Unit 2: ICR

Cerebral Perfusion Pressure

pressure needed to ensure blood flow, oxygen, and nutrients to the brain

cerebral perfusion pressure is impacted by….

Increased ICP

• pushes on the blood vessels in the brain, limiting/constricting blood flow and oxygen and nutrient supply to the brain

• increased ICP → reduces CPP & leads to tissue and brain ischemia, leading to brain tissue death

How does autoregulation help maintain constant cerebral perfusion pressure?

• increased ICP → vasodilation to increase cerebral blood flow to deliver oxygen to brain tissues (can also exacerbate and contribute to increasing ICP)

• decreased ICP → vasoconstriction of cerebral blood vessels to decrease cerebral blood flow

• hypoxia & hypercapnia → leads to vasodilation to increase cerebral blood flow

• hypocapnia → causes vasoconstriction; decreases cerebral blood flow

• overcompensation can cause cerebral edema & contribute to increased ICP

level of consciousness

pt is aware of self and the environment; is able to respond appropriately to stimuli

mental status

• assessment of pt’s cognitive, affective, and behavioral state

• have to be conscious and awake first in order to assess mental status

cognition includes:

• thought processes

• memory

• perception

• communication

• problem solving

• emotion

what can loss of autoregulation lead to?

Cushing’s Triad

s/s of cushing’s triad

1. systolic hypertension where there is a large difference between the systolic and diastolic pressure

2. low HR with bounding pulse

3. irregular/decreased RR

s/s of ICP

• weakness

• lethargy

• headaches

• vomiting

• blurred vision

• changes in behavior

purpose of treatment for increased ICP

to decrease ICP and restore blood flow

effects of impaired ICP

1. elevated ICP leads to the brain being compressed d/t increased blood flow/injury/trauma/mass

2. leads to herniation risk

effects of impaired cerebral perfusion

limited blood flow to brain tissue can lead to brain ischemia and tissue damage

effects of impaired neuronal integrity

caused by damaged or inflamed neurons from trauma, infection, stroke, or neurodegenerative diseases

effects of impaired neuro-transmission

disrupted neurotransmitter release or uptake, leading to issues like seizures or impaired cognition.

effects of impaired cerebral metabolism

hypoxia, hypercapnia, or hypoglycemia can lead to energy deficits, neuronal damage, or brain cell death.

3 direct consequences of impaired ICR

1. Herniation or displacement of brain tissue due to severe increased intracranial pressure

2. Permanent physical, cognitive, or psychological disabilities due to cellular damage

3. Brain death or systemic failure due to severe intracranial dysregulation.

5 functional consequences of impaired ICR

1. consciousness → decreased LOC, coma

2. motor control → motor deficits, speech & language impairment

3. sensory processing → sensory deficits, vision & hearing loss

4. cognitive functions → altered mental status, impaired memory, impaired thought process

5. autonomic functions → dysregulation of HR, BP, temp, and RR

assessing LOC

assess for:

• level of alertness

• response to stimuli (AVPU)

concerning cues during a LOC assessment

sudden change in LOC; early sign of impaired ICR

assessing cognitive function

assess for:

• level of orientation

• memory

concerning cues during a cognitive function assessment

• disorientation

• confusion

• forgetfulness

concerning cues during a vision assessment

• blurred vision

• loss of vision

• papilledema

• impaired eye movement

assessing language function

assess for:

• communicating speech

• understanding speech

concerning cues during a language function assessment

• slurred speech (dysarthria)

• aphasia (no speech)

• incoherent speech

assessing pupils (reflexes)

assess for:

• PERLA

concerning cues during a pupil assessment

unequal pupil size *late sign for impaired ICR

assessing sensory function

assess for:

• sensation in the extremities

concerning cues during a sensory function assessment

• numbness

• tingling

• loss of sensation

assessing motor function

assess for:

• strength

• coordination

concerning cues during a motor function assessment

• weakness

• paralysis

• discoordination (ataxia)

assessing autonomic function

assess for:

• heart

• lungs

• BP

concerning cues during an autonomic function assessment

• irregular respirations

• vomiting (esp. w/o nausea)

• hypertension with bradycardia (indicates cushing’s triad; *late sign)

Babinski reflex

Positive = dorsiflexion of the big toe and fanning of the other toes when the lateral aspect of the sole of the foot is stroked

• in infants/newborns → normal

  • abnormal in those >2 years old

• in adults → concerning; indicates damage to CNS

decorticate

• flexed, indicates damage to the cerebral cortex

• indicates severe brain damage

decerebrate

• extended, more severe, indicates damage to the midbrain or lower brainstem

• indicates severe brain damage

interventions to prevent increasing ICP

1. monitor VS; look for s/s of Cushing’s Triad

2. monitor LOC

3. I/Os - limit fluid intake

4. reduce stimuli + promote energy conservation + reduce brain metabolism

5. raise HOB 30-40 degrees

6. initiate seizure precautions

7. avoid valsalva maneuvers (ie. coughing, sneezing, straining (like pooping))

8. monitor ICP/CCP