Safety and Health Information Bulletin

SHIB 03-24-2004, updated 2011

Suspension Trauma/ Orthostatic Intolerance

Purpose

This Safety and Health

Information Bulletin provides

employees and employers with

important information about the

hazards of orthostatic intolerance

and suspension trauma when

using fall arrest systems. This

bulletin:

• describes the signs and symptoms of orthostatic intolerance;

• discusses how orthostatic intolerance can

occur while workers are suspended following a fall; and

• outlines recommendations for preventing

orthostatic intolerance, as well as recommendations for worker training and

rescue.

Background

Orthostatic intolerance may be defined as “the

development of symptoms such as light-headedness,

palpitations, tremulousness, poor concentration,

fatigue, nausea, dizziness, headache, sweating,

weakness and occasionally fainting during upright

standing” [1,2]. While in a sedentary position,

blood can accumulate in the veins, which is commonly called “venous pooling,” and cause orthostatic intolerance [3]. Orthostatic intolerance also

can occur when an individual moves suddenly after

being sedentary for a long time. For example, a

person may experience orthostatic intolerance when

they stand up quickly after sitting still for a long time.

A well-known example of orthostatic intolerance is that of a soldier who faints while standing at

attention for long period of time. The moment the

soldier loses consciousness, he or she collapses into

a horizontal position. With the legs, heart, and brain

on the same level, blood is returned to the heart.

Assuming no injuries are caused during the collapse,

the individual will quickly regain consciousness and

recovery is likely to be rapid.

Venous pooling typically occurs in the legs due

to the force of gravity and a lack of movement.

Some venous pooling occurs naturally when a

person is standing. In the veins, blood normally is

moved back to the heart through one-way valves

using the normal muscular action associated with

limb movement. If the legs are immobile, then these

“muscle pumps” do not operate effectively, and

blood can accumulate. Since veins can expand, a

large volume of blood may accumulate in the veins.

 This Safety and Health Information Bulletin is not a

standard or regulation, and it creates no new legal

obligations. The Bulletin is advisory in nature,

informational in content, and is intended to assist

employers in providing a safe and healthful workplace.

The Occupational Safety and Health Act requires

employers to comply with hazard-specific safety and health

standards. In addition, pursuant to Section 5(a)(1), the

General Duty Clause of the OSHAct, employers must

provide their employees with a workplace free from

recognized hazards likely to cause death or serious

physical harm. Employers can be cited for violating the

General Duty Clause if there is a recognized hazard and

they do not take reasonable steps to prevent or abate the

hazard. However, failure to implement any

recommendations in this bulletin, is not, in itself, a

violation of the General Duty Clause. Citations can only

be based on standards, regulations, and the General Duty

Clause.

U.S Department of Labor

Occupational Safety and Health Administration

Directorate of Science, Technology and Medicine

Office of Science and Technology Assessment
An accumulation of blood in the legs reduces

the amount of blood in circulation. The body reacts

to this reduction by speeding up the heart rate and in

an attempt to maintain sufficient blood flow to the

brain. If the blood supply is significantly reduced,

this reaction will not be effective.

The body will abruptly slow the

heart rate and blood pressure will

diminish in the arteries. During

severe venous pooling, the reduction

in quantity and/or quality (oxygen

content) of blood flowing to the

brain causes fainting. This reduction

also can have an effect on other vital

organs, such as the kidneys [3].

The kidneys are very sensitive to

blood oxygen, and renal failure can

occur with excessive venous pooling. If these

conditions continue, they potentially may be fatal

[3].

Description of Hazard

Orthostatic intolerance may be experienced by

workers using fall arrest systems. Following a fall, a

worker may remain suspended in a harness. The

sustained immobility may lead to a state of unconsciousness. Depending on the length of time the

suspended worker is unconscious/immobile and the

level of venous pooling, the resulting orthostatic

intolerance may lead to death. While not common,

such fatalities often are referred to as “harnessinduced pathology” or “suspension trauma.”

Unconscious/immobile workers suspended in

their harness will not be able to move their legs and

will not fall into a horizontal position, as they would

if they fainted while standing. During the static

upright position, venous pooling is likely to occur

and cause orthostatic intolerance, especially if the

suspended worker is left in place for some time.

Venous pooling and orthostatic intolerance can be

exacerbated by other circumstances related to the

fall. For example, shock or the experience of the

event that caused the fall, other injuries, the fit/

positioning of the harness, the environmental conditions, and the worker’s psychological state all may

increase the onset and severity of the pooling and

orthostatic intolerance [3,5]. Unless the worker is

rescued promptly using established safe procedures,

venous pooling and orthostatic intolerance could

result in serious or fatal injury, as the brain, kidneys,

and other organs are deprived of oxygen [3].

Recommended rescue procedures are outlined

below in the Conclusions and Recommendations

section.

Conclusions and Recommendations

Prolonged suspension from fall arrest systems

can cause orthostatic intolerance, which, in turn, can

result in serious physical injury, or potentially, death.

Research indicates that suspension in a fall arrest

device can result in unconsciousness, followed by

Faintness

Breathlessness

Sweating

Paleness

Hot Flashes

Increased Heart Rate

Nausea

Dizziness

Unusually Low Heart Rate

Unusually Low Blood Pressure

“Greying” or Loss of Vision

Signs & symptoms that may be observed

in an individual who is approaching

orthostatic intolerance:

References: Seddon, Paul. Harness Suspension: review and

evaluation of existing information. Health and Safety

Executive. Research Report 451/2002. 104 pp.

Sheehan, Alan. Suspension Trauma. Training handout.

Inability to move legs

Pain

Injuries during fall

Fatigue

Dehydration

Hypothermia

Shock

Cardiovascular disease

Respiratory disease

Blood loss

Factors that can affect the degree of risk of

suspension trauma:

References: Seddon, Paul. Harness Suspension: review and

evaluation of existing information. Health and Safety

Executive. Research Report 451/2002. 104 pp.

Sheehan, Alan. Suspension Trauma. Training handout

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death, in less than 30 minutes [4]. To reduce the

risk associated with prolonged suspension in fall

arrest systems, employers should implement plans to

prevent prolonged suspension in fall protection

devices. The plan should include procedures for:

preventing prolonged suspension, identifying orthostatic intolerance signs and symptoms, and performing rescue and treatment as quickly as possible.

OSHA recommends the following general

practices/considerations:

• Rescue suspended workers as quickly as

possible.

• Be aware that suspended workers are at

risk of orthostatic intolerance and

suspension trauma.

• Be aware of signs and symptoms of

orthostatic intolerance.

• Be aware that orthostatic intolerance is

potentially life threatening. Suspended

workers with head injuries or who are

unconscious are particularly at risk.

• Be aware of factors that can increase the

risk of suspension trauma.

Training

OSHA requires employers to train workers to

use fall arrest systems and other personal protective

equipment correctly while performing their jobs, in

accordance with standards 29 CFR 1910.132

(Personal Protective Equipment) 29 CFR 1915.159

(Personal Fall Arrest Systems) and 29 CFR

1926.503 (Training Requirements for Fall Protection).

Workers who wear fall arrest devices while

working, and those who may perform rescue

activities, should also be trained in:

• How to ascertain whether their personal

protective equipment is properly fitted and

worn, so that it performs as intended;

• How orthostatic intolerance/suspension

trauma may occur;

• The factors that may increase a worker’s

risk;

• How to recognize the signs and symptoms

identified in this bulletin; and

• The appropriate rescue procedures

and methods to diminish risk while suspended.

Rescue Procedures

Under 29 CFR 1926.502 (d) (Fall Protection

Systems Criteria and Practices), OSHA requires

that employers provide for “prompt rescue of

employees in the event of a fall or shall assure that

employees are able to rescue themselves.” This

should include identifying rescue procedures that

address the potential for orthostatic intolerance and

suspension trauma. Rescue procedures also should

address how the rescued worker will be handled to

avoid any post-rescue injuries.

Rescue procedures should include the following contingency based actions:

• If self-rescue is impossible, or if rescue cannot

be performed promptly, the worker should be

trained to “pump” his/her legs frequently to

activate the muscles and reduce the risk of

venous pooling. Footholds can be used to

alleviate pressure, delay symptoms, and provide

support for “muscle pumping.”

• Continous monitoring of the suspended worker

for signs and symptoms of orthostatic intolerance and suspension trauma.

• Ensuring that a worker receives standard

trauma resuscitation1

 once

rescued.

• If the worker is unconscious,

keeping the worker’s air

passages open and obtain first

aid.

• Monitoring the worker after

rescue, and ensuring that the

worker is evaluated by a health-care professional. The worker should be hospitalized when

appropriate. Possible delayed effects, such as

kidney failure, which is not unusual in these

cases, are difficult to assess on the scene.

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References

1. Robertson, David. Orthostatic Intolerance.

Vanderbilt University, Nashville, Tennessee.

2. New York Medical College. Orthostatic Intolerance. Vahalla, New York.

3. Seddon, Paul. Harness Suspension: Review and

evaluation of existing information. Health and Safety

Executive. Research Report 451/2002. 104 pp.

4. Sheehan, Alan. Suspension Trauma. Training

handout.

5. Weems, Bill and Bishop, Phil. Will Your Safety

Harness Kill You? Occupational Health & Safety.

72(3): 86-88, 90, March, 2003.

1 National Association of Emergency Medical Technicians

(NAEMT). Provider Textbook section in: PHTLS Basic and

Advanced Prehospital Trauma Life Support Fifth

Edition St. Louis, MO: Mosby; 2003: Section 1. Summary

available at: http://phtls.org/datafiles/

PHTLS%205ed%20Compendium.pdf

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