Trauma to the Head, Neck, and Spine

Neck wounds

The major vessels of the neck run close to the surface, and a wound there carries two risks at once. The first is massive hemorrhage. The second is air embolism: the veins of the neck run at a pressure lower than atmospheric, so air can be sucked into an open vein, travel to the lungs, and cause cardiac arrest. Direct pressure remains a lifesaving step; the only caution is not to interfere with breathing.

Care proceeds in order. Open the airway, then place a gloved hand over the wound immediately. Replace the hand with an occlusive dressing of thick material that extends 2 in past the edges of the wound and is sealed on all 4 sides, and apply pressure to stop the bleeding. Never compress both carotid arteries at the same time. Once the bleeding has stopped, bandage the dressing in place without restricting the airway or the vessels of the neck.

Spinal assessment — NEXUS-based criteria

The NEXUS study validated a tool for judging the risk of spinal injury. It rests on five criteria, and they are written as things that must all be absent before the cervical spine can be considered low risk:

1. No posterior midline cervical tenderness: palpate down the midline of the neck, and the rest of the spine while you are there.
2. No evidence of intoxication: alcohol or drugs blunt the pain that the other criteria depend on the patient reporting.
3. A normal level of alertness: the patient is fully awake and oriented, not confused, drowsy or post-ictal.
4. No focal neurologic deficit: compare grip strength for equality, and check for paralysis, weakness, numbness or tingling.
5. No painful distracting injury: a femur fracture or a large burn can occupy a patient's attention so completely that a broken neck does not hurt yet.

Intoxication and alertness are two separate criteria, not one. They are often taught merged into a single question about whether the patient is "reliable", which is how the list gets miscounted as four — and a patient can be fully sober and still too drowsy to assess, or wide awake and drunk.

In pediatric patients, weight the mechanism of injury (MOI) more heavily. Young children cannot reliably report pain, and because their vertebrae are more cartilaginous, a significant spinal cord injury can occur without external tenderness or deformity.

Long backboard application — practical tips

The patient is log-rolled onto the long backboard, and the EMT holding the head calls the move. Once the patient is on the board, pad the voids between the head or torso and the board. Straps are placed at the upper chest, the pelvis and the thighs, and the head is secured last, after the body has been strapped down.

A full-term pregnant patient is immobilized on the board, and the board is then tilted to the left to reduce compression of the vena cava.

For children 6 years of age or younger, pad beneath the shoulder blades to compensate for a proportionally larger head.

Helmet management

A helmet is left on when it fits snugly, there is no impending airway or breathing problem, removal would cause further injury, and proper spinal immobilization can be achieved with it in place. It is removed when it interferes with assessment or management of the airway or breathing, when it fits poorly and allows excessive movement inside, when it interferes with immobilization, or when the patient is in cardiac arrest.

With a football-, hockey- or lacrosse-style helmet worn with shoulder pads, remove both together or leave both in place. Removing only one forces the neck into hyperflexion or hyperextension.

Primary injury is already done; secondary injury is the one you can prevent

A traumatic brain injury has two halves. The primary injury is the damage done at the instant of impact — torn tissue, bruised brain, sheared axons. Nothing an EMT does changes it; it happened before the call came in.

The secondary injury is everything that damages the brain afterward: swelling, rising pressure inside a rigid skull, and above all hypoxia and hypotension. These two are the reason head-injury care looks so much like ordinary good care. Keeping the airway open, keeping the saturation up, and keeping the blood pressure from dropping is the treatment for a brain injury, because the brain is exquisitely intolerant of low oxygen and low perfusion pressure. Adding hypoglycemia to a head-injured patient does the same thing, which is another reason the glucose gets checked.

Put plainly: the EMT cannot repair the brain, and the EMT can substantially change whether that brain is further injured in the next twenty minutes.

Rising intracranial pressure announces itself in a pattern that is the opposite of shock

The skull is a closed box. Blood or swelling inside it has nowhere to expand, so the pressure rises and squeezes the brain. Late in that process the body mounts a characteristic response, Cushing's triad, and it is worth memorizing precisely because it inverts the pattern you have been taught to look for.

Table 33.1Rising intracranial pressure announces itself in a pattern that is the opposite of shock

A head-injured patient whose pressure is climbing while their pulse slows is not stabilizing. Other signs of rising pressure and impending herniation include a deteriorating level of consciousness — the single most sensitive indicator — vomiting, often without nausea, and a pupil that becomes dilated and unreactive on one side.

One thing not to do reflexively: do not routinely hyperventilate a head-injured patient. Driving down carbon dioxide constricts cerebral vessels and reduces blood flow to a brain that needs more of it, not less. Ventilate at the normal rate, and hyperventilate only if your protocol directs it for specific signs of herniation.

Skull fractures, concussion, and the drainage you leave alone

A basilar skull fracture, at the base of the skull, produces signs that are distinctive and, importantly, late — they can take hours to appear, so their absence early means nothing. Raccoon eyes are bruising around both eyes; Battle's sign is bruising behind the ear over the mastoid; and clear or blood-tinged fluid draining from the nose or the ear is cerebrospinal fluid escaping through the fracture.

Do not pack the nose or the ears to stop that drainage. The fluid is coming from around the brain, and blocking its exit raises the pressure inside the skull. Cover loosely with a sterile dressing and let it drain. This is also the reason an NPA is avoided in a patient with these signs.

A concussion is a transient disturbance of brain function without a structural injury that imaging will show. Expect headache, confusion, dizziness, and amnesia — either for events before the injury or for events after it — and the repetitive questioning ("What happened? Where am I?" asked over and over) that is characteristic. Most resolve. All of them are evaluated, because a concussion and a slowly expanding bleed can look identical in the first hour.

Finally, a point about where to look for shock: in an adult, a head injury alone rarely causes hypotension. An adult head-injury patient who is in shock is almost certainly bleeding somewhere else, and looking for it is the priority. Infants are the exception — their blood volume is small enough relative to their head that intracranial bleeding genuinely can cause shock.

What the cord controls depends on how high the injury is, and breathing is the level that matters most

An injury to the spinal cord removes function below the level of the injury, which means the height of the injury predicts what the patient has lost. The level worth knowing by heart is the diaphragm: the nerves that drive it leave the cord at roughly C3 through C5 — remembered as "C3, 4, 5 keep the diaphragm alive." An injury above that level takes the diaphragm with it and the patient stops breathing. An injury just below it spares the diaphragm but paralyzes the muscles between the ribs, producing diaphragmatic breathing: the belly rises and falls while the chest barely moves. That pattern in a trauma patient is a cord injury until proven otherwise.

Other findings: loss of sensation or movement below a level, numbness or tingling in the extremities, loss of bowel or bladder control, and — in a male patient — priapism, a persistent erection caused by the loss of sympathetic tone, which is a specific and often-tested sign.

Neurogenic shock is hypotension without the tachycardia, and confusing it with blood loss is the trap

A high cord injury cuts the sympathetic nervous system's signal to the blood vessels. The vessels below the injury dilate, the effective size of the container becomes larger than the volume of blood in it, and the pressure falls. That is neurogenic shock, and it looks unlike any other shock on the exam.

Table 33.2Neurogenic shock is hypotension without the tachycardia, and confusing it with blood loss is the trap

The heart rate is the giveaway. The same sympathetic signal that would normally speed the heart in response to falling pressure is the signal that has been cut, so the patient cannot mount the tachycardia. A hypotensive trauma patient with a normal or slow pulse and warm dry skin has a cord injury; a hypotensive trauma patient with a fast pulse and cool clammy skin is bleeding.

Two practical consequences. Because the patient cannot constrict their peripheral vessels, they lose heat continuously and become hypothermic quickly even in a mild environment — cover them. And because a trauma patient can have both problems at once, neurogenic shock is never a reason to stop looking for hemorrhage.

One term to keep separate: spinal shock is the temporary loss of cord function — flaccid paralysis and lost reflexes — immediately after an injury, and it may partly resolve over hours to weeks. It describes neurological function. Neurogenic shock describes the circulation. They often occur together and they are not the same thing.