EMS World

JUL 2018

EMS World Magazine is the most authoritative source in the world for clinical and educational material designed to improve the delivery of prehospital emergency medical care.

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Page 20 of 51

20 JULY 2018 | EMSWORLD.com T he importance of high-quality CPR has been ingrained in our minds for years. We train often to maintain and improve our skills because high-quality CPR leads to improved survival for our patients. Bystander CPR and AED use are also associated with improved survival rates, and bystander CPR has been shown to have a positive association with better neurologic outcomes for out-of-hospital cardiac arrest. However, few studies have examined the quality of CPR provided by bystanders. The limited research is likely due to the difficulty in collecting bystander CPR quality data. Luckily for us, technology is making it easier. Canadian emergency physician Shannon Fernando, MD, et al., recently published a study examining bystander CPR quality dur- ing out-of-hospital cardiac arrest using data derived from AEDs. To do this, the authors utilized data collected by the Resuscitation Outcomes Consortium (ROC) cardiac arrest database. The ROC is a network of clinical and satellite centers that collaborate to facilitate clinical trials and other outcomes- based cardiopulmonary arrest and severe traumatic injury research. The ROC database used for this study was a deidentified regis- try of calls in which EMS cared for a patient suffering from out-of-hospital cardiac arrest. To be included in this database, the OHCA patient had to be evaluated by EMS and have had attempts at external defibrilla- tion by a layperson or emergency provider. Cases were also included if CPR was pro- vided by healthcare professionals who were not 9-1-1 response personnel. Finally, cases were included if the patient was pulseless but did not have defibrillation attempted or CPR provided by EMS. Patients were excluded if they were preg- nant; prisoners; had a DNR; had a blunt, penetrating, or burn-related injury; or had a severe loss of blood. Authors only analyzed patients who were at least 18. They also only included patients whose OHCA was of pre- sumed cardiac etiology. The study period was from July 2011 to July 2016. The ROC database data was matched with data obtained from 550 AED uses from the Ottawa Paramedic Service's AED data- base. Matched cases had a date and time within 4 minutes. All the AEDs were located in public buildings in the Ottawa-Carleton region, and they all had the ability to mea- sure the quality of CPR using an accelerom- eter between the rescuer and patient's chest. The AEDs also provided audio CPR quality feedback to the rescuer. The authors ana- lyzed the first five minutes of each AED use. They also used the Utstein definition of a bystander, which is "any person involved in a resuscitation who is not responding as part of an organized emergency response system to a cardiac arrest." To ensure CPR quality could accurately be assessed, cases were only included if they had at least a minute's worth of CPR data recorded. The authors decided this inclusion criteria was necessary because those cases with shorter durations often represented shockable rhythms and were more likely to achieve return of spon- taneous circulation with improved survival. The outcome measures used to evaluate CPR quality included the chest compres- sion fraction (the proportion of time spent providing chest compressions during resus- citation efforts), average compression rate, average compression depth, and average perishock pause. The perishock pause was the sum of the preshock pause (the time between stopping chest compressions and delivering a shock) and postshock pause (the time from shock delivery to resuming chest compressions). The authors mea- sured adherence to either the 2010 or 2015 American Heart Association guidelines as a secondary outcome of interest. A Very Small Percentage During the study period there were 4,274 OHCAs in the Ottawa-Carleton region. The authors removed 4,126 (97%) cases from the study analysis because these cases met at least one exclusion criteria. The largest percentage (45%) were excluded because they were nontreated. An example of a non- treated case would be a patient with a DNR. The second-largest percentage (39%) of cases excluded were those where no AED was applied or used. The remainder were removed because either the arrest was of a presumed noncardiac etiology, EMS wit- nessed the arrest, there was no available CPR quality data recorded by the AED, or less than one minute of CPR data was available. The final study population included 100 cases. It's easy to understand why so many cases were excluded. The inclusion and exclusion criteria likely led to the most appropriate study population. However, the authors ended up with a very small percent- age of the overall population for analysis. Technology has made collecting this type of data easier, but it's still hard to collect data to evaluate bystander CPR quality. Results The authors did not find any meaningful dif- ferences in patient characteristics between the study population and those who could not be included due to missing data. There were 79 cases in which the AED was used by a police officer and 21 where the AED was Bystander CPR is critical to OHCA survival—but how good is it? By Antonio R. Fernandez, PhD, NRP, FAHA THE TRIP REPORT: TURNING RESEARCH INTO PRACTICE Look for PCRF research podcasts based on the topics featured in this column at www.pcrfpodcast.org. REVIEWED THIS MONTH Analysis of Bystander CPR Quality During Out-of- Hospital Cardiac Arrest Using Data Derived From Automated External Defibrillators. Authors: Fernando SM, Vaillancourt C, Morrow S, Stiell IG. Published in: Resuscitation, 2018 May 16; 128: 138–43. Measuring Bystander CPR Quality

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