Falling from height is still one of the most common causes of fatal accidents at work.

If you have the correct fall protection equipment at your disposal, and it has been serviced regularly, your employees will certainly be protected against the consequences of a possible fall. But after a fall, there is another danger that is sometimes overlooked: the harness suspension trauma. It's not common, but it's life-threatening for anyone who's been left suspended in the air.

We will go into more detail about the causes of harness suspension trauma, how to prevent and what to do after a victim has been rescued.

what is the harness suspension trauma?

Harness suspension trauma is the medical effect of being unable to move when in a vertical position. The official term is orthostatic intolerance.

The term is often used in discussions about fall protection. When someone is suspended vertically in the air after a fall, the leg straps of the harness exert pressure on the thighs.

This causes the blood vessels to be stretched, and consequently too much blood is accumulated in the legs. As a result, the rest of the body and brain are deprived of sufficient oxygen supply. The consequences can quickly become fatal if action is not taken quickly.

An important point to mention: immobility is the determining factor. Danger occurs only when someone does not move or forgets to move due to shock.

To fully understand what happens to your body when you are suspended in the air, we will use an ordinary situation as our starting point:

Your heart pumps blood to all your organs and body parts, including your legs. Meanwhile, gravity is also helping to keep the blood where it is. However, having the blood go only to your legs, is not what's wanted.

Moreover, your heart has one major disadvantage: it can only pump blood, not suck it back in.

So the blood has to return to your heart through the lungs. Luckily, we've developed a method that pumps the blood back up. This is done using the muscle pumps.

The blood vessels in your legs are between the muscles. When you move your legs, the muscles start to squeeze your blood vessels together, pumping the blood back up. Those blood vessels have valves that work in one direction only. With every movement or contraction of the muscles, the blood flows a little closer to the heart.

In the case of suspension trauma, there are three factors that disrupt your normal blood circulation:

1. Lack of movement
2. Constriction of the blood vessels
3. Accumulation of toxic substances

Lack of movement

If you don't move or can't move (because of the harness, fatigue or injury), then your muscles can't pump the blood back up. That's how you lose blood, as it were, and go into shock.

Making yourself move is a temporary solution, but over time fatigue will also strike.

Constriction of the blood vessels

Blood vessels are very flexible for various physical reasons. This allows them to shut off very quickly, causing more and more blood to accumulate in your legs.

As a result, your brain receives insufficient blood and oxygen, and after a few minutes you will faint.  At that point, your body says STOP, and you fall over. This fall is important, because it causes blood to flow back to the brain.

Accumulation of toxic substances

When your blood vessels shut down, litres of blood pile up. This reduces the availability of oxygen to supply the rest of your body.

As a result your organs and muscles produce harmful, toxic substances to survive.

If the toxicity becomes too high, this will eventually become fatal.

Symptoms

If your muscles stop pumping upwards, you'll lose blood. In the first phase, you will become dizzy, you will start to sweat, experience anxiety attacks and show general symptoms of shock. Your heart rate and breathing will gradually increase.

Eventually, so little blood is flowing to your brain that your heart rate and blood pressure suddenly drop rapidly. In no time at all, you lose consciousness. Your brain will suffer irreversible damage due to lack of oxygen.

If you can't respond quickly enough, the victim will be in danger of dying from blocked airways, too little blood or thrombosis.

Prevention

How to prevent harness suspension trauma? What do your employees need to know before they start working at height?

First and foremost, it is important that you have a good rescue plan and that your employees are well trained. It is often a matter of minutes and seconds, that are crucial, and can save a person’s life.

The rescue team must always be present and use the correct equipment. Working alone at height is not a good idea. It is very important to keep in touch with your team.

The next step is to choose a suitable harness. We prefer harnesses with integrated relief straps. These straps are used as a support for the victim to stay upright.

Investing in good equipment is very important here.

After the rescue

After you have rescued the victim, it's not over yet. There's still something else you need to take into account.

The blood that has accumulated in the legs is of poor quality. It is low in oxygen and saturated with CO₂. If you put the victim in a lying position, the poor quality blood will flow back to the brain all at once. This is what we call reflow syndrome.

To prevent this, keep the victim in a sitting position with the trunk upright and the legs bent at the knees (W-position). This allows a small amount of blood to go to the brain, and the greater part remains in the legs.

If the person is unconscious, keep them in an upright position, but make sure the airways are kept clear.

If you have to resuscitate, you will always need to stretch out the victim on the ground. Without a heartbeat, the blood will remain where it is. In any case, following a rescue, you must always call for professional help.

Conclusion

Suspension trauma is extremely complex. Both medically and practically. Even though it is rare, it is very important to include it in your risk and rescue plans, and to follow a preventive policy.

Irrespective of whether you're working at heights of 3, 10 or 100 metres, you must always encourage your colleagues to work safely at height.

Correct use of harnesses, belts, ropes and a rescue system, should all be part of your rescue plan.

Regular training and awareness is very important as well.

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Also read:

• Working at height and why the of hierarchy of controls is important (vdp.com)
• 6 idées de protection antichute permanente pour travailler en hauteur (vdp.com)
• Qu’est-ce qu’un système Davit et quand est-il requis ? (vdp.com)
• Comment choisir et s'attacher au bon point d’ancrage pour votre protection antichute ? (vdp.com)
• La protection antichute pour les débutants : 4 composants essentiels (vdp.com)