If you have the point-of-care ultrasound skills necessary, a second method to block sympathetic tone is to administer a stellate ganglion block.⁵ Case studies and one small randomized trial suggest reduced mortality in refractory VF with this method. The stellate ganglion at the level of C7 conducts sympathetic activity to the heart.

Directly blocking sympathetic outflow to the heart may decrease the sensitivity of the myocardium to arrhythmias.⁶

4. Consider Dual-Shock Defibrillation

If standard defibrillation isn’t working, consider double defibrillation. Animal studies show that most failed shocks are actually successful shocks but that the patient goes back into VF in less than one second. Eighty percent of patients who are resistant to a single shock will respond to dual shock.⁷ The idea is that you need to depolarize 90 percent of the myocardium to achieve effective defibrillation. If the patient has defibrillator pads in the traditional positions on the chest, attach a second set of pads from a second defibrillator in the anterior-posterior “sandwich” position (see image). At the time of defibrillation, both shock buttons are depressed simultaneously.

Adding a second set of pads changes the energy vectors through the myocardium, which helps achieve that 90 percent threshold. A few small studies have shown promising results for ROSC, with one showing 70 percent conversion with dual shock and 30 percent achieving ROSC in the field.⁸ It is important to note that the largest study to date on dual defibrillation in refractory VF did not show any benefit for neurologically intact survival.⁷

Don’t forget that since many patients with shock-resistant VF have an underlying cardiac ischemic event as the primary cause, cardiac arrest experts recommend consulting an interventional cardiologist for consideration of immediate transfer to the cath lab for all VF patients who have achieved ROSC.

Thanks to Jordan Chenkin, Paul Dorian, Laurie Morrison, and Steve Lin for their contributions to the podcasts that inspired this article.

Dr. Helman is an emergency physician at North York General Hospital in Toronto. He is an assistant professor at the University of Toronto, Division of Emergency Medicine, and the education innovation lead at the Schwartz/Reisman Emergency Medicine Institute. He is the founder and host of Emergency Medicine Cases podcast and website (www.emergencymedicinecases.com).

References

1. Tang W, Weil MH, Sun S, et al. Epinephrine increases the severity of postresuscitation myocardial dysfunction. Circulation. 1995;92(10):3089-3093.
2. Ristagno G, Tang W, Huang L, et al. Epinephrine reduces cerebral perfusion during cardiopulmonary resuscitation. Crit Care Med. 2009;37(4):1408-1415.
3. Gao D, Sapp JL. Electrical storm: definitions, clinical importance, and treatment. Curr Opin Cardiol. 2013;28(1):72-79.
4. Driver BE, Debaly G, Plummer DW, et al. Use of esmolol after failure of standard cardiopulmonary resuscitation to treat patients with refractory ventricular fibrillation. Resuscitation. 2014;85(10):1337-1341.
5. Gadhinglajkar S, Sreedhar R, Unnikrishnan M, et al. Electrical storm: role of stellate ganglion blockade and anesthetic implications of left cardiac sympathetic denervation. Indian J Anaesth. 2013;57(4):397-400.
6. Nademanee K, Taylor R, Bailey WE, et al. Treating electrical storm: sympathetic blockade versus advanced cardiac life support-guided therapy. Circulation. 2000;102(7):742-747.
7. Ross EM, Redman TT, Harper SA, et al. Dual defibrillation in out-of-hospital cardiac arrest: a retrospective cohort analysis. Resuscitation. 2016;106:14-17.
8. Hoch DH, Batsford WP, Greenberg SM, et al. Double sequential external shocks for refractory ventricular fibrillation. J Am Coll Cardiol. 1994;23(5):1141-1145.