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").

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.

Human electromuscular incapacitation devices characterization: a comparative study on stress and the physiological effects on swine.

Human electromuscular incapacitation devices or electromuscular disruption (EMD) devices are increasingly used in police and military applications. Most individuals who experience electromuscular incapacitation are in a stress-filled state, and the effects of prolonged or repeated exposures are not well understood. Three different commercially available EMD devices were tested randomly on 6 anesthetized pigs each for a total of 18 pigs. Each animal was exposed to an initial 60-second application of the EMD device as an initial stressor. The animals were then allowed to rest under anesthesia for 60 minutes followed immediately by a 180-second application of the same device. Arterial blood gases and serum samples were collected throughout the experiment to measure catecholamines (epinephrine, norepinephrine, and dopamine) and cortisol. All the devices produced some level of muscle tetany as a result of the electrical delivery to the animal. All the pigs showed a mixed metabolic and respiratory acidosis. Cortisol tended to decrease after the initial exposure and slightly increased over the rest period. The extreme muscular work caused by the electrical stimulation resulting in muscle contractions did not result in a strong stress response but did result in an immediate sympathetic response during both applications of the device leading to the conclusion that initial stressor followed by rest and prolonged EMD device application did not exhaust the sympathetic system. For healthy adult animals, despite the prolonged muscular exertion and physiological stress caused by EMD devices, the body should be able to mount an appropriate sympathetic response and recover normally.