OHS Code Explanation Guide

Published Date: July 01, 2009
Bookmark this page

Part 41 Work Requiring Rope Access

Section 821 and Section 822 Worker rescue

Rescue procedures are a vital part of an employer’s safe work practices. The survival of an injured worker often depends on the speed of rescue and the care given to the casualty during and after rescue. As a result, the work site should be regularly assessed to anticipate emergency situations and to plan how any resulting rescues would be carried out. Specific rescue equipment should always be at the worksite.

Section 811 requires written procedures. After an arrested fall, the fallen worker remains suspended in mid-air from his or her full body harness, awaiting rescue. In most cases, the worker is not injured and can alter body position within the harness to be more comfortable.

Unfortunately, a worker suspended in an upright position with the legs dangling in a harness of any type is subject to what has come to be known as “suspension trauma”. This is one of the reasons that the fall protection plan must include rescue procedures.

Suspension trauma death is caused by orthostatic incompetence. A soldier standing almost motionless at attention for a long period of time and then fainting is an example of the problem. What happens with ortostatic incompetence is that the circulation of blood is reduced because the legs are immobile and the worker is in an upright position.

Gravity pulls the blood into the lower legs, which have a very large storage capacity. Enough blood eventually pools in the legs that return blood flow to the right side of the heart is reduced. This causes blood supply problems for both the heart and the brain. Normally the person faints at this point and falls to the ground. Now that the person is horizontal, blood from the legs flows back to the heart and on to the rest of the body.

While suspended in a harness however, the worker cannot fall into a horizontal position. Fall victims can slow the onset of suspension trauma by pushing down forcefully with the legs, by positioning their body in a horizontal or slightly leg-high position, or by standing up.

However, the design of the harness, the attachment points used, and the presence of fall injuries may prevent these actions. The suspended worker faces several problems:

(1) the worker is suspended in an upright posture with legs dangling;
(2) the safety harness straps exert pressure on leg veins, compressing them and reducing blood flow back to the heart; and
(3) the harness keeps the worker in an upright position, regardless of consciousness.

Rescue must happen quickly to minimize the dangers of suspension trauma. Time is of the essence because the suspended worker may lose consciousness in as few as five minutes.

If a worker is suspended long enough to lose consciousness, rescue personnel must be careful in handling such a person or the rescued worker may die anyway. This post-rescue death is apparently caused by the heart’s inability to tolerate the abrupt increase in blood flow to the right side of the heart after removal from the harness. Current recommended procedures are to take from 30 to 40 minutes to move the victim from kneeling to a sitting to a laying down position. A physician should examine the rescued victim. Among other things, the reduction in blood flow while suspended can affect the kidneys and lead to permanent damage. For more information about suspension trauma, readers are referred to the sources listed below.

A motionless, suspended victim suggests serious injury and a rescue must be performed quickly. A non-breathing, motionless victim must be ventilated within four minutes of when they stop breathing in order to prevent irreversible brain damage. If a work platform or man basket is suspended from a crane or hoist, a fall protection plan must be in place for the rescue of the occupant(s) in the event that the crane or hoist is unable to lower the work platform or man basket.

For more information
Harness suspension: review and evaluation of existing information
A very comprehensive review of the topic, prepared for the Health and Safety Executive, United Kingdom.
 
Will your safety harness kill you?