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Medical
Soon after a spinal cord injury a patient may develop “neurogenic
shock,” which includes significantly low blood pressure (hypotension),
significantly low heart rate (bradycardia) and significantly low
temperature (hypothermia). Independent of whether neurogenic shock
occurs, the patient develops “spinal shock” after a spinal cord injury
which may last days to weeks. Spinal shock is a condition that involves
the lack of tone or contraction of the muscles below the level of
injury, loss of tendon reflexes, and possibly neurogenic shock.
The first week or two after a spinal cord injury is referred to as the
“acute” time. There are conditions that occur during that time that
require special attention and treatment. Below are some of the issues
that occur during this acute time frame and possible interventions that
may take place.
Neurogenic shock
As mentioned above, this can include hypotension, bradycardia, and
hypothermia. Hypotension most often occurs in individuals with spinal
cord injuries from C1 to T6, which includes tetraplegics and mid to high
paraplegics. This is thought to occur because of a significant loss of
the sympathetic nervous system effect on the blood vessels and heart.
Normally the sympathetic nervous system would stimulate the blood
vessels to contract and maintain a normal blood pressure. After a spinal
cord injury at the T6 or above, the absent or limited sympathetic
nervous system input to the blood vessels leads to blood vessel dilation
(vasodilation).
This vasodilation leads to a drop in blood pressure to
potentially dangerous levels. Treatment may include intravenous fluids
and medications called “vasopressors,” which cause contraction of blood
vessels and increase heart rate. Both conditions will lead to an
increase in blood pressure. The heart has nerve supply from both the
sympathetic nervous system and the parasympathetic nervous system. After
spinal cord injury at T6 and above, the sympathetic nervous system input
to the heart is decreased while the parasympathetic nervous system
remains the same. Therefore, the net effect is a slowed heart rate with
less strength of contraction. This combination contributes to
hypotension and bradycardia. Again, vasopressors are used to directly
increase heart rate and strength of contraction of the heart during this
acute time.
Deep Vein Thrombosis (DVT)
Deep vein thrombosis is the development of a blood clot in the legs and,
less often, in the arms. Patients who have suffered a spinal cord injury
are at high risk for developing a DVT. This can be a serious
complication if it breaks off from the leg and travels to the heart and
eventually to the lungs. If this blood clot travels to the lungs it is
called a pulmonary embolism or PE, which can be life-threatening.
Therefore, a significant amount of attention is directed at preventing
either of these conditions during the first two months after a spinal
cord injury. Even with all precautions being taken, these blood clots
can still develop. Signs of a DVT may include swelling or redness in the
leg. If the patient has any intact feeling in the leg he may experience
increased pain in that area. It is possible, however, to develop a DVT
without any signs of swelling, redness or pain.
Prevention or prophylaxis includes the early use of sequential
compression devices (SCD), which are leg-wraps connected to an air pump
that inflates and deflates continuously, keeping blood moving and a clot
from forming. Lovenox is started as soon as the surgeon feels the risk
of bleeding from the surgical site is lower than the risk of developing
a DVT without Lovenox. Once this has started it is usually continued for
8-12 weeks or until leaving rehabilitation depending on several factors.
Some individuals considered to be at high risk for developing a DVT may
have an Inferior Vena Cava (IVC) filter placed. This filter is placed in
a blood vessel that leads to the heart, called the inferior vena cava.
Its role is to catch any blood clots that may have developed in the legs
and broken off and are now traveling to the heart on their way to the
lungs.
If a blood clot does develop in the legs or lungs, a decision has to be
made that weighs the risk of treating with more potent blood thinners
called anticoagulants. The current mainstay of treatment after the
development of a blood clot is the use of warfarin (Coumadin). Treatment
of the clot will possibly put the surgical site at risk for bleeding,
but not treating is another obvious risk.
Orthostatic Hypotension
Orthostatic hypotension is a significant drop in blood pressure when
someone goes from the lying position to a more upright position such as
sitting or standing. The condition of orthostatic hypotension is caused
by blood pooling in the lower extremities and a decrease in blood flow
to the brain with a subsequent dizziness or passing out. This is a very
common early complication of spinal cord injury that almost always
resolves over time, but often interferes with the early phases of the
rehabilitative process. This can occur for several reasons after a
spinal cord injury. A commonly described cause after spinal cord injury
is the interference with the normal processes of the sympathetic nervous
system as it relates to the blood vessels. When a person without a
spinal cord injury changes from lying down to standing up, the blood
attempts to pool in the legs. This condition is detected by the heart
and arteries in the neck (carotid arteries) which then causes an
increase in the sympathetic nervous system to the blood vessels in the
legs. This causes a contraction of the blood vessels, preventing this
pooling of blood in the legs and eliminating dizziness and passing out.
It is important to note that the normal range of blood pressure in
tetraplegia and high level paraplegia (T6 and above) is often much lower
then prior to spinal cord injury. It is not uncommon for a normal
systolic blood pressure (that’s the top number, 120 in the reading
120/70) after spinal cord injury to range from 90-110. For example,
95/55 is not an unexpected blood pressure for a C6 tetraplegic.
Relative dehydration or an inadequate fluid intake can also lead to
orthostatic hypotension or further complicate the above described
condition. Therefore, it is important to make sure that the patient is
receiving enough fluids.
The best way to think about this condition of orthostatic hypotension is
to think about all the blood vessels in the body as a tank and the blood
in the vessels as the fluid in the tank. If the person with a spinal
cord injury goes from lying down to sitting up with the legs down, the
fluid in the tank pools in the legs. Since the fluid (blood) in the tank
remains the same amount, then there will not be enough fluid to reach
the brain and dizziness or fainting occurs. Also, if the tank remains
the same but there is only half the fluid (blood) in the tank, the fluid
will not reach the brain when moving to an upright position.
Treatment often includes a combination of many interventions. It often
begins with making sure that the patient has been getting plenty of
fluids either by drinking or by intravenous fluids. As mentioned above,
the patient's tank must be filled or all other treatment measures will
have limited success. The first step in treatment involves gradually
increasing the patient's position to upright. This can often start in
the intensive care unit. Today many of the hospital beds can transition
to a seated position by lowering the legs and raising the head of the
bed. Another option in the intensive care unit or on the rehabilitation
unit is a tilt-table. This is a long straight padded table that has
multiple straps that go across the chest, waist, and legs. Before the
patient sits upright or is placed on a tilt-table they have elastic
stockings put on the legs and an abdominal binder wrapped around the
torso. The elastic stockings and abdominal binder help to prevent blood
from pooling when upright. There are also medications that can help to
assist maintaining blood pressure, including salt tablets,
fludrocortisone and midodrine. All of these medications can cause
increased blood pressure when lying flat.
This condition of orthostatic hypotension usually lessens over the first
several weeks of rehabilitation but can continue in some circumstances.
Lungs and Breathing
Normal breathing (before a spinal cord injury):
Inspiration is the process of taking in a breath, while expiration is
the process of breathing the air out.
Inspiration involves three groups of muscles: the diaphragm (the most
important muscle involved with inspiration), the intercostals (the
muscles between the ribs), and the accessory muscles (muscles of the
neck, upper back and chest).
Expiration mostly occurs passively (the chest that has expanded during
inspiration gradually falls back to the starting point before
inspiration), but forceful expiration involves the use of abdominal
muscles. For example, a cough is a forceful expiration and requires
contraction of the abdominal muscles.
The diaphragm is supplied by nerves that come from the spinal cord at
the levels C3, C4, and C5. The external intercostal muscles are supplied
by nerves T1 through T11. For example, the T1 nerve supplies the
intercostal muscles between the ribs T1 and T2. The T10 nerve supplies
the intercostal muscles between the ribs T10 and T11. Some of the
accessory muscles such as the trapezius are supplied by cranial nerves
that come from the brainstem. The abdominal muscles are supplied by
nerves from T6 through L1.
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Nerve Supply of Muscle Involved in Breathing:
Muscles Nerve Supply
Inspiration
Diaphragm C3, C4, C5
External Intercostals T1-T11
Accessory:
Trapezius Cranial nerve 11 (brainstem)
Sternocleidomastoid Cranial nerve 11 (brainstem)
Pectoralis C5-T1
Scalene C3-C8
Expiration
Abdominal T6-T11
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Changes in
Breathing (after spinal cord injury)
Individuals who have suffered a spinal cord injury may have changes
in their ability to breathe depending on the area of their spinal cord
that is injured. Whether or not breathing is affected depends upon
whether the nerves that supply these respiratory muscles are intact and
functioning.
When considering the nerves and muscles mentioned above, take the level
of injury and compare it to the nerve levels that go to the particular
muscle to see if it works. All muscles below the injury should either
not work or work to a limited degree if incomplete. For example, an
injury at C5 would mean that muscles supplied by C6 and below will not
work.
Damage to the spinal cord at the L1 level or below will not have any
effect upon their ability to breathe. Injuries from T6 to T12 may lead
to weak abdominal muscles and intercostal muscles, which will limit the
ability to make a strong forceful cough. The lower levels will not
notice much difficulty, but this will become more of a noticeable
problem as the injury becomes higher towards the T6 level. This becomes
an even bigger problem from the C5 to T5 levels. Patients with spinal
cord injury at C3 and C4 usually require ventilator support initially,
but studies (Wicks and Menter) reported that 51% of C3 and 78% of C4
patients were able to be weaned off of the ventilator.
Early Respiratory
Complications (after spinal cord injury)
Atelectasis: this is the condition where the lower part of the lungs
are collapsed and without air or air exchange with the blood. After a
spinal cord injury this often occurs because the patient has weak
breathing and is unable to take deep breaths and expand these areas of
the lungs. The lung is made up of alveoli which look like a collection
of grapes. There are about 700 million alveoli in the lungs. These
alveoli are surrounded by small blood vessels called capillaries. As a
person takes a breath, air enters the alveoli and then travels into the
blood vessel capillary and supplies oxygen to the blood. Therefore, if
these alveoli are deflated or collapsed, air cannot enter the
bloodstream at this location. It is important for all acutely injured
patients who are not on a ventilator to take extra deep breaths
throughout the day. A simple device called an incentive spirometer can
be kept at the bedside and used to prevent atelectasis. Patients on
ventilators benefit from large volume settings to expand their alveoli.
These volume settings are often larger than those chosen for an
individual without a spinal cord injury. Studies have shown that higher
ventilator volumes in spinal cord injury help to prevent atelectasis,
pneumonia, and increase the ability to be weaned off the ventilator.
Pneumonia: this occurs for multiple reasons, but appears to be increased
because of atelectasis and a decreased forceful cough. The best way to
prevent pneumonia is to avoid atelectasis along with early mobilization
of the patient.
Aspiration: this is entry of foreign material into the lungs. This
foreign material is often saliva or liquid or food. In people with
normal strength this is quickly cleared by a strong cough. After spinal
cord injury this cough is often absent or weak and the material cannot
be brought back up before it travels down into the lungs causing
irritation of the lung or pneumonia.
Treatment and
Prevention
Rotating Beds: In the intensive care unit, beds that intermittently or
continuously turn from side to side may be used. The exact reason why
this works is not known.
Assisted Cough (Quad Cough): this is a technique to assist the cough of
patients with weak or no strength in the abdominal muscles. The assisted
cough is accomplished by another person placing his hands on the abdomen
between the “belly button” and the lower part of the sternum or rib
cage. With the patient lying flat, they take a deep breath in and
forcefully attempt to breathe out as if they were forcefully coughing.
The person assisting pushes slightly inward and upward during the time
that the patient is trying to cough or exhale. This does require some
practice but it can be very effective in clearing secretions during a
cough. This should not be used if an inferior vena cava filter is in
place, because it could dislodge with the increase in pressure.
Cough-Assist machine: this can be used in place of or in addition to a
suction catheter going down into the lungs. The cough-assist machine
does not go into the lungs but can fit over the mouth or tracheostomy if
present. This works by blowing air into the lungs first and then quickly
sucking the air out like a vacuum cleaner. The air going into the lungs
often acts to expand the lungs and can mobilize secretions in the lower
lungs. A study has been done that indicates patients prefer the cough
assist to suctioning out the lungs with a catheter. Some people use the
Assisted Cough with the Cough-Assist machine.
Abdominal binder: this device is similar to a corset but is softer and
secured with Velcro. This is useful in individuals with tetraplegia or
high level paraplegia because of the loss of abdominal muscle tone. With
loss of abdominal muscle tone the abdominal organs fall outward and
downward when sitting upright. This makes it more difficult to breathe
because the diaphragm normally travels down until it hits the abdominal
organs. Once the diaphragm contacts the abdominal organs it continues to
move, but the only structure that can give way is the rib cage which can
move outward. As the rib cage moves outward it creates a negative
pressure in the lungs causing air to enter the lungs from the mouth or
nose. An abdominal binder keeps the abdominal contents in a more normal
position and therefore helps to normalize breathing. The abdominal
binder can be taken off when the patient is in bed lying flat because
the abdominal organs remain in a position closer to normal. Because of
this change in abdominal organ position, it is easier for a tetraplegic
and high level paraplegic to breathe while lying flat compared to
sitting upright without an abdominal binder.
Bladder
Immediately after a spinal cord injury the patient is often in spinal
shock, and in this condition the bladder does not contract. It is
recommended that the patient have a Foley (indwelling) catheter placed
in the bladder to allow continuous drainage of urine. A catheter is a
small tube that is inserted into the bladder. A Foley catheter has a
small balloon on the end that is inflated once it is inside the bladder
to prevent it from sliding out.
It is
also important to maintain continuous drainage because emphasis is
placed on adequately hydrating the patient as described in the section
Orthostatic Hypotension. Later during rehabilitation, other methods to
drain the bladder are discussed.
Bowel
Immediately after spinal cord injury the patient is often in spinal
shock, and in this condition the bowel does not contract normally. This
often resolves within days, but it is often recommended not to feed the
patient until bowel sounds are heard by the physician. A “bowel program”
is often started in the intensive care unit. This usually starts with
stool softeners as well as medications that stimulate the bowel to
contract. Suppositories are started during this time as well, and may
include digital stimulation (see below for bowel program) if the patient
does not have sensation.
Stomach Ulcers
There is a possibility that patients who suffer an acute spinal cord
injury are at a higher risk of developing a stomach ulcer because of an
increase in stomach acid production related to stress. Patients are
routinely treated with medications that neutralize or lower the acid
content in the stomach and decrease that risk.
Skin
Individuals who lie in one position for a prolonged period of time are
at risk for developing skin breakdown and pressure ulcers (bedsores).
This is certainly the case for patients who become paralyzed and cannot
move or feel the need to move and shift weight. Therefore, it is
necessary to turn a patient every two hours. This often continues until
the patient is in rehabilitation and has demonstrated increased
tolerance to lying longer than two hours in one position. Tolerance is
determined by the lack of redness over the bony prominences. Once
tolerance is developing, the patient can be gradually allowed to remain
in the same position with frequent checking of his skin for redness.
Most patients still require being turned at the time of discharge from
rehabilitation. Special mattresses that decrease the amount of pressure
on bony prominences and decrease the risk of bedsores are generally used
in the intensive care setting.
Other injuries
The combination of a spinal cord injury with traumatic brain is not
uncommon, although the exact percentages vary. Considering that
possibility, an evaluation can be performed by a speech therapist
performing a traumatic brain injury screen.
Multiple areas of spinal fractures can occur in individuals who have
suffered a spinal cord injury. One study reported a 12% incidence of
fractures in addition to the identified fracture that caused the spinal
cord injury.
Another study reported that 64% of patients who had suffered a spinal
cord injury also had additional injuries somewhere else in their body.
Surgical
The goal and scope of this section is not to describe in detail the
surgical approach that should be taken for various spinal cord injuries,
but to give an overview. It should first be stated that the timing and
specific type of surgery remains a controversial topic among surgeons.
Timing of surgery
This remains a controversial topic regarding surgical intervention after
spinal cord injury. Some physicians recommend no surgery within the
first five days. Other surgeons recommend early intervention. A study
was done that compared outcomes between one group of patients who
underwent surgery within 72 hours (early group) to another group of
patients who underwent surgery on the fifth day or later (late group).
There was not a significant difference between the two groups, although
surgeons who support early intervention criticize this study because
they believe that “early” should be defined as “before 24 hours.”
More recently a study was performed comparing early to late surgical
intervention. “Early” surgical intervention was further subdivided into
day 1 (<24 hours), day 2 (1-48 hours), day 3 (24-72 hours). There were
no significant differences in length of stay or outcome. “Early” (taken
as a group) compared to “late” surgical intervention did show a decrease
in overall length of stay and lung (pulmonary) complications such as
pneumonia and atelectasis. It is agreed upon that individuals who are
demonstrating a decline in their neurological status (increased weakness
or decreased sensation) should not have their surgery delayed and should
immediately be taken to the operating room for decompression (removing
the pressure from the spinal cord) and stabilization (placement of bone
graft and hardware to prevent movement of the fractured bone).
Spine stability or instability
When deciding if surgery is needed, the first issue that must be
determined is whether or not the spine is stable. The cervical spine is
divided into two main categories when determining stability. The lower
part of the skull rests upon C1 and is referred to as “occipital.”
Therefore, the combination of the occipital with C1 and C2 creates the
occipital-atlantoaxial complex. The area of the cervical spine below
this is referred to as the subaxial cervical spine and includes C3
through C7.
Occipital-atlantoaxial complex: fractures of C1 (Atlas) are also called
Jefferson burst fractures. These are most commonly treated with a halo
vest. If the C1 fracture is unstable, then internal stabilization via
the back of the neck (posterior approach) is required. Fractures of C2
(Axis) can also be treated with a halo vest or internal stabilization,
depending on the location and degree of the fracture.
Subaxial cervical:
fractures of this area can include fractured vertebrae or soft tissue
injury such as a ligament tear. The location and degree of injury will
determine whether a non-surgical neck collar or surgery is used. The
most common fracture of the cervical spine is located at C5. Surgical
intervention in the subaxial cervical spine can occur either from the
front or from the back. Halo vests are often used in upper and mid
cervical spine fractures but are avoided in lower cervical spine
fractures because of “snaking.” Snaking describes the increased movement
or hypermobility of the cervical spine in the area between the fixed or
stabilized spine.
The stability of the thoracic and lumbar regions of the spine is often
determined by the three-column theory which was described by Denis in a
paper published in 1983. This describes the thoracic and lumbar regions
as the thoracolumbar spine and divides it into three columns. If two of
the three columns are damaged, then this area of the spine is determined
to be unstable and requires appropriate intervention.
Thoracolumbar spine: the most common area of injury to the thoracic
spine occurs at the T12 vertebra, probably because it is where the
stabilizing ribs end. From T1 to T12, ribs attached to the vertebrae
help to stabilize and protect the thoracic spine from excessive
movement. If the spine is unstable, then surgical stabilization is
required. In the upper thoracic spine, surgical intervention usually
takes place from the back because of the critical organs that make a
frontal approach difficult. In the lower thoracic spine, the surgical
approach can take place either from the front or back. A frontal
approach requires a thoracotomy (cutting through the front or side of
the chest) or entering through the abdominal region. The frontal
approach often uses screws and rods that may lead to a shorter segment
of stabilization.
In the lumbar spine the most common area of fracture occurs at the L1
vertebra. Surgery for fractures of L1 and L2 is often performed with a
frontal approach using screw and rod or a screw plate. Posterior hook
and rods can be used in this area and require a longer segment to
stabilize. The frontal approach is usually not performed below L3
because of technical difficulties related to large blood vessels. In the
lower lumbar region, the surgical approach is usually performed from the
back.
Bone graft: in many of these surgeries the surgeon performs a
corpectomy (removal of the body of the vertebra) of the
fractured vertebra and replaces it with healthy bone from the
patient's own pelvis, which is called the iliac crest.
Rehabilitation (Intensive Care Unit):
Rehabilitation starts in the intensive care unit after surgical
stabilization, if required.
Initially therapy begins with simply moving the affected limbs
through their normal range of motion. The areas of focus for
this range of motion include the shoulders, elbows, hips, knees
and ankles. It is important to maintain normal range of motion
during this early period so that a lack of range of motion does
not slow down or interfere with the rehabilitation process.
As mentioned previously, orthostatic hypotension or a drop in
blood pressure when becoming upright is a significant problem
immediately after a spinal cord injury. Therefore, the therapist
begins to gradually put the patient in an upright position while
monitoring blood pressure, heart rate and signs or symptoms of
lightheadedness or fainting. This often starts with simply
raising the head of the bed and gradually progresses to sitting
on the edge of the bed supported by the therapist. Another
commonly used intervention is the use of a tilt-table, a padded
table that has a footplate and several straps that support the
patient and prevent him from falling. The table is gradually
inclined while the patient’s blood pressure and symptoms are
monitored. Before starting to stand the patient, the nursing
staff usually will put compressive stockings and an abdominal
binder on the patient to prevent blood from quickly pooling in
the legs, leading to a drop in blood pressure.
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By
J. Glen House, MD / Much more at |
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