Suspension trauma , also known as harness hang syndrome (HHS), or orthostatic incompetence is an effect which occurs when the human body is held upright without any movement for a period of time. If the person is strapped into a harness or tied to an upright object they will eventually suffer the Central Ischaemic Response (commonly known as fainting). If one faints but remains vertical, one risks death due to one's brain not receiving the oxygen it requires. People at risk of suspension trauma include people using industrial harnesses (fall arrest

Fall arrest

Fall arrest is the form of fall protection which involves the safe stopping of a person already falling. It is one of several forms of fall protection, forms which also include fall guarding and fall restraint Fall arrest is the form of fall protection which involves the safe stopping of a person...

 systems, abseiling

Abseiling

Abseiling , rappelling in American English, is the controlled descent down a rock face using a rope; climbers use this technique when a cliff or slope is too steep and/or dangerous to descend without protection.- Slang terms :...

 systems, confined space

Confined space

Confined space is a term from labor-safety regulations that refers to an area whose enclosed conditions and limited access make it dangerous.- Description :...

 systems), people using harnesses for sporting purposes (caving

Caving

Caving—also occasionally known as spelunking in the United States and potholing in the United Kingdom—is the recreational pastime of exploring wild cave systems...

, climbing

Climbing

Climbing is the activity of using one's hands and feet to ascend a steep object. It is done both for recreation and professionally, as part of activities such as maintenance of a structure, or military operations.Climbing activities include:* Bouldering: Ascending boulders or small...

, parachuting

Parachuting

Parachuting, also known as skydiving, is the action of exiting an aircraft and returning to earth with the aid of a parachute. It may or may not involve a certain amount of free-fall, a time during which the parachute has not been deployed and the body gradually accelerates to terminal...

, etc), stunt

Stunt

A stunt is an unusual and difficult physical feat, or any act requiring a special skill, performed for artistic purposes in TV, theatre, or cinema...

 performers, circus performers, and so on.

In a 2006 article on the Crucifixion of Jesus

Crucifixion of Jesus

The crucifixion of Jesus and his ensuing death is an event that occurred during the 1st century AD. Jesus, who Christians believe is the Son of God as well as the Messiah, was arrested, tried, and sentenced by Pontius Pilate to be scourged, and finally executed on a cross...

, Phillip Bishop and physiologist Brian Church suggest that suspension trauma is a cause of death in crucifixion

Crucifixion

Crucifixion is an ancient method of painful execution in which the condemned person is tied or nailed to a large wooden cross and left to hang until dead...

.

Prevention

Prevention of suspension trauma is preferable to dealing with its consequences. Specific recommendations for individuals doing technical ropework are to avoid exhausting themselves so much that they end up without the energy to keep moving, and making sure everyone in a group is trained in single rope rescue techniques, especially the single rope pickoff, a rather difficult technical maneuver that must be practiced frequently for smooth performance. If someone is stranded in a harness, but is not unconscious or injured, and has something to kick against or stand on (such as a rock ledge or caving leg-loops) it is helpful for them to use their leg muscles by pushing against it every so often, to keep the blood pumping back to the torso. If the person is stranded in mid-air or is exhausted, then keeping the legs moving can be both beneficial and rather dangerous. On the one hand, exercising the leg muscles will keep the blood returning to the torso, but on the other hand, as the movements become weaker the leg muscles will continue to demand blood yet they will become much less effective at returning it to the body, and the moment the victim ceases moving their legs, the blood will immediately start to pool. "Pedaling an imaginary bicycle" should only be used as a last-ditch effort to prolong consciousness, because as soon as the "pedaling" stops, fainting will shortly follow. If it is impossible to rescue someone immediately, then it is necessary to raise their legs to a sitting position, which can be done with a loop of rigging tape behind the knees or specialized equipment from a rescue kit.

When rescuing a victim it is paramount to let the blood flow to the brain and heart. A suspended victim is more likely to be injured by not raising their legs when rescuing. No change in ABC management should be undertaken based on the above theoretical risk of suspension trauma. The British Health and Safety Executive (HSE) has done an extensive review of this topic 2009 which contradicts its earlier statement 2002.

See also

• reflow syndrome
  Reflow syndrome
  Reflow Syndrome is a potentially fatal condition that can occur after blood pools in a part of the body for a prolonged period, such as during suspension trauma...
  
  , which occurs when toxins that accumulated in pooled blood suddenly return to the body when the patient lies down following suspension trauma
• compartment syndrome
  Compartment syndrome
  Compartment syndrome is a limb threatening and life threatening condition, defined as the compression of nerves, blood vessels, and muscle inside a closed space within the body . This leads to tissue death from lack of oxygenation due to the blood vessels being compressed by the raised pressure...
  
  , a dangerous condition that sometimes occurs with suspension trauma
• Orthostatic intolerance
  Orthostatic intolerance
  Orthostatic intolerance is a subcategory of dysautonomia, a disorder of the autonomic nervous system occurring when an individual stands up....
  
  

External links

Suspension Trauma Article on the Prevention and Treatment of Suspension Trauma

Harness suspension: review and evaluation of existing information

Harness Hang Syndrome: Fact and Fiction