December 27, 2014

suspension trauma in occupational medicine

 

 

 

Suspension trauma
Suspension trauma is the term used to describe the condition which occurs after a person is trapped in an upright position and is unable to move. There is a risk for late phase damage of the muscle (rhabdomyolysis) kidney damage, and sudden death. Most of the late phase problems are the result of a lack of blood flow and perfusion to the brain, kidney and muscles, This locker perfusion is a result of the blood not being able to recirculate because it is trapped in the workers legs, along with toxicity from waste products that may develop within the limbs are dependent. Deaths have been reported after successful rescue as a consequence of these problems. There are various synonyms for this including orthostatic intolerance ( the term preferred by OSHA), harness pathology, and harness hang syndrome. Since the harness is not the cause of this pathology, the term suspension trauma is preferred. Workers must be trained on fall arrest systems and personal protective equipment while performing their jobs, along with how to ascertain whether this equipment is properly fitted ( standard 29 cfr and 1910.132) [1 ]. This training is beyond the medical scope of this document. OSHA requires that workers know:

1. how suspension trauma may occur,
2. factors that may increase a workers risk,
3. how to recognize signs and symptoms,
4. appropriate rescue procedures and methods for suspension

This document will focus on these objectives.

prevention

Employees should carry out suspension tests in a safe place to ensure that the harness fits, and can be adjusted adequately. The workplace environment should be engineered so that there is not a serious risk of suspension trauma. A well thought out and practiced rescue plan should be in place, and appropriate rescue supplies should be on hand. [13,14]. Employees should never be allowed to work at heights alone [15].

 

 

 

 

The causes of suspension trauma

Normally, blood is pumped from the heart through the arteries and returns back through the veins. Gravity helps to pull blood into the lower extremities through the arteries. Muscle contractions in the legs force the blood back towards the heart through the veins. In suspension trauma leg movement and blood flow from the legs can be restricted, and straps may also compress veins. All this reduces blood flow out of the legs and back to the heart. The blood can pool into the legs, resulting in decreasing central volume, enlarging leg size, decreasing heart size, and decreasing kidney blood flow [20] The heart does not have blood to utilize, and it does not pump properly, consequently the brain and other vital organs such as the kidneys become deprived of blood and oxygen. This can result in the loss of consciousness and kidney damage and even death. [2, 10,15]

Factors that may increase risk for suspension trauma [2,10]

1. Inability to move the legs
2. the degree of inclination of the body
3. Comorbid injuries received during the fall, especially head trauma or blood loss
4. Dehydration
5. Hypothermia
6. pre-existing heart disease, respiratory disease, or kidney disease
7. pain (produces vasovagal syncope)
8. fatigue
9. shock
10. unconsciousness

Recognize signs and symptoms of suspension trauma

In suspension trauma, there is a lack of circulation, and the body attempts to overcome this by increasing heart, and respiratory rate. Blood is also shunted from the skin surface to the heart in order to provide more oxygen to the brain and kidney, which causes sweating and cold pale skin.

In the first stages of suspension trauma these physiologic factors result in several symptoms: [2,10]

1. Fast breathing
2. breathlessness
3. Excessive perspiration
4. Increased heart rate and blood pressure
5. Nausea
6. Pale and cold skin
7. Hot flashes
8. Dizziness,
9. faintness

As the disease progresses, there is insufficient blood flow causing the heart rate to slow, and the blood pressure to be decreased, this “shock like response” results in these symptoms:

1. Low heart rate
2. Low blood pressure
3. Decreasing ability to see.

Once this process worsens further, the kidney and the brain are affected and unconsciousness can result as well as renal failure. A big risk here is that the tongue can obstructive the airway. Leaving an unconscious person suspended can lead to death in less than 10 minutes [16], thus once a victim is unconscious they must be rescued as soon as is feasible. Causes of unconsciousness include: [10]

1. Venous pooling
2. vasovagal effect ( 10th cranial nerve stimulation)
3. “Steal” of blood from the brain to the peripheries
4. Low blood sugar
5. Low blood oxygen level
6. Low blood carbon dioxide level.
Appropriate rescue procedures for suspension trauma
Continuous monitoring of the suspended worker while suspended and after rescued is essential, standard trauma resuscitation should be the cornerstone of treatment, with attention towards airway passages (especially if the workers unconscious) being primary. The worker must be evaluated in the hospital to be sure that delayed effects such as kidney failure, and muscle damage ( rhabdomyolysis) have not occurred. [1]

The duration of suspension necessary to produce shock can be as little as three minutes, though the average time is 5 — 20 minutes. Unconsciousness occurs quickly after shock.

Rescue should take place as promptly as possible. First responders should be trained in rescue techniques, and workers should be required to wear fall arrest harnesses when at a height.

rescue

self rescue
The fall the victim should rescue themselves if possible, assistance should be provided if practical during the self rescue. Plans to rescue suspended workers must be created and practice. If rescue equipment is to be used, training with this equipment should be mandatory, and suitable performance and loading characteristics for all equipment should be ensured [10].

assisted rescue

“It is usually quicker and safer to lower casualty to the ground, but sometimes there is no alternative but to rescuing upward.” [10]

If self rescue is not possible, and the employee remains suspended, the victims should engage in several methods to try to prevent venous pooling. [2,10]

Move the joints of the lower extremities as much as possible [2,10,13]
Lift and keep the knees above the hips [12] If rescue must be delayed, straps, or ropes, or other improvised materials can assist this technique.
Move the legs when possible, pushing with the feet against a firm surface at regular intervals.
If your harness will not allow lifting of the knees, the trapped worker should attempt to move their legs and push against the solid surface with the legs. This will also cause blood return to the heart. As a last resort, a cycling motion can be employed. This method is dangerous, it is much better to keep the knees above the hips if this is practical.
If rescue is delayed, footholds should be provided, this can be done by dropping a separate rescue line for the victim with a step on it [10,16]

After the rescue from suspension trauma:
Because the blood has remained in the legs , oxygen and nutrients have been consumed and waste products have been produced and now remain in the lower extremities. Because of the lack of blood flow, toxins have not been removed and can fairly high levels. In addition, the pH of the blood may be low. For this reason, most experts recommend against allowing the blood from the legs to rapidly reflow back into the circulatory system, as this can damage the heart, kidneys, or brain. For this reason it is not a good idea to allow the victim to quickly lie flat on the floor.

Conscious victim from suspension trauma:
The first goal of rescue is to make sure of the “ABCs”. Thus, the first task of the first responder is to be certain that there is a good airway, that there is breathing, and that there is a pulse. If any of these are compromised, an immediate appropriate life-support measures should take precedent over all else. The second goal should be to assure that there is no neck trauma, If the injured worker has “snapped” their neck, a cervical collar should be placed immediately. Once this has been accomplished, evaluate the victim. The injured employee should be moved into a sitting or “huddled” position. This position should be maintained for 20 — 40 minutes [2,10]. Numbness in the legs is a normal sensation until the body has removed toxins from the lower extremities, but if the victim has high magnitude of leg pain, especially if this pain is present when the victim is moved, than a leg fracture or compartment syndrome must be considered. This is an urgent problem, the injured worker should be transferred as quickly as possible to an emergency room if a fracture or compartment syndrome is suspected, and the emergency room should be notified of the possibility of this condition as well as being notified of the suspension trauma.
A treasonable paradigm for first responder treatment would be: [7, 10,13,15, 16,18,19]

1. Removes the victim from the harness as quickly as possible
2. Be sure the scene is safe
3. Assure the ABCs, if appropriate, immediately began CPR and call 911
4. If ABCs are assured, move the victim into the “huddle” position as described above. Do not lye the victim down, the body should be raised above the legs
5. Apply a cervical collar if there is any question of neck injury
6. All restrictive belts and clothing should be unfastened.
7. Keep the victim warm
8. Assessed the victim for further injuries
9. Continuously monitor the victim for stability, ABCs, and the development of shock or dehydration
10. Protect the victim from the environment
11. Supply oxygen if available
12. Do not feed the victim or give them water
13. Transport to an emergency room for further assessment and possible treatment
Do not allow the victim to stand or exercise as they may feel dizzy and fall. Do not allow the victim to eat or drink, as they could aspirate

Unconscious victim from suspension trauma:
Call 911.
Vital signs should be monitored, be sure that the airway is clear, and that the victim is breathing. If the worker is not breathing, the mouth should be opened if possible to be sure that the tongue is not occluding the airway, if it is the tongue should be immediately moved out of the airway. Should the victim not be breathing, basic or advanced life-support measures should be immediately instituted, and appropriate CPR takes precedence over any concern for reflow syndrome. If the victim is breathing and cardiac function is assured, try not to allow the victim to lie flat. Try to assess whether the unconsciousness is due to suspension trauma, or whether it may be due to some other condition, such as electrocution or cerebral trauma. If an etiology other than suspension trauma is suspected to be the cause of the unconsciousness, it may be preferable to allow the victim to lie flat.

Hospitalization after suspension trauma:
Victims of suspension trauma should be sent to the emergency room. Such workers will need to have their kidney, blood chemistry evaluated, and they may need to have intravenous fluids, a cardiac evaluation, and even dialysis. The emergency room Dr. must be reminded to check for rhabdomyolysis and renal failure. Even in the case of a lack of noticeable injury, these secondary problems can occur, and the emergency room should be reminded of these possibilities. A conscious victim can be transported by car if they are stable [2], otherwise an ambulance should be called, and the crew should be advised of the nature of the injury, and of the need to keep the victim remain “huddled” for a total of 30 minutes after being released from suspension. [2].

references for suspension injury by Bradley H. Kline, D.O.

http://www.osha.com/

1: OSHA click takes suspension trauma/orthostatic intolerance
2:WSH Council, information on recognizing, preventing and treating suspension trauma.
3:Turner NL, Wasell Jt suspension tolerance and a full body safety harness, and a prototype harness accessory, journal occupational environmental hygiene, 2008: 5;227 — 231
4:Stuhlinger W. circulation and renal function changes in test subjects suspended from the upper half of the body. Paper presented at: second international conference of mountain rescue doctors, November 18, 1972: Innsbruck Austria
5:Bernard Haselbach. radiological, blood chemistry, and lung function findings and the hanging test. Paper presented at second international conference of mountain rescue doctors: November 18, 1972, Innsbruck Austria
6:Shamsuzzaman ASM. head of suspension in humans: effects on sympathetic vasomotor activity and cardiovascular responses. Journal of applied physiology. 1998; 84: 1513 — 1519
7:Risk and management of prolonged suspension in an alpine harness, Roger B Mortimer MD, Department of family practice medicine, ucsf – Fresno medical education program, University of California at San Francisco, Fresno, California.
8:Flora G. holzl Hr.fatal and nonfatal accidents involving falls onto the road. Paper presented at the second international conference of non-rescue doctors German to English translation, November 18, 1972: Innsbruck, Austria
9: Bosch X,. rhabdomyolysis and acute kidney injury. New England Journal of Medicine. 2009: 361: 62 — 77
10:Seddon P. harness suspension: review and evaluation of existing information. Colgate, Norwhich: health and safety executive; 2002
11: Thomassen ), Skaiaa et al.does the horizontal position increased risk of rescue death following suspension trauma? Emergency medicine Journal 2009: 26: 896 two 898
12:M isadsen P, et al. tolerance to head — up tilt and suspension with elevated legs. Aviat space environmental medicine. 1998: 69: 781 — 784
13:British standard bs 7985;2002, code of practice for the use of rope access methods for industrial purposes
Annex D., suspension trauma
British standards institution, 389 Chiswick High Rd., London 24 4al, England
14:international standard iso 10333 — one: 2000+adm 1: 2002 personal fall — arrest systems — part one: full body harnesses.
International standards organization, Geneva, Switzerland
15:Sheehan A
suspension trauma ( 2000)

 

By accepting this information you understand and agree that my entire responsibility in this matter is to give you medical information and or opinion. Any information in this post (blog) and its attachments is provided with the understanding, that unless indicated otherwise, it is for informational purposes only and is not intended as legal, medical, or other professional advice.

 

 

www.techrescue.org/firstaid/suspension.pdf
www.techrescue.org/firstaid/suspension.pdf
16,17:Petermyer M
Das hangertrauma
(suspension trauma) 1997
German to English translation by hse language services. Translation number 16 367 (a)
Der Notarzt ( January 1997)
Georg Thieme Verlag, Stuttgart, Germany
18:Lieblich M , rescuing people who have fallen and first aid following suspension and a safety harness ( 1997) German to English translation by hse language services AsvorOrt ( magazine) January 1997 (p12)
19:Various
falls onto the rope: school injuries in alpine regions ( 1972)
papers of the second international conference on mountain rescue doctors ( Austria) 1972, German to English translation by hse language services translation number 16 372(I)
20:Toledoy Ugarte J-D. death from orthostatic shock caused by hanging from the rope. Papers presented at the second international conference on mountain rescue doctors, German to English translation by hse language services translation number 1637 two (1), November 18, 1972 Innsbruck, Austria

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