Hi there, everybody. Thanks for coming to this evening's session. My name is Tommy Rappold. I'm a Pediatric Critical Care Medicine Fellow at the Children's Hospital of Philadelphia. And today I'm going to be talking about Chest Compression Release Velocity and Associated Clinical Outcomes in Pediatric Cardiac Arrest, No Financial Disclosures. So three learning objectives for today. So I'll be defining chest compression release velocity, discussing confounders of release velocity, and then describing the associations between release velocity and outcomes in pediatrics. So to start, chest compression release velocity, or CCRV, is the maximum velocity during chest compression release in the posterior to anterior direction during a single CPR cycle. We measure CCRV using accelerometer data from the defibrillators, and it's measured in millimeters per second. And to date, much of the clinical research in CCRV is from the adult out-of-hospital cardiac arrest literature. And a few key studies suggest release velocity does make a difference, such that adult patients who receive faster CCRV had improved survival and favorable neurologic outcomes. So how fast is fast? So from the adult literature, they've described that slow is less than 300 millimeters per second. Medium is 300 to just under 400 millimeters per second. And then fast is greater than 400. Also notably, in these adult studies, CCRV was highly correlated with compression depth, likely because a deeper compression allowed for more time for acceleration during the relaxation phase. But the research for CCRV in pediatrics is scant. To date there are no clinical outcome-related studies of CCRV in pediatrics. And only recently has descriptive data been presented at rest in November in 2022. So to that end, we wanted to investigate, is CCRV associated with clinical outcomes in pediatric patients receiving CPR after in-hospital cardiac arrest? We hypothesized that faster CCRV was positively associated with return of spontaneous circulation, survival to hospital discharge, and survival with favorable neurologic outcomes. So for our study design, we also used PD Rescue. So this was a secondary analysis of prospectively collected data from PD Rescue. Patients were less than 18 years of age who suffered a cardiac arrest. Data collection was done with feedback-enabled defibrillators. And CCRV was derived from accelerometer data using proprietary algorithms. The time the defibrillator pad placement was known so the data could be time-corrected from the start of the CPR event. And data analysis was performed on the first 10 minutes of CPR data. So for our data analysis plan, we split our cohort into groups by age because of previously described physical differences in chest wall compliance that are based on age. For our data analysis plan, we didn't really have a baseline for what fast and slow in pediatric was. We only knew from our descriptive data that children less than 12 years of age didn't really approach adult CCRV values. So for these reasons, for each age grouping we decided to classify patients in the lowest quartile as being exposed to a slow CCRV. And those in the highest quartile being exposed to a fast one. And so the univariable comparison that we decided to do was slow versus fast for release velocity. And then secondary outcomes were survival and then survival with favorable neurologic outcomes. In our statistics, we used uni and multivariable regression modeling. So for our cohort, the registry had 1,783 in-hospital cardiac arrest events. 856 of those events had adequate CPR data. 98 of those events were excluded for having less than 33% of the CPR event actually recorded. And that left us with 744 events. Of those, 230 were excluded for having late PAD placement or unknown time of PAD placement. That left us with 514 events. And then from there we narrowed down to our index events of 383. So onto the results of the 383 index events, 127 of them were in less than 1-year-olds. 64 of them were 1- to 3-year-old. 107 were 3-12, and then 85 were 12-18. The median CCRV was significantly different between age groupings with CCRV increasing as age increased. In our univariable analysis we found patients between 3 and 12 exposed to a fast CCRV achieved ROSC at significantly higher rates than those patients who received a slow CCRV. There was no significant difference for any of the age categories when we looked at survival and then survival with favorable neurologic outcome. However, improved ROSC was not significantly better in our multivariable analysis which controlled for age, illness type, the rhythm or shockable rhythm at time of arrest. So morning or night, the day of arrest, as well as when we clustered by site. But when looking at 3- to 12-year-olds in isolation in a multivariable regression model, those exposed to fast CCRV were three times more likely to achieve ROSC. However, there was still no significant difference for survival and survival with favorable neurologic outcome. So how might fast CCRV improve outcomes? So one proposed mechanism is better hemodynamic power wherein faster CCRV improves the pressure gradient between the systemic venous vasculature in the right atrium, thus improving venous return, cardiac output, better hemodynamics, and that may lead to better outcomes. Our analysis here is important because it suggests there may be an association between chest compression release velocity and ROSC for those 3-12, but not necessarily the other age groupings. One limitation of our study is the definition of fast and slow, particularly for those less than 12 years of age. Are we comparing the appropriate speeds based on quartiles? Or are there lower or higher CCRVs in pediatric patients that may be detrimental or helpful? The second big limitation is the known correlation between depth and CCRV. The deeper the compression, the more distance for recoil and acceleration. It is likely that both measures are important and their correlation varies by patient. So in conclusion, overall fast compared to slow CCRV is not associated with improved ROSC survival nor survival with favorable neurologic outcomes across all pediatric age categories. However, fast compared to slow CCRV was associated with improved ROSC in our cohort for those 3-12 years of age. These findings in the 3-12-year-olds may make sense given chest wall compliance and mechanics changes that have been demonstrated in some animal models and in some humans as well. So future studies should focus on larger sample sizes given the nuances of chest wall and lung development in pediatrics based on age. Also future studies that incorporate a measurement for chest wall compliance in leaning may be able to tease apart the importance of depth in CCRV. So just a few thank yous. There's a lot of people to thank, frankly, for the development of this work in preparation of this talk. So Jennifer Hayes at the Children's Hospital of Orange County, my previous listed co-authors, the Pediarescue investigators, our data analysis team, and then my mentors, Sarah Chopp, Heather Wolfe, Bobby Sutton, Ryan Morgan, and N.V. Nainet Karni. So my references and then thanks for listening. It's almost time for dinner and maybe a drink. But if you guys have any questions, I'd be happy to take them.

chest compression release velocity

CCRV

pediatric patients

cardiac arrest

clinical outcomes