Dr. Jeffrey Ho is an emergency physician at Hennepin County Medical Center in Minneapolis and an associate professor of emergency medicine at the University of Minnesota School of Medicine. He is a licensed deputy sheriff in Minnesota, and currently serves with a county enforcement agency. He also has served as a medical director and operator of an urban SWAT team, is currently a medical director for several Minnesota EMS agencies, and regularly consults with law enforcement agencies and government on issues of in-custody death and conducted electrical weapons. Dr. Ho is also an independent medical consultant to TASER International, where he leads a cadre of researchers in studying human physiologic effects of nonlethal weaponry.
Although there is increasing research evidence that shows no connection between a conducted electrical weapon (most commonly called a TASER) and sudden death or direct permanent disability, the controversy of “helpful device vs. deadly weapon” continues to be fueled by bad logic, media sensationalism, and the use of animal vs. human research.
Make no mistake, a TASER is not risk-free. After all, it is not a child's toy. It is a tool used primarily by law enforcement to incapacitate violent or agitated subjects. While it is true that occasionally people who have had a TASER applied to them subsequently die at some point following an exposure, almost all of these deaths are later determined to be due to other factors such as profound drug intoxication.
The time proximate association of these two events is not evidence of a connection. Attempting to link the application of a TASER and death without good scientific evidence is known as a “post hoc ergo propter hoc” fallacy (“after this, therefore because of this”), and represents an inappropriate use of logic. This would be similar to linking the sun rising with a rooster crowing: Shortly after the rooster crows, the sun rises. While the two events are related in time, they are unrelated once you examine the science involved: roosters are diurnal, and the laws of the solar system that demand the sun to rise are unrelated phenomena.
The job of the media is to report events that occur. Because of competition among the media, however, they know that sensationalism sells. Consider the attention-grabbing headline in the Denver Post: “Man Dies after Denver Police Shoot Him with Taser” (Aug. 20, 2004), and it becomes clear that the lay public is instantly and falsely educated about the cause of death over breakfast. When the cause of death (drug intoxication in this case) is ruled upon months later, people do not remember the case so they will not be able to mentally correct their understanding of the death. Instead, they are left with the vivid impression that a TASER kills. Additionally, when a person dies in custody and a TASER is not used, the headline does not specifically state its absence. This type of media reporting only serves to keep the TASER controversy at the top of the list in a layperson's view.
Finally, when it comes to animal vs. human TASER research, there are important conclusions that do not agree when animal and human data are compared. There have been animal studies showing increases in acidosis and apnea (Forensic Sci Int 2006;161:20), the ability to cause ventricular fibrillation (J Am Coll Cardiol 2006;48:798; IEEE Transactions on Biomedical Engineering 2007;54:503), and the ability to cause ventricular capture. (J Trauma 2007;63:581.) These animal studies have served to fuel the rhetoric that these devices are dangerous.
When compared with the human data, different results are shown. Multiple sets of human data by Ho and Dawes, et al, and Chan, Vilke, and Sloane, et al, show opposite conclusions to the animal data that Dr. James Roberts discusses in his InFocus article this month. Humans are shown to continue to breathe with no evidence of worsening acidosis, exhibit no evidence of cardiac arrhythmia by both ECG and echo monitoring methods, and show no clinically significant changes in multiple serum biomarkers. The most likely explanation for this is that the animal models were significantly manipulated to achieve their results (influenced by general anesthesia and abnormal body position, artificially induced drug states, unrealistic electrode positions or exposure durations, and extreme manipulations of the chest anatomy). While animal research can point us in certain directions in many cases, it can be misleading due to its limitations, and human conclusions may not be able to be made from the results.
In my professional life as an emergency physician, a law enforcement officer, and a researcher on this topic, I have found these three factors to be the most often used and abused reasons that explain why people remain skeptical and uninformed about this topic, educated professionals and laypersons alike. Remember that a critic will always see what he wants, but a true student will learn to dig a little deeper for the truth that lies buried under the surface of the rhetoric.
The Medical Effects of TASERs
TASERs are loved by police, hated by human rights groups, and misunderstood by the public, James Roberts, MD, says in this month's InFocus. In his CME article, Dr. Roberts puts the use of stun guns into medical perspective, and examines whether they actually cause cardiac effects and death. See p. 11.