Can the direct cardiac effects of the electric pulses generated by the TASER X26 cause immediate or delayed sudden cardiac arrest in normal adults?

There is only a small amount of experimental data about whether the TASER X26, a nonlethal weapon that delivers a series of brief electrical pulses to cause involuntary muscular contraction to temporarily incapacitate an individual, can initiate ventricular fibrillation to cause sudden cardiac arrest either immediately or sometime after its use. Therefore, this paper uses the fundamental law of electrostimulation and experimental data from the literature to estimate the likelihood of such events. Because of the short duration of the TASER pulses, the large duration of the cardiac cell membrane time constant, the small fraction of current from electrodes on the body surface that passes through the heart, and the resultant high pacing threshold from the body surface, the fundamental law of electrostimulation predicts that the TASER pulses will not stimulate an ectopic beat in the large majority of normal adults. Since the immediate initiation of ventricular fibrillation in a normal heart requires a very premature stimulated ectopic beat and the threshold for such premature beats is higher than less premature beats, it is unlikely that TASER pulses can immediately initiate ventricular fibrillation in such individuals through the direct effect of the electric field generated through the heart by the TASER. In the absence of preexisting heart disease, the delayed development of ventricular fibrillation requires the electrical stimuli to cause electroporation or myocardial necrosis. However, the electrical thresholds for electroporation and necrosis are many times higher than that required to stimulate an ectopic beat. Therefore, it is highly unlikely that the TASER X26 can cause ventricular fibrillation minutes to hours after its use through direct cardiac effects of the electric field generated by the TASER.     

40‐Hz Square‐Wave Stimulation Requires Less Energy to Produce Muscle Contraction: Compared with the TASER® X26 Conducted Energy Weapon

Conducted energy weapons (CEWs) (including the Advanced TASER^® X26 model produced by TASER International, Inc.) incapacitate individuals by causing muscle contractions. In this study using anesthetized swine, the potential incapacitating effect of primarily monophasic, 19‐Hz voltage imposed by the commercial CEW was compared with the effect of voltages imposed by a laboratory device that created 40‐Hz square waves. Forces of muscle contraction were measured with the use of strain gauges. Stimulation with 40‐Hz square waves required less pulse energy than stimulation with the commercial CEW to produce similar muscle contraction. The square‐pulse stimulation, at the higher repetition rate, caused a more complete tetanus at a lower energy. Use of such a simple shape of waveform may be used to make future nonlethal weapon devices more efficient.     

Muscle contraction during electro-muscular incapacitation: A comparison between square-wave pulses and the TASER(®) X26 Electronic control device

Abstract: Electronic control devices (including the Advanced TASER^® X26 model produced by TASER International) incapacitate individuals by causing muscle contractions. To provide information relevant to development of future potential devices, effects of monophasic square waves with different parameters were compared with those of the X26 electronic control device, using two animal models (frogs and swine). Pulse power, electrical pulse charge, pulse duration, and pulse repetition frequency affected muscle contraction. There was no difference in the charge required, between the square waveform and the X26 waveform, to cause approximately the same muscle‐contraction response (in terms of the strength‐duration curve). Thus, on the basis of these initial studies, the detailed shape of a waveform may not be important in terms of generating electro‐muscular incapacitation. More detailed studies, however, may be required to thoroughly test all potential waveforms to be considered for future use in ECDs.     

Functioning and Effectiveness of Electronic Control Devices Such as the TASER® M‐ and X‐Series: A Review of the Current Literature

Abstract: Conducted electrical weapons (CEWs) such as the TASER^® M‐ and X‐series deliver short high‐voltage, low‐current energy pulses to temporarily paralyze a person by causing electrical interruption of the body’s normal energy pulses. Despite many scientific publications, which classify the health risks of an appropriate use of the TASER device as minor, there still is a continuous uncertainty about possible side effects with human application. Based on a literature search of the National Library of Medicine’s MEDLINE database’s PubMed system of current publications, the following article describes the mechanisms by which the device operates and discusses possible pathophysiological consequences. The majority of current human literature has not found evidence of clinical relevant pathophysiological effects during and after an exposure of professionally applied CEWs. However, to be able to exclude possible health risks, a medical checkup of people who have been exposed to CEWs is essential.     

Damage characteristics of fabrics created by TASER probes

TASER® weapons are conducted energy weapons (CEWs) that are frequently used by police departments around the world. CEWs can be deployed in two methods: drive stun application and probe deployment. This study aims to examine damages caused by TASER devices on fabrics and whether types of fabric material and TASER models could contribute to different damage features. Three types of white fabric were used, including 100% cotton, 100% polyester, and 65:35 polyester-cotton blend. Three models: TASER X26P, TASER X2, and TASER 7 were shot onto each type of fabric, with five repetitions each. Each damaged area on the fabric caused by a probe is a sample (n = 90) and was examined with a Keyence digital microscope. Images were captured by the Keyence microscope and measurements were recorded, including damage dimensions, fabric condition, evidence of burning, and extra findings. The presence of fused yarn ends was found to be statistically significant across the fabric types, and no damage features were found that may assist in the identification of TASER models. Other damage features including damage dimensions, discoloration, and fiber deformation were not found to be showing apparent differences according to statistical analysis. The conclusions made by this research should be used with caution due to the small sample size.     

Technological Innovation and Police Officers' Understanding and Use of Force

Today, the TASER is a ubiquitous less‐than‐lethal force technology lauded for its ability to curb police officers' use of excessive and lethal force. Although less injurious than other weapons, concerns exist that the TASER can still be misused by police officers. This article uses ethnographic observations and unstructured interviews across three urban police departments to describe how the TASER affects officers' understanding and use of force in beneficial and unintended ways. I find that officers understand and use the TASER as a device that can enhance safety for themselves and suspects, including in cases where the TASER is used in lieu of lethal force that officers believe would have been justified. Despite these benefits, understanding of the TASER as a safety‐enhancing technology also influences the use of excessive force via TASER by young, inexperienced officers, ultimately contributing to the very problem TASERs were intended to ameliorate.     

Repetitive TASER X26 Discharge Resulted in Adverse Physiologic Events with a Dose–Response Relationship Related to the Duration of Discharge in Anesthetized Swine Model

The objectives of our study were to investigate the dose–response relationship of the TASER X26 discharge duration in an anesthetized swine model. Fourteen swines were anesthetized and then exposed to TASER X26 discharge for 5 sec (n = 5) or for 10 sec (n = 6). The sham control group (n = 3) was anesthetized and studied using the same protocol except TASER X26 discharges during the experiments. Hemodynamic parameters were obtained. Blood pressure and total peripheral resistance decreased significantly after TASER discharge and returned to baseline value at 15 min after 5 sec of TASER discharge but did not return to baseline values during the 30‐min observation period after 10 sec of TASER discharge. Repetitive TASER X26 discharge resulted in adverse physiologic events with a dose–response relationship related to the duration of TASER X26 discharge in an anesthetized swine model.     

The neuroendocrine effects of the TASER X26®: A brief report

IntroductionLaw enforcement officers use conducted electrical weapons (CEW) such as the TASER X26^® to control violently resistive subjects. There are no studies in the medical literature examining the effects of these weapons on the human stress response. This is the first study to compare the human stress response to conducted electrical weapons, oleoresin capsicum (O.C.), a cold-water tank immersion, and a defensive tactics drill.MethodsSubjects were randomized to one of the four interventions studied. Subjects received either a 5-s exposure from the TASER X26 CEW with the probes fired into the back from 7 ft, a 5-s spray of O.C., a skin and mucous membrane irritant, to the eyes, a 45-s exposure of the hand and forearm in a 0 °C cold water tank, or a 1-min defensive tactics drill.ResultsAlpha-amylase had the greatest increase from baseline at 10–15 min with the defensive tactics drill. Cortisol had the greatest increase at 15–20 min with O.C. Cortisol remained most elevated at 40–60 min in the defensive tactics drill group.ConclusionsOur preliminary data suggests that physical exertion during custodial arrest may be most activating of the human stress response, particularly the sympathetic–adrenal–medulla axis. This may suggest that techniques to limit the duration of this exertion may be the safest means to apprehend subjects, particularly those at high-risk for in-custody death. Conducted electrical weapons were not more activating of the human stress response than other uses of force.     

Blood factors of Sus scrofa following a series of three TASER electronic control device exposures

In a previous study, 18 repeated exposures of anaesthetized swine to an electro-muscular incapacitating device (TASER International's ADVANCED TASER X26 electronic control device) resulted in acidosis and increases in blood electrolytes. In the current study, experiments were performed to investigate effects of a more typical scenario of repeated exposures of the device on muscle contraction and changes in blood factors. Ten swine were exposed for 5s, followed by a 5-s period of no exposure, three times. Selected blood factors were monitored for 3h following exposure. Transient increases in blood glucose, lactate, sodium, potassium, calcium, and pCO(2) were consistent with previous reports in the literature dealing with studies of muscle stimulation or exercise. Blood pH was decreased immediately following exposure, but subsequently returned toward a normal level. Oxygen saturation (measured by pulse oximetry) was not changed significantly. In conclusion, three repeated TASER device exposures had only transient effects on blood factors, which all returned to pre-exposure levels, with the exception of hematocrit (which remained elevated after 3h). Since the increase in this factor was less than that which may occur after short periods of exercise, it is unlikely that this would be an indicator of any serious harm.     

Acidosis, lactate, electrolytes, muscle enzymes, and other factors in the blood of Sus scrofa following repeated TASER exposures

Repeated exposure to electro-muscular incapacitating devices could result in repetitive, sustained muscle contraction, with little or no muscle recovery period. Therefore, rhabdomyolysis and other physiological responses, including acidosis, hyperkalaemia, and altered levels of muscle enzymes in the blood, would be likely to occur. Experiments were performed to investigate effects of repeated exposures of TASER International's Advanced TASER X26 on muscle contraction and resultant changes in blood factors in an anaesthetized swine model. A total of 10 animals were used. Six swine were exposed for 5 s, followed by a 5-s period of no exposure, repeatedly for 3 min. (In five of the animals, after a 1-h delay, a second 3-min exposure period was added.) The remaining four animals were used for an additional pilot study. All four limbs of each animal exhibited contraction even though the electrodes were positioned in areas at some distances from the limbs. The degree of muscle contraction generated during the second exposure period was significantly lower than that in the first exposure series. This finding was consistent with previous studies showing that prolonged activity in skeletal muscle will eventually result in a decline of force production. There were some similarities in blood sample changes in the current experiments with previous studies of muscular exercise. Thus problems concerning biological effects of repeated TASER exposures may be related, not directly to the "electric output" per se, but rather to the resulting contraction of muscles (and related interruption of respiration) and subsequent sequelae. Transient increases in hematocrit, potassium, and sodium were consistent with previous reports in the literature dealing with studies of muscle stimulation or exercise. It is doubtful that these short-term elevations would have any serious health consequences in a healthy individual. Blood pH was significantly decreased for 1h following exposure, but subsequently returned toward a normal level. Leg muscle contractions and decreases in respiration each appeared to contribute to the acidosis. Lactate was highly elevated, with a slow return (time course greater than 1 h) to baseline. Other investigators have reported profound metabolic acidosis during restraint-associated cardiac arrest. Since restraint often occurs immediately after TASER exposure, this issue should be considered in further development of deployment concepts. On the basis of the results of the current studies, the repeated use of electro-muscular incapacitating devices in a short period of time is, at least, feasible, with the caveat that some medical monitoring of subjects may be required (to observe factors such as lactate and acidosis).     

Police use of TASERs in the restraint and transport of persons with a mental illness

The mentally ill are overrepresented in the statistics of individuals killed or injured by police and it is understandable that police would seek a weapon, such as a TASER, that is less lethal than a firearm. However, it appears that use of TASERs is not without risk, especially in certain groups, including the mentally ill. The risk of injury to vulnerable people with a mental illness from TASER weapons must be weighed against the risk that escalation to lethal force may cause if a person with an acute mental illness requires restraint. When police officers are carrying out their duties under mental health legislation it is recommended that TASERs be used only when an individual is imminently likely to sustain or to cause grievous bodily harm. This article recommends changes to the Western Australian Police TASER training programs and proposes mandatory medical assessments after the use of TASER restraint.     

Cardiac Changes Due to Electronic Control Devices? A Computer‐Based Analysis of Electrical Effects at the Human Heart Caused by an ECD Pulse Applied to the Body's Exterior

Electronic control devices (ECDs) deliver high‐voltage, low‐current energy pulses temporarily paralyzing a person. For the ECD–human interaction, we have developed a computer model using the SEMCAD program within which to simulate the electrical effects throughout the body resulting from the imposition of an ECD pulse at a particular point on the body surface. Our human body models were based on cross‐sectional MRIs and CT scans, with the dielectric properties of the various tissues assigned based on previously published values. We simulated the application of a single ECD pulse and calculated the resulting electric field strength and current and charge densities at different body locations. The results were compared with corresponding values obtained by other researchers in similar simulations. Furthermore, we simulated an application of a pulse of 20‐millisecond duration equal to the European household current of 50 Hz and to the ventricular fibrillation threshold. The resulting current level indicated at the heart muscle was 1/5 the level considered the threshold for triggering ventricular fibrillation.     

Examining fatal and nonfatal incidents involving the TASER

Research Summary According to TASER International, nearly 10,000 police departments in the United States have deployed the TASER as a less lethal force alternative in some capacity. Despite the TASER's increasing popularity, serious questions have been raised about the device's physiological side effects; in particular, Amnesty International has reported that more than 300 people have died after being subjected to the TASER. Although a growing body of research has examined the physiological effects of the TASER on animals and healthy human volunteers in laboratory settings, there has been virtually no empirical analysis of “real‐world” fatal and nonfatal TASER cases simultaneously. This article examines all media reports of TASER incidents from 2002 to 2006 through a comprehensive review of LexisNexis and New York Times archives. We compare TASER incidents in which a fatality occurred to TASER incidents in which a fatality did not occur and then employ multivariate analyses to identify the incident and suspect characteristics that are predictive of articles describing TASER‐proximate deaths. Policy Implications Several suspect factors were significantly associated with the reporting of a fatal TASER incident, including drug use (but not alcohol), mental illness, and continued resistance. Multiple deployments of the TASER against a suspect was also associated with the likelihood of the article describing a fatality—especially if the suspect was emotionally disturbed—which raises the possibility that the risk of multiple shocks might not be uniform for all suspects. More research is needed to explore the relationship between mental illness, drug use (illicit or therapeutic), continued resistance, and increased risk of death. In the meantime, police departments should develop specific policies and training governing the use of multiple TASER shocks against individuals who could be in these vulnerable physiological and psychological states.     

The Effects of Continuous Application of the TASER X26 Waveform on Sus scrofa,

This study investigated and evaluated the safety margins of the continuous long duration (up to 30 min) effect of the TASER X26 waveform, using a Sus scrofa model. Long duration continuous stimulus has not been evaluated on humans or human surrogates prior to this study. Swine were used as models due to similarities with humans in their skin and cardiovascular systems. Very long duration was used to determine both exposure dose and possible adverse physiological effects of dose. The trial began with an application of 10 min, and subsequent animals received increasing exposure time up to a survived maximum duration of 30 min. At the onset of this work, it was hypothesized that there would be a time limit after which most animals would not survive consistent with increased dose response. However, this hypothesis was not supported by the experimental results. All animals (10 of 10) survived up to 3 min. Seven of the 10 animals survived up to a 10‐min exposure and 3 of 5 animals with a 30‐min target exposure survived the full exposure. Surviving animals were recovered and observed for 24 h, with no postrecovery deaths. This suggests that swine (based on physiology) will not experience a fatal event when exposed to the TASER X26 for a continuous 3 min. Conclusions regarding longer duration (10–30 min) are not as certain due to the small sample sizes at these time intervals.     

Acute pathophysiological influences of conducted electrical weapons in humans: A review of current literature

Conducted electrical weapons (CEWs) deliver short high-voltage, low current energy pulses to temporarily paralyze a person by causing muscular contraction. The narrative of this article is a methodical analysis on acute pathophysiological changes within the central nervous system, cardiovascular, neuroendocrine, sympatho-adrenergic and muskuloskeletal system which can occur after application of conducted electrical weapons on human subjects. The results are based on wide-ranging literature analysis and source studies. The majority of the recent scientific publications on humans classify the health risks of an appropriate use of the CEWs device as minor. However, there still is an uncertainty about possible side-effects of these devices. Therefore medical supervision with human application is advised.     

Survival of anesthetized Sus scrofa after cycling (7-second on/3-second off) exposures to an electronic control device for 3 minutes

Electronic control devices (ECDs) may eventually be deployed by the military in a manner resulting in longer exposures than those encountered during law-enforcement operations. In a previous study, 18 repeated cycling (5-second on/5-second off) exposures (within a 3-minute period) of anesthetized swine to an ECD (TASER International's Advanced TASER X26 device) resulted in leg muscle contraction, acidosis, and increases in blood electrolytes. In the current study, experiments were performed to examine effects of exposures to a different cycling rate (7-second on/3-second off), from a modified X26 ECD, on 10 swine (Sus scrofa), maintained on propofol anesthesia. In contrast with the previous study, a large number of animals (6/10) died immediately after the exposures. There were no major differences in pre-exposure blood factors from survivors versus nonsurvivors, with the exception of hematocrit and 2 isoenzymes of lactate dehydrogenase. It is doubtful that these factors would be useful in predicting survival after ECD exposure. Blood pH was significantly decreased after exposure, but (in animals that survived) subsequently returned to baseline levels. On the basis of the overall survival rate, further development of useful ECDs (for long-term incapacitation during military operations) may require consideration of longer pauses between repeated exposures over a 3-minute period.     

Sensitivity of TATP to a TASER Electrical Output

A series of experiments were performed to evaluate and document the effect of a TASER (“stun gun”) on triacetone triperoxide (TATP), an easily manufactured explosive used often in IEDs and suicide bombing vests. TATP samples were synthesized and subjected to several tests of their sensitivity. These samples were run through a BAM Friction test with a result of <0.5 N, Impact Test with a result of 5.8 ± 0.4 cm, and Electrostatic Discharge test with a result of 0.073 ± 0.018 J. In addition, TATP was shocked with a TASER in a variety of configurations. The TATP reacted in 17/17 tests when the TASER arced through the TATP and 0/4 times when the TATP was configured in such a way that the TATP was not subjected to the electrical arc. Based on the experimental data, TATP will readily explode in a variety of configurations by a TASER or similar device. Testing should be expanded, as the data presented here are limited to a single formulation of TATP. Just one of a large array of TASER‐like devices by a single manufacturer were tested; other devices, scenarios and formulations of TATP and other likely threat materials should be assessed.     

Effects of Human Electro‐Muscular Incapacitation (HEMI) Devices on Cardiovascular Changes in Anesthetized Swine as Measured by Transesophageal Echocardiography (TEE)

The abundance of, and reliance upon, human electro‐muscular incapacitation (HEMI) devices, especially in law enforcement, has generated scrutiny and examination of these technologies. The purpose of this study was to examine cardiovascular effects resulting from typical (5 sec) and longer activation (20 sec) HEMI applications studying myocardial function and peripheral vascular system using a combination of invasive cardiovascular catheters and transesophageal echocardiography (TEE). Six healthy swine (Sus scrofa) 3–5 months in age and weighing between 60 and 86 kg were anesthetized and exposed to the TASER Model X26 waveform while transesophageal echocardiography was performed. Stroke volume was shown to statistically decrease during HEMI application indicating an increase in systemic vascular resistance, but HEMI application did not result in myocardial dysfunction (“cardiac stunning”).     

Detecting buried metallic weapons in a controlled setting using a conductivity meter

Forensic personnel may face a daunting task when searching for buried weapons at crime scenes or potential disposal sites. In particular, it is common to search for a small firearm that was discarded or buried by a perpetrator. When performing forensic searches, it is recommended to first use non-invasive methods such as geophysical instruments to minimize damage to evidence and to the crime scene. Geophysical tools are used to pinpoint small areas of interest across a scene for invasive testing, rather than digging large areas throughout the site. Prior to this project, there was no published research that tested the utility of the conductivity meter to search for metallic weapons such as firearms and blunt and sharp edged weapons. A sample comprised of 32 metallic weapons including firearms, blunt and sharp edged weapons, and scrap metals was buried in a controlled setting to test the applicability of a conductivity meter for forensic searches. Weapons were tested at multiple depths and after data collection was performed for one depth, the weapons were reburied 5 cm deeper until they were no longer detected. Variables such as weapon size, burial depth, transect interval spacing (25 and 50 cm), and metallic composition were tested. All of the controlled variables influenced maximum depth of detection. For example, size was a factor as larger weapons were detected at deeper depths compared to smaller weapons. Metal composition affected maximum depth of detection as the conductivity meter detected items comprised of ferrous metals at deeper depths than non-ferrous metals. Searches for large buried items may incorporate a transect interval spacing of 50 cm but small weapons may be undetected between transects and therefore a transect interval spacing of 25 cm is recommended. Overall, the conductivity meter is a geophysical tool to consider when searching for larger-sized metallic weapons or to use in conjunction with an all-metal detector, particularly when searching for buried metallic evidence in obstructed areas.     

Police use of TASER devices in mental health emergencies: A review

The proliferation of TASER devices among police forces internationally has been accompanied by concerns about injuries and health effects, and about the use of TASER devices on vulnerable populations such as people with mental illness. TASER devices have generated a flood of research studies, although there remain unanswered questions about some of the key issues. This paper outlines the introduction of TASER devices to policing and their subsequent widespread adoption. The paper considers the role of police in mental health emergencies with a particular focus on use of TASER devices. Some factors contribute to the special vulnerability of people with mental illness to the effects of TASER devices. The paper also reviews research into use of TASER devices and raises issues about conflict of interest in research into TASER devices. We conclude that TASER devices look set to play a significant role in policing in the future. We make suggestions for a future research programme, and suggest guidelines for publication of papers in which there may be a conflict of interest.