Neuroanesthesia Flashcards
Cerebral blood flow is what % of cardiac output?
20%
What is a potential consequence of increasing IC?
Brain herniation
What is flow-metabolism coupling?
As the metabolic rate (CMR) of the brain increases, the cerebral blood flow (CBF) also increases
What is normal ICP?
10-15 mmHg
What is cerebral perfusion pressure?
MAP - ICP
What is the Cushing’s reflex?
Hypertension and bradycardia due to an increase in ICP
Hyperventilation helps resolve this
What is the most potent regulator of CBF?
Arterial CO2 tension
What level of PaCO2 may result in ischemic injury to the brain?
20 or less
A PaO2 of what will cause an increase in CBF?
50 or less
How does prolonged hypoxemia result in vasodilation?
Hypoxemia -> lactic acidosis -> vasodilation
How do CBF and CMR change with body temperature?
7% increase in CBF and CMR per 1 degree C increase in body temp
How does blood viscosity influence CBF?
Increase viscosity (e.g. polycythemia vera) will decrease CBF
Decrease in viscosity (e.g. anemia) will increase CBF
Which drug is contraindicated in patients with seizure?
Acepromazine
Best pre-med choice for patients with seizures?
Benzodiazapines
Which drug is known to cause a decrease in CBF in isoflurane-anesthetized patients?
Dexmed
Can mimic Cushing’s reflex
Which drug increases CBF and CMR?
Ketamine
What qualities should injectable anesthetics have?
Decrease ICP
Decrease CBF
Decrease CMR
Which injectable anesthetics decrease ICP, CBF, CMR?
Propofol
Alfaxalone
Etomidate
Which is the preferred inhalant and why?
Sevoflurane
Increases CBF to lesser degree than isoflurane
Inhalant anesthetics minimally affect CBF when used at what concentration?
Below 1 MAC
The effects of inhalants on CBF and ICP can be minimized by
Hyperventilating
Mild hypocapnia
What are the goals of fluid therapy?
- Maintain euvolemia
- Avoid hypervolemia
- Correct blood loss
What can you do to minimize chance of retching/gagging during intubation?
Make sure patient is in good plane of anesthesia
Lidocaine topically or IV
