Brief Reports
Physiologic Effects of a New-Generation Conducted Electrical Weapon on Human Volunteers

https://doi.org/10.1016/j.jemermed.2013.08.069Get rights and content

Abstract

Background

Conducted electrical weapons (CEWs) are used by law enforcement to restrain or repel potentially violent persons. The TASER X2 CEW is a next-generation device with new technology, including new electrical waveform and output specifications. It has not previously been studied in humans.

Objective

The objective of this study was to evaluate the human physiologic effect of a new-generation CEW.

Methods

This was a prospective, observational human study. Volunteers received a 10-s exposure via deployed probes from an X2 CEW in the abdomen and upper thigh. Measured data included vital signs; 12-lead electrocardiograms; and blood serum biomarkers before, immediately after, and 24 h post exposure. Biomarkers measured included pH, lactate, potassium, creatine kinase (CK), and troponin-I. Real-time spirometry and echocardiography were performed before, during, and after the exposure.

Results

Ten volunteers completed the study. There were no important changes in vital signs or potassium. Median increase in lactate as a consequence of the exposure was 1.2 mg/dL (range 0.6–2.8 mg/dL). Median change in pH was −0.031 (range −0.011 to −0.067). No subject had a positive troponin. Median change in CK at 24 h was 313 ng/mL (range −40 to 3418 ng/mL). There was no evidence of respiratory impairment. Baseline median minute ventilation was 14.2 L/min, increased to 21.6 L/min intra-exposure (p = 0.05), and remained elevated at 21.6 L/min post exposure (p = 0.01).

Conclusions

There was no evidence of dangerous physiology found in the measured parameters. The physiologic effects of the X2 CEW are similar to older-generation CEWs. We encourage further study to validate these results.

Introduction

Conducted electrical weapons (CEWs) are used by law-enforcement officers (LEOs) as intermediate weapons, defined as items that generally can induce subject compliance due to pain or incapacitation and are a level above empty-hand control techniques but less than deadly force. They have filled a gap left by other law-enforcement devices, tactics, or tools and have been shown to reduce LEO and suspect injuries 1, 2, 3. CEWs deliver electrical charge from a capacitor system in discrete pulses at fast rates (19 pulses per second in most models) leading to the depolarization of peripheral motor neurons within a “zone of capture.” This results in subsequent involuntary subtetanic muscle contraction. The devices also depolarize afferent sensory neurons leading to pain.

The TASER X26 CEW (Figure 1) is currently the most prevalent CEW in use in the world and has been in service since 2003. It is considered to be older-generation technology and is based on electrical waveform characteristics developed more than a decade ago. Its operational limitations include the ability to fire a single cartridge only without reloading. This can present a distinct disadvantage during scenarios with unsuccessful current delivery (such as missing probe contact with the intended target), if the probe spread distance is too close to be effective, or there are multiple subjects to engage. There have been numerous human physiology studies performed using the older-technology X26 CEW 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14. The older-technology CEWs are understood by experts to be safe and the newer-technology CEWs are proposed to be even safer. The TASER X2 CEW (Figure 2) represents new-generation CEW technology and has completely different waveform and output specifications that have significantly changed the electrical characteristics of this weapon when compared with previous CEWs. It also has the capability of firing two cartridges in a “semi-automatic” mode. This study is the first to examine comprehensive human physiologic effects of this newer-generation CEW.

Section snippets

Methods

This was a prospective, observational study of human subjects. The Minneapolis Medical Research Foundation Institutional Review Board (Minneapolis, MN) approved this study. The study was conducted at the CEW manufacturer corporate headquarters in Scottsdale, AZ during a 2-day time period. The study volunteers were a convenience sample of LEOs or correctional officers participating in a training exercise and receiving an X2 CEW exposure as part of their training. They were approached during

Results

Ten volunteers were enrolled in this study and none were excluded. Median age of the volunteers was 31.5 years (range 21−44 years), median body mass index (calculated as kg/m2) was 29.4 (range 17.6–34.3), and 80% were male. There were no important changes in vital signs or measured potassium. Median increase in lactate during the exposure was 1.2 mg/dL (range 0.6–2.8 mg/dL). Median change in pH was −0.031 (range −0.011 to −0.067). No subject had a positive troponin immediately after the

Cardiac

We did not find a demonstrably harmful cardiac effect in our study. Studies by several authors have shown no changes in surface ECG or serum troponin, a measure of heart muscle damage, after an exposure to a TASER X26 CEW, from 1 to 15 s, and with and without exertion 4, 6, 8, 9, 10, 14, 15. In addition, human studies involving chest exposures with an X26 CEW have not demonstrated direct cardiac capture, even with prolonged or repetitive exposures, in rested and exhausted volunteers 7, 12, 16,

Conclusions

In our study, there was no evidence of dangerous physiology found with any of our measured parameters. We conclude that the human physiologic effects of the X2 CEW are similar to previously studied older-generation CEWs. We recommend further study of emerging CEW technology to validate these results.

Article Summary

1. Why is this topic important?

  1. Human physiology effects have been studied for older generation CEW technology. As older generation CEWs are replaced with newer CEW technology, it is important for medical professionals to know

Acknowledgments

The study authors would like to acknowledge Mr. Andrew Hinz and Mr. Matt Carver for their assistance on this project.

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  • Cited by (0)

    TASER International, Inc. provided partial funding for this study. Dr. Ho is the medical director to TASER International, Inc. and Dr. Dawes is an expert to TASER International. Both are own shares of stock in the company.

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