ANALYSIS / USA – National Institute of Justice : Study of Deaths Following Electro Muscular Disruption [tasering] (2011-05)

Published on May 31 2011 by admin

 [[SUMMARY / COMMENTS : The conclusion of  this semi-definitive NIJ study, undertaken by an independent medical panel, “because many gaps remain in the body of knowledge with respect to the effects of CEDs [tasers]. The panel finds no conclusive medical evidence in the current body of research literature” to indicate the taser kills when used appropriately … “Law enforcement need not refrain from using CEDs to place uncooperative or combative subjects in custody, provided the devices are used in accordance with accepted national guidelines and appropriate use-of-force policy.  Because the physiologic effects of prolonged or repeated CED exposure are not fully understood, law enforcement officers should refrain, when possible, from continuous activations of greater than 15 seconds, as few studies have reported on longer time frames.” All deaths should be followed by a complete autopsy. Identification of the taser as the cause of death – when no alternative exists – is considered “anecdotal”. “Caution is urged in using multiple or prolonged activations of CED as a means to accomplish subduing the individual. There may be circumstances where repeated or continuous exposure is required; law enforcement personnel should be aware that the associated risks are unknown and that most deaths associated with CED use involve multiple or prolonged discharges.”]]

NCJ 233432: Executive Summary (pages viii – x)

Law enforcement agencies continue to seek alternatives to lethal force and better methods to subdue individuals in order to minimize injuries and death. Less-lethal technologies have been used by law enforcement for this purpose extensively since the early 1990s. As of spring 2010, conducted energy devices (CEDs) causing electro muscular disruption have been procured by more than 12,000 law enforcement agencies in the United States. Approximately 260,000 CEDs have been issued to law enforcement officers nationwide. Police adoption has been driven by two major beliefs: first, that CEDs effectively facilitate arrests when suspects actively resist law enforcement; second, that CEDs represent a safer alternative than other use-of-force methods. Studies by law enforcement agencies deploying CEDs have shown reduced injuries to both officers and suspects in use-of-force encounters and reduced use of deadly force. More recently, independent researchers have come to similar conclusions, when appropriate deployment and training policies are in place.

Nonetheless, a number of individuals have died after exposure to a CED during law enforcement encounters. Some were normal, healthy adults; many were chemically intoxicated or had heart disease or mental illness. These deaths have given rise to questions from both law enforcement personnel and the public regarding the safety of CEDs. Because many gaps remain in the body of knowledge with respect to the effects of CEDs, the National Institute of Justice (NIJ), the research, development and evaluation agency of the U.S. Department of Justice, conducted a study, Deaths Following Electro-Muscular Disruption, to address whether CEDs can contribute to or be the primary cause of death and, if so, by what mechanisms. The study was directed by a steering group that included NIJ, the College of American Pathologists, the Centers for Disease Control and Prevention, and the National Association of Medical Examiners.

To support the study, the steering group appointed a medical panel composed of forensic pathologist/medical examiners and other relevant physicians or specialists in cardiology, emergency medicine, epidemiology and toxicology. To avoid a conflict of interest, no panelists were chosen who had worked as litigation consultants for or against CED manufacturers. This report contains the findings and recommendations of the medical panel.

In 2008, NIJ released its interim report, Study of Deaths Following Electro Muscular Disruption: Interim Report. Among other findings, that report stated, “Although exposure to CED is not risk free, there is no conclusive medical evidence within the state of current research that indicates a high risk of serious injury or death from the direct effects of CED exposure.” The interim report described the risks associated with the use of CEDs and provided a set of accepted research findings in its summary. The report also provided recommendations for death investigation, medical response and further research. Although this final report provides additional, significant detail to many of the findings in the interim report, the study panel’s interim findings still represent its consensus on the issue of risks associated with CED use.

This final report provides findings concerning death investigation, CED use, CED-related health effects, and medical response. The panel recommends a thorough review of the entire report and the associated research literature for medicolegal personnel and those making decisions concerning CED deployment and associated policies. The following findings are provided as those of most general interest to date.

There is no conclusive medical evidence in the current body of research literature that indicates a high risk of serious injury or death to humans from the direct or indirect cardiovascular or metabolic effects of short-term CED exposure in healthy, normal, nonstressed, nonintoxicated persons. Field experience with CED use indicates that short-term exposure is safe in the vast majority of cases. The risk of death in a CED-related useof-force incident is less than 0.25 percent, and it is reasonable to conclude that CEDs do not cause or contribute to death in the large majority of those cases.

Law enforcement need not refrain from using CEDs to place uncooperative or combative subjects in custody, provided the devices are used in accordance with accepted national guidelines and appropriate use-of-force policy. The current literature as a whole suggests that deployment of a CED has a margin of safety as great as or greater than most alternatives. Because the physiologic effects of prolonged or repeated CED exposure are not fully understood, law enforcement officers should refrain, when possible, from continuous activations of greater than 15 seconds, as few studies have reported on longer time frames.

All deaths following deployment of a CED should be subject to a complete medicolegal investigation, including a complete autopsy by a forensic pathologist in conjunction with a medically objective investigation that is independent of law enforcement. The complete investigation should include the collection of information specific to CED-related deaths, such as the manner in which and the location where CED darts or prongs were applied. A recommended checklist is contained in chapter 11, “Considerations in Death Investigation,” pages 36-37 in this report.

Unlike the risk of secondary injury due to falling or puncture, the risk of human death due directly or primarily to the electrical effects of CED application has not been conclusively demonstrated. However, there are anecdotal cases where no other significant risk factor for death is known. Additionally, current research does not support a substantially increased risk of cardiac arrhythmia in field situations, even if the CED darts strike the front of the chest. There are anecdotal cases where no other significant risk factor for death is known and where the temporal association provides weak circumstantial evidence of causation. The panel reviewed studies on ventricular fibrillation with respect to dart placement, demonstration of ventricular fibrillation, pulseless ventricular tachycardia, pulseless electrical activity in animals, and anecdotal examples of capture in humans wearing cardiac pacemakers or defibrillators. These studies suggest plausible but unproven mechanisms for unusual and rare cases of death due to a confluence of unlikely circumstances. In general, the stress of receiving CED discharge(s) should be considered to be of a magnitude that is comparable to the stress of other components of subdual. All aspects of an altercation (including verbal altercation, physical struggle or physical restraint) constitute stress that may heighten the risk of sudden death in individuals who have pre-existing cardiac or other significant disease.

Caution is urged in using multiple or prolonged activations of CED as a means to accomplish subduing the individual. There may be circumstances where repeated or continuous exposure is required; law enforcement personnel should be aware that the associated risks are unknown and that most deaths associated with CED use involve multiple or prolonged discharges.

We offer this report to the police community, the medical community and the public as a contribution to the many considerations necessarily involved in the use of CEDs and other types of force by law enforcement. We offer this report to our colleagues involved in all aspects of medicolegal death investigation to educate them on our findings and to offer possible approaches to their individual case investigations. We know full well that every case is unique and that it is extremely difficult to generalize findings or techniques. We in no way imply that our conclusions or suggestions are the only way to proceed. We offer these for consideration as aids that might be beneficial in formulating a more complete understanding of the circumstances, mechanisms or pathophysiology in determining the cause and manner of death.

It is recommended that law enforcement maintain an ongoing dialogue with medical examiners/coroners and emergency physicians to discuss effects of all use-of-force applications (CED use and other modalities) and evaluate procedures involving life preservation, injury prevention and evidence collection.

Any expert panel brings with it certain limitations. These limitations are due not only to the limitations of our knowledge but also to the perspectives that the panel members bring to the table. This is particularly true with respect to the determination of the cause and manner of death. These differences are not capricious, but derive from varying philosophical viewpoints and traditions regarding how these deaths should be placed within specific cultural and legal contexts. The conclusions in this report represent a strong underlying consensus. In instances when there were disagreements over specific classifications or diagnostic categorizations, the discussions did not reflect differences in the understanding of basic underlying scientific principles but rather the differences inherent in specific jurisdictional-related and historic practices. In fact, there was a strong consensus regarding the principles of these conclusions even in the context of differences in how they might be phrased. In addition, the report is based upon the information available to the panel at this writing. As scientific understanding advances, the opinions of panel members may change to accommodate new findings.

Findings and conclusions of the research reported here are those of the authors and do not reflect the official position and policies of their respective organizations or the U.S.

 https://www.ncjrs.gov/pdffiles1/nij/233432.pdf

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