CorrectCare

After the Zap: Taser Injuries and How to Treat Them

By Sir Scott Savage, DO, FACEP, CCHP

Tasers are gaining popularity as a restraint method in law enforcement settings. Considering that the other alternative officers had in the past were bullets, Tasers are an improvement in public safety for suspects and officers alike. But they are not perfect weapons, and occasionally injuries occur with their use. This article describes Tasers and health concerns associated with their use.

How Tasers Work
The acronym Taser stands for Thomas A. Swift Electric Rifle, a character that appeared in children’s books written in the early 20th century.

Tasers are pistol weapons that fire two darts, each connected to a thin wire. When the darts make contact an electrical current is sent through the wires and into the suspect. The electrical current is designed to override the nerves that control the muscle system, causing the suspect to fall to ground and be briefly incapable of voluntary action.

Tasers have several significant features. First, contacting the target anywhere on the body generally leads to full incapacitation. This makes the device safer for officers: Unlike bullets, even contact with a foot or a wrist will lead to complete restraint.

Second, unlike bullets, Taser restraint is immediate. This prevents the suspect from returning fire after he is hit. Third, the darts need not contact skin for the weapon to work properly. The electrical impulse of certain Tasers can penetrate up to two inches of material, depending on type of cloth.

Finally, while Tasers are high voltage, they are low wattage. This distinction is key to understanding the injury patterns seen with these weapons.

An electrical injury can be considered similar to being struck on the foot with a falling stone. When the stone hits you, the amount of injury you receive will largely be mediated by two factors: the size of the rock and height of the fall. Obviously, a pebble falling from a roof will cause much less injury than a 100-pound boulder falling even a few inches.

In electrical injuries, the voltage can be viewed as the stone’s height and the amperage as its size. Tasers have high voltage (tall height) but low amperage (small size). Thus, a Taser may fire with 50,000 volts, but it has minimal amperage—like a small pebble that falls from a roof. It stings, but is unlikely to crush your foot the way the boulder would.

Body tissues have different sensitivity to electrical current, and this is important to understanding Taser injuries. Of greatest concern is the heart’s electrical conduction system, which is both highly sensitive and poses the greatest health risk through cardiac arrhythmia, especially ventricular fibrillation.

Here the concept of amperage is vital. In advanced cardiac life support, the initial amperage in treatment of ventricular fibrillation is 200 joules. Interestingly, the threshold to induce ventricular fibrillation in a normal heart is much less: generally 10 to 50 joules is considered the minimum. Most Tasers fire at only 0.5 joules or less. The most common model fires at 0.3 joules—about 30 times below the lowest listed threshold of ventricular fibrillation.

Similarly, the duration of a Taser pulse is important. Most of the tissue damage seen in standard electrical injuries is not due to the electrical current directly. Tissue chronaxie, or the heat generated secondarily by the electrical resistance of the human body to the current, is what generally causes an “electrical” burn. Heat generation becomes significant with relatively long durations in pulse. Tasers are designed with short pulse waveforms to reduce this risk.

Interestingly, while the electricity of Tasers may penetrate up two inches of clothing, they often do not work on people wearing bulletproof vests. This is because the barbs may simply bounce off the central steel shock plate, or because the filler material in the vest is an electrical insulator.

Finally, Tasers should not be used near flammable chemicals or gases because there can be an electrical spark as the current arcs across the two wires. Since many older pepper spray products are alcohol-based, officers are cautioned in using the two products together. Fortunately, this appears theoretical, as review of the literature did not disclose a case of this actually happening.

Injuries Types and Treatment
NCCHC standards do not directly address care of patients who have been exposed to Tasers. However, Judith Stanley and Scott Chavez addressed the issue in the Spring 2005 issue of CorrectCare. [See Standards Q&A, Stun Gun Injuries]

They recommend that exposed patients be checked at a hospital, especially if they are pregnant, young, elderly or infirm. They also recommend that reception centers and institutions where Tasers are used adopt joint health care/custody protocols for evaluating exposed patients.

A review of the literature yields interesting findings. A 1987 survey by Ordog et al. and reported in the Annals of Emergency Medicine looked at 218 Taser-related injuries. Most were related to the suspect falling after being shocked. These abrasions, contusions and lacerations were treated in the usual fashion with no unusual sequelae.

There were two cases (1% incidence) of mild rhabdomyolysis from Tasers. This may occur if repeated shocks are required. Neither patient in this study required hospitalization. The researchers also found a single case of testicular torsion, which is not elsewhere reported and appears to be a rare injury associated with Taser use. Of significance, they did not report any case of significant head injury from falling.

Dart Entry Wounds
Taser dart wounds to the throat, face, groin or an implant, especially in the female breast area, require consultation with a physician with emergency medicine or cosmetic surgical experience. Most other Taser entry wounds can be cared for in a manner similar to simple fishhook injuries.

Even the longest barb is only about one-fourth of an inch long, and the probe can penetrate only up to the hilt, a maximum of about one inch even in larger devices.

Usually, the skin at the dart entry site is stunned, leaving it significantly anesthetized. Thus, the dart can be simply removed with a hemostat, and the wound cleansed and dressed in the usual manner. This is generally considered the least painful method of removing the dart.

For darts not easily removed by this method, the wound can be prepared with antiseptic solution and then infiltrated with local anesthesia. Remember that the infiltration process can itself be more painful than simple removal of the dart, so this method is usually done only secondarily. The dart then can be grasped with hemostats and removed. The subsequent wound is treated in the usual fashion. Always inspect the dart to make sure there is no retained foreign body.

Very rarely, a dart will remain even after using the first two techniques. Here, making a small slit path with an 11-blade scalpel may be required. This type of wound probably will require closure with a cyanoacrylate adhesive such as Dermabond® or an equivalent closure method.

Eye Injury
Although Tasers have been in use for nearly 20 years, it was only in April 2005 that Ng and Chehade reported the first serious eye injury from Taser restraint. A 50 year-old man in Australia was struck 1.5 cm below the right eyelid, but the dart angled upward and penetrated the eye. It caused full-thickness penetration with schleral rupture.

They reported that the injury was large enough to cause vitreous leaking but, fortunately, none occurred. This was a special concern because had repeated shocks been used, the muscle contracture caused by these shocks might have caused the contents of the eye to extrude, significantly increasing the damage. At one-week follow-up after surgical repair, the patient had lost about 30% of his vision in the affected eye.

Patients with Taser-related eye injuries require rapid physician evaluation with visual acuity and fluoroscein examination. If significant injury is noted, the patient should be referred to an ophthalmologist for further care.

Pregnancy
One controversial case involved a woman who was 12 weeks pregnant and was shot with a Taser during an assault on corrections officers in a Florida jail. She began to miscarry a week later. Although no direct causal relationship was found, enough indirect evidence was present that she was awarded damages by federal jury.

Women who are Taser-restrained should receive follow-up pregnancy tests, and if found to be pregnant should probably have obstetrical/ gynecological follow-up.

Cardiac Arrest
Whether or not Tasers can cause cardiac arrest is contested. In 1992, Kornblum et al. from the Los Angeles coroner’s office reported autopsy studies in 13 deaths where a Taser had been used. They found no direct evidence of a Taser causing death, but the study is difficult to interpret because the cases of myocardial infarction present also had toxic drug levels that either caused or significantly contributed to the deaths.

In a case reported in the national news in February 2005, a 54-year-old man struggled with police, attempting to bite the officers in order to infect them with HIV. He was Taser restrained and subsequently developed cardiac arrest and died. No further details were given in the report, leaving it uncertain what role the Taser may have had in his death.

Given the number of Taser restraints over the past 20 years, and the lack of conclusive evidence, it is unlikely that Tasers cause cardiac arrest in normal adults. However, patients who complain of developing chest pain after Taser restraint should be taken seriously, and warrant urgent physician evaluation if indicated, particularly if the patient has risk factors for cardiac disease.

Dart Disposal
Because of the high rates of mental illness in correctional settings, one unusual case is worth mentioning. Kosgove reported on a psychiatric patient who swallowed Taser darts. Since these are sharp, he required surgery to remove them.

— About the author:  Sir Scott Savage, DO, FACEP, CCHP, is the assistant medical director for the Ohio Department of Rehabilitation and Corrections.

[This article first appeared in the Summer 2005 issue of CorrectCare.]