricular end-diastolic volume [why the CVP is a poor indicator of volume responsiveness]. Her is a recent review of that paper by Pinsky himself.

http://www.ncbi.nlm.nih.gov/pubmed/24760121

The take home is that while right atrial volume and pressure [and by corollary great vein volume and pressure] can be high, this may not translate to a right ventricle near its elastic limit. Pinsky offers no good explanation as to why this is, but postulates that it may have to do with the complex RV geometry and how this changes during diastole. So until there is a widely accepted means of assessing RV filling with TTE [like an Ea ratio] which could pick up a restricted filling pattern, this is really hard to call on echo. As you are aware, you could look for a flattened septum or D sign during diastole, but I’m not sure how well that sign predicts a patient’s response to a fluid challenge – it certainly screams caution.

This Pinsky paper also highlights a potential disconnect between the physiology proximal to the tricuspid valve and the physiology below it which is also part of my general reluctance to use IVC volume change as a marker of fluid responsiveness, just as I have total reluctance to use CVP [or its change with respiration] as a marker of fluid responsiveness.

Unfortunately, a lot of the time it comes down to ‘guess and check’ – give fluids or give lasix and see what happens. This is why I firmly believe that determining volume status and volume responsiveness are the hands-down hardest party of ICU medicine.

If you’re still reading, I hope this helps.

One more point. I don’t think I gave a full explanation to one of your questions. Please bear with me as this is exceptionally hard to explain with words [indeed why I made heart-lung.org].

The venous return and cardiac function curves are essentially inverse of each other [that is lowering right atrial pressure increases venous inflow but decreases cardiac outflow] so they approximate the letter X [venous return is the \ and cardiac function is the / & the point at which the two lines intersect make up the CVP and defines cardiac output].

If you consider the patient I described, If we assume her venous return is low [because she is venodilated from sepsis and hypovolemic from low PO] then the venous return curve [\] is shifted leftwards. If we assume her cardiac function is poor the cardiac function curve slope [/] is shifted down and to the right.

When she takes a breath in, the lowering of intrathoracic pressure pulls the cardiac function curve leftwards [lowers its pressure relative to venous return] while the increase in in abdominal pressure with diaphragm decent tends to temporarily increase venous return by decreasing abdominal venous capacitance. This effect shifts the venous return curve in a rightward manner.

If the patient’s venous return curve initially intersects the ascending portion of the cardiac function curve [i.e. she is truly volume responsive] BUT, the intersection is very near the plateau of the cardiac function curve [i.e. the portion of the cardiac function curve that will render the patient non-volume responsive and also favour unvarying respiratory change in right atrial pressure/volume with inspiration], THEN with inspiration it is possible to see the intersection of the two curves on the flat portion of the cardiac function curve [as the cardiac function curve is pulled leftwards and the venous return curve is pushed rightwards], even though she does have some cardiac preload reserve. This would be an example of impaired specificity of IVC volume change with spontaneous inspiratory effort as a predictor of volume unresponsiveness [i.e. a false positive for a plump IVC predicting the lack of fluid responsiveness].

I address this physiology in chapter 6 parts C and D and chapter 8 part F.

 

Me: Very, very interesting. I think this discussion, as many, show how medicine is not a “hard science” but remains a “pseudo-science”, inherent to the fact that we are blending physics, chemistry, biology and cannot really apply simple principles of flow and pressures when dealing with elastic, muscular systems lined with microscopic coating whose compliance and resistance change from moment to moment and thru effect of neural and hormonal influence. There are simply too many unmeasurable variables to come up with single guidelines and rules.

I think, as you say, that there remains a need for some degree of trial and error, that we are hopefully narrowing with the appropriate application of technology and proper data integration.

I’ll percolate all this and see how I can tweak my mental model!

Thanks a lot Jon-Emile!

Philippe

 

 

please visit Jon-Emile at http://www.heart-lung.org

Heart-Lung

 

 

cheers!

…and don’t forget to register for CCUS 2015 at http://www.ccusinstitute.org!!!

Philippe

The IVC: Short vs Long Axis…Be The Judge! #FOAMed, #FOAMus, #FOAMcc

So yesterday had a case that really brought out this issue. One of my ICU patients didn’t have a great urine output, so instead of playing a guessing game looking at urea, creatinine, ins & outs, etc, etc (hopefully no one is thinking CVP…), I did what any self-respecting bedside sonographer would and went for a direct look.

Here is what his IVC in standard long axis looked like:

So…it looks like its about 20mm, and not a whole lot of variation seen. Hmm, maybe he’s on the “fuller” side.  Some may even consider that he wouldn’t be volume-responsive.

Before we go on, lets just have a brief physiological review. What we are looking for when assessing IVC is an idea of its volumetric change with respiratory swings. So ideally we should be obtaining a 3D volume measurement, but maybe the traditional 2 point diameter may suffice, assuming that the IVC is a near perfect cylinder. Assuming?

I’ve mentioned this in a previous IVC post (http://wp.me/p1avUV-8E).

So let’s get back to yesterday’s patient. Short axis:

Yes, the IVC is that tall, skinny sliver that collapses completely with (gentle) inspiration. Still think that this patient is in the full side?  Maybe not. Gave him some fluid and the urine output picked up.

 

Bottom Line?

This is why I think much of the IVC literature is imperfect. Unfortunately the appealing idea of standardizing IVC assessment to a single two-point measurement is inherently flawed, due once again to individual patient variation. It would be great to see all those studies re-done with a global IVC assessment strategy. In the end, it isn’t any more time-consuming – just like the Simpson’s disks vs eyeballing.

Cheers!

Oh yeah, again, if you are an acute care doc, and you like the cutting edge, donate forget to register for CCUS 2015, Montreal, may 1-3!  www.ccusinstitute.org!

Philippe

A Bedside Ultrasound Case & Poll: All Infiltrates are not created Equal: A Follow Up! #FOAMed #FOAMcc #FOAMus

Ok so so far, the votes show the following:

CHF 52%

PE 26%

Pneumonia 21%

So, as most of you had figured out, the fever and white count turned out to be fairly insignificant.  I started diuretics on him and stopped IV fluids (in truth, he spent a few hours still receiving IV NS at 100cc/hr as it sadly slipped by me – I know… NS to add insult to injury).  I also stopped antibiotics to the alarm of some, but keep in mind we have a lot of c.difficile in our institution, and I did not believe the had CHF AND a significant pneumonia (that would go against Occam’s razor…). He was not septic, and another discrepancy that led me away from the diagnosis of pneumonia is that a patient with significant bilateral infiltrates due to pneumonia is sick: toxic, dyspneic, fulfills Scott’s LLS score of 1 (Looks Like Shit – range 0 to 1).

Within a few hours and perhaps a negative balance of a liter or so, he feels much better. Here is his IVC at that point:

36 hours later, his CXR is clear and he is off O2.

Angiogram turns out normal – as anticipated – EKG only ever had some vague non-specific ST abnormalities. He likely had a viral cardiomyopathy – some ancillary tests still pending (HIV, etc), but is to be discharged soon.

For those who voted pneumonia, certainly initially it could not be ruled out, only the clinical evolution made it highly unlikely as a significant player.

For those who felt this represented pulmonary embolism, remember that the primary hemodynamic mechanism will be right heart failure, hence the RV would most likely be as large, and potentially larger depending on the severity of the embolism. Again, this cannot be ruled out by bedside ultrasound, it can only be ruled out as a main cause of respiratory failure. Also note that the chest xray is generally normal, or may show the peripheral wedge shaped infarct (Hampton’s hump). Bilateral infiltrates would not be the rule. But it’s always a good thing to keep it in mind!

Bottom Line?

I think this case illustrates well the limitations of physical examination, and although more commonly, pneumonias (especially in the elderly) get digressed because they “had crackles,” sometimes, patients we might not expect may have CHF.

From the moment one notes a large, plethoric IVC, one should anticipate downstream pathology of some kind (overzealous iatrogenic fluid overload being the exception), whether tamponade, pulmonary embolism, LV failure, pulmonary hypertension, but something.

Hence, in this case, bedside ultrasound proved invaluable. After all, he was recieving less-than-optimal therapy for CHF: fluids and antibiotics… This may be a case that would have proceeded to “ARDS”, and although I don’t doubt that at some point along the line, an echo would have been done, the delay may have had consequences. In our center, no one gets into the ICU without at the very least a cardiopulmonary bedside ultrasound. It is done routinely, not only for specific indications – the real indication is having a patient in front of you.

Please don’t forget, if this is up your alley, don’t miss CCUS 2015: Way Beyond EGDT and ACLS!!!  #CCUS2015

cheers!

Philippe

 

Jon Emile says:

Great case, great windows and images. I agree with your management totally. I do recall once, however, having a patient admitted for heart failure following a bedside TTE performed by a great resident, unfortunately [and in retrospect] the patient likely had a septic cardiomyopathy. The patient felt great with diuresis, but then his BP crashed as the sepsis took hold.

Recall the classic paper by Parrillo NEJM 1993 who looked at the left ventricle during the acute phase of septic shock and found LVEDV to LVESV values of 225 ml to 150 mL. The EF was in the low 30s. During the recovery phase, LVEDV to LVESV was 150 to 75 mL and EF of 50%. He noted that dilation of the left ventricle seemed to confer a mortality benefit, & that this may be a compensatory response to maintain stroke volume. This may be more striking in young patients as yours. When I first read your case a mycoplasma peri-myocarditis came to mind [I treated a case of this as a resident in the Manhattan VA]. The classic finding in this disease being bullous myringitis.

Thanks for the awesome echo videos!

 

Great point Jon!  Septic cardiomyopathy – which is very common – is definitely something to keep in mind. Indeed the LV dilation noted by Parillo would be a sensical adaptation to limited contractility. I remember seeing a particularly impressive case in a young woman with significant dilation and an EF in the 15-20% range, with incredibly rapid recovery to the 40’s and 50’s  by a day later. I’ve yet to see septic cardiomyopathy happen, however, in a patient who isn’t that sick, i.e. no pressors, no acidosis, etc…

Great point about mycoplasma, which was brought up by our ID consultant at first, but who also agreed he wasn’t that sick and agreed to stop once noting the CXR had cleared with diuresis.

 

Thanks for reading!

A Bedside Ultrasound Case & Poll: All Infiltrates Are Not Created Equal. #FOAMed, #FOAMcc, #FOAMus

So I get an early morning call from a really good ER guy informing me of a likely ICU admission: a young guy (30’s) with a bilateral pneumonia and fever whom he suspected might get worse before he got better. He’s given him some fluids and started ceftriaxone and azithromycin. Sounds good to me. Sold. I tell him I’ll come take a look as soon as I roll into work (we do home call).

An hour or so later I head to the ED and see a him, in bed at 30 degrees or so with nasal prongs, maybe a little tachypneic but certainly not in severe distress and not particularly toxic. The nurse informs me that his temperature was apparently 40 degrees. The CXR (I’ll try to put it up soon) shows bilateral infiltrates, more predominant in the lower two thirds of the lung fields. WBC is 14, lactate 2.3.

So this guy had been short of breath for about 2 weeks, having some cough and localized left sided pain associated with movement, cough and pressure. The cough was non-productive.  As I was getting this history (yup, generally bedside ultrasound is simultaneous with history-taking for me), this is what I see:

(parasternal long axis)

(parasternal short axis)

(right lower costal margin)

(you can see this in most of the lung fields)

He has no past medical history or notable family history, drinks occasional wine, has not traveled of late and works as an electrician. He is active and played soccer – the last time a few weeks ago. He came to the ED for dyspnea, but had still been able to go up several flights of stairs, albeit with more dyspnea than he normally would have.

 

 

 

check back tomorrow and let’s see what happens!

 

cheers!

 

Philippe

Bedside Ultrasound Case Debate Part 1: A Poll ! #FOAMed, #FOAMcc, #FOAMus

So I’m walking to the ED to reassess a COPD’er that was on BiPAP, and one of the ED docs sees me in passing and says – “I might have a case for you, she’s on her 3rd litre and still a bit hypotensive…I’ll let you know.”  So I re-route and decide to take a look right away, because I’m never fond of shock NYD.

So here is this woman in her 50’s, BP is 93/67, RR 22 and moderately dyspneic. She has been increasingly so for a few days without infectious symptoms. The X-ray is clear and her labs unremarkable aside from a lactate at 3.3 mmol/l.  She is moderately overweight but quite active. Non=smoker without any cardiorespiratory known illness and on no medications.

Here is what we see on ultrasound-enchanced physical examination:

So, what do you see?

In the first clip, we see a large, dilated IVC with little variation – despite the dyspnea, making it a more significant finding – according to the Effort-Variation Index (http://wp.me/p1avUV-9k).   This automatically implies there will be some pathology (unless iatrogenically very volume loaded) to be found downstream.

In the second clip, you have a hyperdynamic and underfilled LV and a dilated, poorly contractile RV.  In the absence of cardiopulmonary disease and in an active patient, this is highly suggestive of an acute process, namely pulmonary embolism.

On further questioning she had done a new yoga stretching class as a possible endothelial-damaging process.

So what did I do? Get a STAT angioscan:

 

What would you do next?

 

I’ll tell you what I did tomorrow, and hopefully have some good bloody arguments!

 

PS for awesome talks by amazing speakers, don’t forget to register for CCUS 2015!!! For more info: http://wp.me/p1avUV-aU and register at www.ccusinstitute.org!

 

cheers

 

Philippe

 

Fluid Responsiveness: Getting the right answer to the wrong question. #FOAMed, #FOAMcc, #FOAMus

Let me start with a clinical scenario: you have a 68 year old male in front of you who is intubated, has bilateral pleural effusions, pulmonary edema, a bit of ascites, significant peripheral edema, elevated CVP/JVP/large IVC, and a moderately depressed cardiac function.  What is the diagnosis?

If you said CHF, you might be right. If you said post-resuscitation state in a septic patient, you might equally be right. Hmmm….

So as any self-respecting FOAMite knows, there is an ongoing and endless debate about fluid responsiveness, how best to detect it, what exact percentage of some variation represents it – is it 9% or 13% – and everyone has the way they swear by.

Well, I think the entire premise behind this is essentially flawed.

The fact that this is the first question implies that the answer should radically change management (eg giving or not giving fluids “generously” – yes, the quotes imply facetiousness).  Basically, that you should stop giving fluids when your patient is no longer fluid-responsive. The implication is that fluids is a better, safer, healthier, more naturopathic, eco-friendly and politically correct therapy than any other option.

I think we should reflect on that a little.

If you put some faith into normal physiology, you have to acknowledge that the only situations in which our cardiopulmonary system finds itself nearly or no longer fluid responsive are pathological: CHF, renal failure, etc. None of those are healthy. None of those are a bridge to healing.

What do we do when we are hypovolemic?  We vasoconstrict, stop peeing, try to drink a bit (if at all possible) and slowly replete our intravascular space via the portal system. We might build up a little lactic acid (helps feed the heart and brain – yup, nothing toxic about it), but we get over it.  Of course, if we lose too much, the system fails and we head to meet our maker.

Now, having remembered that, why do we feel (and I say feel because the evidence isn’t there to back it up) like we have to get to pathological levels of intravascular venous pressure to fix the problem?  Especially when the problem at hand isn’t primarily hypovolemia, but mostly vasodilation, with possibly a relative hypovolemia in part related to increased venous capacitance.

The real question is: does my patient really, truly need a lot of fluid?

And here is the catch: just because someone is fluid responsive doesn’t mean that they need any, or that it is the best thing for them. Whoa… Heretic… I thought “aggressive fluid resuscitation is the cornerstone of resuscitation in sepsis.

I think that answer is relatively simple.

No matter which method you are using (mine is IVC ultrasound: -http://thinkingcriticalcare.com/2014/04/01/the-ivc-assessment-by-bedside-ultrasound-lets-apply-some-common-sense-foamed-foamcc/), if you are deciding based on a millimetre of diameter, or a couple of percentage points of variation whether or not to give liters of crystalloids to your patient, there is no truth to that in the individual patient. Trying to figure out the tiniest of differences to decide our therapeutic options is, in my opinion, a huge waste of time with no scientific basis in the one single patient you are treating.   It’s like haggling for a dollar on a hundred dollar item in a flea market: you’re missing the boat.

“85% of patients with a IVC/SVV/SPV/PLR of …. are volume responsive” or something of the sort does NOT apply to the one patient you have in front of you as a recommendation for fluids. You have to make a complete clinical picture of it – feel the belly, look at the inspiratory effort, examine the tissues for edema, etc.

Grey zone it. The best we can do is a gross categorization of truly hypovolemic (need a lot), full (please don’t give me any), and “normal” which may need maybe a little, but probably not “generous” amounts. You’ll end up generously feeding the interstitial space and making things worse – and later maybe saying “oh well, I guess he/she was just so sick…”

Even if my patient is fluid-tolerant, why to we want to push him into near-pathological states? Is it just the old adage of “You have to swell to get well?”  In the light of much of our literature, I’m not sure that old wives’ tale holds a lot of water.

Are vasopressors that bad?  Not according to what we know…

At least, avoid actually reaching the point of no longer being fluid responsive. You can’t tell me you think that CHF is actually a good thing, can you?

 

Love to hear your thoughts!

 

Philippe

PS, if you like to think out of the box and rather be on the cutting edge, make sure to mark your calendar for the coolest conference in Canada: #CCUS2015….http://wp.me/p1avUV-bh

 

 

COMMENTS

SQS Replies:

Philippe,
I think your logic is sound enough, but the moat that makes it currently unassailable is that you are working in an area with no or very little data. There is clearly a reasonably well developed and continuing to develop literature around the mortality effects of excess volume. There is an older literature that suggests that our vasopressors are actually having their effect on the more normally functioning arterioles and may shunt well oxygenated blood from the well functioning cells of a tissue and to the ones that are shocked and can’t use the oxygen, anyway. At this juncture, your guess is as good as mine, as to which of these is the greater evil. Ergo, your argument is as good as any.

One thing I will say is that the patients who concern us are those in whom endotoxin, blood loss, or other factors have resulted in a shock state wherein cells and even large parts of tissues have both inadequate oxygen supply and inadequate ability to use whatever oxygen is supplied them. Any tool we have to alter this pathological state is blunt. Blood pressure? CVP? IVC size and behavior? SVI? What do any of these say about how well we are doing at the tissue and cellular level? Even the interesting markers of lactate, ScvO2, CV CO2, etc. are blunt instruments. As is our bag of fluid and as are our vasopressors. And think about our end result – “hemodynamic stability”, “better mental functioning”, “good urine output”, “feeling better”, “walking around”, “able to go back to work”. Things that are important to us and to our patient, but barely even measurable. How blunt are they?

My own approach, which I suspect to be yours, too, is to recognize that the new onset shock patient is momentarily different from the chronic CHF patient/”chronic” shock patient you describe above. We know there is an oxygen deficit, and it behooves us to correctly that as quickly as we can. We believe, with some data to back us up, that rapid correction of that deficit, to the extent that we can, can prevent the ugly chronic state. I use the blunt measures of fluid responsiveness in the first hour or two of resuscitation to ensure that the CO component of oxygen delivery is not deficient, and then I stop giving fluid. Early in the course, I am prone to rechecking “volume responsiveness” in some hours, because I know that fluid is leaching out of the vascular space and the patient has not stabilized, yet. All the while, I am highly aware that I am hoping this makes a difference, not knowing that it does. I am aware that it is rather circular to check SVI or IVC, give fluid, see a change and say, “See? Volume responsive.” And all the while knowing that every patient has his or her own line, beyond which more fluid will not be helpful but harmful. And all the while knowing that I can’t see that line, nor measure it with any tool that currently exists.

I think perhaps that we are like Phoenicians, navigating our way across the ocean by the North Star and trying to keep land in sight. We do a pretty good job of getting where we’re going a lot of the time. But won’t it be nice when we come up with GPS? Or even the astrolabe?

SQS

 

Fantastic points!

I can’t agree more. I do check for fluid responsiveness, and I do believe in rapid intervention – just perhaps not quite a vigorous and generous as medical marketing would have us buy. There isn’t more data for that than for a somewhat more conservative approach, in my opinion. Even the rate of administration is rarely looked at, just the totals. There is good animal data showing that, for instance, a more rapid rate of albumin infusion results in greater leak and less intravascular albumin at 6, 12 and 24 hours.  Little reason to think it would be any different in humans.  There is also data showing that the oxygen deficit in sepsis is not as ubiquitous as we think.

Our understanding of the septic disease state is minimal at best, and our tools exceedingly blunt, as you point out.  

GPS or astrolabe would be amazing. I’ve had a few discussions with people working on cytochrome spectroscopy – a possibility to assess mitochondrial “happiness,” which could give us an oxygenation endpoint. Then we could have a trial that might end up showing which degree of mitochondrial oxygenation is optimal, if any.

I know I am playing a bit of a devil’s advocate and that, in strict numbers, I probably don’t give a lot less fluid or a lot slower than most, but I think it is important to keep our minds open to change rather than keep a clenched fist around the ideas we have. 

When we have two docs debating whether IVC, SVV, carotid flow time (I do like Vicki’s stuff a lot) or something else, I think we are mostly in the grey zone, and the good thing is that either way, we are dealing with two docs who are aware and conscientious and doing the rest of the right things. But keep in mind there are a lot of docs out there who are in the acute care front lines who believe that bicarb “buffers” lactate. And by buffers they understand “neutralizes.”

I just hope that when the GPS comes along, we don’t lose ten years of knowledge translation time because we are still clinging to (at that point) outdated ideas like the IVC ultrasound… 😉

cheers and thanks so much for contributing fantastic material!

Philippe

Marco says:

Philippe, I really feel like being on your same wavelength when I read your posts about fluid responsiveness. I think it’s obviously easy to agree that a bleeding hypovolemic patient is fluid responsive AND needs fluids, but the more accurately I think about the physiology of fluid resuscitation when a nurse is asking me “should we give him some fluids?” the more I realise that the “grey zone” is large and its upper limit is not easily detectable. Probably if you fill your patients to the point where they are no more fluid responsive, you are sure that no more fluid is needed, but you should be able to stop a bit earlier.
Blunt instruments and measures are an issue, and integration of the data is a possible solution (at least until a GPS comes along), but critical thinking is always a valuable resource.
The more I grow old the more I become minimalist in my approach to the “chronic acute ill” patient (90% of the patients on an ordinary day in my ICU). If a patient is in the grey zone, with a reasonably good hemodynamic stability, some vasopressor support, low dose diuretics and his urine output decreases, probably the decision of giving him fluids OR diuretics would be equally harmful. When a patient is in the grey zone and your instruments are not so accurate, it’s better to keep him safely in the grey zone. When you are in the mountains, you are caught in a snowstorm and cannot find your tracks, the safest decision is to stop and wait.. or follow your GPS 😉

Marco

thanks!

You hit the nail on the head with “integration is key.

Philippe