Hello, my name is Enya Ablardepe. I have the pleasure of moderating this session. Today we're going to be discussing the year in review emergency medicine and prehospital care. We have a variety of speakers today who are bringing us the topics that are pretty prevalent in the last year. No disclosures for myself or the panelists. First, starting with Dr. Manasco. He's an attending physician at Wake Medical Hospital. Then Dr. Matthew Stull, who is an assistant professor at the University Hospitals in Cleveland. And then Dr. Jessica Nelson, who's an assistant professor at Washington University in St. Louis. Our agenda today is that we, again, will discuss articles of the last year. First, starting looking at prehospital disaster and COVID-19, of course. Then to risk stratification and COVID-19. And then our theme again, COVID-19 and ARDS, what we know now. After our panelists have discussed the articles, we're going to have some time for discussion and questions. So feel free to submit your questions and comments in the chat box. We'll attempt to address them during the discussion period. And with that, we'll get started with our articles. Hi, everyone. I'm Travis Manasco. I am an ER doctor and ICU physician at Wake Med Hospital in Raleigh, North Carolina. I'm going to be talking about the prehospital care here in review. I tried to pick three studies, statements, essentially, that applied kind of across our spectrum. A lot of us are ICU providers, as well as ER providers. And then I just tried to pick a few that kind of span the spectrum. So I have two COVID-related papers and one non-COVID-related paper. I know that, you know, we're watching all of these great lectures virtually, and I'm sure there's a lot of information out there about COVID. But there was another really great prehospital paper that came out this year. I don't have any disclosures, so without further ado, here's the prehospital year in review. This is the first paper that came out in September of 2020, and it is Association of Intra-Arrest Transport versus Continued On-Scene Resuscitation with Survival to Hospital Discharge Among Patients Without a Hospital Cardiac Arrest. So for these patients that have out-of-hospital cardiac arrest, should you transport them quickly, even if they're still coding, or should you stay and resuscitate them? And the accompanying editorial had a good way to summarize this paper, and is it, should you scoop and run or should you stay and play? And so I like thinking of this paper like that. And the primary aim of this paper was to determine whether intra-arrest transport versus continued on-scene resuscitation was associated with survival and hospital discharge. And for in-field resuscitation, a lot of these places with ACLS, very highly trained paramedics, they're doing everything you're doing in the ER. So does it really matter? And it's unclear at this point, and so that's what the authors tried to do. They used a secondary data analysis, and this is an observational paper employing a large registry of cardiac arrests and out-of-hospital cardiac arrests. Ten North American sites that kind of had atraumatic out-of-hospital cardiac arrests. This is between April 2011 to June 2015. They included all patients that had cardiac arrests in their registry. They excluded patients that were DNR, that had missing data, that weren't adults. And the primary variable of interest, what they really looked at, was intra-arrest transport. So did they transport the patient prior to any episodes of return to spontaneous circulation, or ROSC? And then all of the patients that did not have that happen were on-scene resuscitation. The primary endpoint was survival to hospital discharge, and the secondary endpoint was survival with a favorable neurological outcome. They used a time-dependent propensity score analysis, and so this helps account for resuscitation time bias. So a lot of us know clinically and in the data that the longer you have a code progress, the worse the patients do. And so they tried to take that into account using this propensity score analysis. They analyzed other confounders, and then there's a secondary analysis that evaluated this, the association of hospital discharge and intra-arrest transport by time. So looking at kind of five-minute intervals, and then matching the patients that had an arrest versus the patients that were still ongoing on-scene resuscitation. And then they looked at different subgroups and the results. So for this paper, they had 57,725 consecutive out-of-hospital cardiac arrests from April 2011 to June 2015. They analyzed and included 43,969, so a good amount of arrests. 11,625 of those patients had transport intra-arrests. And then 32,344 were treated with on-scene resuscitation or had resuscitation terminated. The median duration of transport is 10 minutes, and 3.8% survived to hospital discharge when they had intra-arrest transport, and 12.6% survived to hospital discharge when they had on-scene resuscitation. And then interestingly, 40% or a total of 17,468 achieved out-of-hospital return to spontaneous circulation. So this is a box and whisker plot that I think is interesting because if you look on this plot, you'll see that this is based on the different EMS sites. And so the x-axis is intra-arrest transport, and the y-axis is survival to hospital discharge, going up to about, the highest it looks like is about 18%, 19%. And so as you have increasing amounts of intra-arrest transport, it does show an association with worse survival to hospital discharge. So if you kind of break this down by EMS places, in every EMS department, like every hospital, every healthcare place has their own culture, their protocols. And so anyway, if you look at this, I think it's an interesting, it brings up some interesting points about different EMS practices. This is a figure three from the study that shows, it might be pretty small if you're looking at this on your computer, but what you can see is on-scene resuscitation on the left, and then intra-arrest transport on the right. And if you look at kind of, this breaks it down by subgroups, looking at the primary outcome of survival to hospital discharge, except the second one, which is neurological outcomes. This is one of the secondary aims, was to find out if patients survived with a good neurological outcome, based on a modified Rankin score. And if you look, many of these significantly favor on-scene resuscitation. If you have a full cohort, you have a better survival to neurological outcome, a better neurological outcome for the patients that survive with on-scene resuscitation. EMS level of care, though, there is not enough data, it looks like, to significantly say that, or there's not enough data to look at BLS only, which is one of the limitations. EMS witness versus shockable rhythm, versus both, versus mechanical. Mechanical CPR was not significant enough to completely favor on-scene resuscitation. Again, small numbers there, as opposed to the entire cohort. And then if you look at, even by time, until you get to about 20 minutes, 25 minutes or longer, you really favor on-scene resuscitation. And interestingly, if you look at the information in the study, the results in the study, they show that as you get longer resuscitations, a lot of these patients, they were transported, and many of these patients got return to spontaneous circulation before they got to the hospital, which is just kind of an interesting point. So conclusion, and how you look at the study, and I'm primarily a clinician, and kind of what I take from the study is that survival to hospital discharge was lower among patients treated with intra-arrest transport. It's better to stay in play, it seems like. And survival with favorable neurological outcome was lower among patients with intra-arrest transport compared with on-scene resuscitation. So in this large observational study, based on a registry of atraumatic cardiac arrests, it seems like the stay-in-play model or on-scene resuscitation has a better association with survival and with the neurological outcome. But, of course, with any study, there are limitations. So every EMS department is different, so that limits generalizability. It wasn't a randomized controlled trial, so they did their best with the propensity score analysis to account for a lot of potential biases, but they still may exist, or other unmeasured biases may be there. The results may be subject to prognostication bias by providers, and other characteristics of the rescue personnel or the patients not available, like we said, may influence transport decisions or care decisions. And then there's a very small amount of patients that actually had a BLS-only resuscitation, so we can't really generalize to that. So that's the non-COVID paper, and the next two papers, looking at kind of the pandemic, I thought would be very helpful for your clinical practice, at least reading these were for mine. And I spoke with some of our EMS directors here at Wake County, and I'm very grateful for them for their time and kind of sharing with me what they found most useful during this pandemic. And this paper is from circulation in the AHA, and it's interim guidance for BLS and ACLS in adult children and neonates with suspected or confirmed COVID-19. Wonderful, you know, very appropriate to have this out by the AHA. So as we know, and this came out in March, so some of it is still ongoing, but as we know, approximately 12 to 19% of COVID-positive patients require hospitalization, hospital admission, hospitalization. Three to 6% become critically ill, and that's what we're still seeing. Healthcare workers are the highest risk profession for contracting COVID, and CPR generates numerous aerosol generating procedures. And so they broke it down into three different principles for BLS and ACLS in patients with suspected or confirmed COVID. So you reduce provider exposure to COVID. Okay, makes sense. You prioritize oxygenation and ventilation strategies that lower aerosolization risk and are better for everybody in the room or on the scene. And I think this third one is very important as an intensivist and an ER physician is considering the appropriateness of starting and continuing resuscitation. And I kind of, you know, just kind of have this under the umbrella of communication about advanced directives, which is always important, but it seems like this has become, it seems even more important during this COVID pandemic. And that is a talk unto itself. So reduce provider exposure to COVID-19. So all rescuers should don PPE. You should limit the personnel in the scene. Might not be the best time to have a lot of different student shadowers or things like that, though I know training must go on. So that's an individual decision. Consider replacing manual chest compressions with mechanical CPR devices and clearly communicate COVID-19 status to new providers and on transfer, which makes sense. Prioritize, second is prioritize oxygenation and ventilation strategies with a lower oxygen aerosolization risk. So HEPA filters, attach them securely. If you're mechanically ventilating, if you're bagging patients, you know, they're obviously helpful and can help reduce the risk of transmission. After healthcare providers assess the rhythm and defibrillate any ventricular arrhythmias. So essentially as you get to a code and start the code, patients in cardiac arrest should be intubated with a cup tube at the earliest feasible opportunity. And I think that, you know, they're trying to kind of move away from, not move away, but essentially say that we know that high quality CPR is extremely important, but also the protection of everybody at a code is important. And so as soon as you can safely intubating the patients and attaching them to a viral filter, HEPA filter will be beneficial to everybody. And then use strategies to assure first pass success. Most experienced provider, if you need a video laryngoscope, pause chest compressions to intubate. So what we do is kind of during a pulse check, just go. And, you know, probably after the first pulse check, we're really trying to intubate these patients as we move on. Again, you know, like we said, these are just more things under the second umbrella of oxygenation and ventilation strategies. So, you know, consider passive oxygenation with a non-rebreathing face mask covered by a surgical mask. If intubation is delayed, you can consider an LMA or supraglottic airway and minimize disconnections. Makes sense. And then third, and I think it's just personally and professionally, I think it's just, you know, very, very important to address goals of care with patients with COVID-19. Or a proxy, a healthcare proxy. On increased level of care, on admission, healthcare systems and EMS agencies should institute policies to, you know, determine terminating CPR in these patients. And there's not enough data to support ECMO CPR in patients with COVID-19. We've had a few, and one survived. And that's wonderful, but there's just not enough data there, especially as we move on. So with the last, we're kind of running out of time, but we have the, this is the pediatric cardiac arrest algorithm. And if you'll just note in yellow at the beginning is non-PPE. And then as you move forward into the arrest is prioritizing intubation and then resuming CPR. And it's the same for the ACLS. So those kind of boxes in yellow just kind of put in how important what we just discussed were in kind of the algorithm form that we're all used to seeing. And so, and for in-hospital cardiac arrest, like we said, address goals of care on hospital admission. If patients are prone, which we found, if patients are prone, you can do CPR in prone patients or you can flip them over. We always flip them over. So, and the last one is a very short statement from the American Heart Association, American Stroke Association. Essentially, they needed a broad policy statement. We know their neurological manifestations. I'm sure there'll be very great presentations on this during the next couple weeks. PPE shortages can hinder stroke team activation. So considering tele-neurology can be very helpful. We've actually moved to that. And also considering taking these post-TPA beds that are stable and putting them on the floor or step-down unit because there's no data to support that. And I'm happy to talk about that in question. So summary, and we're going to run out of time, but intra-arrest transport is associated with worse survival to hospital discharge and neurological outcome compared to on-scene resuscitation. Use PPE for suspected COVID codes. And we are doing in our hospital using it for every code. Intubate early and pause compressions during COVID codes, but not just pausing compressions, but when you intubate. Address goals of care. Consider tele-neurology. Consider ways to decrease provider exposure to patients that may have COVID. And stable post-TPA patients can potentially go to a step-down unit and save you a unit bed for, you know, a COVID patient or a much more critically ill patient so they don't have to board in the ER, which I'm sure a lot of us are seeing now. So I really thank you for your time. And here are my references. And I'm happy to take any questions. Hello, everyone. My name is Matt Stull, and I'm an EM intensivist at the University Hospitals Program in Cleveland. And I'm so excited to be here with you today for really looking at 2020 in review. Hopefully it is in the rear view mirror for all of us at this point. And taking a look at some of the evidence and thought processes about things that we're dealing with down at the intersection of emergency critical care. So to get started, I had the dubious honor of being provided 2020's all-time favorite topic, which is that of the coronavirus. And so we're going to be talking a little bit about the literature in context of coronavirus in the emergency department and the ICUs. So to get started, obviously, I always want to, you know, provide some financial disclosures. I have none financially to speak of. I do want to say that the way I tend to approach this sort of presentation is by talking to you a little bit about literature you may have missed. Maybe not necessarily the big headlines in JAMA, New England Journal, or even in annals of emergency medicine or academic emergency medicine, but instead about some literature that should inform the way we practice in the ED or ICU as an EM intensivist. And so the way I interpret that literature is certainly my own opinion. I want to be clear about that. And I do tend to be a bit of a heretic when it comes to approaching some of this material. So I just want to be clear about that as we get started. So while we're here together today, I want to talk to you about COVID diagnostics as well as some risk stratification that you're going to approach in your patients. And some of my other colleagues are going to talk about COVID in context of true management strategies later. You'll notice I have a QR code here. This contains all of my references, including PDFs of some interesting reads that you may be interested in seeing or reading more about after I talk about them. And so what are we going to talk about today? I really want to cover three important topics. The first one is bacterial infections when COVID patients have respiratory failure. The second is pulmonary embolism in the era of COVID. And third is cardiac arrest when it comes to COVID patients. And I do have to be honest with just a little bit of time, I can't dive too deeply into any of these areas. But I'm going to try to at least give you my perspective on a couple key clinical questions. So let's dive right in. COVID and bacterial infections. Any other year of your life, you see this chest x-ray and what do you do? You treat it with broad-spectrum antibiotics. But 2020 has brought a new challenge for us as we look at this chest x-ray. And when we have COVID-19 patients who have chest x-rays that look like this and are in respiratory failure, should we be giving them empiric antibiotics? Should we be pulling the trigger on Zosyn and Bank in every one of these patients? And so, you know, the quoted literature so far of all comers says that about 7% of all comers that get hospitalized with COVID have a super infection from a bacterial illness. I love this paper in particular in the Journal of Infection, which is a nice systematic review and meta-analysis. Now be careful, because as we know, any meta-analysis is sort of Achilles heel is the quality of the evidence going into it. And the quality of the evidence going into this is not great. But we obviously don't have a ton of data right now. All of this is retrospective looks at patients who were diagnosed with COVID and what kind of co-infections they also have. What's nice about this article is that they also looked particularly at ICU bound or ICU patients. The problem is we don't know when this co-infection developed. And ICU patients had a doubling, a 14% rate of bacterial co-infections compared to all comers that were hospitalized that was more like 7%. And so this is really challenging, because almost all of these patients were receiving antimicrobial therapy, which means we are shooting, you know, the big guns of Zost and Vank and maybe even bigger at some of these patients when only at best 14% of them had some sort of infection. Now, the other challenge is, we don't know when this infection presented its ugly head, right? Was this an infection at the time of admission? Or was this a co-infection three, five, 15 days later, when they had a Foley sitting in them for that time? Okay. And one thing that's nice about this study was it showed us what pathogen was the cause of this infection. In this case, mycoplasm was far and away the most common co-infection. Now, given the N is quite small here, they were looking at 3,800 patients with COVID, when only about 25 actually had a clear isolated organism, at least in the reports that they were looking at. So we have to be really, really careful, but this has really informed the way I approach these patients, as is the fact that we do live in an era where antimicrobial stewardship has kind of gone out the window. When we live in a place like the emergency department of undifferentiated patients and hospitals that care more and more about sepsis metrics that aren't always the most evidence-based. So my answer to COVID and bacteria is, honestly, I probably am not reaching for Zosyn and Bank or really many antimicrobials unless the patient is really, really quite sick or gives me some other reason to believe that they have a bacterial super infection. That said, in the ED, in the undifferentiated patient, it's probably very reasonable to give one dose, but we as ED intensivists have to probably very quickly deescalate these antibiotics. So let's transition into COVID in clots, right? PE in COVID. We know that there is a lot of data saying that these patients that get hospitalized have a much higher rate, reaching about 15%, compared to the 3% of other viral pneumonias that we know are out there. And so should all of our COVID-19 patients in the ED be getting CTs to assess for PE? This is a tough one for me because I have colleagues who I find to be rather conservative, who are like, the Venn diagram is too significant to not be CTing most, if not all of these patients. They all have dyspnea. A lot of them have pleuritic chest pain. I was a big believer of, nah, I don't think that this is necessary unless they show me something else. They have right heart strain. They really seem to be sicker than the average patient. But what does the data say? Many of you probably saw this chest article from a position patient paper from national PE response team consortiums. Obviously, when you're someone who is a hammer, the whole world's a nail, right? And so they definitely advocate for more CTAs if you have any suspicion of PE in a COVID-positive patient. And so it gave a lot of fodder for this discussion. I would assume also that many of you have now seen the PEPCOV study that was published in academic emergency medicine earlier in 2020. This was a multi-institutional, multinational retrospective study, including about 3,000 patients that had received a CTPE, right? This is what's important is they had all already received their CTPE, and then they went back and analyzed which had COVID, about 1,000 of them, and which did not, another 2,300. And they found an exact same rate of PE confirmed on those CTs, okay? So this made a lot of people say, maybe we're over-testing for this, right? Well, they then went on and published in the thrombosis research article a little bit of a deeper dive of looking at these patients in context of non-COVID patients and the rate of CT utilization. And there's no question that CT utilization for PE is increasing, we knew that, but it's particularly increasing in the era of COVID is what they have seen. That said, when you have a suspicion that there is a PE in your COVID patient and you get a CT for it, you have a seven times more likely odds ratio of diagnosing that, right? So one of the things here is that it's very clear that we're finding COVID has a thrombotic risk, unlike a lot of other viral etiologies that we've seen, or at least much more so than some of the others. And so we really, really have to be thinking about this carefully. And it has certainly made me try to hone my spidey sense a little bit more clearly. And I'll be honest, this has really made me rethink, and I'm getting a lot more CTs in patients with COVID that have some element that makes me think that they have a PE. They aren't just there with just plain dyspnea. But as soon as I get a spidey sense, now I have a much lower threshold to see CT people with this data. Okay, let's transition to COVID and death. And I know my colleagues have already addressed a little bit of this, but I wanna hit this, and make sure we are clear about this just briefly, okay? And so should we be resuscitating patients with COVID? I am the resuscitation chair of our hospital, and we have had a long months and months discussion of whether or not this is a worthwhile effort. And many of you have probably seen some of the early reports out of New York, for example, they had a 0% survival to discharge rate in about 100 patients, 120 patients initially. This came out and really sort of made waves. This was a study out of Georgia of a healthcare system, but of only 60 patients, they had a Ross grade of about zero. And so that really made a number of my colleagues say, we gotta rethink this. We should not be even resuscitating them, we're gonna put our safety first. But I would counter that and say, when we look at this a little bit more rigorously with a retrospective, yes, albeit retrospective, but a very large cohort study of about 63 institutions worldwide, including the United States. One of the things they found in these 5,000 COVID patients is that they had an ultimate ROSC and neuro intact survival rate, much closer to 7% in their in-hospital cardiac arrest cohort. So that makes me say, it has really put the brakes on our decision to say, let's not offer CPR to these patients. Don't get me wrong, we're nuanced providers as EM intensivists, right? We love to embrace the nuance of, the intersection of resuscitation, critical care and emergency medicine. And I am not one to say that in the least, but I think we have to at least offer in the right patient population, a consideration for CPR, as long as we do it safely, okay? And so in my opinion, should we be resuscitating patients with COVID? The right ones, absolutely. Younger people who have low level of comorbidities and not a significant past medical history that would make them a poor candidate says, I gotta be safe, but I also have to be a scientist. And we have to be careful. I just wanted to take a moment and say, we gotta be really, really careful as physicians of taking some of the early on anecdotal evidence and applying it to our practice. We are still in that phase. Let me be clear about majority of what we do in COVID, but I would say it really have me put the brakes on the way I was approaching, especially system-wide care about offering patients resuscitation who have COVID. So that was a real quick, you blinked and you missed it, highlight of COVID diagnostics and risk stratification. So what did we learn over the last 15 minutes or so? First, COVID and bacteria. I would say, in the ED setting, when you have a very undifferentiated patient who has really bad signs of maybe septic shock and things like that, we maybe think about broad spectrum dosing. But remember, again, community acquired pneumonia is a different regimen. I'm saying this more for probably my residents, more so than anyone else. It's Zosyn and Bank is not our only tool to treat these patients. But we as EM intensivists have to deescalate this very, very quickly. COVID and clots. This has got me thinking longer and harder about these patients. Don't get me wrong. I give all of my patients their honest due, but this data continues to push me more towards getting more testing than less in a patient who has any sort of condition that would make me think that PE is just as likely on my differential as COVID. And therefore, COVID no longer is a diagnosis that says, okay, once they have that, I'm done. I may need to work them up a little bit more for this thrombotic risk that we are seeing more and more of. And last but not least, and I know you all already do this, but COVID and cardiac arrest, we still have to give our all to. There is a ton of opportunity here for research. One of our colleagues, Cindy Sue out of Michigan has been doing a lot of great basic science research looking at aerosolization and the risk in the era of COVID and cardiac arrest resuscitation. And so I really encourage us to be careful about making conclusions too early on some of this literature. And last but not least, I just wanna say thank you and just keep swimming. We on the front lines as emergency intensivists are clearly working hard during this pandemic, probably in an unparalleled way. And so I just wanna say, you guys inspire me to get up every day and keep doing what I'm doing. And so I hope that you all are staying safe and staying well out there on these front lines. So I wanna thank everyone and I look forward to taking some of your questions here in just a little bit at the end of the panel. Thank you so much. I'm Jessica Nelson from Washington University in St. Louis where I practice emergency medicine and critical care. And I'll be covering the next section of our discussion today. I have no financial disclosures. Opinions in this presentation are my own and are based on the current available evidence. I'm going to be discussing COVID-19 and acute respiratory distress syndrome. We'll start by covering some of the debate over the pathophysiology and then move on to some of the more recently popular therapeutic options that are being trialed in patients with ARDS due to COVID pneumonia prior to intubation. These include high flow nasal cannula, non-invasive positive pressure ventilation and awake prone positioning. What can we say about COVID and ARDS? Well, we know more now than we did a year ago. When the pandemic was first declared, manuscripts were pushed to publication with an astonishing speed. The publication rate has not slowed down, still hovering at almost 2000 peer reviewed publications per week, but we're still left with a lot of unanswered questions about how this virus operates and how best to treat it and its varying manifestations. A large number of trials are ongoing. So I'm going to mix what evidence is currently available, including evidence prior to the pandemic with personal experience and opinion. There is a spectrum of pulmonary manifestations caused by the virus. About 5% of patients who contract the virus require ICU admission, and the rate of intubation among ICU patients has been reported as 71% or higher. The proportion of intubated COVID-19 patients with ARDS approaches 100%. Median time from first symptom onset to ARDS is around eight days. While some patients with COVID, pneumonia, and ARDS will present with the typical stiff lungs that we are used to managing, one of the most confusing paradoxes is those patients who meet the Berlin criteria for ARDS, but have preservation of compliance and pulmonary mechanics. Begging the question, is this ARDS or a separate beast that some are referring to as C-ARDS or COVID-19 associated ARDS? One report by Gattinoni and colleagues described these two phenotypes clearly and labeled them as type one or non-ARDS and type two, typical ARDS. This has been hotly debated, however. Other studies like that of Zier and colleagues have shown intubated patients to have similar pulmonary mechanics to patients with typical ARDS based on lung compliance, dead space, in response to prone positioning. In my experience, there seems to be a spectrum, and patients may initially present with preserved compliance, but develop worsening mechanics over time, possibly as a result of ventilator-induced lung injury, or possibly as a progression of their disease. Direct cytopathic effects of the virus to the pneumocytes have been found on pathology in patients with COVID-19, in addition to the more typical findings of highland membrane formation and inflammatory injury. For now though, I still think it's best practice to stick to existing ARDS protocols and therapies, including low tidal volume ventilation, especially now that many patients are being intubated later in their disease course. This will likely place more patients in the typical ARDS category, with poor compliance due to both disease progression and possibly patient-induced lung injury, or injury from non-invasive strategies. Speaking of delaying or avoiding intubation, let's move on to the use of high flow nasal cannula for COVID-19 patients with respiratory failure. High mortality rates, prolonged requirements for mechanical ventilation, and a shortage of supplies, space, and qualified personnel have pushed back on an initial trend towards early intubation and drawn alternative therapies for COVID patients with ARDS into the mainstream. High flow nasal cannula is primarily a flow generator to flush the nasopharynx, wash out dead space, and provide a very small amount of PEEP to help slow exhalation and decrease work of breathing. The humidification can also help mobilize secretions. But what evidence do we actually have that we are benefiting patients as opposed to just inappropriately delaying intubation? High flow nasal cannula was used prior to COVID and was supported by the FLORALI trial, which showed a decrease in intubation rates for patients with a P to F ratio of less than or equal to 200, as well as decreased mortality in patients on high flow nasal cannula compared to the standard oxygen and non-invasive ventilation groups. A more recent systematic review did not confirm this change in mortality, but it did show that high flow nasal cannula was associated with a significant decrease in need for intubation. There's some data on the use of high flow nasal cannula in patients in Hong Kong during SARS that was published by Yam and colleagues where intubation was avoided in 34% of patients. So this information, as well as the previous from the FLORALI trial was extrapolated to have some relevance in patients with COVID potentially. Yam and colleagues demonstrated higher survival among patients with high flow nasal cannula compared to non-invasive or invasive mechanical ventilation. However, this study was not specifically designed to evaluate high flow nasal cannula. It was not randomized and it was published early in the course of the pandemic with multiple other limitations as well. International guidelines have given varying opinions on the use of high flow nasal cannula, but many support at least a trial based on the admittedly relatively weak available evidence. So the answer right now is that it's probably reasonable to trial high flow nasal cannula for patients with respiratory failure. These patients will need to be in a monitored setting though. If they develop increased tachycardia or hypoxia despite high support, then it may be better to either consider non-invasive positive pressure ventilation or intubate earlier to prevent respiratory arrest, which leads us to non-invasive positive pressure ventilation which can add a significant amount of pressure to assist inhalation and increase functional residual capacity, thereby potentially improving lung compliance. Overall, this tends to be not quite as well tolerated by patients as high flow nasal cannula, but it has been shown to be better at improving oxygenation likely due to the higher mean airway pressure. Patients with the same risk factors that are associated with complications from COVID such as COPD, obesity, sleep apnea may also be ideal candidates for non-invasive positive pressure therapy. Observational studies have shown that non-invasive positive pressure ventilation may stabilize the course of a patient with mild to moderate respiratory failure if the patient does not have high inspiratory drive or exert excessive inspiratory effort. There's also a study by Belani and colleagues though where non-invasive ventilation was used in about 15% of patients with ARDS irrespective of disease severity which showed non-invasive ventilation was associated with higher ICU mortality in patients with a P to F ratio of less than 150. Other studies on the use of non-invasive positive pressure ventilation in patients with viral pneumonia and ARDS are very limited and mostly consists of case series or non-randomized retrospective studies. So caution is certainly advisable when using this modality in patients with more severe ARDS. Non-invasive positive pressure ventilation may reduce the need for intubation but in patients for whom this therapy fails it's really not known currently if they would have had better outcomes with earlier intubation and mechanical ventilation. Observational studies have shown that non-invasive positive pressure ventilation either BiPAP or CPAP may stabilize the clinical course but these studies again were not specifically designed to evaluate this. The recommendations of international societies regarding the use of high-flow nasal cannula and non-invasive ventilation are quite varied and frankly conflicting. However, though the general trend has turned towards at least a trial of these strategies on a case-by-case basis in a closely monitored setting especially for patients with concurrent hypercap respiratory failure. You can see the SCCM guidelines attached here. For patients on high-flow nasal cannula or especially non-invasive support, a high respiratory drive, especially in patients with relatively preserved compliance may actually lead to generation of large tidal volumes and high transpulmonary pressures. This lung stress places the patient at risk of patient self-inflicted lung injury. So for that reason, high-flow nasal cannula may actually be preferred over non-invasive positive pressure ventilation in addition to its comfort benefits. And when non-invasive positive pressure ventilation therapy is used, CPAP should actually be considered as the initial intervention rather than a bi-level pressure support. While high-flow nasal cannula and non-invasive positive pressure ventilation were initially controversial due to the risk of aerosolization of the virus, most studies have found it to be relatively safe for surrounding staff. For high-flow nasal cannula, dispersion was not significantly different from regular nasal prongs. A droplet surgical mask placed over the cannula and worn by the patient also decreases spread. And for non-invasive positive pressure ventilation, a filter should be added to the circuit and masks should be fitted so as to minimize leaks. Patients are ideally placed in negative pressure rooms or at least well-ventilated rooms and staff should obviously be wearing appropriate PPE. So this leads to the conclusion, at least from my perspective, that a trial of non-invasive ventilation, usually after high-flow nasal cannula or in select patients may be reasonable. Populations that have shown the most benefit from non-invasive in the past, such as those with a high PCO2, COPD, sleep apnea, may benefit the most. If patients develop increasing tachypnea, tachycardia, or hypoxia despite high support, then it may be better to intubate earlier to prevent respiratory arrest. And don't be lulled into a false sense of security by mild improvements in oxygenation. Remember, we need to treat the patient, not just a number. Finally, proning. Proning mechanically ventilated patients with ARDS has been shown to improve both oxygenation and mortality, but can this actually be translated to even earlier interventions and proning these patients prior to their need for intubation? A study by Ding and colleagues looked at a small series of patients with moderate to severe ARDS treated with high-flow nasal cannula or non-invasive positive pressure ventilation who underwent BID proning sessions two hours each. The main causes of ARDS for included patients were pneumonia due to influenza or pneumonia due to other viruses. Prone positioning was well-tolerated. The P to F ratio had an upward trend in patients with all four support strategies. 11 of the 20 patients avoided intubation and were considered to be the success group. All patients with a P to F ratio, however, less than 100 on non-invasive ventilation did require intubation and were in the failure group. So patients with severe ARDS seemed less likely to potentially benefit from this therapy. Relatively early in the pandemic, Caputo and colleagues trialed awake self-proning in a series of 50 ED patients and found improvement in median oxygen saturation. Patients requiring non-invasive ventilation were excluded. Improvements in oxygen saturations were also found in a small study of 22 patients in Boston. And then Sartini's group found improvements in the P to F ratio and oxygen saturations in another case series of 15 patients receiving non-invasive ventilation in the prone position for a median of two cycles with a total duration of three hours. All patients also had a decrease in respiratory rate. Most also felt subjectively improved. There are few guideline recommendations for awake proning, but I do believe that a trial is reasonable in patients who can tolerate it. Patients with signs of respiratory distress or a severe ARDS are unlikely to be ideal candidates for this therapy. It does also seem to help to have a timeframe outlined for patients I've found and set a timer for whether you want them to prone for two, four, six hours, whatever. Patients may also benefit from varying between the prone and the left or right lateral decubitus positions. And it's also likely to be better tolerated by patients on standard oxygen therapy or high flow nasal cannula. However, it may still be reasonable to trial in cooperative patients on non-invasive positive pressure ventilation, especially those in lower settings and possibly starting in the lateral decubitus position and for shorter periods of time. As discussed previously though, these patients should be closely monitored and any improvements in oxygenation may in fact be transient. So in summary, we covered COVID-19 and ARDS therapies prior to intubation. So I recommend based on the current pathophysiological evidence, maintaining current standards of care with low tidal volume ventilation to prevent worsening lung injury. High flow nasal cannula followed by a possible trial of non-invasive positive pressure ventilation is reasonable in many of these patients. And finally, those who can tolerate awake proning should trial it. All of these patients should be closely monitored for signs of worsening respiratory failure as significant percentage will still require intubation. For those who do best with an algorithm, my recommendations and practice most closely align with this algorithm by Dr. Roof and colleagues for your reference. Thank you so much for your time. Please feel free to contact me with any questions.

COVID-19

intra-arrest transport

resuscitation

high-flow nasal cannula

non-invasive positive pressure ventilation

ARDS

prone positioning

intubation

Emergency Medicine and EMS Care