EMS World

DEC 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.

Issue link: https://emsworld.epubxp.com/i/1052828

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Page 16 of 83

THE TRIP REPORT: TURNING RESEARCH INTO PRACTICE 16 DECEMBER 2018 | EMSWORLD.com W hen discussing ST-segment elevation myocardial infarc- tion (STEMI), we've all heard that a strategy to reduce mortality is to reduce door-to-balloon times. This has been demonstrated through multiple studies. However, door-to-balloon time is defined as the time from patient contact at a hos- pital to primary percutaneous intervention (PCI). In the study we review this month, Mecklenburg EMS deputy director Jon Stud- nek and his coauthors astutely recognized that door-to-balloon time does not fully account for the impact EMS recognition of STEMI can have on mortality. This and a 2013 study that found a 16-minute reduction in door-to-balloon time was not associated with a decrease in mor- tality were identified as evidence that the prehospital phase of patient care needs to be incorporated and assessed to fully evalu- ate the influence of total ischemic time on STEMI patient mortality. Further, there is lim- ited research available evaluating the impact of prehospital STEMI times on mortality. There was a clear need for this interesting and important study. While there are multiple time periods the authors could have chosen that incorporate the prehospital phase of care, they decided to evaluate the time between when the 9-1-1 call was received and PCI. This is likely the most relevant measure in this EMS system because dispatchers utilize priority dispatch protocols and provide prearrival instructions for patients with suspected cardiac etiolo- gies. Therefore, this time metric truly encom- passes first medical contact. It's also likely a metric that closely captures total ischemic time. The study objective was "to determine if differences in mortality at one year in STEMI patients exist based on variations in the time interval [from] 9-1-1 call pickup to PCI." The authors also stated their hypothesis, which was "As the time interval 9-1-1 call pickup to PCI decreases, mortality will also decrease." To meet the study objective and test their hypothesis, Studnek and coauthors con- ducted a retrospective observational cohort study. Data were obtained from Mecklenburg County, N.C. This county has a longstand- ing and highly integrated STEMI system of care. Since 2007 it has maintained a registry of all prehospital STEMI activations in the county. By utilizing data from this registry, the authors were able to evaluate prehospital and in-hospital patient care records. The study period ran from March 2008 to May 2014. The study specifically evaluated patients who presented with an acute STEMI as identified by a prehospital ECG interpreta- tion. Patients were included if they were at least 18 years of age, were transported to a PCI center in Mecklenburg County, and met the local protocol for prehospital cardiac catheterization lab activation. Patients were excluded from this analysis if they were initially transported to a hospital that did not perform PCI and were subse- quently transported to a PCI center; if they met STEMI criteria after resuscitation from out-of-hospital cardiac arrest; or if they were deemed to not be a STEMI patient following in-hospital assessment. The primary outcome of interest was mortality a year post-PCI. The authors also evaluated a secondary outcome of mortal- ity at one month post-PCI. Studnek and his team took multiple steps to confirm whether the patient survived or died. To verify survival the authors depended on a documented follow-up visit or paramedic contact "at or beyond one year post-PCI." For patients who didn't have a documented follow-up, hospital records as well as records from local and national offices of vital sta- tistics were reviewed to confirm deaths. If a patient did not have a hospital record post- PCI and no death certificate was found, they were classified as having survived. The main independent variable of interest was the time interval between the initial 9-1-1 call and PCI. The authors' statistical analysis Do needle times for STEMI patients correlate with one-year death? By Antonio R. Fernandez, PhD, NRP, FAHA Look for research podcasts based on the topics featured in this column at www.emsworld.com/pcrf-podcasts REVIEWED THIS MONTH Decreased Time From 9-1-1 Call to PCI Among Patients Experiencing STEMI Results in a Decreased One Year Mortality. Authors: Studnek JR, Infinger A, Wilson H, et al. Published in: Prehospital Emergency Care, 2018 Nov–Dec; 22(6): 669–75. Time to PCI vs. STEMI Mortality

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