Construction Health and Safety Consultancy and CDM Adviser Services

Working at heights – what about suspension trauma?
Posted by David Cant on April 11, 2014

Health and Safety working at height When considering working at heights, most consideration is devoted to the practicalities of ladders, scaffolding and safety harnesses. However additional consideration needs to be provided for staff wearing safety harnesses or who will be suspended freely for any period of time – suspension trauma.

What is suspension trauma?

Also known as “harness hang syndrome” (HHS), suspension trauma is caused by holding the body upright and unsupported for an extended period of time. The heart struggles to overcome the effects of gravity, reducing blood flow to the head. Initially the person affected faints, but left in position for too long and they could potentially die as their brain is starved of oxygen.

Suspension trauma is triggered when the person suspended becomes motionless. This could be caused through a medical emergency, such as a diabetic experiencing a hypoglycemic episode, or passing out after a blow to the head.

There is also a risk that someone unexpectedly trapped in a harness will become exhausted, unable to move themselves.

Avoiding suspension trauma

Because suspension trauma is caused by immobility, it is essential that your employee keeps moving if they ever get trapped in a harness or similar. Usually suspension trauma sets in after 20 minutes of free hanging, but in some individuals, they may run into problems in a far shorter time frame.

It is important then that even healthy employees working suspended in harnesses also keep moving or they too could run into difficulties.

The best way to avoid suspension trauma is to train staff carefully to deal with working in such condition in advance. Things to consider are:

  • Ensuring that the employee keeps moving regularly to maintain healthy circulation.
  • In the event of a problem, that they are able to call for help.
  • That the suspended worker is never left unattended, and that their colleagues are able to look for signs of potential problems such as nausea, numbness of the legs and burred vision.

Ideally, anyone trapped in a hanging position should have their legs raised so that they are moved into a seated pose to reduce circulatory problems, while they wait to be rescued. If that is not possible, the trapped person needs to keep their legs moving by pushing off a nearby wall or ‘pedalling’ in the air.  It is extremely important that they do not get exhausted or they may accelerate onset of suspension trauma.

All of your staff involved in projects working at heights should also be trained in single rope rescue techniques. The trapped worker needs to be retrieved as soon as possible to avoid the onset of suspension trauma, and with proper training your team should be able to help each other in such a situation. You also need to factor suspension trauma into your health and safety risk assessment for working at height projects.

Now it’s your turn,

Have you ever heard of suspension trauma? Is it something you consider when commissioning work at height? Please comment below.


David Cant is a Chartered Safety and Health Practitioner extraordinaire. He has a wealth of Industry experience and is the MD of Veritas Consulting. David also Blogs about Health and Safety here Health and Safety Consultants

His aim is to flavour Health and Safety with integrity, served with a side of humour You can find David on - Twitter and Google also Linkedin

This post has been filed in: Construction Health and Safety

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