TASER Safety

Roberts, James R. MD

It is difficult to separate unsubstantiated newspaper articles, emotionally charged TV reports, or current YouTube videos from scientific data with regard to the safety of the TASER. Likewise, so-called scientific studies, either on volunteers or animals, are not the same as the real issue at hand. Autopsy reports often assume that the TASER is related to the death just because it was used premortem and because no specific cause of death can be found (not uncommon in many deaths). In the past, medical examiners have related deaths to the TASER. Most quote reports from the 1990s before any true electrical data were available. (J Forensic Sci 1991;36:434; J Forensic Sci 1992;37:956.)

It should be noted that although studies on this device are very incomplete, there is no credible proof that the TASER induces cardiac arrest when used by law enforcement officials in a prescribed manner. In fact, the voltage required to induce VF has been calculated to be 15 to 42 times the charge possible to be delivered from the TASER. (Pacing Clin Electrophys 2005;28(Suppl 1):S284.) It has been stated that there have been no documented cases of VF directly caused by the device in more than 600,000 police uses. (J Am Coll Cardiol 2007;49[6]:732.) Contrast this with lay press headlines that the TASER kills many people. (167 Cases of Death Following Stun-Gun Use, Arizona Republic, February 5, 2006.) If one reads the UpToDate database, the 2007 version states that the TASER is capable of inducing fatal arrhythmias and other injuries. My analysis: We simply don't know for sure, but many self-proclaimed authorities come down on both sides of the debate, many have a personal, financial, or social bias, and many simply don't read the literature.

Other injuries claimed to be associated with the TASER include burns, lacerations, testicular torsion, and miscarriage. Although the concepts may be believable, these are often anecdotal and poorly characterized reports. A miscarriage two weeks after a TASER application is hardly a scientific cause-effect. Thoracic spine compression fractures from the TASER in a volunteer who did not fall but experienced severe muscle contraction has recently been reported. (Ann Emerg Med 2007;50[5]:584.) Fracture and dislocation from electrical shock are well documented.

Some articles that claim the TASER can cause VF. Reference a short letter to the editor by Kim and Franklin (New Engl J Med 2005;353:958) titled Ventricular Fibrillation after Stun Gun Discharge. If one actually reads this sketchy report, it is hardly proof of the article's title. This is clearly only a worrisome observation and certainly not quotable science based on my read. Specifically, a violently agitated subject was subdued with a TASER. Later he had VF but was resuscitated to normal with ACLS interventions. No drug screen or medical history was reported. Kroll claims that this particular case was misreported with serious omissions. His version (personal communication: Obtained from police records) was that following submission of a violently agitated man with a TASER, paramedics found a normal pulse and respirations. Twenty some minutes after this episode, the subject experienced a cardiorespiratory collapse. It is my understanding that no ventricular fibrillation was documented until many minutes after TASER use, and after interventions including multiple medic-delivered cardiac shocks, atropine and epinephrine were administered. As stated, most agitated patients die via bradycardia. I am leery of this supposed documentation of VF after TASER discharge, yet it is universally quoted. So far, I have received no response from the author to my email query.

A theoretical discussion by Ideker (Am J Forensic Med Patho 2007;28[3]:195) states that fundamental laws of electrical stimulation predicted the TASER pulse will not stimulate an ectopic beat in a large majority of normal adults. It is unlikely, at least from a theoretical stance, that a TASER can initiate ventricular fibrillation. It's a nice theoretical discussion but hardly firm clinical evidence.

Ho et al recently reported on respiratory effects of prolonged electrical weapon application to human volunteers. (Acad Emerg Med 2007;14:197.) Human volunteers received a 15-second application of electrical current while wearing respiratory measurement devices. These were certainly brave volunteers. Respiratory parameters were collected during and after exposure. The aim of the article was to see if the TASER contributed to death by impairing respirations. In this study, respiratory measurements were taken pre-exposure, during electrical weapon exposure, and during the first and second minute after exposure. No respiratory impairment was demonstrated either during prolonged continuous or prolonged intermittent TASER discharge. There was no decrease in tidal volume nor was there hypercapnia, hypoxia, or apnea associated in this volunteer model.

Other work has failed to demonstrate any significant changes in cardiac serum markers, hyperkalemia, or acidosis following TASER application. Transient mild increases in CPK and lactate were observed, likely due to muscle contraction. (Acad Emerg Med 2006;13:589.) Shocking does not cause hyperthermia (Forensic Sci Int November 2007, abstract only), and minimal testing has shown no disruption of pacemakers, ICDs, or their leads when exposed to TASERs. (Europace 2007;9[7]:551.)

Author Credentials and Financial Disclosure:
James R. Roberts, MD, is the Chairman of the Department of Emergency Medicine and the Director of the Division of Toxicology at Mercy Health Systems, and a Professor of Emergency Medicine and Toxicology at the Drexel University College of Medicine, both in Philadelphia. Dr. Roberts has disclosed that he has no significant relationships with or financial interests in any commercial companies that pertain to this educational activity.
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