Neurosurgery TBI and Tumor
Monro-Kellie Doctrine
If one component increases, another must decrease to maintain ICP. Three
compartments: CSF, Blood volume, and parenchyma
CSF volume in the brain **
150ml
Blood Volume in the brain ***
150ml
Brain Parenchyma Volume **
1400ml
Cerebral Blood Flow
50ml/100g/min is necessary for adequate oxygen delivery for maintaining
structural integrity and function
What cerebral blood flows associated with failure of function and on further
decrease with structural damage?
<20-25 ml/100g/min
Autoregulation of CBF is intact between MAP's of:
60-160mmHg
Equation for Cerebral Perfusion Pressure
MAP-ICP
Intracranial Compliance (ICC) **
the change in volume per unit change in pressure
,THE INVERSE OF ELASTANCE
compliance = 1/elastance
Intracranial Compliance determines what?
the ability of the intracranial compartment to accommodate an increase in
volume without a large increase in intracranial pressure
TBI Primary Insult to the brain is...
often irreversible
TBI Primary Insult examples (4)
concussion
fracture
hematoma
contusion
Secondary Insults in a TBI are often the result of what? (8) **
hypoxia
hypercarbia
hypotension
ischemia
anemia
acidosis
vasospasm
hyperthermia
Anesthetic Management of a TBI should focus on what?
minimizing secondary insults and optimizing brain perfusion
Findings indicative of poor outcomes in a TBI (5) **
GCS <5
fixed/dilated pupils
hypoxia (PaO2 <60mmgHg)
hypotension (SBP<90mmHg)
, Mass or lesion
(hypoxia + hypotension = 75% mortality)
S/Sx of Elevated ICP (7) **
headache
nausea vomiting
papilledema (optic disc swelling)
unilateral pupillary dilatation
decreased LOC
irregular breathing
midline shift >0.5cm
What two cranial nerves are assessed during a pupillary exam **
II (optic) & III (oculomotor)
Your patient's pupils are unilateral fixed and dilated. What is this indicative of?
**
supratentorial mass causing Uncal herniation, compresses CN III
Your patient's pupils are mid-position, nonreactive. What is this indicative of?
Midbrain damage
Your patient's pupils are constricted and nonreactive. What is this indicative
of? **
pontine damage/compression
Your patient's pupils are bilateral fixed and dilated. What is this indicative of?
**
massive cerebral damage
Monro-Kellie Doctrine
If one component increases, another must decrease to maintain ICP. Three
compartments: CSF, Blood volume, and parenchyma
CSF volume in the brain **
150ml
Blood Volume in the brain ***
150ml
Brain Parenchyma Volume **
1400ml
Cerebral Blood Flow
50ml/100g/min is necessary for adequate oxygen delivery for maintaining
structural integrity and function
What cerebral blood flows associated with failure of function and on further
decrease with structural damage?
<20-25 ml/100g/min
Autoregulation of CBF is intact between MAP's of:
60-160mmHg
Equation for Cerebral Perfusion Pressure
MAP-ICP
Intracranial Compliance (ICC) **
the change in volume per unit change in pressure
,THE INVERSE OF ELASTANCE
compliance = 1/elastance
Intracranial Compliance determines what?
the ability of the intracranial compartment to accommodate an increase in
volume without a large increase in intracranial pressure
TBI Primary Insult to the brain is...
often irreversible
TBI Primary Insult examples (4)
concussion
fracture
hematoma
contusion
Secondary Insults in a TBI are often the result of what? (8) **
hypoxia
hypercarbia
hypotension
ischemia
anemia
acidosis
vasospasm
hyperthermia
Anesthetic Management of a TBI should focus on what?
minimizing secondary insults and optimizing brain perfusion
Findings indicative of poor outcomes in a TBI (5) **
GCS <5
fixed/dilated pupils
hypoxia (PaO2 <60mmgHg)
hypotension (SBP<90mmHg)
, Mass or lesion
(hypoxia + hypotension = 75% mortality)
S/Sx of Elevated ICP (7) **
headache
nausea vomiting
papilledema (optic disc swelling)
unilateral pupillary dilatation
decreased LOC
irregular breathing
midline shift >0.5cm
What two cranial nerves are assessed during a pupillary exam **
II (optic) & III (oculomotor)
Your patient's pupils are unilateral fixed and dilated. What is this indicative of?
**
supratentorial mass causing Uncal herniation, compresses CN III
Your patient's pupils are mid-position, nonreactive. What is this indicative of?
Midbrain damage
Your patient's pupils are constricted and nonreactive. What is this indicative
of? **
pontine damage/compression
Your patient's pupils are bilateral fixed and dilated. What is this indicative of?
**
massive cerebral damage
