return. It is also important to avoid exter-nal pressure on the lower extremities that may
result from flexion of the knees while the patient is in bed.
Orthostatic Hypotension
For the first 2 weeks after SCI, the blood pressure tends to be unstable and quite low. It
gradually returns to preinjury levels, but periodic episodes of severe orthostatic
hypotension frequently interfere with efforts to mobilize the patient. Interruption in the
reflex arcs that normally produce vasoconstriction in the upright position, coupled with
vasodilation and pooling in abdominal and lower extremity vessels, can result in blood
pressure readings of 40 mm Hg systolic and 0 mm Hg diastolic. Orthostatic
hypotension is a particularly common problem for patients with lesions above T7. In
some patients with tetraplegia, even slight elevations of the head can result in dramatic
changes in blood pressure.
A number of techniques can be used to reduce the frequency of hypotensive episodes.
Close monitoring of vital signs before and during position changes is essential.
Vasopressor medication can be used to treat the profound vasodilation. Thigh-high
elastic compression stockings should be applied to improve venous return from the
lower extremities. Abdominal binders may also be used to encourage venous return and
provide diaphragmatic support when the patient is upright. Activity should be planned
in advance, and adequate time should be allowed for a slow progression of position
changes from recumbent to sitting and upright. Tilt tables frequently are helpful in
assisting patients to make this transition.
Autonomic Dysreflexia
Autonomic dysreflexia (autonomic hyperreflexia) is an acute emergency that occurs as
a result of exaggerated autonomic responses to stimuli that are harmless in normal
people. It occurs only after spinal shock has resolved. This syndrome is characterized
by a severe, pounding headache with paroxysmal hypertension, profuse diaphoresis
(most often of the forehead), nausea, nasal congestion, and bradycardia. It occurs
among patients with cord lesions above T6 (the sympathetic visceral outflow level)
after spinal shock has subsided. The sudden increase in blood pressure may cause a
rupture of one or more cerebral blood vessels or lead to increased ICP. A number of
stimuli may trigger this reflex: distended bladder (the most common cause); distention
or contraction of the visceral organs, especially the bowel (from constipation,
impaction); or stimulation of the skin (tactile, pain, thermal stimuli, pressure ulcer).
Because this is an emergency situation, the objectives are to remove the triggering
stimulus and to avoid the possibly serious complications.
The following measures are carried out:
The patient is placed immediately in a sitting position to lower blood pressure.
Rapid assessment is performed to identify and alleviate the cause.
The bladder is emptied immediately via a urinary catheter. If an indwelling
catheter is not patent, it is irrigated or replaced with another catheter.
The rectum is examined for a fecal mass. If one is present, a topical anesthetic is
inserted 10 to 15 minutes before the mass is removed, because visceral
distention or contraction can cause autonomic dysreflexia.
The skin is examined for any areas of pressure, irritation, or broken skin.
Any other stimulus that could be the triggering event, such as an object next to
the skin or a draft of cold air, must be removed.