From Science to the Scene
Produced by the National Registry’s Research Team, From Science to the Scene is designed to help EMS Clinicians quickly understand important new research and evidence-based practices that impact patient care in the field.
Each episode will be approximately 10 minutes long and will highlight key findings from current research, helping Clinicians, Educators, and EMS leaders translate emerging science into practical knowledge they can apply on the scene.
From Science to the Scene
Intra-arrest Transport vs Continued On-Scene Resuscitation
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Should a Clinician "stay and play" or "load and go?" This question is at the heart of the latest episode of the From Science to the Scene podcast.
Our Research Fellow, Kayla Riel, joins the show to dive into a study that challenges old habits. For a long time, the common thought was that a fast trip to the hospital was the best chance for a patient in cardiac arrest. However, the latest data from the Journal of the American Medical Association tells a more complex story.
The research compares patients who were transported during resuscitation to those who received care on the scene. The results are clear: continuing care where the patient is found is linked to a higher rate of survival. A Clinician who focuses on high quality care on the scene may give their patient a better chance to return home to their family.
Moving a patient while their heart is not beating is a major challenge. It can lower the quality of chest compressions and create safety risks for the crew in the back of the ambulance. Kayla Riel explains how these findings should change the way we think about our protocols and our training.
See the research:
https://jamanetwork.com/journals/jama/fullarticle/2770622
#NREMT #EMS #EMT #cardiacarrest #ambulance #emergencymedicine #podcast #research
Hey everyone, I'm Kayla Real, your EMT National Registry EMS Research Fellow and PhD and Epidemiology student. I am here today to tell you about a study on the association of intra-arrest transport versus continued on-scene resuscitation with survival to hospital discharge among patients with out-of-hospital cardiac arrest. This research, published by Grunau, has a title that does not leave much to the imagination, so let's get into the review. So, for every piece of research, I want to have a better understanding of why they went through all this time, effort, writing, paying for the publication. And in this topic of intra-arrest, we are addressing lots of variability. In EMS systems, agencies at an individual level can perform similar interventions and techniques, but in different ways or with different pieces of equipment, for instance. Here, we are referring to the preference or protocol for transporting all patients, regardless of ROSC, versus how this may be uncommon for others when ROSC is not achieved. We also cover some safety concerns, especially in the realm of intra-arrest where licensed sirens may be present. This was a cited article in this study's reference, highlighting continued paramedic and public safety concerns during rapid transportation. And lastly, a tale as old as time: load and go or stay and play. This covers the extent of transportation and whether this has an effect on the quality of cardiac rest care, arguably all good reasons for pursuing this line of research. But all of this to ask a more simplified question: is there an association with survival to hospital discharge among patients experiencing out-of-hospital cardiac arrest in intra-arrest transport compared to that continued on-scene resuscitation? So, their primary outcome was survival to hospital discharge. Their secondary outcome was survival with a favorable neurological outcome at hospital discharge using a modified ranking score of lesson three. They also reviewed several other endpoints related to patient outcomes. And as you will gather throughout my evaluation here, there were several analyses performed throughout the study. This study utilized the dataset from the Resuscitation Outcomes Consortium, or ROC registry. This is a prospective registry which aims to learn which treatments work when people have a cardiac arrest. In our scenario here, it is intra-arrest and on-scene resuscitation. This design involved a multi-center, time-dependent propensity score-matched cohort study of patients experiencing out-of-hospital cardiac arrest. And for this study, they used 10 North American sites that had standardization of protocols to reduce variability. This study also took place for a four-year period between April 2011 and June 2015. These dates reflected time in which the data definitions varied prior to April, but not after June. And then ROC was discontinued. So time-dependent propensity scoring was a major theme of the epidemiological method of design for this study, especially considering that this can be effective for observational studies when assessing interventions or exposures over time. Now, the decision to transport a patient during resuscitation is influenced by various factors that evolve over time, such as the duration of the arrest and real-time clinical assessments. To account for these dynamic factors, the researchers calculated propensity scores at multiple time points during the resuscitation effort, otherwise called time epics. Then there was propensity matching. Patients who underwent intra-arrest transport were matched with those who continued to receive on-scene resuscitation, then, compared to a patient who, at the same minute, was still on-scene and had similar characteristics up to that point. This process may reduce confounding factors. The advantage of this method is to reduce confounding bias and improve comparability. So before moving on, just reiterating that the exposure group for this study contains those intra-arrest transports initiated prior to any episodes of ROSC, and the unexposed containing those who had on-scene resuscitation. And here in the study, ROSC was defined as a palpable pulse at any time. Primary outcome is that survival to hospital discharge. Here, in the full propensity matched cohort, survival to hospital discharge incurred in 4% of patients who underwent intra-arrest transport versus 8.5% who received on-SIM resuscitation. The negative risk difference indicates that there is a lower probability of survival to hospital discharge for patients who underwent intra-arrest transport compared to those who received on-SIM resuscitation. Their secondary outcome, that survival with favorable neurological outcome, was roughly 3% in the intra-arrest transport group and 7% for the on-scene resuscitation group. No subgroup differences were detected according to initial shockable rhythm or mechanical chest compressions. There were also no significant associations seen in BLS only or mechanical CPR-treated subgroups, but these analyses were limited by the low sample size as indicated by the researchers. Now, I would like to specifically review the time epochs as mentioned earlier. The time-based epic describes the start of EMS resuscitation and the time of matching. With the first 15 minutes, intra-arrest transport was associated with significantly decreased survival. 15 to 30 minutes was neutral, but this greater than 30 minute strata showed a significant association with improved survival, which I will address here later. There was sensitivity testing performed on all the data. The study also included analyses that incorporated cases excluded due to missing data. The adjusted risk ratio indicates that patients who underwent that intra-arrest transport had approximately 54% of lower odds of surviving to hospital discharge compared to those who received continued on-seen resuscitation, that less than one suggesting a negative association. This all to reinforce that the primary outcome was significantly associated with poor survival, despite varying patient characteristics and treatment settings. So, there may be a detrimental effect of intra-arrest transport early in the resuscitation, but this could mean three things. One, we have longer attempts to resuscitate, which could be good. Two, now that time-based strata can get tricky. So those who went intra-arrest transport underwent a median 10-minute additional minutes of resuscitation efforts while en route to the hospital. However, the researchers argue that those who received on-scene resuscitation were likely declared dead soon after with a mean duration until termination of about 26 minutes. And lastly, of those who received intra-arrest transport after 30 minutes and survived, two-thirds of them were successfully resuscitated prior to hospital arrival. Not too shabby. Themes related to their noted limitations include the observational design, association rather than causation, data limitations such as the low number of mechanical CPR cases, the laundry list of confounding factors, maybe even bias if you were to terminate resuscitation early. Missing data was assumed to be random, but may not be the case, and there will still be variability, we cannot escape that. Overall, very interesting research. I hope you learned more about different methods, such as that time-dependent propensity scoring. Thank you all for taking some time to listen and learn. And so, until next time. Whether you're hitting the books or hitting the streets, stay safe, stay curious, and keep bringing the science to the scene.