Study tests REAL-WORLD effects of stun gun use

January 22, 2009
Digital Journal

University of California: San Francisco researchers have completed the first study to test real-world effects of stun gun use. Click here to read the abstract.

A University of California: San Francisco (UCSF) study states the rate of sudden deaths increased six-fold in the first year that California law enforcement agencies deployed the use of stun guns.

The findings also showed a two-fold increase in the rate of firearm-related deaths during the same time period.

The most widely used brand of stun gun is the Taser, and the team surveyed for outcomes related to the deployment of this device.

While some industry-funded controlled human studies have shown Tasers to cause no harm, this study suggests that their real-world effects pose greater medical risk and more danger than previous reports, said study author Zian H. Tseng, MD.

Although the device has been advertised to decrease the number of shooting deaths and officer injuries, study outcomes showed an increase rather than a reduction in the rate of shooting deaths and no change in officer injuries following Taser deployment, he added.

Researchers found that rates of sudden and firearm-related deaths declined back to near pre-deployment levels after the first year of Taser usage. The team postulated that law enforcement agencies self-corrected, likely adjusting their usage protocol or technique after the first year.

Study findings are published online today (Jan. 22, 2009) by the American Journal of Cardiology. The journal will also publish the study in an upcoming print edition.

“Physicians and law enforcement agencies need real-world knowledge of the effects of Taser use so that risks can be weighed in establishing appropriate policies and techniques,” said Tseng, who is senior author on the paper and assistant clinical professor in cardiology at UCSF.

“There have been a number of animal and controlled human studies, but none that test how Tasers are used in the real world, where subjects may have pre-existing medical conditions or be under the influence of narcotics.”

Researchers, under the Public Records Act and the Freedom of Information Act, mailed surveys to 126 police and sheriff departments in California cities and the 10 largest cities in the U.S. The survey requested three types of information: the rates of in-custody sudden deaths in the absence of lethal force, firearm-related deaths, and officer injuries requiring emergency room visits.

Fifty cities provided data on the rates of sudden death pre- and post-Taser deployment , while 21 cities reported firearm deaths and four cities reported officer injuries. None of the 10 largest U.S. cities returned surveys. The team used total annual arrest data per city as reported by the Department of Justice.

For each law enforcement agency that responded, researchers gathered data for the five years prior to the deployment of Tasers and for five years after. This allowed the research team, which included epidemiologists, cardiologists and statisticians, to observe how device deployment impacted the number of emergency events that a law enforcement agency experienced.

“Sudden deaths are extremely rare events, but it is important to look into why these events happen and whether law enforcement agencies are fully informed of the real-world risks of Taser deployment,” said Byron Lee, MD, first author on the paper and assistant clinical professor in cardiology at UCSF.

Stun guns like the Taser deliver a high-frequency, high-voltage current to incapacitate victims by causing momentary neuromuscular incapacitation. They are in use by over 12,000 law enforcement, military and correctional agencies in the U.S. and abroad, according to reporting by Taser International Inc.

Tasers were not examined in this study, but have been demonstrated to cause fatal ventricular tachyarrhythmias, or rapid irregular heartbeat, by capturing the heart at a higher, more dangerous rate. The increased adrenaline state resulting from a struggle and multiple, prolonged device applications near the heart may also make a person more vulnerable to sudden death.

“If law enforcement agencies using Tasers understood the risks and were trained to recognize cardiac arrest, sudden death events could be averted with timely deployment of external fibrillation or by knowing where not to apply the device’s current, such as near the heart,” Tseng said.

The research team noted limitations in its study, which was observational, such as a lack of information about reported sudden death events and the possibility that survey responses could be inaccurate. Also, the analysis only included a portion of cities known to be using the Taser. Several California cities and all of the largest U.S. cities surveyed were unwilling to release information.

“Further epidemiologic research is clearly needed. Without full transparency by law enforcement agencies, it is possible that our observed outcomes may actually be an underestimation of the real risks of Taser use,” Tseng added.

The study was funded by the National Center for Research Resources, a component of the National Institutes of Health and the NIH Roadmap for Medical Research.

Additional co-investigators on the study were Eric Vittinghoff, PhD, Dean Whiteman and Minna Park of UCSF; and Linda L. Lau of Loyola University Chicago School of Medicine.

Taser studies flawed, epidemiologist says

May 24, 2008
Neal Hall, Vancouver Sun

The studies that have been done to determine the risks of the Taser stun gun are flawed, a Vancouver epidemiologist told a provincial Taser inquiry Friday.

"I don't think you can extrapolate the results to the real world," said Dr. Keith Chambers.

He recommended that until more research is done to resolve the many unanswered questions about the risks and benefits of the weapon, limits on its use, with standardized guidelines, should be put in place.

Chambers said the "genie is already out of the bag," meaning it may be too late to conduct proper controlled trials of the weapon. But outcomes could be tracked with better systems of data collection.

He said one of the problems with existing research studies is that the circumstances in them don't occur in the real world. Most of the people on whom Tasers were tested were healthy volunteers who received a single five-second electrical jolt, which incapacitates a person by contracting muscles.

The earliest Taser research involved testing on pigs.

"Animal studies and volunteer studies don't support the real world and don't measure the magnitude of the harms and benefits," said Chambers, an epidemiologist who designs medical research studies. "In my mind, we have no idea of the relative risk in a large population due to Taser use."

In the studies that have been done, the sample sizes were too small to obtain reliable results, he said. For example, one study used only 66 people. "It's a huge problem, the sample size," he told inquiry commissioner Thomas Braidwood, a retired judge.

He noted that there have been seven Taser-related deaths in B.C., a relatively small number, given the growing use of the weapon by police. "You've got to have large numbers [of people tested] because the event rate is so low," he said. He suggested a proper sample size for a study would be 50,000 subjects.

The inquiry heard from a number of municipal police chiefs and RCMP commanding officers who support the use of the Taser. They said that, used properly, it can save lives and reduce injury to officers and suspects.

More than 300 people in North America, including 19 in Canada and seven in B.C., have died after being jolted by a Taser.

Tom Smith, chair of Taser International, the weapon manufacturer, based in Scottsdale, Ariz., told the inquiry that Tasers are like air bags: They save lives but occasionally contribute to a death.

"Are Tasers risk-free? No, they cause people to fall down," Smith told the inquiry, pointing out that Tasers save 70 lives for every life lost.

But several presenters at the inquiry called for a moratorium on Tasers pending further independent research. One was Murray Mollard, executive director of the B.C. Civil Liberties Association.

He said Friday that government control over Taser use by police in B.C. has been an "utter failure," since "police forces sold the technology to [their] political masters and the general public as a weapon that would be used as a substitute for the use of firearms, thus saving lives."

Back in 2000, when Tasers were first used in B.C., the civil liberties association supported their use based on the premise that they would be an alternative to deadly force. Since then, Mollard observed, the weapon has become "the most controversial use-of-force tool employed by police."

His organization is urging the provincial and federal governments to commission new independent research to determine the risks of using Tasers on people with heart disease and mental illness, and the risks of multiple shocks from the stun gun.

He suggested there be standardized regulations on when Tasers can be deployed, as well as uniform training.

He would also like to see the B.C. government publish detailed annual statistics on Taser use "to provide the public with a meaningful ability to understand the circumstances and justification" for the use of the weapon.

The second phase of the inquiry, expected to take place in the fall, will focus on the events surrounding the death of Robert Dziekanski at Vancouver International Airport on Oct. 14, 2007.

After a long flight from Poland, the 40-year-old man wandered around a secure area of the airport for seven hours, looking for his mother, who lives in Kamloops. He appeared tired and disoriented and began behaving erratically.

Dziekanski, who spoke no English, was eventually confronted by police, shocked twice with a Taser and restrained by RCMP officers. He died minutes later.

The B.C. government ordered the Braidwood inquiry to probe Taser use after the Dziekanski incident.