U.S. Department of Justice
Office of Justice Programs
National Institute of Justice

National Law Enforcement
Technology CenterBulletin
June 1995

A National Institute of Justice Program

Positional Asphyxia—Sudden Death
Major portions of this bulletin are drawn from a report prepared by the International Association of Chiefs of Police for the National Institute of
Justice (NIJ), based on research conducted by Dr. Charles S. Petty, Professor of Forensic Pathology, University of Texas, and Dr. Edward T.
McDonough, Deputy Chief Medical Examiner, State of Connecticut, and reviewed by the Less-Than-Lethal Liability Task Group.

Police, sheriffs, and correctional officers
have a limited and largely inadequate set
of tools to use to safely subdue violent
and aggressive subjects. Through NIJ’s
National Law Enforcement Technology
Center (NLETC), the Federal Government is working to identify and support
the development of a range of less-thanlethal technologies—from those suitable
for one-on-one encounters to those that
might be used for stopping fleeing
vehicles. In a recent analysis of incustody deaths, we discovered evidence
that unexplained in-custody deaths are
caused more often than is generally
known by a little-known phenomenon
called positional asphyxia.
This NLETC bulletin presents information relevant to positional asphyxia—i.e.,
death as a result of body position that
interferes with one’s ability to breathe—
as it occurs within a confrontational
situation involving law enforcement
officers. We offer this information to help
officers recognize factors contributing to
this phenomenon and, therefore, enable
them to respond in a way that will ensure
the subject’s safety and minimize risk of
death.
The bulletin identifies factors found to
precipitate positional asphyxia, and
provides recommendations for ensuring a
subject’s safety and advisory guidelines
for care of subjects. Information regarding the collection of potential evidence in

cases involving positional asphyxia is
also included. Through officer awareness
and resultant action, it is anticipated that
deaths attributable to this cause will be
reduced.
Sudden in-custody death is not a new
phenomenon—it can occur at any time,
for a variety of reasons. Any law enforcement agency may experience a sudden incustody death, and while rare, such
deaths appear to be associated most often
with the following variables:
■

■

■

Cocaine-induced bizarre or frenzied
behavior. When occurring while
confined by restraints, cocaineinduced excited delirium (an acute
mental disorder characterized by
impaired thinking, disorientation,
visual hallucinations, and illusions)
may increase a subject’s susceptibility
to sudden death by effecting an
increase of the heart rate to a critical
level.
Drugs and/or alcohol intoxication.
Drug and acute alcohol intoxication is
a major risk factor because respiratory
drive is reduced, and subjects may not
realize they are suffocating.
Violent struggle extreme enough to
require the officers to employ some
type of restraint technique. Subjects
who have engaged in extreme violent
activities may be more vulnerable to
subsequent respiratory muscle failure.

■

Unresponsiveness of subject during
or immediately after a struggle.
Such unresponsive behavior may
indicate cardiopulmonary arrest and
the need for immediate medical
attention.

It is important to understand how
preexisting risk factors, combined with
the subject’s body position when subdued
or in transit, can compound the risk of
sudden death. Information contained in
this bulletin may help to alert officers to
those factors found frequently in deaths
involving positional asphyxia.

Basic Physiology of
a Struggle
A person lying on his stomach has
trouble breathing when pressure is
applied to his back. The remedy seems
relatively simple: get the pressure off his
back. However, during a violent struggle
between an officer or officers and a
suspect, the solution is not as simple as it
may sound. Often, the situation is
compounded by a vicious cycle of
suspect resistance and officer restraint:
■

A suspect is restrained in a face-down
position, and breathing may become
labored.

■

Weight is applied to the person’s
back—the more weight, the more
severe the degree of compression.

■

The individual experiences increased
difficulty breathing.

■

The natural reaction to oxygen
deficiency occurs—the person
struggles more violently.

■

Officer Subduing a Violent Suspect and How It Can Interfere With Breathing

Subject’s chest
fully extended.

The officer applies more compression
to subdue the individual.

Breathing becomes
labored due to
pressure being
exerted on
subject’s
back.

Predisposing Factors to
Positional Asphyxia
Certain factors may render some individuals more susceptible to positional
asphyxia following a violent struggle,
particularly when prone in a face-down
position:
■

Obesity.

■

Alcohol and high drug use.

■

An enlarged heart (renders an individual more susceptible to a cardiac
arrhythmia under conditions of low
blood oxygen and stress).

The risk of positional asphyxia is
compounded when an individual with
predisposing factors becomes involved in
a violent struggle with an officer or
officers, particularly when physical
restraint includes use of behind-the-back
handcuffing combined with placing the
subject in a stomach-down position.

Officer subdues violent suspect.

■

As soon as the suspect is handcuffed,
get him off his stomach.

■

Ask the subject if he has used drugs
recently or suffers from any cardiac or
respiratory diseases or conditions such
as asthma, bronchitis, or emphysema.

To help ensure subject safety and
minimize the risk of sudden in-custody
death, officers should learn to recognize
factors contributing to positional asphyxia. Where possible, avoid the use of
maximally prone restraint techniques
(e.g., hogtying). To help minimize the
potential for in-custody injury or death,
officers should:

■

Monitor subject carefully and obtain
medical treatment if needed.

■

Be trained to recognize breathing
difficulties or loss of consciousness
and immediately transport the individual to the emergency room, or call
for an emergency medical team
(EMT) unit if such signs are observed.

Follow existing training and policy
guidelines for situations involving
physical restraint of subjects.

■

Advisory Guidelines for
Care of Subdued Subjects

■

Obtain medical care upon subject’s
request.

2

■

If the subject is turned over to a
detention facility, inform the facility’s
custodians of any preexisting medical
conditions (cardiac, respiratory) or
that the subject requested or needed
medical treatment because of respiratory difficulty or because he became
unconscious.

Collection of Potential
Evidence
Officers involved in confrontational
situations should collect information that
may later be of value in a civil or perhaps
criminal action.
A use-of-force report should include
details of how the individual was

restrained. The following information
should be included:
■

What was the nature of the postarrest
restraint procedure? Identify whatever
type of restraint (including chemical
incapacitants) was used.

■

How long was the subject face down
and/or restrained?

■

How was the subject transported, and
in what position was the subject
during transport?

■

How long did the transport phase last,
and what observations were made of
the subject’s condition?

To reasonably establish the cause of
death or serious injury, a broad range of
factors must be examined:
■

Nature of the confrontation.

■

Weapon(s), if any, employed by
officers.*

■

Duration of the physical combat.

■

System or type of postarrest restraint
employed.

■

Transportation of the subject: destination, duration, mode of transport, and
position of subject during transport.

■

Emergency room observations and
actions, names of attending medical
personnel.

■

Postmortem examination (autopsy) of
subject: nature of injuries, diseases
present, drugs present, and other
physical factors.

Conclusion
To help minimize the risk of positional
asphyxia, diligent observation and
monitoring of subjects displaying any one
or a combination of the described
indicators are procedurally warranted.
Furthermore, the use of maximal, prone
restraint techniques should be avoided. If
prone positioning is required, subjects
should be closely and continuously
monitored. By implementing such
procedural protocols, the potential for incustody deaths may be lessened.

NLETC Bulletin
The NLETC Bulletin is designed as a forum
for disseminating to the law enforcement
and criminal justice communities the most
current information on technologies
relevant to your needs. We welcome your
comments or recommendations for future
Bulletins.
The National Law Enforcement Technology Center is designing data bases to help
respond to agencies that want to know who
manufactures a specific product and what
other agencies may be using that product.
Your contributions to the Center’s
information network are important. What
technologies or techniques are you using
that you would like to share with colleagues? Please call or write to the National
Law Enforcement Technology Center, P.O.
Box 1160, Rockville, MD 20849,
800–248–2742.

NYPD’s Guidelines to Preventing Deaths
in Custody
■

As soon as the subject is handcuffed,
get him off his stomach. Turn him on
his side or place him in a seated
position.

■

If he continues to struggle, do not sit
on his back. Hold his legs down or
wrap his legs with a strap.

■

Never tie the handcuffs to a leg or
ankle restraint.

■

If required, get the suspect immediate
medical attention.

■

Do not lay the person on his stomach
during transport to a station house or
hospital. Instead, place him in a seated
position.

■

An officer should sit in the rear seat
beside the suspect for observation and
control.

The New York City Police Department
(NYPD) has developed a training tape on
positional asphyxia. The Department has
agreed to make the tape available to interested
law enforcement agencies. To request a
complimentary copy, please send your written
request on departmental letterhead, and a blank
VHS tape, to the Deputy Commissioner of
Training, NYPD, 235 East 20th Street, New
York, New York 10003.

The National Law Enforcement Technology Center is supported by Cooperative
Agreement #95–IJ–CX–K002 awarded by
the U.S. Department of Justice, National
Institute of Justice.
The National Institute of Justice is a
component of the Office of Justice
Programs, which also includes the Bureau
of Justice Assistance, Bureau of Justice
Statistics, Office of Juvenile Justice and
Delinquency Prevention, and Office for
Victims of Crime.

*If any incapacitant was used (e.g., pepper
spray), the delivery system should immediately be secured for possible analysis.

3

U.S. Department of Justice
Office of Justice Programs
National Institute of Justice
Washington, DC 20531
Official Business
Penalty for Private Use $300

BULK RATE
POSTAGE & FEES PAID
DOJ/NIJ
Permit No. G–91