Every year, three EMS experts take to the stage at the National Association of EMS Physicians annual conference to sum up the top five research articles of the previous year. Their goal? Identify research that is relevant, counter-intuitive and practice changing—research that is important to the patients who call 9-1-1 with the expectation that they will be served with the best available care possible. This year, paramedic and emergency room resident Blair Bigham describes the articles he and co-experts Drs. Jon Rittenberger and Michael Millin selected.
The Case of the Shockable Woman
The Case: A 59-year-old woman suffers a cardiac arrest in a gymnasium. An athletic trainer applies a defibrillator while 9-1-1 is activated. Three shocks are administered before the EMS crew arrives. Coarse ventricular fibrillation is identified on the monitor, and high-quality CPR is ongoing by the gym staff. Epinephrine, lidocaine and three additional shocks are given, and the patient is intubated. She is transported without a pulse to hospital and remains in VF the entire time. The hospital administers amiodarone and delivers additional shocks. After 40 minutes of ongoing resuscitation, and a total of 11 shocks, the woman is pronounced dead.
The Evidence: Kudenchuk PJ, et al. Amiodarone, lidocaine, or placebo in out-of-hospital cardiac arrest. N Engl J Med, 2016; May 5;374(18):1711-22.
This is a high-quality randomized controlled trial conducted by the Resuscitation Outcomes Consortium. Patients in cardiac arrest who received two shocks were randomized to either amiodarone, lidocaine or placebo. From time of 9-1-1 call, it took approximately 19 minutes to administer the study medication.
Results for amiodarone, lidocaine, placebo:
ROSC: 35.9%, 39.9%, 34.6%, not statistically different;
Survival to hospital discharge: 24.4%, 23.7%, 21.0%, not statistically different.
Results for witnessed arrest for amiodarone, lidocaine, placebo:
Survival to hospital discharge: 27.7%, 27.8%, 22.7%, not statistically different.
The Bottom Line: While no difference was found in the total population, in patients who had witnessed cardiac arrest with shock-resistant ventricular fibrillation, absolute survival rates were 5% higher in patients who received an antiarrythmic. Earlier administration of antiarrythmics may lead to higher survival rates. The experts debated if removing amiodarone to simplify cardiac arrest care and allow providers to focus on proven strategies like high-quality CPR and defibrillation would achieve better outcomes; no consensus was achieved. Previous studies, while less rigorous, have shown amiodarone to be beneficial for return of spontaneous circulation and survival to hospital admission, but not survival to hospital discharge. The experts also noted that double-sequential defibrillation offers exciting possibilities for shock-resistant patients, but felt more research was needed to best understand how to care for patients requiring multiple defibrillations.
After a decade working as a helicopter paramedic, Blair Bigham, MD, MSC, ACPF, completed medical school in Ontario, Canada, where he is now a resident physician in the emergency department. He has authored over 30 scientific articles, led major national projects to advance prehospital research and participated in multiple collaboratives, including the Resuscitation Outcomes Consortium. He has taught and mentored clinical and academic paramedics and loves his new role teaching medical students. He serves as a volunteer on the board of directors for the MedicAlert Foundation of Canada and is a task force member for the International Liaison Committee on Resuscitation.
Michael Millin is a board certified EM and EMS physician from Baltimore, MD. He is a member of the faculty of the Johns Hopkins University School of Medicine and medical director of the Johns Hopkins Lifeline critical care transport program. He is also medical director for the BWI Airport Fire and Rescue Department, Maryland Search and Rescue, and associate medical dDirector for the Prince George’s County Fire/EMS Department.
Jon Rittenberger, MD, is an associate professor of emergency medicine and medical command physician for UPMC Prehospital Care. In addition to his emergency medicine practice, he is a founding member of the Post Cardiac Arrest Service at UPMC Presbyterian hospital. His research interest is in brain resuscitation during critical illness states. He brings over 20 years of EMS experience as a provider and researcher.