The skull and its contents may be injured by blunt or penetrating trauma.
It is worthy to note that the patient's brain and surrounding tissue may be injured even when no evidence of skull fracture exists.
The brain is relatively fixed within the skull; however, it can move when significant acceleration and deceleration forces are applied.
Primary and Secondary Injury
The mechanical disruption of brain tissue and cerebral vessels is referred to as the primary brain injury. It occurs from direct trauma applied to the skull, brain and its surrounding structures. It often results in lacerated vessels, mechanical disruption of brain cells and increases in vascular permeability.
Mechanisms that lead to secondary brain injury are:
- Hypoxia (Low oxygen levels)
- Hypotension (Low Blood Pressure)
- Increased intracranial pressure ( Elevated pressure within the skull)
- Hypercarbia (Ineffective respirations leading to increased carbon dioxide levels)
- Acidosis (Acid build-up within the blood stream due to low blood pressure and increased carbon dioxide levels)
Management of the patient with a brain injury and suspected increase in intracranial pressure and decrease in cerebral blood flow must be centered on reversing hypoxia, hypotension, hypercarbia and acidosis (through effective ventilation).
Deterioration in the level of consciousness or changes in behavior, nausea/vomiting, gait abnormalities (ability to walk in a steady manner) or hypertension (high blood pressure) can all be signs of increased intracranial pressure.
Emergency care must include:
Spine stabilization
If the cervical spinal immobilization collar interferes with your ability to establish or maintain an airway, delay its use until advanced airway maneuvers can be performed. Consider complete spinal immobilization prior to moving the patient.
Airway management
Airway management is a key component in ensuring adequate alveolar ventilation and oxygenation and preventing hypoxia, hypercarbia and acidosis. Insertion of an oropharyngeal airway and manual airway maneuvers may be an effective alternative in managing the patient's airway. Suction any blood, secretions, vomitus, bone, tissue or other debris during airway management. Ensure that the airway remains clear.
Oropharyngeal Airways
Assist ventilations
If the patient has an inadequate respiratory rate or ventilation volume, it is necessary to provide positive-pressure ventilation. If no signs of herniation (brain contents being pushed through the brain stem at the base of the skull) exist, ventilate an adult at 10/minute, a child at 20/minute, and an infant at 25/minute.
Oxygenation
If the patient requ
ires assisted ventilation or hyperventilation, deliver 100% oxygen via the ventilation device. If the patient is breathing spontaneously and adequately, apply a nonrebreather mask at 15 liters per minute (LPM)
Nonrebreather Mask
Patient positioning
If the patient is immobilized to a backboard, slightly elevate (15° or less) the head end of the board or keep the patient in a supine position.
Rapid transport
Rapidly transport the patient to a medical facility that is capable of managing a brain-injured patient. A head injured patient is a true emergency.
Manage seizures
This may occur with head injured patients. If this does, protect the patient by sitting Indian style with your legs and support the head between your legs. Do not force anything in the mouth. Patients will not swallow their tongues. They may bite down hard so do not place any appendage you wish to keep into their mouths while the seizure is in progress. These victims need intravenous access so that seizure-stopping medications can be given.
Summary
Increased intracranial pressure can be a catastrophic event that may lead to death or permanent disability. Without prompt recognition and reversal of hypoxia, hypotension, hypercarbia, acidosis and increased intracranial pressure, the cerebral blood flow and resultant cerebral perfusion can be inadequate, leading to an increased risk of secondary brain injury.
