ICP and Cerebral Edema Flashcards
ICP and Cerebral Edema
What is ICP normally bewteen?
What is the overall damage from increased ICP AND what’s it related to?
2-12mmHg
ischemic and related to the difference bewteen ICP and BP in the major cerebra arteries
ICP and Cerebral Edema
What are plateau waves?
What COULD happen after plateau waves?
when rises in ICP spontaneously interupt the resting ICP, CPP, and Compliance
signs of transtentorial herniation such as
- pupillary enlargement
- dealth
ICP and Cerebral Edema - Compensation
What happens with increased CPP?
Decreased?
the vessels vaso-constrict so less blood flows in
Vaso-dilate so blood flows in
ICP and Cerebral Edema - Compensation
Describe the metabolic auto regulation mechanism?
What happens if CO2, pH, & lactic acid increase OR if O2 decreases?
If CO2, pH, & lactic acid decrease OR if O2 increase?
Chemo-receptors analyze the serum, CO2, O2, pH, and lactic acid
Blood vessels dilate to allow more blood flow to the area
Blood vessels constrict to allow less blood to the area
ICP and Cerebral Edema - Compensation
C.S.F regulation?
What happens when pressure increases?
125-250ml of C.S.F is moved to the arachnoid space.
C.S.F is reabsorbed readily every 3-4h
Production of CSF is decreased
ICP and Cerebral Edema - Compensation
Tissue tolerance - what size of masses becomes too large and the mechanisms can no longer tolerate it?
150cc supra-tentorial mass
5cc brainstem mass
ICP and Cerebral Edema
What is cushing’s triad?
What does it suggest?
Results/complications?
High systolic BP
Widening pulse pressure
Bradycardia (bounding)
the coning of the brainstem through the medulla oblongata
shortly thereafter = brain death
ICP and Cerebral Edema - Decompensation
What happens as ICP increases?
What are the bloodflow complications to cerebral edema? (hint bp)
How does cerebral edema develop?
Cerebral blood flow decreases
CO2, pH, lactic acid all increase
O2 decreases
Blood vessels dilate to compensate BUT that only increases the ICP further - cerebral ischemia
Unaffected arterial
Venous blood is trapped i.e. decreased venous return
The brains mechanisms further vaso-dilate increasing the permeability to sodium, glucose, and water which moves into the interstitial space.
K+ also moves to the interstitial space decreasing neuronal function
ICP and Cerebral Edema - Decompensation
What does the C/O or heart do when there’s cerebral edema?
The rate decreases considerably due to the pressure from the vagus nerve.
Large quantities of epi and norepi are released due to the SNS ischemia resulting in vasoconstriction + increased contractile force
C/O is thus increased
Cerebral Edema
Where would the lesion be to be affecting the right body motor + left facial motor function?
What controls the RAS and consciouness?
left supra-tentorial lesion
the midbrain - RAS
Medulla oblongata - consciouness
ICP and Cerebral Edema
What would suggest herniation?
unilateral focus becoming bilateral
Decreased sensorium
Seizure activity
Posturing (decerebrate or decorticate)
Cranial nerve changes (3rd especially)
Projective vomiting
Vital signs changes:
- Decreased LOA
- Slow, bounding pulse (vagus-SNS)
- High systolic pressure (180+ )
- Widened pulse pressure (120/80 = 40)
180/100 = 80
Safe # 65
