Research Study Examines Epinephrine’s Effects on Cardiac Arrest

Hagihara A, Hasegawa M, Abe T, et al. Prehospital epinephrine use & survival among patients with out-of-hospital cardiac arrest. JAMA. 2012;307(11):1161—1168.

Epinephrine has been the mainstay of cardiac arrest management for decades, but is it effective? These authors used a Japanese national database of prospectively collected cardiac arrest data to see whether epinephrine was associated with positive outcomes. This analysis included 417,188 arrests between 2005—2008.Return of spontaneous circulation was observed in 18.5% of patients who received epinephrine (2,786 of 15,030), and 5.7% (23,042 of 402,158) of patients who didn’t receive epinephrine.

The overall survival rate for the epinephrine group was 5.4%, but only 1.4% had good neurological outcomes. The non-epinephrine group had a 4.7% survival rate, and 2.2% had good neurological outcomes. Although this study sampled a large number of patients and was published in a prestigious medical journal, we need to be careful about the conclusions we draw from it.

The authors discuss some major limitations: Japanese EMS personnel started giving epinephrine in 2006, but the data doesn’t include the amount that was given. Hospital care was variable. The authors don’t know whether in-hospital epinephrine was given or whether therapeutic hypothermia was used.

I also think the study needs information on immediate conversion of v fib and v tach without prolonged resuscitation, rate of compressions, mechanical compression/decompression, ventilation rates, oxygen administration, excessive pauses and use of an impedance threshold device.

Effective, outcome-driven cardiac arrest management is multi-factorial. The authors addressed the need for a randomized placebo controlled trial, and I completely agree. Obtaining ethics board approval for a trial of such a standard medication as epinephrine will be challenging. We should applaud these authors for taking another step to lay the groundwork for more intentional studies in the future.

The bottom line is we should remind ourselves that all interventions come with unintended consequences. We need to continue with practicing the status quo, but we also need to be careful with epinephrine and get more involved in research.

IV Analysis
Selker HP, Beshansky JR, Sheehan PR, et al. Out-of-hospital administration of intravenous glucose-insulin-potassium in patients with suspected acute coronary syndromes: The IMMEDIATE randomized controlled trial. JAMA. 2012;3;307(18):1925—1933.

By way of disclosure, I want to state that one of my medical directors is involved in this study. So I claim immediate bias and conflict of interest, but I still think it’s a good idea to report on this study and its results, especially because this column previously reported the initial use of the “ACI-TIPI” predictive ischemia scale used in this trial. (Search for “research review.”)

The group of researchers studied the use of glucose insulin and potassium (GIK) to protect from myocardial injury during acute coronary syndromes. The idea was to give agents that might protect the cells from metabolic derangements (promoted by elevated free fatty acids, or FFAs) and reperfusion injury. Cellular FFAs and their derivatives are believed to accumulate during ischemia, disrupt the mitochondria, increase intracellular calcium and promote arrhythmias. GIK might be a relatively safe, cost effective and plausible way to begin prehospital treatment.

The original goal of this study was to enroll more than 15,000 prehospital patients because the benefits were thought to be dependent on early administration. Unfortunately, the National Institutes of Health changed the study due to the lack of resources and funding to include in-hospital administration, and enrollment was curtailed at 880 patients. One-year outcome data is still being collected. So the final data isn’t yet available.

For now, this paper reports that GIK didn’t seem to stop further myocardial damage (i.e., no statistical difference was found in the patients who progressed). The authors suggest this may be because the medication wasn’t administered early enough because the damage had already started.

Interestingly, although not statistically significant, the mortality rate at 30 days was 4.4% with GIK and 6.1% without GIK. If we add a composite end point of cardiac arrest in combination with mortality (e.g., patients who arrest, as well as those who died), then the difference would be statistically significant (6.1% with GIK and 14.4% without GIK; P=0.01). GIK needs to be tested more, but it appears that it may be a safe and effective therapy to decrease cardiac arrest and death in patients with acute myocardial infarctions.

Emotion & Work
Williams A. A study of emotion work in student paramedic practice. Nurse Educ Today. 2012;Apr 2 [Epub ahead of print].

Too often we focus on research that’s quantitative (research that attempts to measure something numerically). Qualitative research is focused on descriptive and human factors. In this project, Williams interviewed eight paramedic interns in England. The objective was to describe the emotions and coping mechanisms that a new paramedic student has when they’re faced with cardiac arrests and other critical cases.

This study is a great reminder that our new clinicians need support as they’re involved in new critical events. They observe these through the lens of a novice, like a magnifying glass that accentuates their emotions and reactions. Williams discusses two main themes: “getting on with the job” and “struggling with emotion,” the latter of which relates to students struggling to control and suppress their emotions. Educators beware: It’s essential for you to prepare for and support your students through these emotions. This article originally appeared in June 2012 JEMS as “Epinephrine’s Effects: Study examines drug’s influence on cardiac arrest survival.”

Previous articleGerman Shepherd Named National Hero
Next articleReaders Share Feedback on JEMS and Articles

No posts to display