Intro to Neuro anesthesia PPt-josh Flashcards by Diana Hathaway

The adult brain weighs about ______or 2% of tbw

1350gm

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CBF is how much

(not a single number but _-_/__/__)

45-55 mL/100g/min

Avg is 50mL/100g/min

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What is the avg CBF ml/min

750mL/min

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What is the equation for CBF

CBF= CPP/CVR

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the brain receives what % of CO

12-15%

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CMRO2 is what % of O2 consumption

20%

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What is avg CMRO2

(__/__/__)

3.5mL/100g/min

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what is equation for CPP

CPP= MAP-ICP (or CVP which ever is more)

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what happens to CMRO2 during sleep

decreases

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CBF decreases ___% for every __C decrease in body temp below 37C

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what do VAA do to CMRO2?

decrease it

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what is autoregulation

MAP 60-160mmHg

(or her slide says 70-150 mmHg)

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Autoregulation of CBF is know as what type of regulation?

Myogenic regulation

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Rapid changes in MAP can result in transient periods of Altered _____ (probally no more than 3-4 min)

CBF

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what are the 2 types of regulation for CBF?

Myogenic
Neurogenic

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Myogenic regulation on CBF is thought to occur why?

b/c of the autoregulation and rapid changes in MAP in transiet periods of altered CBF, probaly occurs d/t direct muscle changes in the tone of vascular smooth muscle

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the Neurogenic regulation of CBF has its greatest neurogenic effect on the larger cerebral arteries. what is the most important determinant?

viscosity (HCT)

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the CNS is derived form what 2 primary cells?

Neurons
Neuroglial cells

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what are the 5 neuroglial cells?

astrocytes
Ependymal cells
Microglia
Olgodendrocytes
Schwann cells

(All Ethipoians Munch On Snails)

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Neuroglial cells: Functions

Astrocytes

Support
metobolic
nutritive functions

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Neuroglial cells: Functions

Ependymal Cells

lines cavities in teh CNS and make up walls of ventricles

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Neuroglial cells: Functions

Microglia

Phagocytosis

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Neuroglial cells: Functions

Oligodendrocytes

insulation for axons in teh CNS (myelin sheath in brain and spinal cord)

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Neuroglial cells: Functions

Schwann Cells

Insulation-myelin sheath in peripheral nervous system

(Schwann in your arms)

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Blood Brain Barrier: BBB it is for effective _______ of the brain and spinal cord

Insolation

Blood Brain Barrier: BBB \_\_\_\_\_\_\_\_ Cells of the CNS form tight junctions b/t cells.

Endothelial cells

Blood Brain Barrier: BBB what is the function of the endothelial cells of the CNS that form tight junctions b/t cells?

to prevent intracellular transfer

Blood Brain Barrier: BBB Midline structures receive neurosecretory products from blood and exist OUTSIDE the BBB (AKA not protected by BB) what are the 5 parts of the brain not protected by teh BBB?

* Area of Postrema * Pituitary gland * Pineal gland * Choroid plexus * portions of the hypothalamus

VAA's effect on CBF: VAA's during normocapnia @ \> 0.5 MAC do what 3 things? and all this results in what?

* Dose related _suppression on Cerebral Metabolism_ * _Vasodilation_ d/t direct effects on vascular smooth muscle * CBF/CMRO2 ratio altered \*\* results in\*\*\* increases in CBF

VAA's effect on CBF: in recap all VAAs greater than 0.5 MAC cause what?

increases in CBF

VAA's effect on CBF: list which ones increase CBF In order from least to greatest?

Halothane enflurane _Des=ISO_ Sevo (found that des and iso are equal is very interesting)

N2O effect on CBF: what 3 things does N2O increase

* CBF * ICP * CMRO2 (is questionable)

Ketamine: w/o controlled ventilation what 3 things are increased?

1. PaCO2 2. CBF 3. ICP

Ketamine: if given w/ controlled ventilation or another sedative what happens to the SE?

they are negligible

Ketamine: what do most providers do with it? (use it/avoid it)

Avoid it

Benzo, barbs, and prop reduce _____ and _____ in a dose dependent fashion

* CMRO2 * CBF

Narcs likely have little effect on ____ and \_\_\_\_

* CMRO2 * CBF

NDMR: do they effect CBF, ICP, or CMRO2?

* no * only effects are from histamine release!! * Atracurium and Mivacurium should only be used in doses not associated w/ hypotension

SCh: does what to ICP

increases it

SCh: does what to CBF?

* Increases it * D/t cerebral activation from muscle spindle apparatus

SCh: is it contraindicated when RSI is required?

nope (u can give a defasiculate dose)

ICP: what are the 3 determinants of ICP not including the brain?

IC water (78%) CSF (75mL) Blood 50 mL

ICP: what is normal ICP?

5-15 mmHg (miller says 8-12mmHg) \*\*miller also said the world was flat so maybe we shuould just agree with everything he says even if everything else says something else fucking jackass\*\*\*

ICP: what is the total fluid volume in the brain? Including the 3 determininats of ICP IC water, CSF, and Blood

## Footnote 1200-1500mL

ICP: elevated ICP is above what #

15mmHg

ICP: what can cause and increase in ICP?

any of the 3 determinants of ICP Blood/ IC water/ CSF

ICP: Intracranial HTN is a sustained increase in ICP above what?

15-20mmHg

ICP: when ICP rises above 30mmHg what ensues?

* CBF decreases * Ischemia * Cerebral edema * Increased ICP * CBF decreases more * More ischemia * More edema * Repeat!!!

ICP: S/S of Increased ICP

* Nausea/vomiting * HTN * Bradycardia * Personality changes * Altered level of consciousness * Altered breathing pattern * Papilledema

ICP: what are ways to decrease ICP

* Elevate head (improves venous outflow) * Hyperventilation * Surgical Decompression * CSF drainage * Osmotic Diuretics/Loop diuretics

## Footnote ICP: what are 2 main drugs that decrease ICP

* Barbs * Prop

ICP: one way to decrease ICP is to the avoidance of cerebral vasodilating drugs. what is a cerebral vasodilating drug that we use everyday that can be avoided or used in decreasd amounts to help in this?

VAAs

ICP and HYPERventilation: is it a clear fix?

Nope controversial and efficacy and duration of effect are unclear

ICP and HYPERventilation: the effects of hyperventilation decrease over time, there is usually no benefit after ___ hours

6 hrs

ICP and HYPERventilation: what is a concern w/ hyperventilation

* Decreasing CBF will increase likelihood of ischemia and more edema

Intracranial Mass Lesions: what should u avoid if elevated ICP

Sedatives

Intracranial Mass Lesions: you want to prevent undesirable changes in what?

CBF and ICP

Intracranial Mass Lesions: what is the plan for intubation

do it deep and fast (so not to increase ICP)

Intracranial Mass Lesions: why is it important to do a timely wakeup?

to allow for post op neuro eval

Intracranial Mass Lesions: what is a good anesthesic plan?

Opioid plus prop or VAA (1/2 MAC)

Intracranial Mass Lesions: You want to \_\_\_\_\_ICP and maintain adequate \_\_\_\_

* Minimize * CPP

Intracranial Mass Lesions: Why is N20 controversial

* d/t role in increasing CBF * (but has been used for yeears w/o notable difference in pt outcomes)

Intracranial Mass Lesions: What diuretic should you have ready to go? and how much of it?

* mannitol * 0.25-1g/kg

Intracranial Mass Lesions: what do you wanna do with fluid balance?

* Maintain euvolemia (no fluid boluses)

Intracranial Mass Lesions: what do you want to avoid during extubation

* Coughing * Straining * Bucking * HTN

Intracranial Mass Lesions: what should you ask the surgeon prior to the sx r/t hemdynamics?

ask if they have a preference for the MAP

Intracranial Mass Lesions: what are the 2 different types of Space occupying lesions of the cranial vault

Supratentorial Infratentorial

Intracranial Mass Lesions: S/S of supratentorial

* H/A * SZ * decline in cognitive fxn * hemiplegia * Focal neuro deficits * Aphasia (Almost CVA like)

Intracranial Mass Lesions: S/S of infratentorial

* H/A * Sz * Cerebellar dysfunction (ataxia, nystagmus, dysarthria) * Brainstem compression (cranial nerve palsies, Altered LOC, Altered Respirations)

Intracranial Mass Lesions: where are supratentorial located

Above the tentorium

Intracranial Mass Lesions: what structures are located w/in the supratentorial area

* occipital lobe * Parietal lobe * Cerebrum * frontal lobe * Temporal lobe (main brain)

Intracranial Mass Lesions: where is the tumor located with Infratentorial mass

* below the tentorium

Intracranial Mass Lesions: what structures are located in the infratentorial area

* Cerebullum * Spinal cord * Brainstem * Pons * Medulla

## Footnote Just 2 pic for references

Anesthesia for Neurosurgery: if the surgeon complains the "Brain is tight" what does the fuck face mean? and what are the causes?

* Brain is full of fluid * usually from cerebral edema or increasing ICP

Anesthesia for Neurosurgery: What can you do if the surgeaon says the brain is tight? or the ICP is high or there is cerebral edema forming in a surgery?

* Commiincate w/ the surgeon * Dexamethasone * Fluid restriction * Osmotic diuretics * Moderate hyperventilation (PaCO2 25-20 mmHg) * Mannitol (0.25-1g/kg IV) * Loop Diuretics

Anesthesia for Neurosurgery: although they work slow, what is an advantage of Loop Diuretics

may actually help decrease the production of CSF

Anesthesia for Neurosurgery: Preop prep whata are 2 things you really want to look in the chart for? dont say consent or something stupid.. somthing specific for the neuro pt

* CT/MRI * Neurological exams

Anesthesia for Neurosurgery: Preop prep what are 3 main meds you want to have and/or give

* Corticosteroids * Diuretics * Anticonvulsants

Anesthesia for Neurosurgery: Preop prep why is it important to check labs

* Steroid induced Hyperglycemia * Electrolyte disturbances d/t diuretics * Anticonvulsanr levels

Anesthesia for Neurosurgery: Monitoring what monitors do you want?

* Standard ASA * A-Line (may zero at the head to give acurate CPP) * Bladder cath * CVP (if vasoactive drugs or blood therapy is possible)

Anesthesia for Neurosurgery: Induction what is the main goal?

* Achieve a sufficiant level; of anesthesia before the stimulation of DL w/o compromising CPP by increasing ICP or decresing MAP

Anesthesia for Neurosurgery: Induction what should you always have available?

vasoactive support

Anesthesia for Neurosurgery: Maintenace you want to optimize what?

CPP

## Footnote Anesthesia for Neurosurgery: Maintenace you want to minimize what?

ICP

Anesthesia for Neurosurgery: Maintenace what do you want to keep EtCO2?

* 28-33 (PaCO2 30-35mmHg)

Anesthesia for Neurosurgery: Maintenace try to keeo MAC of agent at what level?

0.6 or lower

Anesthesia for Neurosurgery: Maintenace why do you want to avoid directing acting vasopressors like (NTG/Nipride/CCB) until after the dura is opened

* B/c Direct acting Vasodilators increase CBF and ICP while decreasing B/P

Anesthesia for Neurosurgery: Maintenace VAAs case a dose related _____ in amplitude and ____ in latency of the cortical components of medial nerve somatosensory evoked potentials

decrease increase

Anesthesia for Neurosurgery: Maintenace rapidly infused mannitol can cause what?

Hypotension

Anesthesia for Neurosurgery: Emergence when is a good time to get pt back breathing

whan skin is getting closed

Anesthesia for Neurosurgery: Emergence many CRNA's give lido 1.5mg/kg how long b4 suctining to supress cough reflex

3-5 min

Anesthesia for Neurosurgery: Emergence carefully considr opioid needs and do not give additional opioid for ___ min b4 the end of sx if you can help it

30 min

Anesthesia for Neurosurgery: Emergence why would you not want to give opioids 30 min b4 sx end?

* delayed wakeup * Interference w/ pupil dilation/assessment

Anesthesia for Neurosurgery: Emergence is post op pain a real big concern

nope

Posterior Fossa considerations: what are the greatest concerns for this sx

* Obstructive hydrocephalus * brain stem injury * Positioning * Pneumocephalus * Postural hypotension * VAE

Anesthesia for Neurosurgery Posterior Fossa: whenever the pt os positioned w/ the head above the heart, there is a chance for what?

VAE

Anesthesia for Neurosurgery Posterior Fossa: b/c of the risk f sitting many surgeons are doing these sx in what position now?

Prone

Anesthesia for Neurosurgery Posterior Fossa: brain injury can occur 2ndary to what 2 things

trauma Swelling

Anesthesia for Neurosurgery Posterior Fossa: what can occur from the tractioon during sx

ischemia

Anesthesia for Neurosurgery Posterior Fossa: you should anticipate what changes abruptly

BP and HR

Anesthesia for Neurosurgery Posterior Fossa: what do you want to look for with return of spont ventilation

Irregular breathing patterns

VAE: can occur in any sx w/ head above what?

the heart

VAE: can be caused whent he _____ \_\_\_\_\_ in cut edges of bone do not collapse when transected

venous sinus

VAE: Microvascular bubbles can precipitate bronchoconstriction and release of endothelial mediators causing what?

Pulmonary edema

VAE: the air can reach the coronary system in pt's w/ a ____ \_\_\_ ____ (20% of population) causing an MI or CVA

Patent foramen ovale

VAE: these occur in \_\_\_-\_\_\_% of all sitting craniotomies

25-40%

VAE: the use of ____ can worsen the VAE and should be avoided!

N2O

VAE: what is the most sensitive way to detect an VAE?

transesophageal Echo

VAE: what are other ways to detect VAE?

Precordial Precordial US Decreased EtCO2 (usually seen B4 hemodynamic changes) Increased Et nitrogen Mill Wheel Murmur

VAE: treatment

1. Notify surgeon 2. flood operative area w/ NS & bone wax to Bone edges 3. Gentle compression of IJs 4. Head down 5. D/C N2O 6. 100% O2 7. Volume infusion 8. Vasopressors

what is the most common cause of intracranial hemorrhage?

Intracranial Aneurysms

Anesthesia for Intracranial Aneurysms: S/s

* Severe H/A * N/V * Focla neuro signs * Decreased LOC

Anesthesia for Intracranial Aneurysms: complications of sx

* death * re-bleeding * Vasospasms

Anesthesia for Intracranial Aneurysms: Induction what is triple H therapy

Hypervolemia hemodilution Hypertension

Anesthesia for Intracranial Aneurysms: everything else is the same as all other crani's

only difference is you give fluids to these and ask sx if they want HTN or HYpotension

Anesthesia for Spinal Cord transection: Paralysis of lower extremities

paraplegia

Anesthesia for Spinal Cord transection: paralysis of all extremities

quadriplegia

enough easy shit

hope you feel good about yourself

Anesthesia for Spinal Cord transection: what is the most comon cause?

* Trauma * Cervical spine

Anesthesia for Spinal Cord transection: the hemodynamic instability depends on what?

Level of injury

Anesthesia for Spinal Cord transection: what is our main concern with airway?

Is c-spine clear

Anesthesia for Spinal Cord transection: can you use SCh?

yep if in teh 1st 24 hours

Anesthesia for Spinal Cord transection: is HYPO or HYPER thermia a hazard

HYPOthermia

Anesthesia for Spinal Cord transection: what d/o may thay get?

Autonomic dysreflexia (autonomic Hyperreflexia)

Autonomic dysreflexia (autonomic Hyperreflexia) when does this occur

Post spinal cord injury

Autonomic dysreflexia (autonomic Hyperreflexia) lesions ___ and above are very susceptible

Autonomic dysreflexia (autonomic Hyperreflexia) occurs in 85% of pt's with lesions ___ and Above

Autonomic dysreflexia (autonomic Hyperreflexia) lesions of ___ to ___ may also be susceptible

T6-T10

## Footnote Autonomic dysreflexia (autonomic Hyperreflexia) \_\_\_ and below are not usually susceptible

T10

Autonomic dysreflexia (autonomic Hyperreflexia) the ____ the injury the less likely it is to occur

Older

Autonomic dysreflexia (autonomic Hyperreflexia) is untreated it can lead to \_\_\_, \_\_\_, and \_\_\_\_\_

* Sz * Stroke * Death

Autonomic dysreflexia (autonomic Hyperreflexia) basically it is an over activity of the ___ \_\_\_ \_\_\_

Autonomic Nervous System (ANS)

Autonomic dysreflexia (autonomic Hyperreflexia) manifest in anesthesia as an abrupt _____ w. barorecptor mediated \_\_\_\_\_

HTN Bradycardia

Autonomic dysreflexia (autonomic Hyperreflexia) \_\_\_\_ or _____ stimulation leads to a reflex SNS vasoconstriction below the level of the lesion

cutaneus Visceral

Autonomic dysreflexia (autonomic Hyperreflexia) the problem occurs b/c _____ impulses from the CNS cannot reach the level below the lesion

Vasodilatory

Autonomic dysreflexia (autonomic Hyperreflexia) what type of anesthesia os most effective to prevent this?

Spinal (this is from her ppt, when i did research before on this subject spinal does not really prevent this at all)

Autonomic dysreflexia (autonomic Hyperreflexia) treatmemnt may require what infusion

Nipride

Thats it ya!!!! time for your reward