“Don’t Taze me Bro!”Taser is an acronym for Thomas A. Swift’s Electric Rifle. Arizona inventor Jack Cover designed and patented it in1969. It is named after the science fiction teenage inventor and adventure character Tom Swift.It is a battery-operated unit that resembles a handgun and fires two barbed electrodes attached to copper wires at180 feet/secWires come in various lengths ranging from 15 to 35 feetAimed by Laser siteThe barbs attach to the subject’s skin or clothingThe current can cross up to two inches of clothing or air space.The device’s current causes uncontrollable muscle contraction and overwhelming pain that can incapacitate asubject if the barbs are a sufficient distance apart.The barbs remain attached until removed
TASERS - The ScienceDeliver a lot of volts, but very few ampsA very high voltage ensures that the pulse will reach its target (Penetrating clothing and skin), and the verylow amperage keeps it from doing any permanent damage.Basic overview of the terms voltage and amperage: Think of HIGH VOLTAGE as water under high pressure.LOW AMPERAGE is a very low volume or stream of water. The injury inflicted by an electric shock depends onthe interaction between this "pressure", or voltage, and "flow rate", or amperage of the electricity.Tasers differ from standard stun guns, which typically work by pressing a pair of electrodes against the skin ofa victim completing an electric circuit, in that the electrodes are tethered to long, insulated wires and can befired from the weapon with a burst of carbon dioxide. A standard stun gun can only be used at close range;Tasers can shoot someone from 20 feet away.Once the electrodes hit their target, the Taser sends a pulse with about 50,000 volts and a few milliamps. Onits standard setting, the pulse cycles for five seconds before shutting off. (The pulse continues for as long asyou hold the trigger.) The five-second shock sends intense signals through the victims nervous system, whichcauses considerable pain and triggers a contraction in all his muscles. Temporary paralysis can set in, andmost victims fall to the ground.Tasers can also be used like regular stun guns in whats called "drive stun" mode. This causes more localizedpain and less widespread muscle contraction.
Volts versus AmpsWater Cannon versus high pressure water pistol
MECHANISM OF EFFECT“An important concept in electrical injuries is that of the "let-go" current, defined as themaximum current a person can tolerate as evidenced by volitional use of muscles directlystimulated by that current. A person receiving a shock with a current exceeding the "let-go"current threshold cannot release a hand-held conductor transmitting the current. It has beenconjectured that the Taser®delivers a current that exceeds the let-go current threshold,resulting in the Tasered patient being unable to free himself from the device as long as thecurrent is delivered.”
Most effective where large muscle groups canbe recruitedApplying Taser shock to more sensitive parts ofthe body, obviously, more painful“Shock” is caused by muscles twitchinguncontrollablyOutput voltages range 50 to 1,000 kilovolts(usually 200-300 KV)
REGARDING BALLISTICS"The initial velocity is substantiallyless than that of a BB gun (91 m/s) or .38 special handgun (332 m/s). The kinetic energy delivered by the Taser® dart,proportional to its mass x velocity, is very low. Hence the dart is ballistically a very low-velocity, low- energy weapon. Themanufacturer reports that darts fired point-blank into the bare chest of a man resulted in only the barb and needle portion ofthe dart becoming imbedded in the skin.”
60 Minutes PieceWhat the public has seen...(willneed to return to lecture after hyperlink)
Deaths with TazersUnexpected Deaths have occurred with Taser Use By PD“Cardiac Monitoring of Human Subjects Exposed to Taser,”involved monitoring cardiac rhythms on healthy police (notindividuals in ﬁeld who might have AICDs, Pacemakers,under the inﬂuence,etc.). With shock of 2.2 seconds heartrate increased in 76 subjects by 19.4 beats/minute with nochange in QRS morphology. One Individual had PVCsClaims of “Excited Delirium” as cause of death - and not theTaser per manufacturer and plaintiff experts
“Excited Delirium?”Not a valid medical termNot listed in the Diagnostic and Statistical Manual of MentalDisordersAMA and American Psychological Association don’trecognize this as a mental health condition
OK - so what is the def?“A delirium characterized by a severe disturbance in the levelof consciousness and change in mental status over a relativelyshort period of time”Loss of clarity, awareness, focus, disoriented and may exhibitsigns of hallucinations.Bizarre, violent behavior, public nudity, aggression,hyperactivitiy, paranoia, hallucinations, incoherent speach,imperviousness topain, hyperthermia
Bogus term?Panic Attacks can do some of that...So Can Delirium TremensThyroid stormPCPMany others......
“Most patients presenting to the ED have been Tasered because of violent or erratic behavior, often as a result of drugintoxication (particularly with phencyclidine [PCP]) or as a result of a psychiatric disturbance.”
Real World versus LabA major concern is fibrillatory current - the current that produces ventricular fibrillation. For externally applied current,the fibrillatory current in human beings is believed to be a function of the duration, frequency, and magnitude of thecurrent, as well as the patients body weight The threshold of ventricular fibrillation for men (for an externally applied,60-Hz current) has been proposed to be 500 mA for shocks of less than 200 ms du- ration and 50 mA for shocks of morethan two secondsThe current produced by the Taser ® appears to be under the proposed fibrillatory threshold and under the theorizedasphyxia threshold. Therefore, if these estimations are correct, it appears unlikely that a Tasered victim with normal car-diopulmonary function will develop ventricular fibrillation or paralysis of respiratory muscles. The effects of the deviceon individuals with coronary artery disease, conduction defects (eg, sick sinus syndrome), Wolff Parkinson- Whitesyndrome, or preexisting arrhythmias, or on patients under the influence of alcohol or other drugs is not well studied.
The manufacturers own product warnings caution that CEWs "have notbeen scientifically tested on at-risk susceptible populations, " such as"frail, elderly, pregnant, small children, and individuals with lowbody mass indexes
Typical sudden deathViolent subject requiring multiple ofﬁcers to restraincontinues to struggle in custodysuddenly goes quietOften due to respiratory arrestTreat as for any other respiratory arrest
Follow the MoneyManufacturer wants to sell unitsPolice would like to have alternative unit than gun or clubSome physicians have compromised ethics or present skewedviews when hired as expert witnesses for trial
EMS ResponseScene SafetyListen to police ordersPatients can remain agitatedSudden cardiac arrests can occur despite rapid transport andtop-notch careMajority of deaths minutes to hours after application
If still agitated... Bring to the Emergency Department Most ofﬁcers will be willing to comply You may need to be a patient advocate Be wary of hyperthermia, tachycardia, volume depletion, rhabdomyolysis, metabolic acidosis - may need ALS!
General PrinciplesAll Tasered patients should be assessed with Full Head to ToePhysical ExamPatients can fall if they were standing! Think Head and Neckinjuries!Pregnant patients need evaluation following Taser
Many Agencies Allow Barb removal inCertain Circumstances (follow localprotocols)Barb is a straight ﬁshhook, with barb length4mm with overall length 9.53 mmAn XP barb exists for “extra penetration” andis 13.33 mm in length
Recommended by AEMOne of three methods may be used to remove It is unknown if any particular method of ex-Taser®barbs from the skin per Annals of Emergency traction results in a higher rate of wound infection.Medicine. In descending order of ease they are: Patients typically are not placed on antibiotic prophylaxis for these minor wounds1) grasping the wire connected to the dart andfirmly pulling it away from the skin; - The disadvantage isthe production of more irregular wound margins2) placing a 16-gauge needle over the barb portionof the dart and gently backing the dart out of theskin; -produce a wound margin with sharper edges and, hence, better healingand cosmesis.3) prepping the skin, infiltrating locally withlidocaine, cutting down to the barb with a sterilescalpel, and removing the barb through theincision. -produce a wound margin with sharper edges and, hence, betterhealing and cosmesis.
Stabilize barb with one hand and pull directlyoutIf patient cannot tolerate removal, treat asimpaled object and transport to ED. Perliterature, area around barb insensateMinimal bleeding because of local “Cautery “effect of the electric current
Treat any barbs embedded in major vascularstructures as impaled objects!
Theoretical risk to neck vasculature andgenitaliaEye injury possible - often requiring surgicalrepairPneumothorax possible
Clinical management of a penetration of the eye should consist of leaving the dart in place, placement of a protectivemetal eye shield, and immediate ophthalmologic consultation. In addition, as with any penetration of the body surface bythe dart, appropriate tetanus immunization should be given.
Other injuries include Skull Penetration(Range of ﬁring possible culprit - Also, whoremembers the movie “Unbreakable?”Osteogenesis Imperfecta)SeizuresSpinal Fractures due to severe muscle spasm
Bottom LineProjectiles being ﬁred at peopleProjectiles can penetrate and cause injuriesBe Safe - follow police instructionsBe an advocate for the patientFollow your training in regards to trauma andcardiopulmonary arrest management