Industrial fall safety harnesses are a crucial measure to take when protecting workers from drops and the impact injuries that can result. But prolonged suspension can also lead to suspension trauma, also known as “orthostatic shock while suspended,” orthostatic intolerance, harness induced pathology, or harness hang syndrome (HHS). While suspension trauma is a rare occurrence, employers and safety managers should be aware of this potentially serious condition, as well as tips on how to avoid it.
Harness hang syndrome occurs when the human body is held upright without any movement. Such a situation may occur when, for instance, a worker using a fall arrest system drops and remains immobile in the harness, suspended in the air. Suspension trauma is primarily caused by venous pooling, or the accumulation of too much blood in the veins. As a result of immobility and gravity, blood begins to pool in the legs. Additionally, the pressure on the leg veins from the safety harness can compress the veins, further reducing blood flow to the heart. When the circulation is thus significantly impeded, the heart rate slows and the flow of oxygen to the brain is reduced.
Eventually, the suspended worker will suffer a central ischaemic response, commonly known as fainting. Normally, fainting is the body’s way of re-positioning itself so that the head, heart, and legs are at the same level, and normal blood and oxygen flow is resumed. However, in a suspension situation, the harness prevents the worker from collapsing into a horizontal position. As a result, the faint fails to restore normal blood flow, and the brain and other major organs remain oxygen deprived. Serious health and safety problems can result. In fact, suspension trauma can become fatal in less than 30 minutes.
All those who work at heights, or in any situation where harness hand syndrome is a possibility, should be well prepared. Employees should be trained to recognize the warning signs of suspension trauma, which include faintness, dizziness, breathlessness, paleness, sweating, hot flashes, nausea, “greying” or loss of vision, and unusually low or unusually high heart rate. Also, workers should be aware of the factors that affect their susceptibility to the syndrome, which include general health and hydration level. Your team can preemptively avoid suspension trauma by training in fall prevention and safety. Most importantly, an effective rescue plan should be set up and rehearsed so that it can be put into action in a timely manner when a drop occurs.
Even with a comprehensive rescue plan firmly in place, crew members should be prepared with additional safety measures. The fall victim should be continually monitored and instructed to pump the legs frequently in order to increase blood flow and prevent pooling while awaiting rescue. An even more effective method is to use suspension trauma safety straps. These sturdy accessories provide hanging workers with footholds that allow them to simulate standing on solid ground. Standing slows the progression of harness hang syndrome by causing the leg muscles to contract, putting pressure on the veins, which helps blood flow to the heart and reduces blood pooling in the legs. Once the suspended worker is rescued, he or she should be immediately examined by a medical professional and continuously monitored for delayed internal effects, such as kidney failure. If unconscious, the worker should be resuscitated according to the standard procedure.
These simple preparedness steps and tips should be sufficient to prevent harness hang syndrome. A little background knowledge and some practice with suspension trauma relief straps could save lives.