Tanner Smida: AHA ReSS 2024 Abstract Review (11/22/2024)

So Tanner's going to take us through the abstracts. They were all online and he took the time to go through that. So Tanner, looking forward to it. Take it away.

All right. So in the next about 15 minutes, I'm going to go through about just as many abstracts from the Resuscitation Science Symposium that I think are relevant to all of us as EMS clinicians and people who are interested in EMS research. So just to start off, the largest subcategory of abstracts here concerned airway management during out of hospital cardiac arrest. Always a hot topic. The first of these was a sub analysis of the part trial. The part trial cluster randomized patients to either receive endotracheal innovation as their first line advanced airway management strategy versus a king laryngeal tube as the first line airway management strategy. They went back and they looked at the data from this trial, the electronic health record data and biosignal data from cardiac monitors. They asked the question, when you arrive on scene, what is the first advanced life support intervention that you should prioritize? Should you put the advanced airway in first or should you go for vascular access and your first dose of epinephrine first? What they found in this study was essentially no association between the order of airway versus vasopressor and outcomes not associated with survival to discharge or survival with a favorable neurologic outcome. It was also not associated with process measures, so things like chest compression rate or ventilation rate.

This next one is a single center study. So it looked at a cohort of patients who were presenting with ventricular fibrillation. And they used audio recording data and then biosignal data from monitored defibrillators to calculate something called the apnea interval. This was defined as basically the time from the last breath prior to the first endotracheal innervation attempt to the next breath delivered after that endotracheal innovation attempts. They looked at about 185 patients. The median apnea interval was 89 seconds. Most of that interval was the actual attempt at laryngoscopy. And they found that an apnea interval greater than 120 seconds or 2 minutes was associated with decreased odds of pre hospital ROSC but not survival to hospital discharge. I think this one, we think that things like first pass success are important to the outcomes of out of hospital cardiac arrest patients. But this adds another dimension. If it takes you two minutes to get that first pass success, it's probably detrimental to patient outcomes.

So the next couple advanced airway abstracts I wanted to cover are all registry studies. So this is from a Korean cardiac arrest registry, very similar to cares. And so they looked at adult non traumatic cardiac arrests that received pre hospital advanced airway management. They stratified patients based on whether they received supragotic airways, endotracheal innovation facilitated by direct laryngoscopy or endotracheal innovation facilitated by video laryngoscopy. And these others found that video laryngoscopy was associated with greater rosc. However it was not associated with survival to discharge or survival with a good neurologic outcome. I thought this is interesting. It's a hard question to answer retrospectively. There's a lot of reasons why these patients might have gotten video laryngoscopy so they could be more well resourced agencies, more experienced providers if outcomes are improving across time. This is a relatively recent recently introduced technology so it could be a cohort effect. But again in the end despite whatever bias exists, no difference in the outcomes that we're really interested in.

This next one is a secondary analysis of the rock epistry. They used some interesting methodology so time dependent propensity score matching to compare patients who received pre hospital advanced airway management to patients who just had BLS management in the pre hospital setting. And so they matched patients who received advanced airway management, so that was either supraglottic or endotracheal tube to patients who are at risk of receiving advanced airway management in the same minute but did not. They found in about 44,000 patients that pre hospital advanced the management was associated with greater odds of survival to discharge. A small difference there, but it was consistent across subgroups defined by age. Again a heavily confounded question here. There's a lot of reasons why people may or may not receive advanced airway management that could also be associated with outcome. But it's definitely hypothesis generating.

This study very similar methodology. They also use time dependent propensity score matching but it focused on a different population. It looked at pediatric in hospital cardiac arrest. Looking at the get with the guidelines registry they looked at about 3,000 patients and they found that intra arrest inhibition among again pediatric patients who did not have an advanced airway at the time of their cardiac arrest was not associated with greater survival to hospital discharge except among children greater than eight years of age. It's unclear whether this is just kind of random chance in this subgroup or whether there's some underlying physiology that kind of drives this change. But I'm looking forward to see the full paper come out on this One.

So moving on to the delivery of basic life support from the airway. One of the first decisions that we make when we're managing out of hospital cardiac arrest patients at the BLS level is we decide where to put our hands on the chest when we're delivering chest compressions. So I thought this was kind of an interesting study. It uses a video review registry of cardiac arrest at a single emergency department. And so basically this study included all patients in that video registry that had either end tidal recording or or invasive arterial blood pressure monitoring during cardiac arrest. Investigators reviewed the videos of the resuscitations, they looked at where operators were providing chest compressions, and then they tried to associate that with Both end tidal CO2 values and systolic blood pressures. And while they found no association between end tidal CO2 values and compression location, they did find that compression to the left of the sternum was associated with higher systolic blood pressure than on the standard position on the lower part of the sternum. While this is interesting and hypothesis generating, I think there are probably more important hemodynamic variables than systolic blood pressure during cpr, right? So things like coronary perfusion pressure are likely more important to outcome, but again, definitely hypothesis generating. And it's possibly a very basic aspect of cardiac arrest care is important to hemodynamics and outcomes.

This next study that's related to some of the ventilation studies that Dr. Anteby talked about. This was a secondary analysis of data collected during the ROC CCC trial. It looked at patients who were assigned to the 30 to 2 arm and had greater than 2 minutes of impedance data. So kind of same methodology here. They classified patients who had.

Detected ventilations in greater than 50% of pauses as having good quality ventilations and patients who had basically no ventilations detected in greater than 50% of pauses as poor ventilation. And what they found was, of course, good ventilations were associated with better outcomes, but they found that the difference in outcomes was most pronounced at chest compression fractions less than 85%. And so, you know, they kind of postulate that this may suggest that kind of the optimal combination of chest compressions and ventilation may include kind of sacrificing some chest compression fraction with the goal of providing higher quality ventilations, or maybe stating that kind of conversely, you know, pursuing an ultra high chest compression fraction may compromise the quality of the ventilations we're providing and adversely affect outcomes. Again, definitely needs some kind of prospective study and further validation, but it's definitely hypothesis generating and drives home the point that we need to pay more attention to ventilation during cardiac arrest.

This next one is related to transfer of care. So when we're bringing patients into the emergency department who are undergoing active resuscitation from that same video review registry I discussed before, and they basically studied if there was a difference in time to initial rhythm analysis and time to initial defibrillation if indicated, based on whether resuscitation teams used EMS cardiac monitors for the first analysis and defibrillation versus ED equipment. If they waited to transition the patient to the pads attached to the ED defibrillator before they did rhythm analysis and defibrillation, their findings here were pretty striking. So they found that for teams that use the EMS equipment, their time to first ed rhythm analysis was much shorter, so 96 versus 255 seconds. And also for patients where defibrillation was indicated, the time to defibrillation was strikingly different. So if they use the EMS cardiac monitoring, time to defibrillation was 1.7 minutes after ED arrival, versus almost 7 minutes if they waited the transition to emergency department equipment prior to rhythm analysis and defibrillation. So I think this just kind of highlights we need to collaborate with our receiving emergency departments and make sure that our patients are getting the best possible care as they proceed through kind of the system of care we've set up for them.

These next two abstracts look at kind of cardiac arrest care in Chicago. So the first one looks at bystander CPR rates from 2014 to 2023. They found kind of Dramat across that period, from 12.4% to over 40% of patients receiving bystander CPR in 2023, they got a 5% increase per year after 2018. So pretty sharp increase there. They stratified their cohort by race and sex and basically saw similar trends across the board. And not surprisingly, when they went and looked at their CARES data, they've also made great strides in improving cardiac arrest outcomes overall. So in 2023, they reported their best survival to date. So among those patients who are witnessed and advised standard CPR and initial rhythm of VF or VT, about 40% of those patients survived. When they looked at all comers, their survival to hospital discharge rate was 10.6%, which exceeds the national average for 2023. Again, when you look back comparing previous years to their outcomes in 2023, big increases in survival to hospital discharge and neurologically intact survival. When you account for important variables that predict patient outcomes, I think this just goes to show we talk a lot in these abstracts about kind of fancy interventions, airways drugs. But if you really want to move the needle on cardiac arrest survival, the key really is investing in your community and making sure that patients are getting this early care that we know makes a difference in outcomes. So a little bit of a hopeful story there.

The next abstract looks at end tidal CO2 values. So this is a study using the NEMSIS national data sets. The study looked at out of hospital cardiac arrest cases with end tidal CO2 values documented. The authors calculated basically two metrics for every case. They looked at the maximum distance between sequential end tidal CO2 values during these cases and then also the total distance between the minimum and maximum end tidal CO2 value for each case.

They looked at over 270,000 out of hospital cardiac arrest 1.7 million end tidal values in total. Basically what they found was the larger that delta, whether we looked at, regardless of which metric they looked at, it was associated with increased odds of ROSC. So about 20% increased odds of ROSC per 10 millimeter of increase in both of those metrics. One thing that I thought was really interesting about this abstract, when you look at the patients who had a maximum change in end tidal CO2 in the pre hospital setting, between 0 and 10 millimeters of mercury, their end tidal CO2 values were relatively flat. Still, about 1 in 3 of those patients achieved ROSC in the pre hospital setting. I think this goes to show that in isolation end tidal CO2 isn't very sensitive and specific for any outcome, including prehospital rosc. I definitely think it's useful and should be recorded and should be used in context with all the other variables that are being considered during resuscitation. There's a lot of things that influence it and it's a complex value. And taken in isolation.

This next one was the only abstract, I believe, in the science symposium that looked at traumatic brain injury. And not surprisingly, it was a secondary analysis of data collected during epic. And so what these authors did is they looked at both monitor file data so that from the time a monitor was turned on to the time a monitor was turned off, they basically had continuous second by second monitoring of SpO2 values and ECG, et cetera. And what they did was they looked at this monitor file data, they looked at the second by second recording of SpO2 and the SpO2 pleth wave, and they looked for evidence of hypoxia in the monitor files. And then they went and looked at associated EMS completed electronic health records and they looked at how many of those electronic records had documented evidence of hypoxia. And the results were pretty striking. So in the actual electronic health records, only about 12.7% of their cohort, or eight patients, had documented evidence of hypoxia. Whereas what they actually went and looked at the objective monitor file data, they found that about 37% of patients had documented hypoxia at some point during the prehospital interval. And so I think this highlights two things. I think first of all, it may highlight that basically we're under recognizing hypoxia in these patients and maybe missing an opportunity to treat it. Right. Which may influence outcomes. And I think the second big takeaway is for people who are responsible for quality improvement, right? Medical directors, QI officers, if you're going to be evaluating how safely or, you know, your crews are performing a procedure like RSI or how effectively you're taking care of traumatic brain injury patients, it's not sufficient to just look at the run sheets or the electronic health records, right? You actually have to delve into the monitor files, you have to get case review, you have to get code stat, and you have to look at the actual bio signal data to make sure you're able to pick up events like unrecognized hypoxia reliably and then again work to improve care for this population of patients. I'm not saying that this is because clinicians are dishonest. It could be that these episodes of hypoxia are just being unrecognized while you're not looking at the monitor, you're starting an iv, you're on the radio with medical command, et cetera. But I thought this one was really thought provoking and important.

There were two, two abstracts on rearrest. Nothing really surprising here. So this first one looked at in hospital cardiac arrest using defibrillator and electronic health record data, they found that about 40% of patients rearrested, most of them rearrested non shockable rhythms. And they found that risk of re arrest was highest very early following ROSC in this first couple minutes. So it kind of supports prior data.

This other study, you know, very similar, except it used out of hospital cardiac arrest data.

50% rearrested in this cohort. Again, non shockable rearrest was most common. They identified some predictors of rearrest, older age, female sex, some comorbidities, as well as longer downtimes. Not surprisingly, re arrest was associated with mortality.

This next one is an interesting study from the University of Pittsburgh. These authors, basically they looked at electronic health Record data from the City of Pittsburgh EMS that were recorded during the first half of 2023. They identified encounters that documented evidence of unhoused patients that were treated by EMS in the free text fields occurred near in homeless encampments or encounters that took place at known homeless shelters. They ended up with 424 encounters or electronic health records. 204 of those encounters included the treatment of unsheltered homeless people. They found no difference in their primary outcome of response times. They were interested in differences in access to care among these two populations. But I think an interesting secondary finding was they found much higher rates of trauma and overdose among this unsheltered population. The authors suggest that targeting these populations in these geographic locations with training about bystander interventions, things like administration of naloxone and stop the bleed training might get these interventions delivered to the population of patients who need it most.

To finish it up, I have two studies here about some technology that's on the horizon that might be impacting EMS care. This first one is about a wristband that can detect cardiac arrest. This is a single center study. They basically went and put this wristband on people in the hospital who had undergone withdrawal of life sustaining care. So they were predicted to die within the next 24 hours, as well as patients who were undergoing different cardiothoracic procedures. During the study, 15 cardiac arrests occurred to patients who were wearing these wristbands. The cardiac arrest was detected successfully in 14 out of 15 of those cases. The one false negative was caused by initiation of resuscitation. So CPR, administration of medications, vascular access, et cetera. And interestingly, there were no false positives. And so you can imagine a future where the outcomes of unwitnessed cardiac arrests are revolutionized by transforming many of these to witness arrests, providing automated notifications to EMS agencies of patients that have gone down alone in their homes, hopefully maintaining the kind of no false positive claim that's made by this abstract, hopefully more successfully than the kind of automated vehicle accident notifications that we're all familiar with.

And then this last one. So for patients who present with PEA cardiac arrest, we don't really have a lot of good therapeutic options for these patients. Their outcomes are pretty dismal. This looks at a possible therapeutic option for patients who present in pseudo pea. This is a swine model. Pseudo PEA was induced by infusion of esmolol to very low mean arterial pressures. And then these investigators either administered chest compressions that were synchronized to native cardiac activity versus unsynchronized chest compressions at a rate of just 100 per minute. And so what they found was that synchronized chest compressions generated better hemodynamics during cpr, less diastolic compromise, higher coronary perfusion pressure. And so trialing of kind of this methodology might be a future therapeutic avenue for those patients that present in pea. That's all I have. Thank you very much for listening.

Awesome. Great job. Um, I'll open it up for any comments. I see some folks on the. On the call who I'm sure. I know this was a lot of information. What I will say the beauty about the abstracts is that it's kind of a preview of what will end up getting published. And then it'll. It's a preview of what the. The guidelines folks will end up looking at. And so that was a great. A great review of that little preview. Anyone have any thoughts, comments about.

The guidelines? Anything shake you or anything that you thought you would like to see?

All right. And clearly, in 30 minutes, we just threw a whole bunch of information on that. We'll have this thing recorded, and we'll put it up on the YouTube channel. I also plan on doing a much deeper dive into just the pediatric side of the house, and. And then we can do the same thing on the adult side. So let me. Let me go to Dr. Miramantes. David, any. Anything that struck you there, or are you going to continue on with what you're doing?

I still think we don't know if mechanical CPR works better. I mean, I still think that we don't know that. And again, in all these studies, the problem with here is we can't really control title, volume, and rate in the study because there's no way to document that.

Right.

So those are my two little concerns.

Yeah. Yeah. And, you know, they. Oh, does somebody want to make a comment? Okay. It's. It's very interesting. I think reading through these documents will make you recognize what information they will look at and what information that they just won't look at or won't look at just yet. I'm still. And I'll still put my heels. And I'll. I'll dig my heels in and I'll say that the namsp, The EMS side of the house. Right. We are a subspecialty. We need to look at this information and evaluate this based on out of hospital. Strictly when you have to go through these guidelines and pick apart each of these recommendations, look to see whether or not these are in or in or out of hospital studies that are being reflected, it makes this whole thing much harder, and then you end up getting wide variability across the country. So I'm hoping that the folks at the NEMSP finally make a move to have some sort of guidelines that are unique to ems rather than lumping all of these guidelines in to in versus out of hospital cardiac arrest. Anyone have any opinion on that?

So, Peter, I think we have somebody on that board, right? I check with Jose, but I think we have. We have an assigned board member as a L officer to this.

The problem with that is, is that, you know, it ends up being groupthink. I know people who are. Who sit. Who sit on in these committees, and when they raise their hand to say something, they're basically, you know, people just look at them and stare at them and then they move on to the next question.

So, yeah, you could have one person sitting in the room, but a majority of these people have never ridden the back of an ambulance. And that. That's really my. My biggest concern here. So. But I'll keep. I'll keep beating the drum. All right, the Eagles webinar link is on the right hand side. Thank you guys for joining. Tanner, great job and I appreciate everything. And I will put this up on YouTube for later on. Get your credit, get your CME, and we'll see you guys on the other side in the Pepe webinar. Thank you, guys.