traumatic brain injuries Flashcards
Define TBI
A form of acquired brain injury, occurs when a sudden trauma causes damage to the brain. Can result when the head suddenly and violently hits an object, or when an object pierces the skull and enters brain tissue
Outline effects of a TBI located in the brain stem
changes in:
- heart rate
- breathing
- blood pressure
- vomiting
- swallowing
Outline effects of a TBI located in the cerebrum
changes in:
- intelligence, learning, judgement
- speech and memory
- sense of hearing, vision, taste and smell
- skeletal muscle movements
Outline effects of a TBI located in the cerebellum
- balance and coordination
- posture
What is the wenicke’s area responsible for?
Understanding speech
Outline how and why cerebral blood flow is controlled
The brain has the ability to control its blood supply to match its metabolic requirements through vasoconstriction and dilation
CBF increases with metabolic rate, hyperthermia, seizures, pain, anxiety
What is an epidural haematoma?
Artery
Middle meningeal artery rupture usually due to blow to the side of the head, area where skull is easiest to fracture
What is a subdural haematoma?
Tars in bridging veins that cross the subdural space
What is meningitis?
Inflammation of the meninges of the brain, spinal cord or both
What are the 3 compartments of the brain?
- cerebrospinal fluid
- blood
- brain tissue
Explain the monro Kellie doctrine
Swelling due to an increase in the cranial compartments.
Sum of volumes of brain, CSF, and intracranial blood is constant. An increase in one should cause a decrease in one or both of the remaining two.
What is the formula for cerebral perfusion pressure?
Mean arterial pressure - intracranial pressure = cerebral perfusion pressure
What is the normal cerebral perfusion pressure?
> 60mmHg
Outline examples of mechanisms of brain injury
- blunt
- penetrating
- Motor vehicle collision
- falls
- burns
Explain what a primary injury is
Primary injury at the time of the event
Only treatment is by prevention
Explain what a secondary injury is
Follows initial event - preventable
Occurs as an indirect result of the primary injury and the body’s response to that injury
e.g. hypoxia, hypotension, hypercapnia
Identify the 3 different types of TBI
mild - GCS 13-15, slight nausea and confusion
moderate - GCS 9-12, amnesia
severe - GCS 8, poor outcomes, secondary brain injury
What is a concussion and the effects
Mild TBI
- direct blow concussion
- acceleration or deceleration injury
- reticular activating system
- transient amnesia/LOC
- nausea, vomiting, headache, vision loss, concentration
What is a diffuse axonal injury?
- severe type of TBI
- microscopic diffuse bleeding in the brain
- damage to the reticular activating system - unconscious
- damage to the axons causing them to not communicate properly
What is a diffuse axonal injury?
- severe type of TBI
- microscopic diffuse bleeding in the brain
- damage to the reticular activating system - unconscious
- damage to the axons causing them to not communicate properly
What is an epidural haematoma
Bleeding between the skull and dura matter
- focal injury - can be seen under CT scan
- commonly a torn meningeal artery
- surgical intervention needed
What is a subdural haematoma?
Bleeding into the subdural space - rupture of bridging veins
Features: LOC, hemiparesis, fixed + dilated pupils
What is a subarachnoid haemorrhage
Bleeding into the subarachnoid space
Causes hydrocephalus, cerebral vasospasm, fibrous scarring
What is a cerebral contusion?
Bruise to the surface of the brain - caused by movement within the cranial vault
Outline contributors to poor TBI outcome
- hypoxia
- hypercapnia
- hypotension
- hyperthermia
- prevent coagulopathy (defection clotting cascade)
Outline contributors to poor TBI outcome
- hypoxia
- hypercapnia
- hypotension
- hyperthermia
- prevent coagulopathy (defection clotting cascade)
Identify factors affecting ICP
- cerebral blood flow
- cerebral venous return
- oxygen
- carbon dioxide
- blood pH
Outline the ongoing management of TBI
- sedation/analgesia
- imaging/diagnosis
- monitor MAP
- observe for signs of impending
- herniation
What is the cerebral oedema
Cellular response to injury
- hypoxic-ischaemic injury
- injured neutrons have increased metabolic needs
Outline treatment to reduce ICP
- reduce cerebral oedema - hyperosmolar therapy
- promote venous return
- reduce cerebral oxygen requirement
- reduce hyperthermia
- management of pain and agitation
- neurologic exam
Outline nursing care of TBI
- Hourly GCS, head positioning
- temperature
- cluster care
- adequate analgesia (prevent ICP)
- DVT prophylaxis
- calf compressions
- positioning
