221 Mod 2.1 - ICP, Meningitis, Brain
Tumors & Surgery
Intracranial pressure (ICP)
Pressure exerted by the brain against the skull
How is ICP measured?
-Intraventricular catheter (aka ventriculostomy)
-Subarachnoid bolt
-Epidural catheter
-Fiber optic transducer catheter
Cerebral perfusion pressure
-Amount of pressure used to provide blood flow to the brain
Monro-Kellie Hypothesis (aka brain-in-the-box)
-The skull contains brain, blood, and CSF
-Any change in any one of these components must be accompanied by a reciprocal
change in one or both of the other components.
Which of the three skull components is the easiest to adjust to reduce ICP?
CSF
Cerebral spinal fluid (CSF)
-Mostly water, + protein, electrolytes, glucose
-Cushions, supports, and nourishes the brain and spinal cord
-Produced in the choroid plexus (4th ventricle)
-Usually 90-200 mL in adults
**Study guide: What is the danger of sustained IICP?
-Decreased cerebral perfusion
-Further edema/swelling
-Shifting brain tissue --> brain herniation --> brainstem death
,**Learning outcome: what is the relationship of BP, ICP, and CPP?
CPP = MAP - ICP
**Learning outcome: what is a normal range for ICP?
**Study guide: What is the goal range for ICP? At what level ICP is intervention
needed?
5-15
-If >20, intervention required
-If >30, compliance is lost, can no longer autoregulate/compensate
-If >40, prognosis is poor
-If >60, almost always fatal
What happens if ICP is equal to MAP?
-Cerebral circulation ceases
-CPP = 0
**Learning outcome: what is a normal range for CPP?
**Study guide: What is the goal range for CPP?
70-100 mmHg
-Goal is to keep CPP >60 or 70 (depending on the source)
What is the danger of having low CPP?
-Inadequate blood flow in the brain
-If CPP <50 mmHg, irreversible neurologic damage occurs
**Study guide: Describe how Blood Pressure (MAP) relates to CPP? How does this
impact the brain?
-MAP must be high enough to overcome ICP in order to perfuse the brain adequately
Autoregulation
-Brain can dilate or constrict blood vessels to maintain constant cerebral blood flow
(CBF) despite changes in systemic blood pressure and CPP
-Maintains CBF within a stable range across a range of MAP values (60-130
mmHg) and CPP values (50-150)
-This mechanism can be impaired in pts with IICP
**Study guide: Early signs of IICP in adults (H&C Chart 61-1)
-Changes in LOC - earliest (e.g. agitation, slowed speech, delayed responses,
restlessness, confusion, drowsiness)
, -Pupillary changes and impaired extraocular movements (pressure on oculomotor
and optic nerves)
-Weakness in an extremity or one side of the body
-Constant headache, getting worse, aggravated by movement
**Study guide: Early signs of IICP in infants/children
-Projectile vomiting
-High-pitched cry
-Bulging fontanelles
-Separation of suture lines
Cushing's Triad
1) Elevated SBP, widening pulse pressure
2) Bradycardia
3) Irregular respirations (e.g. Cheyne-Stokes)
**Study guide: Late signs of IICP (H&C Chart 61-1)
-LOC continues to deteriorate until comatose
-May only respond to noxious/painful stimuli
-HR and RR decrease, become irregular, or fluctuate (Cheyne-Stokes)
-BP and temp increase
-Pulse pressure widens
-Projectile vomiting
-Abnormal motor responses (e.g. decortication, decerebration, flaccidity)
-Eventually brain death - loss of all brain stem reflexes
What should a nurse be monitoring to identify IICP?
-GCS
-PERRLA, vision changes
-VS - widening pulse pressure, bradycardia, fever
-Respiratory pattern
-Headache
-N/V
-Urine specific gravity
-Reflexes
**Learning outcome: Apply nursing process for client who is at risk for increased
intracranial pressure and secondary injury prevention
**Study guide: What are nursing care considerations in caring for clients with IICP?
See following...
What is the function of a intraventricular catheter?
-Measures ICP
-Drain blood or CSF
-Administer meds
Tumors & Surgery
Intracranial pressure (ICP)
Pressure exerted by the brain against the skull
How is ICP measured?
-Intraventricular catheter (aka ventriculostomy)
-Subarachnoid bolt
-Epidural catheter
-Fiber optic transducer catheter
Cerebral perfusion pressure
-Amount of pressure used to provide blood flow to the brain
Monro-Kellie Hypothesis (aka brain-in-the-box)
-The skull contains brain, blood, and CSF
-Any change in any one of these components must be accompanied by a reciprocal
change in one or both of the other components.
Which of the three skull components is the easiest to adjust to reduce ICP?
CSF
Cerebral spinal fluid (CSF)
-Mostly water, + protein, electrolytes, glucose
-Cushions, supports, and nourishes the brain and spinal cord
-Produced in the choroid plexus (4th ventricle)
-Usually 90-200 mL in adults
**Study guide: What is the danger of sustained IICP?
-Decreased cerebral perfusion
-Further edema/swelling
-Shifting brain tissue --> brain herniation --> brainstem death
,**Learning outcome: what is the relationship of BP, ICP, and CPP?
CPP = MAP - ICP
**Learning outcome: what is a normal range for ICP?
**Study guide: What is the goal range for ICP? At what level ICP is intervention
needed?
5-15
-If >20, intervention required
-If >30, compliance is lost, can no longer autoregulate/compensate
-If >40, prognosis is poor
-If >60, almost always fatal
What happens if ICP is equal to MAP?
-Cerebral circulation ceases
-CPP = 0
**Learning outcome: what is a normal range for CPP?
**Study guide: What is the goal range for CPP?
70-100 mmHg
-Goal is to keep CPP >60 or 70 (depending on the source)
What is the danger of having low CPP?
-Inadequate blood flow in the brain
-If CPP <50 mmHg, irreversible neurologic damage occurs
**Study guide: Describe how Blood Pressure (MAP) relates to CPP? How does this
impact the brain?
-MAP must be high enough to overcome ICP in order to perfuse the brain adequately
Autoregulation
-Brain can dilate or constrict blood vessels to maintain constant cerebral blood flow
(CBF) despite changes in systemic blood pressure and CPP
-Maintains CBF within a stable range across a range of MAP values (60-130
mmHg) and CPP values (50-150)
-This mechanism can be impaired in pts with IICP
**Study guide: Early signs of IICP in adults (H&C Chart 61-1)
-Changes in LOC - earliest (e.g. agitation, slowed speech, delayed responses,
restlessness, confusion, drowsiness)
, -Pupillary changes and impaired extraocular movements (pressure on oculomotor
and optic nerves)
-Weakness in an extremity or one side of the body
-Constant headache, getting worse, aggravated by movement
**Study guide: Early signs of IICP in infants/children
-Projectile vomiting
-High-pitched cry
-Bulging fontanelles
-Separation of suture lines
Cushing's Triad
1) Elevated SBP, widening pulse pressure
2) Bradycardia
3) Irregular respirations (e.g. Cheyne-Stokes)
**Study guide: Late signs of IICP (H&C Chart 61-1)
-LOC continues to deteriorate until comatose
-May only respond to noxious/painful stimuli
-HR and RR decrease, become irregular, or fluctuate (Cheyne-Stokes)
-BP and temp increase
-Pulse pressure widens
-Projectile vomiting
-Abnormal motor responses (e.g. decortication, decerebration, flaccidity)
-Eventually brain death - loss of all brain stem reflexes
What should a nurse be monitoring to identify IICP?
-GCS
-PERRLA, vision changes
-VS - widening pulse pressure, bradycardia, fever
-Respiratory pattern
-Headache
-N/V
-Urine specific gravity
-Reflexes
**Learning outcome: Apply nursing process for client who is at risk for increased
intracranial pressure and secondary injury prevention
**Study guide: What are nursing care considerations in caring for clients with IICP?
See following...
What is the function of a intraventricular catheter?
-Measures ICP
-Drain blood or CSF
-Administer meds
