Tasered pigs

Credit: COURTESY OF TASER INTERNATIONAL"> Credit: COURTESY OF TASER INTERNATIONAL A few years ago, John Webster heard that the US Department of Justice was looking for applications to study the possibility of a link between Tasers and ventricular fibrillation. Amnesty International has claimed that 70 people in the United States have died in association with Tasers since 2001, and "there was an allegation that the heart was getting electrocuted," says Webster, a professor emeritus of biomedical engineering at the University of Wisconsin, Madison. Having studied the effects of electricity on the body, he was intrigued by the lack of direct data on how Tasers affect the heart. Webster applied for a $500,000 grant with the intention of using anesthetized and then Tasered pigs as models for humans. After all, says Webster, pig size, skin, and heart structure are comparable to humans. The grant was approved in 2004. His latest study, which has been presented as a poster at the 2006 Experimental Biology Meeting in April, used ten 50-71 kg anesthetized pigs, whose sternums were opened. That allowed direct access to the ribs for the Taser darts, which are normally fired but remain connected to the Taser, transmitting a charge to the target. A hole was then created between two ribs of each pig, a Taser dart inserted, and fired at different distances from the heart. "We wanted to answer the question of how close to the heart do you have to get to induce ventricular fibrillation," says Webster. With a dart of 9 mm, the researchers had to get within 17 mm to cause an effect on the pig hearts. "This suggests that if a dart landed on the soft tissue of a pig within 26 mm of the heart, it could be dangerous," he says. "It also suggests that if a person has on average a distance from the skin to the heart of less than 26 mm, they might be electrocuted by the Taser." Wayne McDaniel, a biomedical engineer at the University of Missouri in Columbia, has also studied the Taser effect on pig hearts. He got into the research in 1999 when manufacturer Taser International asked him to test a new higher-power stun device. "The concern was that if you hit someone in the thorax with one ... [would it] induce ventricular fibrillation," says McDaniel.McDaniel has used a custom-designed Taser that could give a charge about 40 times that of a normal device. His research team shocked pigs through the skin and then looked for an effect on the heart. They found that their Taser needed 15 to 42 times the charge of a normal Taser to induce ventricular fibrillation through the skin.McDaniel says that because Webster opens the sternum, his work ignores the effect of the skin's conductivity. Webster says McDaniel's research ignores the effects of differing fat and muscle layers between pigs and humans. People for the Ethical Treatment of Animals (PETA) finds the work of both groups objectionable, calling it cruel and unnecessary.Jeffrey Ho, a physician in the emergency department at the Hennepin County Medical Center in Minneapolis who is also a police officer, says pigs aren't a great model for humans. Ho instead prefers to collect human data. His interest in the topic led him to attend Taser International's training courses. Back in Minneapolis, he began testing people who had been hit with a Taser for markers of cardiac muscle injury. "We couldn't demonstrate any effect on the heart," says Ho, whose work is in its early stages.The shift to work in humans will likely come as a relief to PETA, which has argued that enough people have been hit with stuns guns to enable collection of relevant information on safety. Webster insists that some studies, such as measuring dart-to-heart distances, can be done only in animals. The alterative of not acquiring such safety data means the use of Tasers might be undermined, he says, "and then the police are left with bullets."

Tasered pigs

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