Individuals who have been on the wrong end of a TASER are common denizens of the emergency department, and these cases are loaded with social and racial overtones, often accompanied by accusations of police brutality. Although the jolt of a TASER is an electrical insult to the body, the evidence shows that it is relatively harmless.
Last month's column concluded that the physiological effects of the TASER, even after exercise or in exhausted adults, are minimal by multiple scientific standards, and essentially are clinically inconsequential. Occasionally individuals are brought to the ED to have darts removed, to evaluate or treat the event that prompted the TASER in the first place, or as a standing protocol by law enforcement. The quandary for the clinician is what to do for asymptomatic patients brought to the ED for evaluation of a TASER event.
Emergency Department Evaluation after Conductive Energy Weapon Use: Review of the Literature for the Clinician
Vilke GM, Bozeman WP, Chan TC
J Emerg Med
Conductive energy weapons, AKA the TASER, through a series of brief electrical pulses, produce transient pain and violent muscular contractions. The electricity is delivered by touching the recipient's skin with electrodes (stun gun) or via a pair of skin-embedded sharp metal projectile probes (darts) attached to conductive wires. Some clinicians admit TASERed patients for telemetry monitoring. Others simply remove the darts, perform a brief exam, and discharge to police custody. No standards mandate any blood tests or cardiac evaluations. Some EMS personnel remove the darts and bypass the ED, delivering otherwise asymptomatic victims directly to jail.
These authors, all erudite researchers in this field, reviewed the medical literature to proffer evidence-based recommendations for emergency physicians evaluating patients with recent TASER exposure. They aimed to clarify if TASER exposure requires any specific radiographic, laboratory, or cardiac evaluation based solely on TASER exposure. This report
has become a position statement for the American Academy of Emergency Medicine's clinical guideline section.
The database included a variety of studies. From 140 publications, the authors culled 20 articles deemed appropriate for review, including two randomized controlled trials, two prospective trials, 13 prospective cohort studies, and three retrospective cohort studies. Articles were reviewed to assign a standard ranking for level of evidence, and consigned to the categories of “supportive,” “neutral,” or “opposed” to the TASER device. Importantly, all utilized reference sources were deemed “supportive” of the TASER, none to “neutral” or ”opposed.”
Cardiac monitoring and EKG screening after conductive energy weapon use. Class A level recommendation. The authors concluded that the human literature found no evidence of immediate or delayed cardiac ischemia or dysrhythmia after conductive energy weapon exposures up to 15 seconds. Note that the standard single TASER exposure is five seconds. They also concluded that the literature does not support routine performance of an EKG, prolonged ED observation, or hospitalization for ongoing cardiac monitoring in an otherwise asymptomatic awake and alert patient with a short duration of exposure.
Their evaluation found no reports of clinically relevant ectopy, dysrhythmia, QT prolongation, interval changes, or other EKG abnormalities immediately related to conductive energy weapon use, or with delayed monitoring up to an hour post-exposure. EKGs performed during conductive energy weapon use have found no abnormalities during the activation and delivery of electricity to suggest electrical capture of the heart or structural cardiac damage.
Laboratory testing after CEW use. Class A level recommendation. The reviewed medical literature did not support routinely performing any laboratory studies, prolonged ED observation, or hospitalization for continued monitoring. There have been no clinically significant changes in electrolyte levels, renal function, or troponin levels following conductive energy weapon exposure. Minimal elevations in CPK and lactate levels have been termed clinically insignificant, and merely related to muscular contractions. There have been no reported clinically significant acid-based disturbances.
Other recommendations: Evaluation after touch or dart mode exposure. Class B level recommendation. Those who have undergone touch stun gun exposure may experience minor local effects such as skin irritation or minor contact burns. No particular damaging effects have been demonstrated, and no specific treatment is necessary.
The obvious potential injury from TASER darts to eyes is highlighted as are injuries due to intense muscle contractions and trauma due to falls. Compression fractures of the thoracic spine have been noted rarely as have other soft tissue injuries. Falls secondary to loss of muscular control or protective reflexes can result in blunt trauma. Significant injuries due to these mechanisms are rare, occurring in less than 0.5 percent of real-world deployments.
No studies have demonstrated any adverse effects on pregnant women, but data are lacking. The authors also caution that prolonged conductive energy weapon exposure greater than 15 seconds may have potential adverse physiological effects. Prolonged exposure, which requires the user to activate the device continually, has not been well studied. While there is relatively scant literature to support specific guidelines for excessive exposure, serious events have not been documented.
Clinical judgment should be used in those cases where multiple shocks were delivered or prolonged exposure occurred. The authors caution that the underlying condition, such as alcohol or drug intoxication or the many other causes of excited delirium, require individual assessment.
Summary recommendations. The current medical literature does not support the routine performance of any laboratory studies, EKG or cardiac monitoring, prolonged ED observation, or hospitalization in otherwise asymptomatic awake and alert patients who have been exposed to conductive energy weapons for 15 seconds or less. Treatment for patients with complicated histories, those with persistent and unusual symptoms (chest pain, shortness of breath, and palpitations), and those with exposure of more than 15 seconds should be on a case–by-case basis. Coexisting conditions, the effects of falling, and consequences of prolonged struggling must be appreciated.
COMMENT: Conductive energy weapons consist of a touch mode, where electrical probes are held against the individual, or a probe mode, where darts attached to wires from the electrical source are shot into the target's skin and create an electrical arc. The consequences of either device should be the same, but law enforcement primarily uses the probe mode.
As TASERs become more widespread, particularly now in the hands of individuals for personal protection, the ED becomes the end of the funnel for many socially charged and potentially medically complicated issues. Deploying your personal conductive energy weapon on your annoying neighbor, obnoxious drunken relative, or daughter's paramour may cause a modicum of angst in the community. One wonders when a child will accidentally tase a sibling, similar to an errant EpiPen discharge.
Although the TASER appears benign, the prescient and sagacious clinician should be squeaky clean in his evaluation of potential injuries that may have occurred during the TASER event. Understandably, many recipients will not be the quintessential ideal, cooperative, or willing patient. It is axiomatic to be sensitive to psychosocial and medical-legal ramifications of such encounters. The clinician rarely knows exactly what happened in the field. We often get one story from the TASER user and another from the recipient so we must proceed with caution when dealing with local authorities and the often irate, drunk, drugged, psychotic, and always litigious TASER recipient.
It appears that the EP need not do any blood tests, EKGs, or provide prolonged observation or monitoring for a simple TASER exposure. It may not be possible to ferret out subtle fractures or other injuries in an intoxicated or delirious patient, and those individuals obviously require further investigation. Pregnant women likely warrant an OB evaluation.
The TASER dart has a barb of about ¼-inch long on a shaft up to one inch. The probe can penetrate only up to the hilt. Although a dart is relatively short, it has potential to injure superficial vessels or nerves in the face or neck. The face was reported to be the location of dart embedment in about one percent of cases in an early series. (Ann Emerg Med 1987;16:73.) Some temporary anesthesia may surround the dart site, and the dart often can be simply removed with a hemostat and treated as a minor puncture. Tetanus prophylaxis recommendations should be followed. Infiltration of the area with local anesthesia and making a small slit with a #11 blade may be required in some deeply imbedded darts. No specific infections are related to dart use. Probably the most dreaded injury from a TASER dart is an ocular injury. (Am J Ophthalmol 2005;139:713.) Rare cases of ruptured globes have been reported.
A single case of intracranial dart penetration was reported, with the dart penetrating the dura and the brain, but there were no complications, and the patient had an uneventful course following removal. (Am J Emerg Med 2007;25:773.e3-4.) Some have said testicular torsion and miscarriage followed TASER use, but such complications are undocumented and difficult to decipher.
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Dr. Roberts is the chairman of emergency medicine and the director of the division of toxicology at Mercy Catholic Medical Center, and a professor of emergency medicine and toxicology at the Drexel University College of Medicine, both in Philadelphia.
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Reader Feedback: Readers are invited to ask specific questions and offer personal experiences, comments, or observations on InFocus topics. Literature references are appreciated. Pertinent responses will be published in a future issue. Please send comments to firstname.lastname@example.org. Dr. Roberts requests feedback on this month's column, especially personal experiences with successes, failures, and technique.
▪ Read Dr. Roberts' first article on TASERs and other EMN TASER coverage in a special collection, TASER/Excited Delirium Syndrome, on the EMN website at http://bit.ly/EMNTASER.
▪ The “Study of Deaths Following Electro Muscular Disruption: Interim Report” from the U.S. Department of Justice is available at http://1.usa.gov/DOJTASER.
▪ Read the American College of Emergency Physicians' “White Paper Report on Excited Delirium Syndrome” at http://bit.ly/ACEPExDs.
▪ Read all of Dr. Roberts' past columns in the EM-News.com archive.
▪ Comments about this article? Write to EMN at email@example.com.