ICP Flashcards
Factors that influence ICP?
BP, intrabd/intrathoracic pressure, posture, temp, blood gases (CO2 levels)
The Monro-Kellie Doctrine states?
- If there is an increase in 1 of the 3 components total intracranial volume will not change
- Ability to compensate is limited
How to calculate Cerebral Perfusion Pressure (CPP)?
MAP - ICP = CPP
What factors increase Cerebral Blood Flow and why?
- ↑ CO2
- ↑ H+
- ↓ O2
- cause vasodilation
What is normal CPP?
60-100 mmHg
At what CPP does ischemia occur?
< 50 mmHg
Sustained ↑ICP leads to?
- brainstem compression
- herniation of brain from one compartment to another
Increased ICP Clinical Manifestations?
- changes in LOC
- Cushing’s triad
- ↑BP and widening PP, ↓HR, Resp irreg
- Ocular signs
- Cranial Nerve III
- Headache in AM
- Vomiting (no nausea)
- projectile in peds
- Motor function ↓
type of decerbrate where the neck and back are arched?
Opisthotonic posturing
Increased ICP Diagnostic Imaging?
CT/MRI
What is the Cushing’s Triad?
- late sign of ICP
- ↑BP and widening PP, ↓HR, Resp irregularites
Inaccurate ICP measurement readings are due to?
CSF leak, catheter obstruction, difference in HT of bolt/transducer, incorrect HT of drainage system relative to pt’s reference point
Major complications fo uncontrolled ICP?
- inadequate cerebral perfusion leading to ischemia and infarction
- Brain herniation which may result in resp arrest
Why is the optic nerve prone to herniation?
it is located at the base of the skull
Drug therapy ICP?
- Osmotic therapy
- Corticosteroids
- Acetaminophen
- Barbituates
- Antiseizure meds
- stool softeners
Osmotic therapy for ICP?
- Mannitol to reduce fluid volume
- Hypertonic solution
What should be done prior to administering mannitol?
check for crystalization, warm and use filter if this occurs
Corticosteroid therapy for ICP?
- Dexamethasone (Decadron)
- monitor blood glucose, infections,
- prevent GI bleed-use H2 blocker or PPI
Why are barbiturates given to tx ICP?
- to decrease cerebral metabolism
- causes respiratory depression
Antiseizure med of choice for ICP?
phenytoin - give loading dose followed by maintenance doses
IV Dilantin (phenytoin) is only give with which soluntion?
Normal saline
What is the max rate of administration for IV dilantin and what happens if given to quickly?
- 50 mg/min or 1-3mg/kg/min whichever is slower
- to quick can cause decreased in BP
Why is D5W not given to tx ICP?
- it decreases serum osmolarity and could increase edema
- is an isotonic soln, but acts as a hypotonic soln in the body
Fluid of choice to keep the ICP patient normovolemic?
IV 0.9% NaCl
