The Double Down

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Out-of-hospital cardiac arrest is a common occurrence in the U.S. For one ED team, a ‘double pad shock’ meant the difference between life and death.

Roused by noise, a patient’s wife is awakened suddenly in the morning. She heads down stairs to find her husband collapsed on the stairwell, unresponsive. He is 47, has no significant medical history and is in generally good health.

With prior BLS training, she attempts to save his life. Dialing 911, she shouts for help while pushing hard on his chest.

Within forty-five minutes, the patient’s wife goes from laying next to him to standing next to me. She sees him on the ED gurney, naked, his clothes torn and on the floor. There is a bleeding lip from multiple out-of-hospital intubation attempts and two men twice her size alternating the same compressions she had done.

After receiving a pre-arrival call by the EMS crew, I prepare the resuscitation team for an unusual approach. According to their report, he appears to be in refractory ventricular fibrillation. Despite copious amounts of exogenous epinephrine, amiodarone, and numerous attempts at defibrillation, he remains in a ventricular storm. Instead of reciting the typical script which concludes our resuscitation efforts in a prolonged code (recapping the events that took place and asking for any other thoughts before halting CPR), we planned to “double” our efforts.

After a failed shock in the ED, I ask for a second set of defibrillator pads. We “double down” the electricity and defibrillate with 400J. Forty-five minutes of downtime, tombstoning on the monitor, one drug-eluting stent, a week-long stay in the hospital, and numerous broken ribs later, the heroine wife brings her husband home.

Discussion
Although his outcome was remarkable, this patient’s story is not at all unfamiliar. Out-of-hospital cardiac arrest (OHCA) is a common occurrence in the United States, with an estimated 424,000 incidents every year. It remains a significant cause of death, with a survival rate of roughly 10% [1]. In a shockable rhythm, our current treatment strategy focuses on early defibrillation and high-quality CPR. As seen with our patient, VF does not always respond to these interventions.

Refractory VF (also known as an electrical storm) is an entity that is yet to be clearly delineated. One commonly proposed definition is VF without response to five standard shocks [2]. What is known about refractory VF is that it is difficult to manage and is associated with poor outcomes; neurologically intact one-month survival for shock-resistant VF is reported to be 5.6% [3]. The underlying pathophysiology is thought to be cardiac electrical instability in the setting of sympathetic overdrive.

The process of double simultaneous external defibrillation (“double-down”) has been shown to be effective in treating refractory VF in several case studies. Hoch et al. first described double defibrillators in the setting of intentionally induced VF in the electrophysiology lab [4]. In 2014, Leacock published a case similar to our own where double-down was successful in achieving ROSC with good neurologic outcome in a 51-year-old man after 25 minutes of standard ACLS [5]. There is also a recent retrospective 10-patient case series by Cabanas et al. in which double-down was successful in breaking refractory VF in 7 patients (with 3 obtaining ROSC) [2]. The technique has also been discussed on several educational EM blogs [9].

The etiology of the efficacy of double-down is unknown, but there are several hypotheses. Broader energy vector leading to depolarization of more myocardium and increasing rates of obesity causing transthoracic impedance of electrical energy have been suggested [2,5]. Regarding the latter point, Zhang et al. showed some evidence of an inverse relationship between body mass and success of defibrillation in the animal model [6]. This suggests one simply needs more energy to get to an obese patient’s myocardium.

The procedure for performing a “double-down” has not been standardized. It is important to note that the only literature on this subject exists in the forms of case series and anecdotes. A “double down” should be used only in the setting of refractory VF after a failure of high-quality CPR, multiple attempts at standard defibrillation, and appropriate medications. To perform this procedure, using a second defibrillator, place the second set of external pads either next to the first set or in the opposite orientation (i.e. one set anterior-posterior and the second set in the anterior-anterior position). Be sure no pads are touching. Then, charge both defibrillators (200 J biphasic each), ensure everyone is clear and simultaneously press the shock button on each defibrillator. Immediately start CPR after that.

Some literature also shows that short-acting beta-blockers may be of benefit in refractory VF. A recent retrospective study in an urban academic ED compared OHCA in 6 patients with refractory VF or VT who, in addition to standard ACLS, received esomolol, compared to 19 who received standard ACLS alone. Although the sample size was small, 50% in the esomolol group survived to discharge compared to 11% in the standard therapy only [7]. Previous studies have reached a similar conclusion [8]. The hypothesis: avoid epinephrine and use a beta-blocking agent that blunts the sympathetic drive.

We have presented yet another case of intractable VF that responded to double simultaneous defibrillation. While the supporting literature is not as robust as we would like, this is something to consider as a last-ditch effort in the patient in refractory VF. What does the patient have to lose?


REFERENCES

  1. Go AS, Mozaffarian D, Roger VL, et al. on behalf of the American Heart Association Statistics Committee and Stroke Statistics Subcommittee. Heart disease and stroke statistics—2014 update: A report from the American Heart Association. Circulation. 2014;129:e28-e292.
  2. Cabanas JG et al. Double Sequential External Defibrillation in Out-of-Hospital Refractory Ventricular Fibrillation: A Report of Ten Cases. Prehospital Care 2015; 19 (1): 126 – 130.
  3. Sakai T, Iwami T, Tasaki O, et al. Incidence and outcomes of out-of-hospital cardiac arrest with shock-resistant ventricular fibrillation: data from a large population based cohort. Resuscitation. 2010. August: 81 (8): 956-61.
  4. Hoch et al. “Double sequential external shocks for refractory ventricular fibrillation.” Journal of the American College of Cardiology. April 1994. 23(5): 1141.
  5. Leacock, BW. Double simultaneous defibrillators for refractory ventricular fibrillation. J Emerg Med. 2014 Apr;46(4):472-4. doi: 10.1016/j.jemermed.2013.09.022. Epub 2014 Jan 21.Driver BE, Debaty G,
  6. Zhang Y et al. Body Weight is a Predictor of Biphasic Shock Success for Low Energy Transthoracic Defibrillation. Resuscitation 2002; 54: 281 – 7
  7. Plummer DW, Smith SW. Use of esmolol after failure of standard cardiopulmonary resuscitation to treat patients with refractory ventricular fibrillation. Resuscitation. 2014 Jul 14. pii: S0300-9572(14)00642-X. doi: 10.1016/j.resuscitation.2014.06.032
  8. Miwa, Y. et al. Effects of Landiolol, an Ultra-Short-Acting β1-Selective Blocker, on Electrical Storm Refractory to Class III Antiarrhythmic Drugs. Circ J 74, 856–863 (2010).
  9. Nickson, C. “Electrical Storm or Refractory VF/VT.” LITFL Life in the Fast Lane Medical Blog. 14 Sept. 2014. Web. 01 Apr. 2016.
ABOUT THE AUTHORS

Dr. Clark is an Emergency Medicine resident at Baystate Medical Center in Spring field, Massachusetts.

Dr. Singh is a graduating Chief Resident and future ultrasound fellow at Baystate Medical Center.

Dr. McCafferty a graduating ultrasound fellow and attending at Baystate Medical Center. She will begin working as an emergency physician at Lahey Clinic in Burlington, Massachusetts.

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