| There are wide ranges of situations requiring a | | | | The heart can only pump the blood available, so |
| safety harnesses in work and play. What is little | | | | the heart's output begins to fall. The heart speeds |
| known however is that these harnesses can also | | | | up to maintain sufficient blood flow to the brain, |
| kill. | | | | but if the blood supply to the heart is restricted |
| Harnesses can become deadly whenever a | | | | enough, beating faster is ineffective, and the body |
| worker is suspended for durations over five | | | | abruptly slows the heart. |
| minutes in an upright posture. It is called | | | | In most instances this solves the problem by |
| suspension trauma. This can occur in many | | | | causing the worker to faint. |
| different situations in industry. A carpenter | | | | After fainting and slumping, blood can now be |
| working alone is caught in mid-fall by his safety | | | | returned to the heart and the person typically |
| harness, only to die 15 minutes later from this | | | | recovers quickly. In a harness, however, the |
| suspension trauma. Another example is a worker | | | | person can't fall into a horizontal posture, so the |
| being lowered into a shaft. After five minutes he | | | | reduced heart rate causes the brain's blood supply |
| will be unconscious and in 15 minutes later a dead | | | | to fall below the critical level. |
| body will be hauled out. Fall protection researchers | | | | Orthostatic incompetence doesn't occur often |
| have recognized this phenomenon for decades. | | | | because it requires that the legs remain relaxed, |
| Most users of fall protection equipment, rescue | | | | straight, and below heart level. If the leg muscles |
| personnel, and safety and health professionals | | | | are contracting in order to maintain balance and |
| remain unaware of the hazard. | | | | support the body, the muscles press against the |
| Suspension trauma death is caused by orthostatic | | | | leg veins allowing for normal blood flow. In |
| incompetence; it can occur any time a person is | | | | suspension trauma, several unfortunate things |
| required to stand quietly for prolonged periods and | | | | occur that aggravate the problem. First, the |
| may be worsened by heat and dehydration. It is | | | | worker is suspended in an upright posture with |
| most commonly encountered in military parades | | | | legs dangling. Second, the safety harness straps |
| where soldiers must stand at attention for | | | | exert pressure on leg veins, compressing them |
| prolonged periods. Supervisors can prevent it by | | | | and reducing blood flow back to the heart. Third, |
| training soldiers to keep their knees slightly bent | | | | the harness keeps the worker in an upright |
| and not locked. | | | | position, regardless of loss of consciousness, |
| How orthostatic incompetence occurs is that the | | | | which is what kills workers. |
| legs are immobile with a worker in an upright | | | | A planned rescue policy will need to be |
| posture. Gravity pulls blood into the lower legs, | | | | implemented for people requiring to wear fall |
| which have a very large storage capacity. Enough | | | | arrest harnesses. The equipment used to save |
| blood eventually accumulates so that return blood | | | | the life from a fall can also be the danger that |
| flow to the right chamber of the heart is reduced. | | | | can kill them. |