A direct relationship is noted between the level of cord injury and the degree of respiratory dysfunction, as follows:
With high lesions (ie, C1 or C2), vital capacity is only 5%-10% of normal, and cough is absent.
With lesions at C3 through C6, vital capacity is 20% of normal, and cough is weak and ineffective.
With high thoracic cord injuries (ie, T2 through T4), vital capacity is 30%-50% of normal, and cough is weak.
With lower cord injuries, respiratory function improves.
With injuries at T11, respiratory dysfunction is minimal; vital capacity is essentially normal, and cough is strong.
Other findings of respiratory dysfunction include:
Agitation, anxiety, or restlessness
Poor chest wall expansion
Decreased air entry
Increased heart rate
Paradoxical movement of the chest wall
Increased accessory muscle use
Hemorrhagic shock may be difficult to diagnose because the clinical findings may be affected by autonomic dysfunction. Disruption of autonomic pathways prevents tachycardia and peripheral vasoconstriction that normally characterizes hemorrhagic shock. This vital sign confusion may falsely reassure. In addition, occult internal injuries with associated hemorrhage may be missed.
The following are clinical "pearls" useful in distinguishing hemorrhagic shock from neurogenic shock:
Neurogenic shock occurs only in the presence of acute spinal cord injury above T6; hypotension and/or shock with acute spinal cord injury at or below T6 is caused by hemorrhage
Hypotension with a spinal fracture alone, without any neurologic deficit or apparent spinal cord injury, is invariably due to hemorrhage
Patients with a spinal cord injury above T6 may not have the classic physical findings associated with hemorrhage (eg, tachycardia, peripheral vasoconstriction); this vital sign confusion attributed to autonomic dysfunction is common in spinal cord injury
The presence of vital sign confusion in acute spinal cord injury and a high incidence of associated injuries requires a diligent search for occult sources of hemorrhage
For more on the presentation of spinal cord injuries, read here.
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Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.
Cite this: Richard H. Sinert. Fast Five Quiz: Test Your Knowledge of Common Summer Injuries - Medscape - Jun 26, 2017.