taser international's response

ECD Event Analysis and Evidence Collection Subject Info

Event Date and Time Subject Sex Subject Age Subject Height Subject Weight (including the subject’s build): e.g., Skinny, Medium Build or Fairly Large Pre-Event Behavior Physical exertion type (running, fighting, etc.) Physical exertion / duration of struggle (Y/N) Subject’s influence (drugs, alcohol, EDP) Any other use of force employed and what type?

Evidence Collection

Photos of wounds and probe impacts with scale or drive stun marks Photos showing distance of spread (scale) Keep the original battery in the device (DO NOT REMOVE). This will keep the integrity of the

internal clock. Do not discard probes and/or wire; do not let EMS place probes in sharps as information can be

gathered from the probes/wires concerning the deployment Download device dataport and/or TASER CAM™ recording info within 48 hours of the event.

Contact TASER if there are any technical issues at [email protected] or 480-905-2036. Collect 2-3 AFID tags and note their location; this is helpful if multiple devices/cartridges were

deployed. TASER Deployment Circumstances

What type of TASER deployment (probe or drive stun)? Deployment duration and how many cycles occurred? What was the distance the ECD was deployed from the subject? What was the probe spread between the two probes? If this was a drive stun(s) only, a drive stun follow-up, or a combination of the probes and drive

stun please note the location and duration of each application when applied to the subject Where were the probes located specifically? Include top location(s) and the bottom location(s) Was the TASER device effective? TASER device effects (was there a change in behavior?)

IF DEATH OCCURRED OR AN AED or DEFIBRILLATOR WAS USED

Obtaining hair and toenail samples can be crucial for forensic and medical testing. Body Core Temperature at time of death. If death occurred, within 24 hours, brain samples must be collected for the University of Miami

(UM) Brain Endowment Bank to conduct critical brain chemistry changes and dopamine reviews. Contact this organization IMMEDIATELY for further details. Provide this timely info to the Medical Examiner/Coroner at: 1-800-UM-BRAIN (1-800-862-7246) is the telephone number. Dr. Deborah Mash is the lead researcher on this matter. This is one critical act that many MEs miss out on because of delays. It’s imperative to get this info to the ME as soon as possible.

The time between TASER device application and pronouncement of death is crucial to document: o Was subject initially responsive (walking / talking) after exposure(s) and if so, for how long? o Approximate time that subject went into distress (or died) after TASER deployment.

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mailto:[email protected]

Was an AED or defibrillator used? o If so, did it shock and what was the rhythm? o Did the AED report “No shock?” o Is there a printout/download strips from the AED? (This will be needed for evidence)

If collapse occurred, how long between the ECD exposure and time to collapse? Hospital exam information (if conducted). Medical examiner’s contact info or supporting info from medical attendants/ER.

If the Device Did Not Perform as Expected

What was the failure/challenge? Was the deployment an issue of an ineffective deployment such as a single probe hit, clothing

disconnect, wire breakage, low muscle mass deployment, or short spread between the probes? Was the unit dropped/subject to a high-moisture environment? Did the unit deploy the probes? When was a successful download/spark test done? Was the dataport download saved and was the clock accurate in time or was there a slight clock

drift issue (A Clock Drift Issue PDF is available on this issue)

Media Info

Provide the media with the following contact info: www.TASER.com o The primary MEDIA Contact is: Steve Tuttle, TASER International’s VP of Communications o Provide the “MEDIA HOTLINE” for media calls: 480-444-4000 and [email protected] to

answer any TASER issues not related to the on-going investigation or to general safety or technical TASER related questions.

Safety Info: The latest electronic control device (ECD) safety research and other related issues helpful in an investigation are listed below:

http://taser.com/support/critical-event-assistance-resources http://taser.com/support/critical-event-assistance-resources/arrest-related-scenarios-field-studies http://taser.com/support/critical-event-assistance-resources/medical-safety-research http://taser.com/support/critical-event-assistance-resources/evidence-collection

Additional

Best contact information of the investigator to:

Name Agency Phone number Email Relation to investigation

ME’s contact info or supporting info from attendants / ER Additional notes / info:

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http://www.taser.com/


http://taser.com/support/critical-event-assistance-resources

http://taser.com/support/critical-event-assistance-resources/arrest-related-scenarios-field-studies

http://taser.com/support/critical-event-assistance-resources/medical-safety-research

http://taser.com/support/critical-event-assistance-resources/evidence-collection

Below is email with attachments from Taser to VSP and forwarded to me. Jennie V. Duval, M.D. Deputy Chief Medical Examiner Office of the Chief Medical Examiner 246 Pleasant Street Suite 218 Concord, New Hampshire 03301 (603) 271‐1235 (Tel) (603) 271‐6308 (Fax) [email protected] > STATEMENT OF CONFIDENTIALITY > The information contained in this electronic message and any attachment to this message may contain confidential or privileged information and are intended for the exclusive use of the addressee(s). Please notify the Attorney General's Office immediately at (603) 271‐3658 or reply to [email protected] if you are not the intended recipient and destroy all copies of this electronic message and any attachments. > ‐‐‐‐‐Original Message‐‐‐‐‐ From: Burnham, Lance [mailto:[email protected]] Sent: Thursday, June 21, 2012 2:34 PM To: Duval, Jennie Cc: Nolan, Aimee Subject: FW: URGENT: VT State Police Arrest Related Death? Importance: High Detective Sergeant Lance Burnham Vermont State Police 2777 St. George Road Williston, VT Ph: 802‐878‐7111 Ext. 2020 Fax: 802‐878‐2742 EMAIL HAS CHANGED: NEW EMAIL IS [email protected] ‐‐‐‐‐Original Message‐‐‐‐‐ From: O'Donnell, Hugh Sent: Thursday, June 21, 2012 1:59 PM To: Robinson, Russ; Burnham, Lance Subject: Fw: URGENT: VT State Police Arrest Related Death? Importance: High Sgt Hugh O'Donnell VSP ‐ Bradford 1594 Waits River Road Bradford, VT 05033

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‐‐‐‐‐ Original Message ‐‐‐‐‐ From: Steve Tuttle [mailto:[email protected]] Sent: Thursday, June 21, 2012 01:56 PM To: Aamodt, Michael; Busby, Justin; Danoski, Jeffrey; Decker, Lyle; Henry, Michael; Hill, Matthew; Thomas Jacques <[email protected]>; O'Donnell, Hugh; O'Donnell, Hugh; Patno, Eric; Peters, Jeremy; Smith, Larry R; Vitali, Eric; Wilkins, Todd; Young, John D. Subject: URGENT: VT State Police Arrest Related Death? Dear TAESR Certfied Instructors, I apologize sending 15 of you this mail, BUT I understand there may have been an arrest related death involving a TASER ECD. Can someone tell me if there is a specific person that needs to get this information or who is handling this investigation? I am the point man for these issues and available by phone at 480‐905‐2006 to assist your agency. In the meantime, I have added several important issues to review and to pass along to your investigators. 1. The attached Critical Event Checklist is crucial investigative reminder about investigative issues that should be addressed such as AED strip readouts (if used), body core temperature, TASER dataport downloads, probe locations, hair and nail samples, etc. in the event of an ARD. Please feel free to share the checklist with your investigators or any outside agencies that may have taken over the investigation. 2. The attached sample press releases by law enforcement agencies on arrest related deaths involving TASER devices. I always suggest that agencies provide the media information that doesn’t compromise any on‐going investigation so that the media doesn’t operate in a vacuum. 3. If you would like to have contact from our Medical Director Dr. Jeff Ho, he is available. Dr. Ho is an ER physician at a Level 1 Trauma Center at Hennepin Co Hospital in Minneapolis, MN. He is an expert on TASER safety and research, emergency medicine, and is a tactical surgeon for a MN law enforcement agency. Let me know and I can have your agency contacted by him. 4. The attending medical examiners should urgently know that the University of Miami Brain Endowment Bank is available with cutting edge research center that can determine drug abuse and look for excited delirium markers: 1‐800‐UM‐BRAIN (1‐800‐862‐7246) is the telephone number. Dr. Deborah Mash is the lead researcher on this matter. This is one critical act that many MEs miss out on because of delays. It’s imperative to get this info to the ME as the brain tissues must be collected ASAP. Deborah Mash Professor of Neurology and Molecular and Cellular Jeanne C. Levey 1501 NW 9th Ave, Room 4013 (D4‐5) Miami, FL 33136 (800) UM‐BRAIN (800‐862‐7246) Tel: (305) 243‐6219

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Fax: (305) 243‐3649 5. I also provided links below on the latest electronic control device (ECD) safety research and resources that maybe helpful in an investigation. The links to download these PDFs are at: • http://taser.com/support/critical‐event‐assistance‐resources • http://taser.com/support/critical‐event‐assistance‐resources/arrest‐related‐scenarios‐field‐studies • http://taser.com/support/critical‐event‐assistance‐resources/medical‐safety‐research • http://taser.com/support/critical‐event‐assistance‐resources/evidence‐collectionkbeatt Please call me if there is anything I can offer further assistance. PLEASE let me know if you would like Dr. Ho to contact your agency, too. Steve Tuttle Vice President of Communications TASER INTERNATIONAL, INC. 17800 N 85th St Scottsdale, AZ 85255 Phone: 800‐978‐2737 ext. 2006 Media Hotline: 480‐444‐4000 TASER: Protect Life. Protect Truth. As of today, more than 89,000 people have been saved from potential death or serious injury using TASER® devices.

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Below is email thread with VSP.

Jennie V. Duval, M.D. Deputy Chief Medical Examiner Office of the Chief Medical Examiner 246 Pleasant Street Suite 218 Concord, New Hampshire 03301 (603) 271-1235 (Tel) (603) 271-6308 (Fax) [email protected]

STATEMENT OF CONFIDENTIALITY The information contained in this electronic message and any attachment to this message may contain confidential or privileged information and are intended for the exclusive use of the addressee(s). Please notify the Attorney General's Office immediately at (603) 271-3658 or reply to [email protected] if you are not the intended recipient and destroy all copies of this electronic message and any attachments.

From: Duval, Jennie Sent: Tuesday, June 26, 2012 2:13 PM To: 'Burnham, Lance' Subject: RE: Taser prongs

I don’t think it is that critical Lance. Take care of yourself and send it whenever.

Jennie



From: Burnham, Lance [mailto:[email protected]] Sent: Tuesday, June 26, 2012 1:53 PM

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To: Duval, Jennie Subject: RE: Taser prongs

Dr. Duval,

I am out of the office due to an injury. I hope to be back in next week. I am working on the report at home when I can but it is slow. As soon as I get it completed I will send it your way.

Thank You,

Lance

Detective Sergeant Lance Burnham

Vermont State Police

2777 St. George Road

Williston, VT

Ph: 802‐878‐7111 Ext. 2020

Fax: 802‐878‐2742

EMAIL HAS CHANGED: NEW EMAIL IS [email protected]

From: Duval, Jennie [mailto:[email protected]] Sent: Tuesday, June 26, 2012 11:51 AM To: Burnham, Lance Subject: RE: Taser prongs

U of Miami (Excited Delirium researchers) is requesting a copy of the police report on this incident. Can you email me what you have?

Jennie V. Duval, M.D. Deputy Chief Medical Examiner

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Office of the Chief Medical Examiner 246 Pleasant Street Suite 218 Concord, New Hampshire 03301 (603) 271-1235 (Tel) (603) 271-6308 (Fax) [email protected]


From: Duval, Jennie Sent: Monday, June 25, 2012 11:08 AM To: 'Burnham, Lance' Subject: RE: Taser prongs

Great thanks.



From: Burnham, Lance [mailto:[email protected]] Sent: Monday, June 25, 2012 11:06 AM To: Duval, Jennie Subject: Re: Taser prongs

Dr. Duval, That would be fine. They can call the barracks at 802‐878‐7111.

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Lance

From: Duval, Jennie [mailto:[email protected]] Sent: Monday, June 25, 2012 11:03 AM To: Burnham, Lance Subject: RE: Taser prongs

I’ve received a few media calls on this case. Can I direct them to you?



From: Duval, Jennie Sent: Thursday, June 21, 2012 7:15 PM To: 'Burnham, Lance' Subject: RE: Taser prongs

thanks


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From: Burnham, Lance [mailto:[email protected]] Sent: Thursday, June 21, 2012 7:14 PM To: Duval, Jennie Subject: Re: Taser prongs

Certainly, I will send it first thing in the morning. Lance

From: Duval, Jennie [mailto:[email protected]] Sent: Thursday, June 21, 2012 07:11 PM To: Burnham, Lance Subject: RE: Taser prongs

Got them. Thanks. If you have a chance, can you measure the length of the barbs or send a photo with a scale?



From: Burnham, Lance [mailto:[email protected]] Sent: Thursday, June 21, 2012 2:49 PM

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To: Duval, Jennie Subject: Taser prongs

Here are pictures of the taser prongs removed from the decedent.

Detective Sergeant Lance Burnham

Vermont State Police

2777 St. George Road

Williston, VT

Ph: 802‐878‐7111 Ext. 2020

Fax: 802‐878‐2742

EMAIL HAS CHANGED: NEW EMAIL IS [email protected]

v

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Forensic Science International xxx (2009) xxx–xxx

G Model

FSI 5715; No of Pages 7

Lactate and pH evaluation in exhausted humans with prolonged TASER X26exposure or continued exertion

Jeffrey D. Ho a,*, Donald M. Dawes b, Jon B. Cole a, Julie C. Hottinger a,Kenneth G. Overton c, James R. Miner a

a Department of Emergency Medicine, Hennepin County Medical Center, 701 Park Avenue South, Minneapolis, MN 55415, USAb Department of Emergency Medicine, Lompoc District Hospital, 508 East Hickory Avenue, Lompoc, CA 93436, USAc City of Phoenix Fire Department, 150 S. 12th Street, Phoenix, AZ 85034, USA

A R T I C L E I N F O

Article history:

Received 4 April 2009

Received in revised form 18 May 2009

Accepted 22 May 2009

Available online xxx

Keywords:

TASER

Conducted Electrical Weapon

Electronic control device

Acidosis

Custodial death

A B S T R A C T

Objective: Safety concerns about TASER1 Conducted Electrical Weapon (CEW) use and media reports of

deaths after exposure have been expressed. CEWs are sometimes used on exhausted subjects to end

resistance. The alternative is often a continued struggle. It is unclear if CEW use is metabolically different

than allowing a continued struggle. We sought to determine if CEW exposure on exhausted humans

caused worsening acidosis when compared with continued exertion.

Methods: This was a prospective study of human volunteers recruited during a CEW training course.

Volunteers were from several different occupations and represented a wide range of ages and body mass

index characteristics. Medical histories, baseline pH and lactate values were obtained. Patients were

assigned to one of four groups: 2 control groups consisting of Exertion only and CEW Exposure only, and

the 2 experimental groups that were Exertion plus CEW Exposure and Exertion plus additional Exertion.

Blood sampling occurred after Exertion and after any CEW exposure. This was repeated every 2 min

until 20 min after protocol completion. Descriptive statistics were used to compare the four groups. The

experimental groups and the control groups were compared individually at each time point using

Wilcoxon rank sum tests. Lactate and pH association was assessed using multiple linear regression.

Results: Forty subjects were enrolled. There were no median pH or lactate differences between CEW

Exposure groups at baseline, or between Exertion protocol groups immediately after completion. The

CEW Exposure only group had higher pH and lower lactate values at all time points after exposure than

the Exertion only group. After completing the Exertion protocol, there was no difference in the pH or

lactate values between the continued Exertion group and the CEW Exposure group at any time points.

Conclusion: Subjects who had CEW Exposure only had higher pH and lower lactate values than subjects

who completed the Exertion protocol only. CEW exposure does not appear to worsen acidosis in

exhausted subjects any differently than briefly continued exertion.

� 2009 Elsevier Ireland Ltd. All rights reserved.

Contents lists available at ScienceDirect

Forensic Science International

journal homepage: www.elsev ier .com/ locate / forsc i in t

1. Introduction

The Conducted Electrical Weapon (CEW) is currently availablefor law enforcement and it is designed to subdue or repel agitatedor violent individuals. It has come under scrutiny by national andinternational media and human rights organizations because therehave been unexpected deaths of persons in custody following itsuse [1,2]. Although most deaths in law enforcement custody occur

* Corresponding author. Tel.: +1 612 873 4904; fax: +1 612 904 4241.

E-mail addresses: [email protected] (J.D. Ho), [email protected]

(D.M. Dawes), [email protected] (J.B. Cole), [email protected]

(J.C. Hottinger), [email protected] (K.G. Overton), [email protected]

(J.R. Miner).

Please cite this article in press as: J.D. Ho, et al., Lactate and pH evaluatcontinued exertion, Forensic Sci. Int. (2009), doi:10.1016/j.forsciint.2

0379-0738/$ – see front matter � 2009 Elsevier Ireland Ltd. All rights reserved.

doi:10.1016/j.forsciint.2009.05.016

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when no CEW has been applied (70%) [3,4], a causal association hasbeen suggested in the lay press [5 7]. This association is largelymade due to time proximity of CEW application and death.Theories about this association have included production ofimmediate fatal arrhythmias or some type of delayed organsystem damage that manifests itself as sudden death at a later timeperiod [8]. Previous work in this area has not demonstrated aclinically dangerous effect on human volunteers [9 14].

The CEW is often applied to subjects in the field who havephysically exerted and exhausted themselves just prior to theapplication and may continue to exert themselves throughout thearrest and control process. This exhaustion may be due to profoundagitation, or fleeing from and resisting law enforcement. Intensestruggling is an activity that has been associated with suddencustodial arrest related death (ARD) [15]. Acidosis is a condition that

ion in exhausted humans with prolonged TASER X26 exposure or009.05.016







http://dx.doi.org/10.1016/j.forsciint.2009.05.016

http://www.sciencedirect.com/science/journal/03790738


J.D. Ho et al. / Forensic Science International xxx (2009) xxx–xxx2

G Model


has also been associated with death in this population [16]. It isbelieved that the acidosis is due to several factors including use ofillicit stimulants in this population and continued fleeing, fighting orresisting law enforcement authorities [17,18]. There is controversysurrounding the use of a CEW in this subject population.

There is animal data to suggest that CEW exposure to restedanimals under laboratory conditions can lead to worseningacidosis [19]. The effect of a CEW on pH immediately after itsapplication has been reported but the effect over the subsequentshort term period following application has not [13]. It is notknown what the effect of a CEW is on an exhausted subject’smetabolic physiology during this short term period after exposure.

The first objective of this study was to determine the pH andlactate changes in the 20 min after a CEW exposure, and tocompare them to the effects of the Exertion protocol used in thisexperimental model. Determining this would allow comparison ofthis model to previous human studies that have not obtainedshort interval acidosis measurements during this time period. Thenext objective was to determine the metabolic effect of aprolonged CEW exposure in exhausted and rested subjects inthe 20 min immediately following exposure, and to compare thisto subjects who continued to exert themselves but were notexposed to a CEW. Our null hypothesis was that there would be nodifference in the pH or lactate at any time point in exhaustedsubjects who were exposed to a CEW than in exhausted subjectswho continued to exert themselves.

2. Material and methods

2.1. Study design

This was a prospective study of adult volunteers recruited at a TASER

International training course in August, 2008. The institutional review board of

Hennepin County Medical Center approved the study. All subjects provided

informed consent before enrollment. This study received partial funding from

TASER International in the form of an unrestricted research grant that covered the

cost of phlebotomy and laboratory services. The study sponsor had no role in

designing the study, collecting the data, analyzing the data, writing the manuscript

or submitting it for publication.

2.2. Study setting and population

This study was performed with volunteer human subjects attending a training

course. As a voluntary part of their training course, they were to receive a CEW

exposure from a TASER device. All adult subjects (age > 18 years) who were going to

receive this exposure were eligible for enrollment in the study. Volunteers were

personnel involved in various occupations including: medicine, sales, law

enforcement, corrections, public relations, public utility maintenance, long-haul

transportation and political campaign management. They did not have to

participate in the study as a requirement for successful course completion but

declining to participate in the study did not absolve them from receiving a CEW

application as part of the training course. The exclusion criteria were known

pregnancy and persons with known mental illness diagnoses. Volunteers were

given a TASER CEW upon successful completion of the study protocol.

2.3. Study protocol

All volunteers completed a medical questionnaire that included: age, gender,

occupation, body mass index (BMI) parameters, past medical history, current

medication use, and history of recent heavy exertion. After completion of the study

questionnaire, all volunteers had an 18 or 20 gauge intravenous catheter placed in

an upper extremity and had blood drawn from this for baseline analysis of venous

pH and lactate.

Upon completion of the baseline blood analysis, each volunteer was randomly

placed into 1 of 4 study groups. Randomization was accomplished by having

volunteers present themselves for testing on a first come, first served basis and then

cycling them through the next available testing group station. The groups were:

group 1 – Prolonged CEW Exposure protocol only without exertion; group 2 –

Exertion protocol only; group 3 – Exertion protocol followed by Prolonged CEW

Exposure protocol; and group 4 – Exertion protocol followed by Additional Exertion

Protocol. Detailed explanation of the group protocols are as follows:

2.3.1. Exertion protocol (groups 2, 3, 4)

After informed consent and baseline blood sampling, volunteers that were

placed into groups 2–4 performed a series of intense, rigorous physical activities

Please cite this article in press as: J.D. Ho, et al., Lactate and pH evaluacontinued exertion, Forensic Sci. Int. (2009), doi:10.1016/j.forsciint.2

0000

designed to invoke anaerobic exhaustion. This activity began with a 30-s timed

period of push-ups. The volunteer was instructed to perform as many push-ups as

they were able to during this time period. If they could not continuously perform

push-ups for the 30-s duration, they were allowed to rest in the ‘‘up’’ position (arms

at full extension, feet in contact with the floor) until they could continue.

Immediately (defined as within 5 s) following the push-ups, the volunteer ran on a

treadmill that was moving at 8.0 miles per hour at 8 degrees of elevation. They were

instructed to run until they could no longer keep up with the pace of the treadmill.

Subjects were instructed to step off the treadmill at that time. At this point, they

were defined as being subjectively exhausted and immediately (within 45 s)

underwent blood sampling from their intravenous catheter for repeat pH and

lactate evaluation. Total time (minutes:seconds) of exertion was recorded for

volunteers in these groups.

2.3.2. Prolonged CEW Exposure protocol (groups 1, 3)

Volunteers that were selected into groups 1 and 3 received a prolonged CEW

application. Group 1 volunteers received the Prolonged CEW Exposure protocol

only with no prior exertion (they were in a rested state at time of CEW exposure).

Group 3 volunteers received the Prolonged CEW Exposure protocol immediately

after completing the Exertion protocol.

The Prolonged CEW Exposure protocol consisted of a 15 s application with

applied electrodes powered by a TASER X26 CEW (TASER International, Scottsdale,

AZ.) The exposure consisted of manually applying electrodes to the volunteer while

they were lying on a padded mat in a supine position. The electrodes were manually

placed and taped into position within conductive gel instead of being fired from the

CEW at the subject to assure exact placement from volunteer to volunteer. The

electrodes were placed on the subject’s trunk in ipsilateral, anterior thorax

positions to span a majority of the trunk while including trans-diaphragmatic

positioning. The electrodes were always placed on the side of the thorax opposite

that of the extremity that the intravenous catheter was placed in order to avoid

catheter displacement in the event of upper extremity contraction during the event.

Placement was always in the mid-pectoral region for the superior electrode and at

the waistline for the inferior electrode in a vertical position (Fig. 1).

The TASER X26 CEW internal software had a single modification that allowed the

exposure duration to run for a continuous 15 s of duration with each pull of the

trigger (a standard TASER X26 CEW trigger pull yields a 5 s run duration). No other

modification was made to the CEW. The purpose of the software modification was

to enable the CEW current application to be delivered in an objective, reproducible

and controlled fashion. With the exception of this, the CEW was not altered from the

factory standard. Immediately following the CEW application (within 45 s), all

subjects had blood sampled by the investigators.

2.3.3. Additional Exertion Protocol (group 4)

Following completion of the Exertion protocol and the subsequent blood

sampling, the subjects in group 4 underwent an additional 1-min of running on the

treadmill at 8 miles per hour and 8 degrees of elevation. Subjects were instructed to

stop if they became too exhausted to keep up with the treadmill prior to 1 min.

Upon completing this additional period of exertion, the subject immediately

(within 45 s) had blood sampled and was allowed to recover in a sitting or semi-

recumbent position.

2.3.4. Universal protocol (all groups)

All subjects in all 4 groups had an 18 or 20 gauge venous catheter placed into an

upper extremity at the start of the investigation so that serial venous blood samples

could be taken at various times during the study period. Intravenous cathether

insertion was performed by either a certified paramedic or one of the physician

investigators. After each blood sample was drawn, the specimens were labaled and

analyzed immediately on a portable I-STAT1 point of care analyzer using a CG4+

analysis cartridge (Abbott Diagnostics, Abbott Park, IL). The blood samples were

analyzed for pH and lactate. Blood sampling occurred universally at 2-min intervals

after the final stressor event (either final exertion event or CEW exposure) was

completed. The blood sampling continued until 20 min after the final stressor event.

Following the completion of the blood sampling, all subjects were allowed to

recover in a sitting or semi-recumbent position, the intravenous catheter was

removed aseptically, the area was bandaged, and the subject was offered a light

snack and oral hydration.

2.4. Data analysis

Data were entered in an Excel (Microsoft Excel 2008, Redmond, WA)

spreadsheet for analysis. Data analysis was performed using STATA 10.0 (STATA

Corp., College Station, TX). Descriptive statistics were used where appropriate.

Values at time points were compared between groups 1 and 2 and between groups

3 and 4 using Wilcoxon rank sum tests. The association between pH and lactate

over time within and between the exposure groups was assessed using multiple

linear regression. Power analysis of the Wilcoxen rank sum test revealed that in

order to detect a 10% difference between lab values at the post-exposure time

point, with a significance of 0.05 and a power of 80%, 9 subjects were required in

each group.

tion in exhausted humans with prolonged TASER X26 exposure or009.05.016

14


Fig. 1. Electrode placement example (ipsilateral, anterior thorax at mid-pectoral

area and waistline on the side opposite of the IV catheter).

J.D. Ho et al. / Forensic Science International xxx (2009) xxx–xxx 3

G Model


3. Results

There were 40 subjects enrolled, 10 in each group. Subjectdemographics are in Table 1. All post exertion and post CEWexposure blood draws were completed within 45 s of exertion or

Table 1Volunteer demographics.

Group 1 (CEW only) Group 2 (Exertion only) Gr

Number 10 10 10

# Females 3 4 2

BMI (median, range) 22.9, 16.6–35.4 28.1, 20.4–47.3 27

Past medical history 1 asthma 1 high cholesterol No

1 high cholesterol 1 hypertension

Medication 1 albuterol/advair 1 statin No

1 statins 2 synthroid

1 diuretic

Recent exertion 2/10 4/10 2/

Median age in years

(range)

38, 22–54 32, 20–46 35


000015

exposure conclusion. There was 1 volunteer in group 4 that did notcomplete the full minute of additional treadmill exertion at thediscretion of the lead investigator due to fatigue. For this volunteer,the treadmill was shut down at 57 s upon noticing that the studysubject was experiencing difficulty in keeping up with thetreadmill and there was a safety concern when the study subjectnearly fell. There were no adverse events that occurred related tothis study.

Tables 2 and 3 and Figs. 2 5 display pH and lactate values at alltime points. There were no differences between the groups atbaseline. The CEW Exposure only group had higher values of pH andlower values of lactate at all time points after the CEW Exposure thanthe Exertion only group. There were no differences in groups 3 and 4immediately after the Exertion protocol was completed. After theExertion protocol, the Additional Exertion group showed nodifference in median pH or median lactate than the CEW Exposuregroup at any time point. Multiple linear regression demonstratedthat change in pH did not correlate with the groups over time(coefficient 0.001, 95% CI �0.0001 to 0.003, p = 0.21) but change inlactate did (coefficient 0.30, 95% CI 0.21 0.40, p < 0.001).

4. Discussion

CEWs are categorized as non lethal weapons by the UnitedStates Department of Defense and offer law enforcement personnelan option for control of agitated or potentially violent persons [20].CEWs have become increasingly popular tools of force used by lawenforcement and corrections personnel and are considered bymost agencies to be in a class known as an intermediate weapon.Intermediate weapons are devices that generally can inducesubject compliance due to pain or incapacitation and are more thanthe use of ‘‘empty hand’’ control techniques but less than deadlyforce devices. Examples of intermediate weapons include aerosolized chemical irritants, impact batons, and projectile beanbags.

This project utilized the TASER brand of CEW. TASER1 is anacronym for Thomas A. Swift’s Electric Rifle and is a name based on afictional series of children’s literature. Our work focused on theTASER X26 model of CEW because it is currently the most popularhandheld law enforcement CEW in use and is the model most likelyto be encountered in the field. The X26 is programmed to deliver aroughly rectangular pulse of approximately 100 ms duration withabout 100 mC of charge at 19 pulses per second for 5 s [21]. The peakvoltage across the body is approximately 1200 2400 V but theweapon also develops an open circuit arc of 50,000 V to traverseclothing in cases where no direct contact is made. The averagecurrent is approximately 2.1 mA. It uses compressed nitrogen to fire2 metallic darts up to a maximum of 35 feet with a pre determinedangled rate of spread. When it makes adequate contact and the dartsare of adequate separation, it causes involuntary contractions ofthe regional skeletal muscles that render the subject incapable of

oup 3 (Exertion + CEW) Group 4 (Exertion + Exertion) Total

10 40

1 10

.6, 19.7–28.9 27.1, 22.4–54.8 26.0, 16.6–54.8

ne 1 high cholesterol

1 left bundle branch block

ne 2 statins

10 4/10 12/40

, 20–44 36.5, 20–49



Table 2pH.

Group 1, CEW only

(median, range)

Group 2, Exertion only

(median, range)

Wilcoxon rank sum

(group 3 vs. 4)

Baseline 7.37, 7.29–7.40 7.35, 7.29–7.40 0.724

Immediately after exertion – 7.13, 7.03–7.34

Immediately after CEW/2nd exertion 7.35, 7.30–7.39 –

2 min after CEW/2nd exertion 7.33, 7.26–7.39 7.07, 7.04–7.15 <0.001

4 min 7.35, 7.27–7.40 7.10, 7.06–7.14 <0.001

6 min 7.34, 7.31–7.41 7.11, 7.05–7.30 <0.001

8 min 7.35, 7.32–7.42 7.13, 7.07–7.28 <0.001

10 min 7.37, 7.35–7.40 7.14, 7.05–7.30 <0.001

12 min 7.37, 7.34–7.40 7.17, 7.00–7.32 <0.001

14 min 7.37, 7.34–7.39 7.18, 7.07–7.33 <0.001

16 min 7.38, 7.34–7.40 7.20, 7.09–7.31 <0.001

18 min 7.38, 7.33–7.40 7.22, 7.10–7.32 <0.001

20 min 7.38, 7.36–7.40 7.24, 7.13–7.30 <0.001

Group 3, Exertion + CEW

(median, range)

Group 4, Exertion + Exertion

(median, range)

Wilcoxon rank sum

(group 3 vs. 4)

Baseline 7.38, 7.32–7.41 7.36, 7.13–7.43 0.774

Immediately after exertion 7.19, 7.05–7.26 7.14, 6.95–7.39 0.653

Immediately after CEW/2nd exertion 7.12, 7.01–7.23 7.11, 6.98–7.26 0.791

2 min after CEW/2nd exertion 7.11, 7.01–7.25 7.09, 7.00–7.20 0.495

4 min 7.11, 7.00–7.25 7.10, 7.00–7.21 0.437

6 min 7.13, 6.99–7.26 7.08, 6.97–7.24 0.596

8 min 7.13, 7.01–7.28 7.12, 7.00–7.26 0.910

10 min 7.16, 7.22–7.31 7.15, 7.00–7.28 0.567

12 min 7.18, 7.02–7.34 7.17, 7.00–7.32 0.624

14 min 7.20, 7.05–7.36 7.19, 7.04–7.39 0.689

16 min 7.21, 7.06–7.36 7.20, 7.05–7.35 0.682

18 min 7.22, 7.10–7.38 7.25, 7.06–7.36 0.790

20 min 7.26, 7.10–7.36 7.25, 7.08–7.38 0.967


G Model


voluntary movement. If the darts are fired at very close range and donot achieve adequate separation, full muscular incapacitation maynot be achieved and the device is then used to encourage certainbehavior through pain compliance.

Table 3Lactate (mmol/L).

Group 1, CEW only

(median, range)

Baseline 1.6, 0.6–2.9

Immediately after exertion –

Immediately after CEW/2nd exertion 2.1, 1.8––3.3

2 min after CEW/2nd exertion 3.6, 2.5–5.5

4 min 4.1, 2.5–5.3

6 min 4.5, 2.7–5.2

8 min 3.4, 2.3–5.3

10 min 3.4, 2.2–4.9

12 min 3.2, 1.7–4.5

14 min 2.9, 1.8–4.1

16 min 2.7, 1.7–3.8

18 min 2.6, 1.5–3.6

20 min 2.0, 1.3–3.3

Group 3, Exertion + CEW

(median, range)

Baseline 1.3, 0.9–1.7

Immediately after exertion 9.1, 6.1–13.1

Immediately after CEW/2nd exertion 11.6, 7.8–15.0

2 min after CEW/2nd exertion 16.0, 10.4–20.0

4 min 16.7, 10.3–20.0

6 min 16.4, 10.2–19.8

8 min 15.6, 9.7–19.1

10 min 15.3, 9.4–19.4

12 min 15.4, 8.2–18.9

14 min 19.5, 7.9–18.8

16 min 13.9, 7.5–18.3

18 min 13.0, 6.7–17.5

20 min 12.3, 6.1–17.6


0000

Agitated persons confronted by law enforcement have beenassociated with states of severe exhaustion and metabolic acidosis[16]. It is not clear whether this state of exhaustion, coupled withthe application of a CEW might lead to adverse acidosis parameters

Group 2, Exertion only

(median, range)

Wilcoxon rank sum

(group 3 vs. 4)

1.4, 0.7–3.0 0.597

13.2, 5.7–17.8 <0.001

– <0.001

14.6, 10.4–18.3 <0.001

13.0, 10.5–17.5 <0.001

14.7, 10.0–18.1 <0.001

14.5, 9.8–18.3 <0.001

14.6, 8.8–17.9 <0.001

13.2, 8.7–17.2 <0.001

12.5, 8.1–16.5 <0.001

12.0. 7.8–18.9 <0.001

11.9, 7.3–18.6 <0.001

11.3, 2.0–17.7 <0.001

Group 4, Exertion + Exertion

(median, range)

Wilcoxon rank sum

(group 3 vs. 4)

1.6, 0.7–3.4 0.270

10.2, 0.9–18.1 0.165

12.7, 8.0–18.2 0.821

16.0, 10.9–19.2 0.734

16.1, 10.0–19.5 0.935

15.4, 10.5–20.0 0.706

15.3, 10.6–19.3 0.880

14.6, 9.6–20.0 0.807

14.5, 9.1–20.0 0.722

14.1, 8.5–20.0 0.832

13.3, 7.8–18.9 1.000

11.9, 7.3–18.6 0.683

11.3, 7.0–17.7 0.929


16


Fig. 2. Median pH of control groups. Fig. 4. Median lactate of control groups.


G Model


shortly after application. This study was designed primarily toexamine what the physiologic differences are in terms of acidosisbetween ending a situation with a prolonged CEW exposure versusallowing a person to continue on with their resistive behavior. Ithas been theorized that the application of a CEW on an alreadyacidotic person could potentially lead to a worsening acidosiscondition that causes death. Prior work in this area by Ho et al. hasexamined exhausted human subjects that received prolonged CEWexposures and reported biomarkers for acidosis immediately(within 1 min) following the exposures and 16 24 h after CEWexposure [13]. However, the time period following the first minuteafter CEW exposure has not been specifically examined. The lack ofinformation for this short window of time partially led to a recentsuccessful argument that CEW application likely worsenedacidosis and caused an ARD within this short window of time[22]. However, our current work in this area specifically attemptsto address this previously unstudied time frame.

We found that when applying a CEW to an acidotic subject, thisshort term interval is not physiologically worse with regard toacidosis parameters than allowing the subject to continue withtheir exertional activity. This is an important finding because lawenforcement authorities in a situation requiring them to immediately intervene generally have 1 of these 2 choices available tothem (immediately stopping the resistance through incapacitationwith a CEW or using time consuming control techniques that relyon pain such as pepper spray or ‘‘hands on’’ methods that allow thesubject to continue to resist, fight or flee).

Fig. 3. Median pH of experiment groups.


000017

Because the goal of this project was to address CEW applicationin acidotic subjects undergoing restraint, it was important for us toattempt to reproduce the conditions of acidosis that are present inthe field during an interaction with law enforcement. Weconsidered exercising our volunteers to 85% of maximal predictedheart rate as this exercise protocol is widely used for physicalfitness training but decided against this because we were notattempting to evaluate fitness. We designed our Exertion protocolto induce intense anaerobic exhaustion over a short period of time,a time situation that we believe is similar to the dynamic fieldconditions faced by law enforcement authorities. In this study,subjects exerted themselves to subjective exhaustion. We haveused this Exertion protocol in a prior study [13]. Subjects wereinstructed to perform the Exertion protocol event until theyperceived themselves to be exhausted. Their level of exhaustionwas objectively measured by their venous pH status immediatelybefore and after the event. We believe that this allowed us to trulytest for the effect that exhaustion has when coupled with CEWapplication. In reality, an agitated person with delirium orintoxication is likely able to ignore their internal cues ofexhaustion that our non impaired volunteers heeded. This couldlead to severe anaerobic exhaustion as the subject vigorouslyfights, flees and resists any efforts to attempt to control them.

Anaerobic exhaustion and metabolic acidosis are generallymeasured by serum pH and lactate values [23]. We elected touse venous pH as a measurement of acid/base balance inthe volunteers. Although arterial sampling is often thought of as

Fig. 5. Median lactate of experiment groups.




G Model


the ‘‘gold standard’’ for pH measurement, current literatureindicates that there is good correlation for pH values betweenarterial and venous samples [24 26]. Electing to utilize a venoussample in this experiment allowed us to place a peripheral venoussampling catheter that was more comfortable for our volunteersinstead of having to perform a more painful percutaneous arterialpuncture or undergo an indwelling arterial catheter placement.

We found that utilizing a CEW in this simulated study situationwas no worse than allowing the subject to briefly continue exertingthemselves (for 1 min) from an acid/base physiology standpoint.The effect of allowing a subject to continue prolonged exertionbeyond 1 min is unknown. Exposure to a CEW alone did not induceacidosis similar to exertion, and exhausted subjects did not show adifference in pH or lactate whether they exerted themselves or notfor an additional minute, or were exposed to a CEW. Becauseexhausted subjects are associated with ARD, it may be intuitivelysafer to use a device such as the CEW that could quickly end aprolonged struggle instead of allowing an exertional struggle tocontinue unabated.

It is important to note that in group 4 (Additional ExertionProtocol), the goal was to simulate what occurs in a realistic scenariowhen an agitated subject has a prolonged and exhaustive strugglewith law enforcement authorities. We believe that the initial periodof exhaustion simulated by our Exertion protocol demonstrates thata state of anaerobic exhaustion quickly occurs. The AdditionalExertion Protocol was meant to simulate the continued resistive andhypermetabolic behavior that is often exhibited by subjects unlessforced to stop through CEW application or chemical sedation. It isour experience and belief that in field encounters with lawenforcement officials, continued resistive behavior by agitatedsubjects generally lasts much longer than a period of 1 min.However, for the purposes of this study, 1 min was the predetermined limit to ensure the safety of the study volunteers. Webelieve that had the volunteers been able to continue exertingthemselves beyond 1 additional minute, that our findings woulddemonstrate a worsening acidosis that is different and more severethan what was demonstrated by prolonged use of a CEW. In asubsequent study by Jauchem et al., blood pH and lactate weresignificantly changed after only three 5 s applications of a CEW. Inthat study, however, animals were also anesthetized [27].

There has been controversy about animal model studies thatdemonstrate CEW induced acidosis in rested swine [19,28]. CEWcritics have pointed out that these studies are reasonable proof thata human being in an exhausted condition should exhibitsignificantly greater acidemia after CEW application [29]. Webelieve these animal studies need to be interpreted with caution.Both represent relatively unrealistic field CEW exposure durations(360 and 80 s respectively) and utilized animals that were deeplyanesthetized and on life support ventilators without ability tocompensate through respiratory mechanisms. In the Jauchem et al.study, complete cessation of breathing was noted during the CEWexposure time period. In the latter study, the ventilator was shutoff during the exposure time period. Respiratory limitations inboth studies would have artificially and significantly changed theacid/base physiology of the animal. This respiratory limitation hasnot been noted to occur in human research [30]. We believeJauchem’s cautionary statements to be correct in that they warnreaders to not draw full conclusions between his study and real lawenforcement use on humans due to methodology limitations [31].Our data would also support Jauchem’s statements since ourfindings in humans did not mimic his in swine.

The previous work by Ho et al. that demonstrates humansubjects breathe above their baseline parameters during prolongedCEW application relates to our findings [30]. This is an importantconclusion relative to our findings since continued ventilation atlevels above baseline minute ventilation during CEW exposure of


0000

an acidotic subject should only serve to improve an altered acidbase state. The demonstration by this study that CEW applicationto an exhausted cohort did not demonstrably worsen their acidoticcondition has ramifications beyond simple acid base physiology.Our data suggests that the modern day practice of utilizing a CEWto subdue or repel an agitated, exhausted individual may be auseful control option in this type of subject.

There was a significant increase in serum lactate that occurredfollowing the Exertion protocol. This level also increased a smallbut statistically significant amount in volunteer group 3 and group4. Lactate formation from exertion has been a classic explanation ofacidosis and fatigue. However, a review by Robergs et al.demonstrates that lactate production increases only when thereis an excess of cellular proton release with metabolism and itsincrease functions to supply the necessary nicotinamide adeninedinucleotide for glycolysis [32]. Therefore, increased lactatecoincides with cell acidosis and remains a good marker for thiscondition but does not necessarily cause the acidosis to occur.Since lactate is a marker of exercise, exertion and metabolism, theelevations seen after exertion and after CEW exposure causingskeletal muscle activation were expected.

5. Limitations

A limitation of this study is that our study population did notexactly mimic the characteristics of human subjects that tend tohave custodial death events. Literature indicates that in custodialdeath situations, the persons who die tend to have mental illnesswith psychotic features or illicit stimulant abuse histories [4].These factors were presumably not present in our volunteerpopulation. However, we do not believe that this limit equates to a‘‘healthy population bias’’. The volunteers that we studied were notyoung, did not have exceptional levels of physical fitness, and weremade up of a variety of people in various occupations. They had awide age range and some had medical problems that requiredcontrolling medication. Additionally, their average body massindex calculations place them in the ‘‘overweight’’ category byfederal standards and does not suggest a superior level of fitness[33]. While our study population most likely did not have a historyof psychosis or chronic illicit stimulant abuse, which are commondescriptors of persons who die suddenly in custody, they do appearto represent the average adult citizen of this country [34]. It shouldalso be noted that our data may not apply to situations of longerduration CEW exposures or repetitive or numerous repetitivedischarges beyond what we have studied [35,36].

An additional limitation is the possibility that the randomization process did not result in an equal distribution of volunteerdemographics across all 4 groups of the study. Specifically, group 1had a lower age grouping and BMI than the other 3 groups. We donot believe that this affects the results based on our prior workwhere we have exposed older and higher BMI subjects to a solitaryCEW exposure while evaluating metabolic markers and have seensimilar results [12].

6. Conclusion

Subjects who were exposed to the CEW but did not undergo theExertion protocol had a higher pH and lower lactate than theexhaustion group at all time points after the baseline. CEWexposure does not appear to worsen acidosis in exhausted, acidoticsubjects differently than continued exertion.

Contributions

Jeffrey Ho contributed to the study concept and design,acquisition of the data, drafting of the manuscript, critical revision


18



G Model


of the manuscript for important intellectual content, obtainedfunding, administrative, technical, or material support, and studysupervision.

Donald Dawes contributed to the study concept and design,acquisition of the data, critical revision of the manuscript forimportant intellectual content, administrative, technical, ormaterial support, and study supervision.

Jon Cole contributed to the acquisition of the data and administrative, technical, or material support.

Julie Hottinger contributed to the acquisition of the data andadministrative, technical, or material support.

Ken Overton contributed to the acquisition of the data andadministrative, technical, or material support.

James Miner contributed to the study concept and design,acquisition of the data, analysis and interpretation of the data,drafting of the manuscript, critical revision of the manuscript forimportant intellectual content, statistical expertise, and studysupervision.

Acknowledgments

The authors would like to thank Mr. Andrew Hinz and Mr.Matthew Carver for their technical assistance. This project wouldnot have been possible without their help.

Funding sources: TASER International, Inc., Scottsdale, AZ; Dept.of Emergency Medicine, Hennepin County Medical Center,Minneapolis, MN.

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BASIC INVESTIGATION

Acidosis and Catecholamine EvaluationFollowing Simulated Law Enforcement‘‘Use of Force’’ EncountersJeffrey D. Ho, MD, Donald M. Dawes, MD, Rebecca S. Nelson, Erik J. Lundin, MS, Frank J. Ryan, PhD,Kenneth G. Overton, Adam J. Zeiders, EMT-P, and James R. Miner, MD

AbstractObjectives: Law enforcement authorities are often charged with controlling resisting suspects. Theseencounters sometimes result in the sudden and unexpected death of the suspect. Drug intoxication,excited delirium syndrome, or excessive uses of force are factors that are often blamed, but sometimesthe mechanism of these deaths is not fully understood. It is possible that worsening acidosis or excessivecatecholamine release play a part. The objective of this study was to determine the effect on markers ofacidosis and catecholamines of various tasks intended to simulate common arrest-related situations.

Methods: Subjects were assigned to one of five task groups: 1) a 150-meter sprint and wall hurdle (sim-ulated flight from arrest); 2) 45 seconds of striking a heavy bag (simulated physical resistance); 3) a10-second TASER X26 electronic control device exposure; 4) a fleeing and resistance exercise involvinga law enforcement dog (K-9); or 5) an oleoresin capsicum (OC) exposure to the face and neck. Baselineserum pH, lactate, potassium, troponin I, catecholamines, and creatine kinase (CK) were evaluated.Serum catecholamines, pH, lactate, and potassium were sampled immediately after the task and every2 minutes for 10 minutes posttask. Vital signs were repeated immediately after the task. Serum CK andtroponin I were evaluated again at 24 hours posttask.

Results: Sixty-six subjects were enrolled; four did not complete their assigned task. One subject lost theintravenous (IV) access after completing the task and did not have data collected, and one subject onlyreceived a 5-second TASER device exposure and was excluded from the study, leaving 12 subjects ineach task group. The greatest changes in acidosis markers occurred in the sprint and heavy bag groups.Catecholamines increased the most in the heavy bag group and the sprint group and increased to a les-ser degree in the TASER, OC, and K-9 groups. Only the sprint group showed an increase in CK at24 hours. There were no elevations in troponin I in any group, nor any clinically important changes inpotassium.

Conclusions: The simulations of physical resistance and fleeing on foot led to the greatest changes inmarkers of acidosis and catecholamines. These changes may be contributing or causal mechanisms insudden custodial arrest-related deaths (ARDs). This initial work may have implications in guiding appli-cations of force for law enforcement authorities (LEAs) when apprehending resisting subjects.

ACADEMIC EMERGENCY MEDICINE 2010; 17:E60 E68 ª 2010 by the Society for Academic Emer-gency Medicine

Keywords: law enforcement, restraint, physical, catecholamines, acidosis, weapons

ISSN 1069 6563 ª 2010 by the Society for Academic Emergency MedicineE60 PII ISSN 1069 6563583 doi: 10.1111/j.1553 2712.2010.00813.x

From the Department of Emergency Medicine, Hennepin County Medical Center (JDH, RSN, JRM), Minneapolis, MN; theDepartment of Emergency Medicine, University of Minnesota Medical School (JDH, JRM), Minneapolis, MN; the EmergencyDepartment, Lompoc Valley Medical Center (DMD), Lompoc, CA; the University of Louisville School of Medicine (DMD, EJL),Louisville, KY; the Laboratory Corporation of America (FJR), Burlington, NC; and the Phoenix Fire Department (KGO, AJZ),Phoenix, AZ.Received November 25, 2009; revisions received January 25 and January 28, 2010; accepted January 30, 2010.Presented at the Scientific Symposium of the American College of Emergency Physicians, September 2009, Boston, MA.TASER International, Inc., provided partial funding for the study.Disclosures: Dr. Ho serves as the contractual medical director and a medical consultant to TASER International, Inc. Dr. Dawesserves as a medical consultant to TASER International, Inc. Both personally own shares of stock in this company.Supervising Editor: Jeffrey A. Kline, MD.Address for correspondence and reprints: Jeffrey D. Ho, MD; e-mail: [email protected].

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S udden and unexpected deaths have occurred incustodial situations for centuries.1 The mecha-nisms of many of these deaths remain unclear.

These types of deaths in modern-day society are mostoften associated with violent and resistive encounterswith law enforcement authorities (LEAs) attempting acustodial arrest. These arrest-related deaths (ARDs) tendto yield scrutiny of the LEAs’ tools and tactics used in theencounter.

There has been speculation about the mechanismsresponsible for ARD. While drug intoxication, exciteddelirium syndrome, or LEA excessive force practiceshave been implicated, the possible mechanisms leadingto ARD have not been well studied. Worsening acidosisand a hyperadrenergic state are two possible mecha-nisms.2,3 In this study, we examined these parameterswithin the context of commonly used tools, tactics, andsuspect behaviors to establish a better understandingof the physiologic state of a person at the time of ARD.The objective of this study was to determine the effecton markers of acidosis and catecholamines of varioustasks intended to simulate common arrest-related situa-tions.

METHODS

Study DesignThis was a prospective, experimental study of humansubjects. All subjects provided informed consent. Theinstitutional review board at Hennepin County MedicalCenter approved the study.

Study Setting and PopulationThe study was conducted at the Thomas A. HontzPolice and Fire Training Facility (Scottsdale, AZ) in thecontext of a LEA training environment. Data gatheringtook place in March 2009 during daylight hours. Dailyoutdoor temperatures ranged from 43.3 to 76.5� F overthe 3 days of testing.

The participants were a convenience sample of lawenforcement and corrections officers, non-LEA publicsafety personnel, TASER International, Inc., employees,and academic researchers participating in a trainingevent sponsored by TASER International, Inc. (Scotts-dale, AZ). Attendees at the training event were notifiedof the research and instructed to contact the investiga-tors if interested. All participants were aware that theywere participating in training that could subject themto various uses of force, including a TASER deviceexposure. All of the training conditions used in thisresearch are common situations used in the training ofpolice and corrections officers and were familiar to per-sons at this event. This training event was chosen as arecruitment site because participants had familiaritywith the events in each arm of the study, allowing themto make informed decisions about enrollment in thestudy.

Each subject was asked to complete one of five tasksmeant to simulate various custodial arrest-related con-ditions. Each subject then completed a medical screen-ing questionnaire describing medical history, currentmedications, and recent exercise, which was reviewedby a study physician. Inclusion criteria were the ability

to participate in vigorous physical exercise. Knownpregnancy was the only exclusionary criteria. Each sub-ject was given a TASER device as compensation forparticipation at the completion of the study.

Study ProtocolEach subject was prospectively assigned to one of fivetasks that were meant to simulate suspect behaviorsthat commonly occur or the LEA use of tools and tac-tics that are commonly used during custodial arrest sit-uations of a resisting subject: 1) 150-meter sprint andwall hurdle, simulating flight on foot from LEAs;2) 45 seconds of hitting and kicking a heavy bag, simulat-ing the physical exertion of resisting arrest by LEAs;3) 10-second continuous TASER X26 device exposure;4) an LEA-trained dog (K-9) resistance exercise simulat-ing fleeing on foot from and resisting a K-9; or 5) anoleoresin capsicum (OC) foam exposure to the face ⁄ neck.

Subjects assigned to the K-9 resistance task groupwere screened first for prior K-9 training or handlingexperience. Subjects who had prior K-9 training or han-dling experience were not eligible for the K-9 resistancetask and were assigned the next available task. All sub-jects were asked not to engage in any physical exerciseregimens for 48 hours prior to testing and until theirfinal blood draw 24 hours after the task.

Details of the Task GroupsTask Group 1 (150-meter Sprint and Wall Hur-dle). The subject sprinted 150 meters in a straight lineon a blacktop covered level surface. The subject had10 yards at the end of the sprint to slow and preparefor a wall hurdle. The wall hurdle required the subjectto jump ⁄ climb over a 44-inch wall. The time to completethe task was recorded. The subject was encouragedverbally during the event.

Task Group 2 (45 Seconds of Heavy Bag PhysicalResistance). The subject was required to keep a sus-pended heavy bag away from him- or herself by anymeans possible. This included punching, kicking, headbutting, and throwing knees and elbows offensively atthe bag. The subject had the option to use any or all ofthese methods. The subject wore athletic shoes, hadhands wrapped with protective athletic tape during thetask, and was encouraged verbally during the event.

Task Group 3 (10-second TASER X26 Device Expo-sure). The subject was exposed to a 10-second contin-uous TASER X26 electronic control device discharge tothe back with deployed probes. The probes weredeployed with the subject in the prone position on aprotective mat from a distance of approximately 7 feet;the operator fired from an elevated position on a step-ladder. The probes and the TASER device were stan-dard products from the manufacturer. The spreadbetween the probes was measured to indicate the areaof the subject exposed to the current.

Task Group 4 (K-9 Fleeing and Physical ResistanceExercise). The subject wore a protective suit. The twoK-9s used in this task were both on active police duty.

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Their handlers were with them during the entire task.The subject sprinted 160 feet in front of and away fromthe K-9. Near the completion of the sprint, the K-9 wasreleased to chase the subject. The subject wasinstructed to present an arm for the K-9 to bite whennearing the completion of the sprint. The K-9 stayed onthe bite for 20 seconds and the subject had beeninstructed to attempt to resist the K-9 during this timeby pulling away and trying to stay on his or her feet.The K-9 handler provided verbal commands to the K-9and the subject, simulating an arrest situation. The totaltask time was approximately 30 seconds.

Task Group 5 (OC ‘‘Pepper Spray’’). The subject wassprayed with 10% OC foam (Sabre Red, Security Equip-ment Corp, Fenton, MO) for a period long enough induration to cover the face and the anterior portion ofthe neck (approximately 2–3 seconds). The subject wassprayed with eyes and mouth closed and was allowedto rinse the foam off with water after 10 seconds ofexposure time. The subject was allowed access to con-tinuous fresh air, running water, and a cooling fan ifdesired following the exposure.

MeasuresEach participant had an 18- or 20-gauge intravenous(IV) catheter placed in the left or right antecubital fossaby a physician or paramedic prior to the test. Baselineautomated blood pressure and heart rate wererecorded by a Nonin 2120 device (Nonin Medical, Inc.,Plymouth, MN). Baseline venous blood specimens formeasurement of serum catecholamines (epinephrine,norepinephrine, dopamine, and total), pH, lactate,potassium, troponin I, and creatine kinase (CK) wereobtained through the IV catheter.

Each subject then participated in his or her assignedtask. Catecholamines, pH, lactate, and potassium weredrawn immediately (within 30 seconds) after the taskand every 2 minutes until 10 minutes posttask. Vitalsigns were repeated immediately (within 30 seconds to1 minute) after the task. CK and troponin I wereobtained again at 24 hours. All samples for fractionatedcatecholamines, potassium, troponin, and CK were cen-trifuged and held on ice for off-site analysis and deter-mination (LabCorp, Inc., Phoenix, AZ). Venous pH andlactate were determined on-site, using the i-STAT sys-tem and CG4+ cartridges (Abbott Point-of-Care, EastWindsor, NJ).

Data AnalysisOn-site data were compiled in an Excel spreadsheet(Microsoft Corporation, Redmond, WA). Data wereexported into STATA 10.0 (StataCorp, College Station,TX) for analysis and SigmaPlot 11 (Systat Software,Inc., San Jose, CA) for graphical presentation. Descrip-tive statistics were used where appropriate. Data werenot normally distributed and are reported as mediansand ranges. Proportions describing subject characteris-tics were compared using chi-square tests. Values ateach time point were compared between groups usingthe Kruskal-Wallis equality of populations rank test.Within each group, the baseline value was compared tosubsequent values using Wilcoxon signed-rank tests.

Catecholamine values were reported as means withstandard errors of the mean. To detect a 5% differencein the pH value between the groups at any time point,assuming a standard deviation (±SD) of 5%, with a sig-nificance of 0.05, and a power of 90%, 11 subjects wereneeded in each group.

RESULTS

Sixty-six subjects were enrolled. Three subjects weredisqualified secondary to an inability to obtain IVaccess, and one of them had vasovagal syncope associ-ated with multiple attempts to place an IV catheter. Onesubject was excluded secondary to refusal to participatein the prospectively assigned group. This subject hadsignificant anxiety leading to vasovagal syncope whentold that he or she was being assigned to the OC foamexposure-task group.

Sixty-two subjects completed the assigned tasks. Twoof these subjects had their data excluded: one subjectassigned to the heavy bag group had an IV catheterfailure after the task, and further attempts at catheterplacement were unsuccessful. The other subject was inthe TASER X26 exposure group and had a 5-secondcontinuous exposure instead of a 10-second exposuredue to operator error. Data from both of these subjectswere excluded from the group analysis (Table 1).

There were 12 subjects in each of the task groups forthe final analysis. The subject characteristics and vitalsigns are presented in Table 2. There was no differencebetween the groups in age (p = 0.31), sex (p = 0.10), orbody mass index (BMI; p = 0.10). Health historiesincluded anxiety (n = 1), hypertension (n = 5), highcholesterol (n = 3), asthma (n = 1), chronic backpain (n = 1), gastroesophageal reflux disease (n = 1),depression (n = 3), Hashimoto’s disease (n = 1), andhypothyroidism (n = 1). One subject had prior sex-reconstructive surgery, one had recent hand surgery,and one listed ‘‘low blood pressure’’ as a current medi-cal condition. The median sprint task group time was25.6 seconds (range 22.0–31.6 seconds). The medianTASER X26 probe spread was 12 inches (range6–13 inches).

One subject reported musculoskeletal shoulder painafter the TASER X26 device exposure that persisted,but was improved at 24 hours. On later telephone fol-low-up with this subject, there were no further com-plaints, and the issue had resolved. One subject in theTASER X26 device exposure task group had an appar-ent vasovagal syncopal episode after the completion ofthe exposure, but became responsive within 5 secondswith gentle stimulation and had no complaints uponrecovery. Five of the heavy bag subjects had abrasionsto the knuckles after the task. In addition, five of thesesubjects became nearly syncopal and vomited after thetask and had to be placed supine to recover. One sprintgroup subject had a syncopal episode 8 minutes afterhis task (he had been lightheaded and nauseated sincecompleting the task). No other adverse events werereported. All subjects recovered and felt as at baselineprior to releasing them from the testing site.

The pH and lactate values are presented in Tables 3and 4. The groups were not different at baseline.

E62 Ho et al. • USE OF FORCE PHYSIOLOGY

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The pH and lactate (normal pH values 7.35 to 7.45 andlactate 1–2 mmol ⁄ L) changed from baseline at everytime point for all groups (p < 0.001 for each, Wilcoxonsigned-rank test). There were no differences in potas-sium (normal 3.5 to 5.0 meq ⁄ L) between the groups atbaseline (median 4.0 meq ⁄ L, range 3.6–4.6 meq ⁄ L;p = 0.755). The sprint group and TASER group had a

decrease in potassium at all time points (p < 0.01). Themaximum decrease from baseline for the sprint groupwas 0.2 meq ⁄ L (from 3.9 to 3.7 meq ⁄ L), and for the TA-SER group was 0.3 meq ⁄ L (from 4.0 to 3.7). The heavybag group had a decreased potassium at the first fourtime points (p < 0.01; maximum decrease from baseline0.4 meq ⁄ L, from 4.0 to 3.6 meq ⁄ L), no difference from

Table 1Results From Excluded Subjects

Subject; Reason Pre Post 2 Minutes 4 Minutes 6 Minutes 8 Minutes 10 Minutes 24 Hours

Heavy bag #8;IV catheter failure

a) 299 a) 1,359 a) X a) X a) X a) X a) X a) Xb) 7.32 b) 7.11 b) X b) X b) X b) X b) X b) Xc) 2.04 c) 16.96 c) X c) X c) X c) X c) X c) Xd) 580 d) X d) X d) X d) X d) X d) X d) Xe) 4 e) 3.8 e) X e) X e) X e) X e) X e) Xf) <0.2 f) X f) X f) X f) X f) X f) X f) X

TASER #1; 5 secondexposure only

a) 590 a) 727 a) 697 a) 616 a) 621 a) 597 a) 630 a) Xb) 7.367 b) 7.334 b) 7.331 b) 7.340 b) 7.335 b) 7.387 b) 7.387 b) Xc) 1.65 c) 1.33 c) 1.46 c) 1.56 c) 1.73 c) 1.69 c) 1.69 c) Xd) 106 d) X d) X d) X d) X d) X d) X d) 129e) 3.9 e) 3.4 e) 3.8 e) 3.7 e) 3.7 e) 3.9 e) 3.9 e) Xf) <0.2 f) X f) X f) X f) X f) X f) X f) <0.2

a) Total catecholamines (pg ⁄ mL); b) pH; c) lactate (mmol ⁄ L); d) CK (U ⁄ L); e) K (mmol ⁄ L); f) troponin I (ng ⁄ mL); X = not obtained.

Table 2Subject Characteristics and Vital Signs

Group

Sprint OC TASER Heavy Bag K 9

Age, yr 36.5 (24 49) 40 (21 48) 34 (24 67) 36 (24 50) 26 (19 47)Male sex, % 91.7 75.0 92.3 100 66.7Median BMI 26.2 (20.9 31.9) 30.0 (26.2 39.3) 26.5 (22.1 36.9) 28.2 (21.7 44.1) 25.8 (19.1 42.8)Pretest BP, mm Hg 128 ⁄ 73

(119 ⁄ 61 152 ⁄ 100)148 ⁄ 98

(121 ⁄ 74 184 ⁄ 123)139 ⁄ 88

(126 ⁄ 71 175 ⁄ 101)141 ⁄ 92

(118 ⁄ 73 191 ⁄ 117)129 ⁄ 85

(105 ⁄ 67 171 ⁄ 100)Posttest BP, mm Hg 151 ⁄ 82

(87 ⁄ 65 198 ⁄ 100)170 ⁄ 90

(106 ⁄ 85 202 ⁄ 130)141 ⁄ 84

(122 ⁄ 87 178 ⁄ 86)168 ⁄ 71

(108 ⁄ 95 202 ⁄ 111)166 ⁄ 90

(133 ⁄ 92 192 ⁄ 100)Comparison to baseline 0.011 0.013 0.564 0.035 0.004Pretest HR, beats ⁄ min 72 (62 98) 91 (69 110) 92 (60 109) 74 (64 117) 80 (60 100)Posttest HR, beats ⁄ min 130 (88 170) 88 (53 110) 96 (66 115) 146 (115 181) 122 (71 141)Comparison to baseline 0.002 0.266 0.889 0.002 0.002

Values reported are median (range) unless otherwise noted.BP = blood pressure; BMI = body mass index; HR = heart rate; OC= oleoresin capsicum.

Table 3Median pH (Range)

Group Baseline Immediate Post 2 minute Post 4 minute Post 6 minute Post 8 minute Post10 minute

Post

Sprint 7.32 (7.30 7.44) 7.16 (7.05 7.31) 7.17 (7.09 7.31) 7.18 (7.11 7.28) 7.19 (7.12 7.29) 7.21 (7.13 7.31) 7.22 (7.16 7.32)OC 7.36 (7.33 7.39) 7.37 (7.33 7.40) 7.37 (7.32 7.47) 7.39 (7.36 7.45) 7.37 (7.34 7.48) 7.36 (7.34 7.48) 7.37 (7.32 7.48)TASER 7.37 (7.32 7.43) 7.29 (7.24 7.35) 7.29 (7.25 7.33) 7.32 (7.28 7.35) 7.33 (7.31 7.36) 7.34 (7.31 7.39) 7.36 (7.34 7.39)Heavybag

7.36 (7.28 7.39) 7.04 (6.95 7.18) 7.01 (6.91 7.09) 7.01 (6.91 7.09) 7.06 (6.94 7.11) 7.05 (6.96 7.13) 7.06 (6.99 7.15)

K 9 7.34 (7.30 7.40) 7.26 (7.14 7.36) 7.25 (7.17 7.35) 7.26 (7.17 7.34) 7.27 (7.18 7.35) 7.27 (7.20 7.35) 7.31 (7.22 7.38)p value* 0.07 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001

OC = oleoresin capsicum.*Kruskal Wallis test.


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baseline at the 8-minute time point (p = 0.475), and anincrease of 0.3 meq ⁄ L at the 10-minute time point (from4.0 to 4.3 meq ⁄ L, p = 0.002). There were no ‘‘positive’’troponin I values (normal < 0.4 ng ⁄ mL). CK data arepresented in Table 5. No subjects had rhabdomyolysisbased on a CK value greater than 5,000 U ⁄ L (normal 60to 400 U ⁄ L). The highest CK value was 1,161 U ⁄ L in aheavy bag subject (his baseline value was elevated priorto the task at 758 U ⁄ L).

Catecholamine data are presented in Figure 1. Due todilution-related difficulties, fully quantified values forcatecholamines were not available for several subjectswith very high levels. These were only reported as‘‘greater than’’ the last value obtained before the quan-tity was not sufficient for further dilution. This limita-tion affected the sprint task group primarily (n = 6), butalso affected the K-9 resistance task group (n = 5) andthe heavy bag task group (n = 4). It did not affect theTASER group or OC group. For total catecholamines,there was no difference between the groups at baseline(p = 0.769). The values increased from baseline in allgroups at all time points (p < 0.002 for all groups byWilcoxon signed-rank test). For norepinephrine, therewas no difference among the groups at baseline. Thevalues increased from baseline in all groups at all timepoints (p < 0.002 for all groups by Wilcoxon signed-rank test). For epinephrine, there was a difference atbaseline in epinephrine, which was noted to be highestin the TASER device exposure and the heavy baggroups. All groups had increases from baseline at time

point 2 (p < 0.001); by time point 3 the TASER groupwas no longer increased from baseline (p = 0.21), butthe other groups were (p < 0.01). By time point 4, theK-9 resistance (p = 0.67) and TASER device (p = 0.78)exposure groups were no longer increased from base-line, while the other groups were (p < 0.01); by timepoint 5 the OC exposure (p = 0.31), TASER device expo-sure (p = 0.35), and K-9 resistance (p = 0.72) groupswere not changed from baseline. These groupsremained unchanged from baseline at subsequent timepoints. The sprint and heavy bag groups remainedincreased from baseline at all time points (p < 0.001).For dopamine, there was no difference among thegroups at baseline but there was a difference at allgroups at each subsequent time point (p < 0.02).

DISCUSSION

Metabolic acidosis can cause autonomic instability,depressed myocardial function, arrhythmias, and car-diovascular collapse. There is literature to support met-abolic acidosis as a possible mechanism of ARDs. Hicket al.4 reported a series of five patients who sustainedcardiac arrest temporally associated with LEA custodialarrest. The subjects had a pH range of 6.25 to 6.81.Four of the subjects died despite aggressive manage-ment. Gass et al.5 found that lactate peaked at the sixthminute of inactive recovery in subjects completinga maximum exercise regimen on a motor-driven tread-mill. The mean peak lactate was 14.2 mmol ⁄ L. Allsop

Table 4Median Lactate, mmol ⁄ L (Range)

Group Baseline Immediate Post 2 minute Post 4 minute Post 6 minute Post 8 minute Post 10 minute Post

Sprint 1.19 (0.67 3.55) 10.98 (3.25 14.60) 12.74 (6.17 16.72) 13.26 (6.50 16.47) 13.93 (8.49 16.66) 13.02 (8.55 16.56) 11.47 (7.61 15.77)

OC 1.01 (0.76 2.03) 1.39 (0.6 2.39) 1.45 (0.61 2.40) 1.50 (1.07 2.15) 1.49 (0.65 2.13) 1.34 (0.65 2.10) 1.50 (0.72 2.67)

TASER 1.30 (0.81 1.93) 5.49 (1.33 7.18) 5.52 (1.46 6.66) 5.31 (1.56 6.16) 4.76 (1.73 5.67) 4.60 (1.69 5.29) 4.06 (1.69 4.78)

Heavy

bag

1.44 (0.73 2.61) 15.46 (8.85 18.65) 17.22 (15.14 20.0) 17.88 (15 01 20.0) 17.09 (13.81 20.0) 18.26 (13.67 20.0) 17.33 (13.88 20.0)

K 9 1.05 (0.61 1.45) 5.01 (1.54 9.58) 5.76 (2.30 10.16) 6.13 (2.87 11.0) 6.53 (2.81 10.55) 6.34 (2.85 10.41) 5.90 (2.42 9.87)

p value * 0.066 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001

OC = oleoresin capsicum.

*Kruskal Wallis test.

Table 5Creatinine Kinase, U ⁄ L

Group Baseline 24 hour Post Difference From Baseline (Range) p value*

Sprint 144.8 (±55.4) 57 231 196.8 (±91.6) 57 440 30.5 ( 19 to 205) 0.006OC 215.3 (±145.8) 98 597 214.1 (±139.9) 69 508 5.5 ( 120 to 92) 1.000TASER 184.4 (±155.3) 42 576 241.1 (±133.5) 59 447 26 ( 205 to 329) 0.25Heavy bag 303.8 (±221.8) 99 758 351.6 (±285.3) 109 1161 74 ( 160 to 403) 0.31K 9 137.4 (±137.4) 58 366 174.8 (±170.5) 57 536 3 ( 32 to 322) 0.57p value� 0.038 0.157 0.70

Values are reported as mean (±SD) range unless otherwise noted.OC = oleoresin capsicum.*Wilcoxon signed rank test.�Kruskal Wallis test.


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et al.6 found that venous pH decreased from 7.39 to7.04 after a 30-second maximal sprint. The pH was 7.29at 30 minutes. Lactate peaked at 15.76 mmol ⁄ L 5 min-utes after the completion of the sprint, declining to10.30 mmol ⁄ L at 30 minutes.6 In our study, we founddecreases in pH after tasks designed to simulate com-mon subject behaviors and tools and tactics used onresistive subjects by LEAs during a custodial arrest sit-uation. The pH was lowest and the lactate was highestin the heavy bag resistance task group, followed by thesprint group.

The phenomenon of ARD is often associated withbehaviors that can contribute to inducing or worseningacidosis. These factors include illicit stimulant abuse,agitated behavior, excited delirium syndrome, andheavy physical resistance to LEA or health care person-

nel attempting to control a person in this condition torender aid.2,3,7 Our study demonstrates that physicalresistance and fleeing may be significant contributorsto acidosis. Based on this, the intuitively dangerousconcepts of running from and resisting LEAs or LEAK-9s appear to be true at a metabolic level. The impor-tant implications of this are that of the actions studied,the top three that appear to worsen acidosis are underthe control of the subject and not the LEAs.

We believe that our data support the concept thatLEAs should attempt to limit the length of time that asuspect is allowed to vigorously or violently resistrestraint, and that once restrained, continued resis-tance should be viewed as potentially harmful andmay require emergent medical intervention. Our studyindicates that continued vigorous exertion that may be

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Figure 1. Catecholamines (pg ⁄ mL) mean value (error bar = SEM). OC = oleoresin capsicum.


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typically displayed by an agitated, intoxicated, anddelirious suspect may worsen acidosis and play a rolein ARD.

There is also literature supporting a direct correlationbetween worsening acidosis and increasing catechol-amine levels. A study by Goldsmith et al.8 showed thatfor a given level of exercise, acidosis significantly corre-lates with an increasing rise of systemic catecholam-ines. Dimsdale et al.9 noted increases in catecholaminesin the period immediately after the cessation of exerciseand hypothesized this as a mechanism for the increasedrisk of cardiac arrhythmias and ischemia in the periodimmediately after strenuous exercise. This hypothesismay be a factor in the sudden and unexpected natureof ARDs, which often involves cardiovascular collapsein the period just after the subject is restrained follow-ing significant physical exertion such as resistance andfleeing.10,11 Some authors have hypothesized that this isrelated to a hypersympathetic state and an acute stresscardiomyopathy.12–14 The phenomenon of acute stresscardiomyopathy has been referred to as ‘‘tako-tsubo’’cardiomyopathy in Japan and has also been reported inthe United States.15 However, acute stress cardiomyop-athy is not regularly described as progressing to sud-den death.

Another theory linking catecholamines and ARDssuggests that the postexercise period might pose a riskbecause of the peripheral arteriolar dilation associatedwith exercise.16 The vasodilation, coupled with a sud-den decrease in venous return from the termination ofmuscular activity, may reduce cardiac output suddenlyand reduce coronary artery perfusion at a time whenthe heart rate and oxygen demand are elevated due tohigh catecholamine levels.17,18

A prior study by Dawes et al.19 used salivary amylaseand cortisol as measures of the sympathetic-adrenal-medulla (SAM) axis and hypothalamus-pituitary-adrenal(HPA) axis responses to a prolonged TASER X26 deviceexposure, OC exposure, a defensive tactics drill, andthe cold pressor task. This study demonstrated that OCexposure and physical exertion activated the SAM andHPA axes, similar to our findings. Increases in plasmacatecholamines following physical exertion have beenfound previously by Allsop et al.6 as well, who foundlarger changes than those detected in our study.

According to Karch,20 under ‘‘normal exercise condi-tions’’ (not described as maximal), epinephrine levels are700 pg ⁄ mL, and norepinephrine 299–300 pg ⁄ mL. In heartfailure, they are 35–75 and 500–800 pg ⁄ mL; in cocaineuse, 30–40 pg ⁄ mL and 1000–2000 pg ⁄ mL; and in cardiacarrest, 10,000–100,000 pg ⁄ mL and 500–600 pg ⁄ mL. How-ever, Karch’s data are based on only a single-time-pointanalysis. There is also evidence of elevations in catechol-amines with animal-based restraint stress models(300%–600% increase) and with exercise stress com-bined with cocaine exposure (200%-500% increase), sim-ilar to the heavy bag group (600% increase in totalcatecholamines after the task) found here.21,22

It is possible that catecholamine excess, when com-bined with exertional stress during restraint, maydecrease electrical cardiac stability making the myocar-dium more sensitive to arrhythmogenic drugs.23 Thismay have important implications, because the majority

of subjects in ARDs test positive for stimulant drugs intheir system at time of autopsy.11,24–26 However, Lakkir-eddy et al.27 showed a 50% to 100% increase in the ven-tricular fibrillation threshold to a TASER deviceelectrical shock in the setting of cocaine intoxication ina swine model.

We evaluated CK because rhabdomyolysis is a com-mon complication of heavy exertion.28,29 Heavy exertionfrom agitation, delirium, and custodial resistance isoften described as a feature associated with ARDs. Ithas also been theorized that because a TASER worksby causing skeletal muscle activation it might also causesignificant rhabomyolysis. In a 2006 study by Ho etal.,30 the mean change in CK at 24 hours was 57.2 U ⁄ Lwith a 5-second TASER X26 device-deployed probeexposure to the back. In our current study, the highestvalue was 1,161 U ⁄ L in a heavy bag subject. The highestmedian change from baseline in CK occurred with theheavy bag group followed by the sprint group, but onlythe sprint group change was significant. Our data sug-gest that rhabdomyolysis that is present in associationwith a resistive LEA interaction is likely due to voli-tional fleeing and resistance rather than LEA tools andtactics.

Hypokalemia in the period immediately after the ces-sation of exercise has been proposed as a possible con-tributory factor in ARDs. This potential ‘‘period ofperil’’ has been thought to occur when exertion ceasesbecause catecholamine-induced potassium absorptionby cells continues.2 The potassium changes we found,however, were not clinically significant. Our data donot suggest that hypokalemia plays a role in the mecha-nism of ARDs.

Our results for the TASER device exposure groupwere consistent with prior studies that showed minimalserum pH, lactate, and potassium changes and no asso-ciated troponin I elevations.30–32 Our pH and lactatechanges were more pronounced than those that Vilkeet al.31 found for the TASER, but we sampled pH valuesalmost immediately after the exposure and used alonger exposure time. Prior research has shown that inexhausted subjects, TASER exposures are not associ-ated with worsening acidosis differently than continuedexertion.33,34

Oleoresin capsicum exposure appeared to cause con-tinued rising catecholamine levels. This may be impor-tant because this effect could continue long after thesubject was restrained. In addition, OC exerts its pri-mary effect by pain and disorientation (due to an inabil-ity to open the eyes) and can also cause brieflaryngospasm and bronchospasm.35 This effect maycause even more release of catecholamines in a subjectin a noncontrolled setting, especially in a subject withagitated delirium, already exhibiting paranoid behavior.Finally, it is theoretically likely that OC application in afield situation could result in a subject fleeing due topain, further exposing him or her to the physiologicresponses we saw in our Task Group 1 (sprint).

In ARD studies, death has usually been preceded bysignificant physical exertion and restraint.4,10,11,13 Ourdata suggest that the most deleterious factor inLEA ⁄ subject encounters is physical resistance (heavybag group) followed by fleeing on foot (sprint group).


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These simulations resulted in the highest catecholaminelevels and the greatest change in pH, lactate, and CK.In studies that have reviewed initial cardiac rhythmsfollowing collapse in ARD situations, the vast majorityare pulseless electrical activity or asystole.4,11,36 Theseterminal rhythms are consistent with severe acidosisthat could occur in a prolonged or intense struggle.

LEAs are often challenged with protecting the publicfrom agitated, violent subjects. The results of our studymay be important in considering the best methods toensure safety in custodial arrest situations and preven-tion of ARDs. We believe that our study demonstratessubject physiology during these encounters. Theseencounters cannot be without risk. When LEAs arecalled to deal with resistive subjects, the risk for injuryand death to both the subject and the LEAs is elevated.The TASER device, K-9, and OC groups show that LEAintervention with these tactics and tools may have lessnegative consequences for acidosis and catecholaminelevels than physical resistance or allowing the subjectto flee and may be safer approaches to restraint.

LIMITATIONS

The volunteers were assigned to task groups based ontesting station availability, and volunteers with priorsignificant LEA K-9 experience did not participate inthe K-9 resistance task, introducing selection bias. Also,the number of volunteers was not large, limiting ourability to detect differences between groups. The num-ber of volunteers in the study was kept to a minimumdue to the logistical difficulties in carrying out the fivetasks. Although the numbers are small, we believe thatour data show consistent and important differencesbetween groups. We encourage further investigation inthis area.

Many of the subjects with very high catecholaminelevels did not have fully quantified results. This affectedthe sprint, K-9 resistance, and heavy bag task groups,but not the TASER device exposure or OC exposuretask groups. Because a true maximum quantificationcould not be performed for these three groups, wehave underestimated the catecholamine levels in thesethree groups and limited our ability to find a difference.Therefore, we used nonparametric statistics robust tothe variation in values higher than the median.

The K-9 resistance task group may have had ablunted response because the volunteers were notblinded to the fact that they were wearing a protectivebite suit and only experienced pressure or pinchingfrom the bite. Additionally, several of the study subjectscomplained when they were not assigned to the dogbite task (they were looking forward to trying that task).We believe that this may have also yielded an underes-timation of the true effects that would occur in a realLEA K-9 custodial arrest interaction (since field situa-tions would more likely involve fear).

The time limit chosen for the heavy bag resistancetask group in the study was felt to be a conservativeestimate of the time to physically restrain a combativesubject. In situations in which the LEAs and suspectsare not evenly matched, or in cases of supranormalability to offer resistance (e.g., drug intoxication or

excited delirium syndrome), it would likely take muchlonger than 45 seconds to physically restrain the sub-ject. It appeared that the heavy bag task group was fati-gued after 30 seconds. We may have underestimatedthe true physiologic burden of a real field encounter inthe heavy bag group.

CONCLUSIONS

We believe that this is the first study to evaluate thehuman acid ⁄ base and catecholamine response of aresisting subject during a simulated law enforcementauthority custodial arrest encounter. This physiologymay be important in understanding the root cause ofarrest-related death events. The actions of physicallyresisting and fleeing appear to be the most harmfulwith respect to acid ⁄ base and catecholamine physiol-ogy. This suggests that tactics and tools that limit thistype of activity may be important in limiting the effectof the custodial arrest process on suspects.

The study authors acknowledge the following for their assistancein this project: Mr. Andrew Hinz (technical assistance), Mr. MattCarver (technical assistance), Ms. Victoria Gronkowski (data entry),Ms. Jennifer Knowles (LabCorp technician), and Ms. WendyHolmes (Lab Corp technician). The authors especially recognizethe contributions of Sgt. Doug Dirren and the City of Scottsdale(AZ) Police Department. This project would not have been possiblewithout their help and assistance.

References

1. Bell L. On a form of disease resembling someadvanced stages of mania and fever, but so con-tradistinguished from any ordinary observed ordescribed combination of symptoms as torender it probable that it may be overlooked andhitherto unrecorded malady. Am J Insan. 1849;6:97–127.

2. Di Maio TG, Di Maio VJ. Excited Delirium Syn-drome Cause of Death and Prevention. 1st ed. BocaRaton, FL: Taylor & Francis Group, 2006.

3. Ross DL, Chan TC (eds.). Forensic Science andMedicine: Sudden Deaths in Custody. Totowa, NJ:Humana Press, 2006.

4. Hick JL, Smith SW, Lynch MT. Metabolic acidosisin restraint-associated cardiac arrest: a case series.Acad Emerg Med. 1999; 6:239–43.

5. Gass GC, Rogers S, Mitchell R. Blood lactate con-centration following maximum exercise in trainedsubjects. Br J Sports Med. 1981; 15:172–6.

6. Allsop P, Cheetham M, Brooks S, Hall GM, Wil-liams C. Continuous intramuscular pH measure-ment during the recovery from brief, maximalexercise in man. Eur J Appl Physiol. 1990; 59:465–70.

7. Stevens DC, Campbell JP, Carter JE, Watson W.Acid-base abnormalities associated with cocainetoxicity in emergency department patients. ClinToxicol. 1994; 32:31–9.

8. Goldsmith SR, Iber C, McArthur CD, Davies SF.Influence of acid-base status on plasma catecholam-ines during exercise in normal humans. Am J Phys-iol. 1990; 258:R1411–16.


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9. Dimsdale JE, Hartley LH, Guiney T, Ruskin JN,Greenblatt D. Postexercise peril: plasma catechol-amines and exercise. JAMA. 1984; 251:630–2.

10. O’Halloran RL, Frank JG. Asphyxial death duringprone restraint revisited: a report of 21 cases. Am JForensic Med Pathol. 2000; 21:39–52.

11. Stratton S, Rogers C, Brickett K, Grunzinski G. Fac-tors associated with sudden death of individualsrequiring restraint for excited delirium. Am JEmerg Med. 2001; 19:187–91.

12. Cevik C, Otahbachi M, Miller E, Bagdure S, NugentK. Acute stress cardiomyopathy and deaths associ-ated with electronic weapons. Int J Cardiol. 2009;132:312–7.

13. Lee B, Vittinghoff E, Whiteman D, Park M, Lau L,Tseng Z. Relation of TASER (electrical stun gun)deployment to increase in in-custody suddendeaths. Am J Cardiol. 2009; 103:877–80.

14. Wetli C, Mash D, Karch S. Cocaine-associated agi-tated delirium and the neuroleptic malignant syn-drome. Am J Emerg Med. 1996; 14:425–8.

15. Sharkey SW, Lesser JR, Zenovich AG, et al. Acuteand reversible cardiomyopathy provoked by stressin women from the United States. Circulation. 2005;111:472–9.

16. Halliwill JR, Taylor JA, Eckberg DL. Impaired sym-pathetic vascular regulation in humans after acutedynamic exercise. J Physiol. 1996; 495:279–88.

17. Fletcher GF, Balady GJ, Amsterdam EA, et al. Exer-cise standards for testing and training: a statementfor healthcare professionals from the AmericanHeart Association. Circulation. 2001; 104:1694–740.

18. Goodman JM, Busato GM, Frey E, Sasson Z. Leftventricular contractile function is preserved duringprolonged exercise in middle-aged men. J ApplPhysiol. 2009; 106:494–9.

19. Dawes D, Ho J, Miner J. The neuroendocrineeffects of the TASER X26: a brief report. ForensicSci Int. 2009; 183:14–9.

20. Karch SB. Karch’s Pathology of Drug Abuse. 4thed. Boca Raton, FL: Taylor & Francis Group CRCPress, 2009.

21. Buhler HU, Da Prada M, Haefely W, Picotti GB.Plasma adrenaline, noradrenaline, and dopamine inman and different animal species. J Physiol. 1978;276:311–20.

22. Han DH, Kelly KP, Fellingham GW, Conlee RK.Cocaine and exercise: temporal changes in plasmalevels of catecholamines, lactate, glucose, andcocaine. Am J Physiol Endocrinol Metab. 1996;270:E438–44.

23. Sun AY, Li DX, Wang YL, Li QP. Restraint stresschanges heart sensitivity to arrhythmogenic drugs.Acta Pharmacol Sin. 1995; 16:455–9.

24. Ho JD, Heegaard WG, Dawes DM, Natarajan S,Reardon RF, Miner JR. Unexpected arrest-relateddeaths in America: 12 months of open source sur-veillance. West J Emerg Med. 2009; 10:68–73.

25. Strote J, Hutson HR. TASER use in restraint-relateddeaths. Prehosp Emerg Care. 2006; 10:447–50.

26. Grant JR, Southhall PE, Mealey J, Scott SR, FowlerDR. Excited delirium deaths in custody: past andpresent. Am J Forensic Med Pathol. 2009; 30:1–5.

27. Lakkireddy D, Wallick D, Ryschon K, et al. Effectsof cocaine intoxication on the threshold for stungun induction of ventricular fibrillation. J Am CollCardiol. 2006; 48:805–11.

28. Sinert R, Kohl L, Reinone T, Scalea T. Exercise-induced rhabdomyolysis. Ann Emerg Med. 1994;23:1301–6.

29. Lin AC, Lin CM, Wang TL, Leu JG. Rhabdomyolysisin 119 students after repetitive exercise [abstract].Br J Sports Med. 2005; 39:e3.

30. Ho JD, Miner JR, Lakireddy DR, Bultman LL, Heeg-aard WG. Cardiovascular and physiologic effects ofconducted electrical weapon discharge in restingadults. Acad Emerg Med. 2006; 13:589–95.

31. Vilke G, Sloane C, Bouton K, et al. Physiologicaleffects of a conducted electrical weapon on humansubjects. Ann Emerg Med. 2007; 50:569–75.

32. Sloane C, Chan T, Levine S, Dunford J, Neuman T,Vilke G. Serum troponin I measurement of subjectsexposed to the TASER X-26. J Emerg Med. 2008;35:29–32.

33. Ho JD, Dawes DM, Bultman LL, Moscati RM, Jan-char TA, Miner JR. Prolonged TASER use onexhausted humans does not worsen markers of aci-dosis. Am J Emerg Med. 2009; 27:413–8.

34. Ho JD, Dawes DM, Cole JB, Hottinger JC, OvertonKG, Miner JR. Lactate and pH evaluation inexhausted humans with prolonged TASER X26exposure or continued exertion. Forensic Sci Int.2009; 190:80–6.

35. Steffee CH, Lantz PE, Flannagan LM, ThompsonRL, Jason DR. Oleoresin capsicum (pepper) sprayand ‘‘in-custody deaths.’’ Am J Forensic MedPathol. 1995; 16:185–92.

36. Swerdlow CD, Fishbein MC, Chaman L, LakkireddyDR, Tchou P. Presenting rhythm in sudden deathstemporally proximate to discharge of TASER con-ducted electrical weapons. Acad Emerg Med. 2009;16:726–39.


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Calculation of the TASER® X26 Internal Time Circuit Drift for Event Reconstruction

Andrew Hinz TASER International

Abstract: The TASER® X26 system has quickly become the electronic control device of choice for law enforcement, military, and civilian organizations, with over 12,000 law enforcement agencies currently deploying the TASER X26. The X26 device has the ability to record the last 1500 trigger pulls, providing a time record of how the device was fired, as well as how long the device was activated. A TASER device’s ability to accurately record when the device was activated is of a great benefit when reconstructing an event. The X26 has an internal timing circuit powered by the microprocessor with a clock running in Greenwich Mean Time (GMT). All timing circuits are subject to clock drift, which is inherent to all electronic devices that have an internal timing mechanism. Keeping the time record as accurate as possible can sometimes be critical in event reconstruction and also important when multiple devices are involved in an event. A TASER X26 device’s internal timing circuit will drift a maximum of minus 3 minutes 00 seconds per month under average temperature ranges. From temperatures of −20 °C to +50 °C, those time ranges can vary up to 2 minutes 33 seconds in colder environments and up to 3 minutes 41 seconds in warmer environments. By using this formula, we can determine a time range window of when a device was activated in real time for the reconstruction of events.

Key Words: TASER, X26, Internal Clock, Time Drift, Stun, Conducted Energy Weapon, Electronic Control Device (ECD)

A TASER X26 has a small amount of internal clock drift compared to other computer devices (timing crystal of personal computers, digital watches, alarm clocks,, etc…)

Normal clocks such as clocks at home and wristwatches will drift compared to the actual time. That is why one must reset their time periodically. Clocks often drift differently depending on their quality, the exact power they get from the battery, the surrounding temperature, and so on. Thus the same clock can have different clock drift rates at different occasions.

Accuracy (the closeness of computer time to UTC in our case) is the systematic (not random) error in the time offset. When your average computer clock is left free running, the major causes of its inaccuracy are the initial time offset error (the outside source to which we are setting our clock), and the average frequency offset error, (drift) causing time to move away from the true time at a variable rate.

When the computer clock is disciplined to an external reference (a time standard that everyone can agree on, for example), the accuracy is orders

of magnitude better and is determined by the accuracy of the external reference, by the offsets introduced by the time dissemination technique used (e.g. network delays or latencies in the interface to the attached reference clock), and by the ability of the software to properly adjust the computer clock. Depending on the time scale one has in mind, slow fluctuations in frequency of the computer clock oscillator can be counted as a contributor to imprecision or the inaccuracy of the computer clock.

The drift for the TASER X26 is not a constant for each device and can vary in the degree of drift from month to month for each device. If the device is not synchronized to an outside source after a period of time, the device may be of inaccurate significantly compared to real time (hours, maybe even days in some cases were a device has been in service for years without being synchronized).

When the device is downloaded , The TASER X26 will only alert the user of a time synchronization error if the device time is ± 10 minutes difference from the indicated system time (Figure 1).

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(Figure 1)

Once the device time is synchronized, the user will then be able to view the firing records from the device.

With the current version of X26 Dataport Download software the user is able to see the difference in device time compared to time as reported by the download station. (Figure 2)

(Figure 2)

For example in Figure 2 above, the X26’s internal clock was a one–minute, five-second positive

difference compared to the time reported by the download station. The user can manually synchronize the time if desired. Dataport download software displays a firing record in Greenwich Mean Time as well as local time determined by what time zone the download station is reporting.

A TASER X26 device should be periodically downloaded for maintenance purposes. TASER International recommends that a TASER device be downloaded every 90–120 days to verify accurate data recording.

The recommendation of the 90-120 days was determined by predicting the most likely time period of when a Time Synchronization Warning would occur by calculating the internal timing circuit drift.

To determine the exact drift this test was performed over a one-week period using six production TASER X26 devices. The six X26 devices had never been used in the field and were in out-of-box condition. All devices used the X26 digital power magazine (DPM) registering 99% at the time of the test. Each device, after being removed from the chamber, was fired three times for 5-second durations each time to verify proper time recording.

The temperature points used were −20 °C, 20 °C, and 50 °C. An environmental chamber preconditioned to the test temperature was used. Each device was placed into the chamber for a 24-hour period (Figure 3).

(Figure 3)

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The device internal timing circuit variation was determined by firing the unit before and after placing the unit in an Esqec ESX-3C temperature chamber and noting the time from the National Institute of Standards and Technology website at http://nist.time.gov/timezone.cgi?Mountain/s/-7/java (Technology, 2007)(Figure 4)

(Figure 4)

Time synchronization was performed for each device before each temperature point so internal clock time and real time were matched with a difference of 0 seconds.

The X26 internal timing circuit operates in seconds, not in milliseconds, as is the case of a modern desktop computer. Because the timing circuit is part of the microprocessor, power for the internal clock is supplied via the Digital Power Magazine (DPM), which consists of two 1.5-volt lithium power cells.

Results

1. The average time lost over all the temperature ranges for all units pre- and post-chamber was that the units lost 6.0 seconds in a 24-hour period.

2. The units exposed to −20 °C lost a total average of 4.67 seconds over a 24-hour period. The range was -4 to -5 seconds. The units were all time synchronized pre-chamber. There was no pre-drift to calculate (all units were 0.00 seconds).

3. The units exposed to 50 °C lost a total average of 6.83 seconds over a 24 hour time period. The range was -4 to -10 seconds. The units were all time

synchronized pre-chamber. There was no pre-drift to calculate (all units were 0.00 seconds).

4. The units exposed to 20 °C lost a total average 6.83 seconds over a 24-hour time period. The range was -4 to -10 seconds. The units were all time synchronized pre-chamber. There was no pre-drift to calculate (all units were 0.00 seconds).

If a unit is losing an average of 6.00 seconds per day, then we can estimate an average loss of 3 minutes 00 seconds per month (6 seconds per day X 30-day month). In colder climates, we can expect to see a maximum of −4.67 seconds per 24 hours (2 minutes 33 seconds per month). Warmer climates will have an average maximum loss of 6.83 seconds per 24 hours (3 minutes 41 seconds per month). No Positive time drift (accelerating) clock times were observed during testing.

A TASER X26 Electronic Control Device’s internal timing circuit drift can be determined for event reconstruction if a device has not been synchronized for a extended period of time or to line up multiple devices to one time reference for accurate event reconstruction. An X26 should be downloaded within 48 hours of an event so the exact internal clock reference point can be determined.

Law enforcement agencies that deploy the TASER X26 devices should have a program in place for maintenance downloads every 90–120 days to ensure that an X26 device’s internal clock is as accurate as possible as this will ensure the most accurate times being recorded in the firing log.

Technology, N. I. (2007, July 23). Retrieved from http://nist.time.gov/timezone.cgi?Mountain/s/-7/java

AIR TASER, M26, and X26 are trademarks of TASER International, Inc. TASER® and ADVANCEDTASER® are registered trademarks of TASER International, Inc.

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For further information please contact:

Andrew Hinz

TASER International

Technical Programs mamanger

17800 North 85th St

Scottsdale, AZ 85255

[email protected]

1/800-978-2737

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