Conducted Electrical Weapon Fire Risk in the Presence of Supplemental Oxygen.

BACKGROUND: Conducted electrical weapons (CEWs) are nonlethal weapons used in tactical environments. Tactical EMS (TEMS) operators provide patient care in environments where CEWs are present. CEWs may produce a spark that can be a source of ignition. When supplemental oxygen is in use by a TEMS operator, the flammability risk from the CEW is unknown. METHODS: We measured oxygen levels over 20 minutes in an enclosed space with a supplemental oxygen source maximally flowing. Measurements were taken at various distances from the oxygen source to establish baseline concentrations. These concentrations were replicated within a plexiglass box where a CEW was activated to create a sparking arc between probes embedded in a fresh swine shoulder (with skin intact). Various flammable materials, typically found in a patient care setting were used as potential fuel sources. RESULTS: The highest oxygen levels were achieved directly at the source. At 15cm from the source, the maximum oxygen concentration was 31.5%. Within the box, ignition was only achieved at oxygen concentrations greater than 45% and only when human hair was present as fuel. No ignition was achieved at oxygen levels below this regardless of the tested fuel present. CONCLUSION: Ignition from a CEW is possible at supplemental oxygen levels greater than 45% when human hair is present. In an enclosed space, oxygen concentration levels of 45% are only present within 15cm of a flush rate oxygen source. The likelihood of CEW-caused ignition in such settings with supplemental oxygen in use is extremely low.

A comparison of three conducted electrical weapons in a surrogate swine cardiac safety model.

We used a previously described methodology in a swine model to compare the relative cardiac safety of the Axon T7 Conducted Electrical Weapon (CEW), released in October of 2018, to two prior generations of Axon CEWs to include the X2 and the X26E. A total of 5 swine (252 total CEW exposures) were tested by alternating the three weapons at each chest exposure location. Our testing, using systemic hypotension as the quantitative surrogate for cardiac capture, demonstrated that the T7 and X2 were not statistically different. Both were superior, in terms of reduced hypotension during exposure, to the X26E. This study is important as it demonstrates that the newly released weapon is non-inferior to the X2 and superior to the X26E using this surrogate safety model. It is also important because it is the first study to examine the cardiac effects of simultaneous multi-bay exposures. Our prior study compared the X2 to the X26E but examined only single bay exposures from the X2. Lastly, we feel we have improved the methodology for studying the comparative cardiac effects of CEWs.

A comparative study of conducted electrical weapon incapacitation during a goal-directed task.

Conducted electrical weapons (CEW) are ubiquitous in law enforcement given their unique ability to physically incapacitate violently resisting subjects. Early use of animal models to study CEW incapacitation effectiveness (e.g. porcine model with 4-limb strain gauges) proved to be poorly predictive of human incapacitation effectiveness. In a previously published human study, we developed a methodology for the prospective assessment of the incapacitation effectiveness of CEWs in highly motivated human subjects. Here we use this methodology in Part 1 to compare the incapacitation effectiveness of the newly released Axon® (formerly TASER® International) T(ASER) 7 to the TASER X26E, the "gold standard", and the TASER X2, a current model. The T7 has a new "adaptive cross-connect" technology that may improve incapacitation effectiveness in the scenario of small spreads between probe pairs, a common cause of weapon "failure" in the field. In Part 2, we use our methodology to test the functionality of the T7 cross-connect technology by comparing different bay and probe configurations. This is the first published study in the literature comparing different CEW models using this human model. For Part 1, 29 subjects completed the study and had data available for analysis. For Part 2, 21 subjects completed the study and had data available for analysis. The subjects were motivated to complete the task of reaching a suspended martial arts dummy 3.4 m (11 ft) away while being exposed "under power" to the CEW. In Part 1, subjects were assigned to 1 of 6 groups with probe spreads of 10, 20, and 30 cm (4, 8, 12 in). Subjects were exposed to a "control" CEW (either the X2 or X26E) and the T7 on alternating sides. Exposures with the X2 and T7 included 2 bay-exposures. In Part 2, 21 subjects were assigned to 1 of 5 groups of different T7 bay and probe configurations all with a theoretical effective spread of 30 cm (12 in). Subjects were rated on their progress towards successfully reaching the dummy and on the extent of limb incapacitation using a quasi-blinded expert-observer scoring panel based on high-speed video review. In Part 1, all CEW models achieved maximal or near-maximal subject control with the 30 cm probe spread. With probe spreads of 10 and 20 cm the pooled data showed the T7 to be superior to the X2 for goal achievement (p < 0.001) and limb incapacitation (p = 0.002) mostly driven by differences seen with the 10 cm spread (2-bay exposures). The T7 was non-inferior to the X26E. In Part 2, there was no statistical significance between the limb capture scores, but there was a statistically significant difference in goal scores. The results overall validate that the T7 CEW cross-connect feature performed as expected. The T7 adaptive cross-connect feature with two simultaneous deployed probe pairs demonstrated a significant improvement in incapacitation effectiveness compared to the current X2 CEW with two simultaneously deployed probe pairs. Small probe spreads are a common reason for limited incapacitation effectiveness in the field and this study suggests the T7 may offer an improvement in this scenario. The T7, with single-bay exposures, was non-inferior to the single-bay X26E.

The physiologic effects of a new generation conducted electrical weapon on human volunteers at rest.

Axon Enterprise, Inc. (Axon) released its newest generation conducted electrical weapon (CEW), the T7, in October 2018. In order to compare the effects of this new CEW to prior generations, we used our previously described methodology to study the physiologic effects of CEWs on human volunteers at rest. This was a prospective, observational study of human subjects consisting of two parts. Part 1 was testing a single cartridge (2-probe) exposure. Subjects received a 10-s exposure from the T7 to the back with a 30 cm (12 in.) spread between the two probes. Part 2 was testing a simultaneous two-cartridge (4-probe) exposure. Subjects received a 10-s exposure from the T7 to the back with two cartridges with a 10 cm (4 in.) spread between each probe pair. The probe pairs were arranged cephalad to caudal such that the distance between the top probe of the first cartridge and the bottom probe of the second cartridge was 30 cm (12 in.). Vital signs were measured immediately before and after the exposure. Continuous spirometry was performed. ECG monitoring was performed immediately before and after the exposure. Venous pH, lactate, potassium, CK, catecholamines, and troponin were measured before and immediately after the exposure, at 1-h post-exposure, and again at 24 h. 11 subjects completed part 1 of the study. 9 subjects completed part 2 of the study. No subjects had a dysrhythmia or morphology change in the surface ECG. There were no statistical changes in vital signs pre- and post-exposure. While subjects did not have a statistical change in spirometry parameters pre-exposure to exposure except for a small drop in PETCO2, there was an increase in minute ventilation after the exposure that could have several explanations. A similar pattern was seen with prior generation weapons. No subject had elevated troponin levels. Other blood parameters including venous pH, lactate, potassium, CK, and catecholamines had changes similar to prior generation weapons. Comparison of the data for the single-cartridge exposures against the simultaneous two-cartridge exposures yielded no difference in vital signs, but the minute ventilation was higher for the two-cartridge exposures. The blood data, where there was a difference, was mixed. In our study, the physiologic effects of the Axon T7 are modest, consistent with the electrically-induced motor nerve-driven muscle contraction, and were similar to prior generation weapons.

Effect of Body-Worn Cameras on EMS Documentation Accuracy: A Pilot Study.

INTRODUCTION: Current Emergency Medical Services (EMS) documentation practices usually occur from memory after an event is over. While this practice is fairly standard, it is unclear if it can introduce significant error. Modern technology has seen the increased use of recorded video by society to more objectively document notable events. Stationary mounted cameras, cell-phone cameras, and law enforcement officer Body-Worn Cameras (BWCs) are increasingly used by society for this purpose. Video used in this way can often clarify or contradict recall from memory. BWCs are currently not widely used by EMS. The hypothesis is that current EMS documentation practices are inaccurate and that BWCs will have a positive effect on documentation accuracy. METHODS: This prospective, observational study used a convenience sample of paramedics in a simulation lab. The Paramedics wore a BWC and responded to a simulated call of "One Down" (unresponsive from heroin abuse) involving Role Players (RPs). The paramedics received standardized cues from the RPs during the simulation to keep it on track.  The simulation contained many factors of concern (e.g., weapons and drugs in plain view, unattended minors, etc.) and intentional stressors (e.g., distraught family member, uncooperative patient, etc.). Upon completion of the scenario, paramedic documentation occurred from memory on an electronic template.  After initial documentation, paramedics viewed their BWC recording and were allowed to make tabulated changes. Changes were categorized by a priori criteria as minor, moderate, or major. RESULTS: Ten paramedics participated with an average age of 33.3 years (range 22-43), 8 males and 2 females. The average length of paramedic career experience was 7.7 years (range 2 months to 20 years). There were 71 total documentation changes (7 minor, 51 moderate, 13 major) made after video review. Linear regression (ANCOVA) indicated changes made indirectly correlated with years of experience (coefficient 8.27, 4.22-12.3, 95% CI, p = 0.002), but all made some changes. CONCLUSION: Current EMS documentation practices demonstrate significant inaccuracy regardless of years of experience. Use of BWC technology appears to significantly improve EMS documentation accuracy in this pilot study.

An evaluation of two conducted electrical weapons using a swine comparative cardiac safety model.

Arrest-related deaths proximate to the use of a conducted electrical weapon (CEW) continue to generate controversy despite a better understanding of the multi-factorial nature of many of these deaths. With the rapid adoption of this technology by law enforcement, and the proliferation of companies entering the marketplace, it is important to have a method to assess the relative safety of these weapons. We had previously developed a model to assess the relative cardiac safety of CEWs. In this study, we use this model to compare the TASER X2 and the Karbon Arms MPID. Our results suggest that the TASER X2 may have an improved cardiac safety margin over the Karbon Arms MPID as determined by a smaller area of cardiac pacing on the anterior chest in our model. This model seems to offer a reproducible means of comparing the cardiac effects of CEWs.

Physiologic effects of a new-generation conducted electrical weapon on human volunteers.

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.

The neurocognitive effects of simulated use-of-force scenarios.

While the physiologic effects of modern conducted electrical weapons (CEW) have been the subject of numerous studies, their effects on neurocognitive functioning, both short-term and long-term, are less well understood. It is also unclear how these effects compare to other use-of-force options or other arrest-related stressors. We compared the neurocognitive effects of an exposure to a TASER(®) (TASER International, Inc, Scottsdale, AZ) X26™ CEW to four other use-of-force scenarios during a training exercise using a well-established neurocognitive metric administered repeatedly over 1 h. Overall, we found that there was a decline in neurocognitive performance immediately post-scenario in all groups, but this effect was transient, of questionable clinical significance, and returned to baseline by 1 h post-scenario.

Markers of acidosis and stress in a sprint versus a conducted electrical weapon.

Both profound acidosis and catecholamine excess have been proposed as underlying physiologic derangements in subjects at high risk for arrest related death (ARD). In this study, the objective was to determine a level of physical exertion that is "equivalent" in terms of levels of acidosis and catecholamines to a "standard" TASER X26 exposure. Data were collected on subjects who underwent a 5-s TASER X26 exposure or a sprint of variable distances during a law enforcement training exercise. Our results show that levels of acidosis and catecholamines are less among subjects exposed to the TASER X26 than among subjects who sprinted 20 yards or more.

Successful management of excited delirium syndrome with prehospital ketamine: two case examples.

Excited delirium syndrome (ExDS) is a medical emergency usually presenting first in the prehospital environment. Untreated ExDS is associated with a high mortality rate and is gaining recognition within organized medicine as an emerging public safety problem. It is highly associated with male gender, middle age, chronic illicit stimulant abuse, and mental illness. Management of ExDS often begins in the field when first responders, law enforcement personnel, and emergency medical services (EMS) personnel respond to requests from witnesses who observe subjects exhibiting bizarre, agitated behavior. Although appropriate prehospital management of subjects with ExDS is still under study, there is increasing awareness of the danger of untreated ExDS, and the danger associated with the need for subject restraint, whether physical or chemical. We describe two ExDS patients who were successfully chemically restrained with ketamine in the prehospital environment, and who had good outcomes without complication. These are among the first case reports in the literature of ExDS survival without complication using this novel prehospital sedation management protocol. This strategy bears further study and surveillance by the prehospital care community for evaluation of side effects and unintended complications.

Excited delirium syndrome (ExDS): treatment options and considerations.

The term Excited Delirium Syndrome (ExDS) has traditionally been used in the forensic literature to describe findings in a subgroup of patients with delirium who suffered lethal consequences from their untreated severe agitation.(1-5) Excited delirium syndrome, also known as agitated delirium, is generally defined as altered mental status and combativeness or aggressiveness. Although the exact signs and symptoms are difficult to define precisely, clinical findings often include many of the following: tolerance to significant pain, rapid breathing, sweating, severe agitation, elevated temperature, delirium, non-compliance or poor awareness to direction from police or medical personnel, lack of fatiguing, unusual or superhuman strength, and inappropriate clothing for the current environment. It has become increasingly recognized that individuals displaying ExDS are at high risk for sudden death, and ExDS therefore represents a true medical emergency. Recently the American College of Emergency Physicians (ACEP) published the findings of a white paper on the topic of ExDS to better find consensus on the issues of definition, diagnosis, and treatment.(6) In so doing, ACEP joined the National Association of Medical Examiners (NAME) in recognizing ExDS as a medical condition. For both paramedics and physicians, the difficulty in diagnosing the underlying cause of ExDS in an individual patient is that the presenting clinical signs and symptoms of ExDS can be produced by a wide variety of clinical disease processes. For example, agitation, combativeness, and altered mental status can be produced by hypoglycemia, thyroid storm, certain kinds of seizures, and these conditions can be difficult to distinguish from those produced by cocaine or methamphetamine intoxication.(7) Prehospital personnel are generally not expected to differentiate between the multiple possible causes of the patient's presentation, but rather simply to recognize that the patient has a medical emergency and initiate appropriate stabilizing treatment. ExDS patients will generally require transfer to an emergency department (ED) for further management, evaluation, and definitive care. In this paper, we present a typical ExDS case and then review existing literature for current treatment options.

Excited Delirium Syndrome (ExDS): defining based on a review of the literature.

BACKGROUND: Patients present to police, Emergency Medical Services, and the emergency department with aggressive behavior, altered sensorium, and a host of other signs that may include hyperthermia, "superhuman" strength, diaphoresis, and lack of willingness to yield to overwhelming force. A certain percentage of these individuals will go on to expire from a sudden cardiac arrest and death, despite optimal therapy. Traditionally, the forensic community would often classify these as "Excited Delirium" deaths. OBJECTIVES: This article will review selected examples of the literature on this topic to determine if it is definable as a discrete medical entity, has a recognizable history, epidemiology, clinical presentation, pathophysiology, and treatment recommendations. DISCUSSION: Excited delirium syndrome is characterized by delirium, agitation, acidosis, and hyperadrenergic autonomic dysfunction, typically in the setting of acute-on-chronic drug abuse or serious mental illness or a combination of both. CONCLUSIONS: Based upon available evidence, it is the consensus of an American College of Emergency Physicians Task Force that Excited Delirium Syndrome is a real syndrome with uncertain, likely multiple, etiologies.

Effect of position and weight force on inferior vena cava diameter--implications for arrest-related death.

INTRODUCTION: The physiology of many sudden, unexpected arrest-related deaths (ARDs) proximate to restraint has not been elucidated. A sudden decrease in central venous return during restraint procedures could be physiologically detrimental. The impact of body position and applied weight force on central venous return has not been previously studied. In this study, we use ultrasound to measure the size of the inferior vena cava (IVC) as a surrogate of central venous return in the standing position, prone position, and with weight force applied to the thorax in the prone position. METHODS: This was a prospective, observational study of volunteer human subjects. The IVC was visualized from the abdomen in both the longitudinal and transverse section in the standing and prone positions without weight force applied, and with 100 lbs (45 kg) and 147 lbs (67 kg) of weight force on the upper back in the prone position. Maximum and minimum measurements were determined in each section to account for possible respiratory variation of the IVC. RESULTS: The IVC significantly decreased in size with each successive change: from standing to prone, from prone to prone with 100 lbs (45 kg) weight compression, from prone with 100 lbs (45 kg) weight compression to prone with 147 lbs (67 kg) weight compression (p < 0.0001). The vital sign measurements had no statistical change. CONCLUSIONS: The physiology involved in many sudden, unexpected ARDs has not been elucidated. However, in our study, we found a significant decrease in IVC diameter with weight force compression to the upper thorax when the subject was in the prone position. This may have implications for the tactics of restraint to aid in the prevention of sudden, unexpected ARD cases.

The respiratory, metabolic, and neuroendocrine effects of a new generation electronic control device.

INTRODUCTION: Electronic control devices (ECDs) have become popular in law enforcement because these devices have filled a gap left by other law enforcement devices, tactics, or tools and have been shown to reduce officer and suspect injuries. The TASER X3 is the latest generation device from the manufacturer. This device has the capability of firing three cartridges in a "semi-automatic" mode. This study is the first of the metabolic, neuroendocrine, and respiratory effects of this newer generation device. METHODS: This was a prospective, observational study of human subjects. A master instructor shot subjects with a TASER X3 in the anterior thorax with either one or two cartridges. Each subject received a 10-s exposure from the device. Vital signs were measured before and after the exposure. Venous pH, lactate, electrolytes, and catecholamines were measured before and after the exposure. Creatine kinase (CK) was measured before and at 24h post-exposure. Continuous spirometry was also performed. RESULTS: Fifty-three subjects completed the study. There were no important changes in vital signs or electrolytes. Venous pH, lactate, and catecholamine changes were similar to previous studies on earlier generation devices. There was no evidence of impairment of breathing. CK changes were greater for multiple "circuits". CONCLUSIONS: In our study, the respiratory, metabolic, and neuroendocrine effects were similar to previous generation devices. There was an increase in CK with more probes deployed.