week 4 Flashcards
What is ICP?
- Intracranial pressure
- The pressure exerted by fluids such as cerebrospinal fluid (CSF) inside the skull and on the brain tissue
What is the Monro-Kellie Hypothesis?
Increase in volume of one of intracranial component must be compensated by decrease in one or more of other components so that volume remains fixed
What is normal intracranial pressure?
- 5-15 mmHg
- Greater than 20mmHg must be treated
How to measure intracranial pressure?
With a intraventricular catheter
What is cerebral blood flow?
Amount of blood that passes through the brain at any time
What is autoregulation?
The automatic alteration in the diameter of the cerebral blood flow to maintain a constant flow of blood to the brain during during systemic arterial pressure
What is CPP?
- Cerebral perfusion pressure
- Pressure to ensure blood flow to brain
What is normal CCP?
60-100mmHg
What does CCP of lower than 50mmHg indicate?
Ischaemia and neuronal death
What does CCP of lower than 30mmHg indicate?
Incompatibility with life
What is the nursing assessment of ICP and how frequently?
- Frequent neurological observations (30 mins-1 hr)
Why must a nurse complete frequent neurological observations for possible increased ICP?
Because a small change in volume can have dramatic effect on ICP
What can increased ICP?
- Anything that increased brain tissue, blood of CSF volume
- Cerebral oedema common factor
What causes cerebral oedema?
Mass lesion
- Head injuries
- Brain surgery
- cerebral infection
- Vascular insult
- Toxic or metabolic encephalopathic conditions
What are complications of increased ICP?
- Inadequate cerebral perfusion
- Cerebral oedema
- Cerebral herniation
What does herniation cause?
1) A potentially reversible process to become irreversible
2) Ischemia and oedema increase
3) Compression of brainstem and cranial nerves
4) Brain death
What is the progression of increased ICP?
- Cranial insult
- Tissue oedema
- Increased ICP
- Compression of blood vessels
- Decreased cerebral blood flow
- Decreased oxygen with death of brain cells
- Oedema around necrotic tissues
- Increased ICP with compression of brainstem and respiratory centre
- Accumulation of carbon dioxide
- Vasodilation - Increased ICP resulting from increased blood volume
- Death
What are clinical manifestation of increased ICP?
- Change in LOC
- Change in vital signs (Cushings triad=high bP with low diastolic, bradycardia, increased temp, erratic/decreased breathing)
- Ocular signs
- Decrease in motor function
- Headache
- Vomiting (projectile without nausea)
What do we assess in a neurological assessment?
- Glasgow coma scale
- Pupillary check for size and response
- Test strength and movement
- Vital signs
Checking for signs of Cushing’s triad which indicates severely increased ICP
What is a decorticate response?
Flexion of arms, wrists and fingers with adduction in upper extremities. Extension, internal rotation and plantar flexion in lower extremities
What is a decerebrate response?
All four extremities in rigid extension, with hyperpronation of forearms and plantar flexion of feet
What is opisthotonic posturing?
When the back becomes extremely arched
What are the types of head injuries?
- Scalp laceration
- Skull fractures
- Head trauma: diffuse or focal
What is a diffuse injury?
- Generalised
- Concussion
- Diffuse axonal injury
What is a focal injury?
Localised minor head injury. E.g:
- Contusion
- Hematoma
How do you class head injuries?
- Minor: GCS 13-15
- Moderate: GCS 9-12
- Severe: GCS 3-8
What is a coup-contrecoup injury?
Cerebral contusion on the side of the brain opposite the area that was hit. The neck must not be bent backwards until considered safe
What is a coup injury?
Cerebral contusion at site of impact with an object
What is a concussion?
- Minor head injury
- Sudden transient mechanical head injury with disruption of neural activity and a change in LOC
What are signs of a concussion?
- Brief LOC
- Amnesia regarding the event
- Headache
- Post concussion syndrome can last 2 weeks to 2 months
S/S of a concussion?
- Persistent headache
- Lethargy
- Personality and behaviour changes
- Short attention span
- Decreased short-term memory
- Changes in intellectual ability
What something to be aware of with scalp laceration?
profuse bleeding
What are different types of skull fracture?
- Linear
- Depressed
- Simple
- Comminuted
- Compound
Symptoms vary depending on where the fracture is
What to watch for when a patient has a skull fracture?
CSP leaking from nose or ears- indicates tear in dura
What are clinical signs of basilar skull fracture?
- Periorbital oedema and bruising
- Bruising behind the ears
- CSF leaking
What is a basilar fracture?
Base of skull fracture
What is contusion?
Bruising
Head trauma complications: types of hematoma
- Subdural hematoma
- Intracerebral hematoma
- Epidural hematoma
What is a subdural hematoma?
Bleeding between the dura mater and arachoid layer
What is a intracerebral hematoma?
Bleeding within the brain
What is a epidural hematoma?
blood between the dura and the skull
Neurological emergency as associated with arterial bleed
What are nursing interventions during the acute phase (head injury/increased ICP)?
- Maintaining respiratory function
- Maintaining fluid and electrolyte balance
- Monitoring ICP
- Body position
- Protection from injury
- Psychological consideration
- Care of the family/ significant other
Why monitor respiratory function in the acute phase?
Injury stops brain regulating breathing
Why monitor fluid and electrolyte balance in the acute phase?
Injury causes excessive loss of fluids in form of urine causing abnormalities
What is diabetes insipidus?
Disease in which the pituitary hormone vasopressin is impaired, resulting in the production of very large quantities of dilute urine.
S/S- dehydration and insatiable thirst.
