Answers to questions about the safety of electronic weapons

By Police1 Columnist Greg Meyer
Sponsored by Taser

The critics will never be satisfied.

Amnesty International and other police critics call for “independent studies” of TASERs. The federal government, via the Department of Justice, awards research grants for exactly that: independent studies. The latest study hits the street, and the critics are quoted across the land: “Well, we’re not sure how independent the study was.”

Never mind the study results, in this case that the TASER caused no serious injury in 99.7% of nearly 1,000 uses in multiple jurisdictions, where local doctors studied every incident.

The critics live in a delusional world where force is never used, and there is no need for police officers. The media lives in a dollars-and-cents world, where the critics make headlines on the back of your professional efforts to keep society safe. Conflict sells newspapers and airtime.

“And that’s the way it is,” as Walter Cronkite used to say at the end of each broadcast.

Maybe so, but after nearly 32 years in law enforcement, I’m still not used to it. Silly me!

You, on the other hand, live in a world that presents its difficulties to you day in, day out, and on a moment’s notice, or no notice at all. And your mission, should you decide to accept it, is to keep that world as safe as you can, despite the cries of those who wouldn’t know a legitimate use of force if it hit them in the face.

Enough of my rant!

The best thing I can do for you this month is arm you with a list of recently completed studies that help answer questions about the safety of electronic weapons. You can be sure that the critics will say that there aren’t enough of these studies, or they aren’t independent, or whatever else they can dream up.

Here goes:

The TASER safety study referred to above was conducted at Wake Forest University by Dr. William Bozeman, an associate professor of emergency medicine at Wake Forest University School of Medicine. The study was funded by the National Institute of Justice. In 962 incidents, just three resulted in serious injury, two of those from falling. One was a case of rhabdomyolysis, or muscle tissue breakdown, which is sometimes seen in people experiencing excited delirium. This study was widely publicized in early October.

Another study compared TASER effects to other types of use of force. Entitled, “The impact of conducted energy devices and other types of force and resistance on officer and suspect injuries,” published in October by Emerald Group Publishing Limited’s “Policing: an International Journal of Police Strategies & Management,” this study was authored by Michael R. Smith, Robert J. Kaminski, Jeffrey Rojek, Geoffrey P. Alpert and Jason Mathis, of the Department of Criminology and Criminal Justice, University of South Carolina.

Quite a few new medical studies have been released in the past few weeks. All of these studies affirmed the general safety of the TASER® electronic control device. Six (6) of these studies were presented at the Fourth Mediterranean Emergency Medicine Congress (MEMC IV), in Sorrento, Italy during September 15-18, 2007.

Several of these studies used human volunteers that underwent cardiovascular and physiologic evaluations on the effects of TASER activation in a human body and reached the following conclusions

(Abstract) (Poster) (09/17/07) Ultrasound Measurement of Cardiac Activity During Conducted Electrical Weapon Application in Exercising Adults. J. Ho; R. Reardon; D. M. Dawes; M. Johnson; J. Miner.

Conclusions: A 15-second CEW application on exercised volunteers did not demonstrate any evidence of induced tachyarrhythmia. It is unlikely that CEW exposure induces cardiac rate capture or tachyarrhythmia in humans.

(Abstract) (Poster) (09/18/07) Absence of Electrocardiographic Change Following Prolonged Application of a Conducted Electrical Weapon in Physically Exhausted Adults. J. Ho; D. Dawes; H. Calkins; M. Johnson.

Conclusions: Prolonged 15-second CEW application in a physically exhausted adult human sample did not cause a detectable change in their 12-lead ECGs. Theories of CEW induced dysrhythmias are not supported by our findings.

(Abstract) (Poster) (09/19/07) 15-Second Conducted Electrical Weapon Exposure Does Not Cause Core Temperature Elevation In Non-Environmentally Stressed Resting Adults. D. M. Dawes; J. Ho; M. Johnson; J. Miner.

Conclusions: In summary, our results do not show that a 15-second conducted electrical weapon discharge significantly affects core body temperature in non-environmentally stressed resting adults. While additional studies are needed, our data suggests that theories about conducted electrical weapons contributing to hyperthermia are likely unfounded.

(Abstract) (Poster) (09/19/07) The Neuroendocrine Effects of the TASER X26 Conducted Electrical Weapon as Compared to Oleoresin Capsicum. D. M. Dawes; J. Ho; M. Johnson; J. Miner.

Conclusions: The results suggest a significant greater level of activation of the stress cascade with O.C. compared to the CEW. Overlapping confidence intervals preclude a definitive statement about the other measurements, but do not suggest a greater activation of the stress cascade by the CEW than O.C.

(Abstract) (Poster) (09/19/07) 15-Second Conducted Electrical Weapon Application Does Not Impair Basic Respiratory Parameters, Venous Blood Gases, or Blood Chemistries. D. M. Dawes; J. Ho; M. Johnson; J. Miner.

Conclusions: As with the previous study, this study suggests that exposure to a CEW does not significantly impair respiration. As in the previous study, pCO2 decreased and pO2 increased as a result of the exposure. There was no change in blood pH. While this study is small, it adds to the growing body of literature that is demonstrating that these weapons have a favorable risk-benefit ratio and are appropriate additions to the use of force continua of police agencies.

(Abstract) (Poster) (09/19/07) Breathing Parameters, Venous Gases, and Chemistries with Exposure to a New Wireless Projectile Conducted Electrical Weapon. D. M. Dawes; J. Ho; M. Johnson; J. Miner; E. Lundin.

Conclusions: This study demonstrates that the new CEW has no important deleterious effects on respiratory parameters, blood chemistries, or venous blood gases. These results are consistent with previous results for the TASER X26 CEW.

(08/29/07) Physiological Effects of a Conducted Electrical Weapon on Human Subjects, Gary M. Vilke, MD, Christian M. Sloane, MD, Katie D. Bouton, BS, Fred W. Kolkhorst, PhD, Saul D. Levine, MD, Tom S. Neuman, MD, Edward M. Castillo, PhD, MPH, Theodore C. Chan, MD. Article in Press, Ann Emerg Med. 2007;xx:xxx.

Conclusion: A 5-second exposure of a TASER X26 to healthy law enforcement personnel does not result in clinically significant changes of physiologic stress.

The above studies can be reviewed here (create login, and open “search” tab and search by author’s last name or abstract title or number).

The abstracts below can be viewed here.

(09/19/07) Cardiac Current Density Distribution by Electrical Pulses from TASER Devices, Panescu D, Kroll MW, McDaniel W, Stratbucker RA., Conf Proc IEEE Eng Med Biol Soc. 2006;1(1):6305-6307.

Conclusions: TASER ECDs deliver electrical pulses that can temporarily incapacitate subjects. The goal of this paper is to analyze the distribution of TASER currents in the heart and understand their chances of triggering cardiac arrhythmias. The models analyzed herein describe strength-duration thresholds for myocyte excitation and ventricular fibrillation induction. Finite element modelling is used to compute current density in the heart for worst-case TASER electrode placement. The model predicts a maximum TASER current density of 0.27 mA/cm2 in the heart. It is conclude that the numerically simulated TASER current density in the heart is about half the threshold for myocytes excitation and more than 500 times lower than the threshold required for inducing ventricular fibrillation. Showing a substantial cardiac safety margin, TASER devices do not generate currents in the heart that are high enough to excite myocytes or trigger VF.

(09/19/07) Finite Element Modeling of Electric Field Effects of TASER Devices on Nerve and Muscle. Panescu D, Efimov IR, Kroll MW, Sweeney JD. Conf Proc IEEE Eng Med Biol Soc. 2006;1(1):1277-1279.

Conclusions: TASER ECDs deliver electrical pulses that can temporarily incapacitate subjects. The goal of this paper is to analyze the distribution of currents in muscle layers and understand the electro-muscular incapacitation safety and efficacy of TASER ECDs. The analyses describe skeletal muscle and motor nerve activation, cell electroporation and current and electric field distributions through skin, fat and muscle layers, under worst-case assumptions for TASER electrode penetration and separation. For the muscle layer, the analysis predicts worst-case current-density and field-strength values of 94 mA/cm² and 47 V/cm. Both values are higher than thresholds required for neuromuscular activation but significantly lower than levels needed for permanent cellular electroporation or tissue damage. The results indicate that TASER ECDs are safe and effective in producing temporary subject incapacitation.

(08/28/07) Can the Direct Cardiac Effects of the Electric Pulses Generated by the TASER X26 Cause Immediate or Delayed Sudden Cardiac Arrest in Normal Adults? Raymond E. Ideker, MD, PhD, and Derek J. Dosdall, PhD. Am J Forensic Med Pathol 1 Sep 2007 28(3): p. 195.

Conclusion: It is highly unlikely that the TASER X26 can cause ventricular fibrillation either instantly or minutes to hours after its use through direct cardiac effects of the electric field generated by the TASER.

More medical studies and TASER use studies are in the works.

That’s it for now! Stay safe.