Neuro

Question 1

What is the cardiovascular response to ECT?

Answer 1

Transient bradycardia (occasional asystole)

leads to hypertension and tachycardia

Question 2

Do you want patients undergoing ECT to be hypo or hypercapneic?

Answer 2

Hypo

Improves the quality and duration of the seizure

Question 3

What artery supplies 70% of the brain’s blood supply?

Answer 3

the two internal carotid arteries

The rest comes from the vertebral arteries

Question 4

What percent of oxygen consumption does the brain use?

Answer 4

20%

Question 5

What percent of the body’s glucose is used up by the brain?

Answer 5

25%

Question 6

What percentage of the CO goes to the brain?

Answer 6

15%

Question 7

Cerebral autoregulation of blood flow remains intact for MAP between _____ and ______

Answer 7

60-160

Question 8

What is the Monroe-Kellie doctrine?

Answer 8

an increase in the volume of one compartment in the brain will increase ICP unless another compartment decreases its volume by the same amount

Question 9

What is normal ICP?

Answer 9

7-15

Question 10

Poor neurologic outcomes are associated with ICP above _____

Answer 10

20-25

Question 11

What most commonly causes an increase in ICP?

Answer 11

cerebral edema

Question 12

There are three types of cerebral edema:

Answer 12

Cytotoxic (increased intracellular water from membrane breakdown)

Vasogenic (usually around tumors, abscesses, or contusions)

Interstitial (increased extracellular water from hydrocephalus or osmotic gradients)

Question 13

How do acute and chronic spinal cord injuries differ in manifestation?

Answer 13

Acute: flaccid paralysis and hypotension

Chronic: spastic paralysis, pain, autonomic hyperreflexia

Question 14

What constitutes a significant change to the SSEP waveform?

Answer 14

amplitude decreases by 50%

Latency increases by 10%

Question 15

MEPS are useful for monitoring:

Answer 15

motor cortex and anterolateral spinal cord

Question 16

What constitutes a significant change in MEPs?

Answer 16

decreased amplitude of 50%

Need to increase the stimulation intensity to get a signal

changes in latency aren’t as worrisome

Question 17

What is EMG used for?

Answer 17

To measure the integrity of distinct peripheral or cranial nerves/nerve roots

Question 18

EMGs measure _______

SSEPs and MEPs measure ______

Answer 18

EMGs measure thermal and mechanical injury but NOT ischemia

SSEPs/MEPs measure monitor all three

Question 19

Is EMG effected by NMBAs?

Answer 19

Very much so

Question 20

What are BAEPs used for?

Answer 20

assess integrity of hearing in an unconscious patient

Question 21

What are VEPs used for?

Answer 21

Monitor the integrity of the visual tract during anesthesia

Question 22

Are VEPs sensitive to NMBAs?

Answer 22

yes! in fact they’re sensitive to all anesthetics so it’s very difficult to get and interpret signals, so they’re not used very often

Question 23

If MEPs are being monitored, what’s the most common anesthetic technique?

Answer 23

TIVA

Can use 0.5 MAC inhaled volatile anesthetic

Question 24

If a Transcranial doppler detects increased flow velocity, what does that indicate?

Answer 24

Stenosis, emboli, or vasospasm

Question 25

Can Transcranial doppler be used to determined cerebral blood flow?

Answer 25

No. It's measuring velocity (speed of flow), not amount of flow

Question 26

Which ICP Lundberg waves are pathologic?

Answer 26

A waves occur due to intense vasodilation and are always pathologic

Question 27

Which is more effective at lowering CMRO2: anesthesia or hypothermia?

Answer 27

Hypothermia!

Question 28

How does hyperthermia impact cerebral ischemia?

Answer 28

It's really, really bad For every 1 degree Celsius rise, infarct size triples

Question 29

What degree of midline shift indicates severe pathology?

Answer 29

Obviously any shift is bad, but over 5mm is advanced

Question 30

The induction of patients with elevated ICP should be _____ and \_\_\_\_\_

Answer 30

slow and controlled

Question 31

What's worse in patients with elevated ICP: hypertension or hypotension?

Answer 31

Hypotension YOU CANNOT decrease CPP or it won't be sufficient to overcome ICP

Question 32

For patients with elevated ICP, how much volatile anesthetic should they receive?

Answer 32

A maximum of 0.5 MAC if at all

Question 33

What is the optimal anesthesia technique for neurosurgery?

Answer 33

TIVA with propofol and remifenanil

Question 34

If you can't give muscle relaxants or volatile anesthetics, what can you give in a neuro case to ensure immobility?

Answer 34

A remifentanil infusion of 0.2 mcg/kg/min can achieve immobility

Question 35

Describe ventilatory management of a patient during neurosurgery.

Answer 35

Vt 6-8 ml/kg Peak pressures \< 40 No PEEP since it impedes cerebral vascular drainage

Question 36

Why is PPV preferred in neurosurgery?

Answer 36

You'd think spontaneous breathing would be better because it wouldn't increase intrathoracic pressure BUT PPV allows tight control of CO2 and helps prevent Venous Air Emboli by avoiding negative pressure in the thorax

Question 37

Which neurosurgical procedures constitute a high risk of bleeding?

Answer 37

AVM resection Aneurysm clippings tumor craniotomies that invade the sinuses

Question 38

Should a patient have a type and cross for spinal surgery?

Answer 38

They should be T&C and have units available in the room High risk of hemorrhage

Question 39

Controlling hypertension during emergence is CRITICAL in which neurosurgery?

Answer 39

AVM resection

Question 40

Decadron is not a good PONV prevention tactic in which patients?

Answer 40

Those having pituitary axis surgery can suppress the HPA axis and create a false positive for postop hypopituitarism

Question 41

The most common metastatic tumors to the brain are from:

Answer 41

melanoma lung breast kidney

Question 42

You should be vigilant while giving mannitol to patients with which comorbidities?

Answer 42

Any disease where a temporary massive increase in vascular volume will be hard to handle: CHF pulmonary edema renal failure

Question 43

What kind of fluid status is ideal during neurosurgery?

Answer 43

Euvolemia with dextrose free isotonic crystalloids or colloids

Question 44

What surgical positions put patients at risk for VAE?

Answer 44

when the operative site is above the level of the RA in the presence of open, non-collapsible venous channels

Question 45

Prevention measures for VAE include:

Answer 45

decreasing the heigh difference between the operative site and the heart as much as possible maintaining euvolemia using bone wax to occlude open sinuses

Question 46

Treatment of VAE includes:

Answer 46

notifying the surgeon to flood the field Administering 100% O2 Aspirating air through a CVC

Question 47

What would you be aware of in developing an anesthetic plan for a patient with a GH secreting tumor?

Answer 47

Acromegaly of the mandible and hypertrophy of tissues → OSA and difficulty ventilating/intubating They'll need a smaller ETT prone to cardiac rhythm issues and hypertrophic cardiomyopathy (avoid cardiac depressants)

Question 48

What should you be aware of in the patient with an ACTH secreting tumor?

Answer 48

glucose intolerance fragile skin impaired wound healing hypertension

Question 49

SIADH is common with ______ tumors

Answer 49

Sellar

Question 50

What are risk factors of cerebral aneurysm rupture?

Answer 50

Over 40 Female Smoker Hypertension Connective tissue disorder

Question 51

What is the most common cause of SAH?

Answer 51

Ruptured aneurysm

Question 52

When is a cerebral vasospasm most likely to occur with an aneurysm?

Answer 52

greater than 72 hours

Question 53

There are two drugs proven to reduce the risk of vasospasm:

Answer 53

nimodipine and statins

Question 54

What is the greatest risk from AVM surgery?

Answer 54

Bleeding!

Question 55

Why is hypotension so dangerous with AVM resections?

Answer 55

Many of these patients have seizures or focal neurologic deficits due to ischemic steal hypotension makes these worse and can trigger a seizure

Question 56

What is Normal Perfusion Pressure Breakthrough?

Answer 56

AVMs inhibit the autoregulation of the arterioles in the healthy tissue surrounding them, and they eventually lose the ability to vasoconstrict. The AVM sucks all the blood from them. But when the AVM has been resected, these vessels are filled with blood (the AVM is no longer stealing it) but can't constrict back down, and so they lead to hyperemia, edema, headache and postop bleeding

Question 57

What percent of patient who undergo AVM resection have seizures postop?

Answer 57

50%! They have to be on anticonvulsants postop

Question 58

If a patient becomes agitated, confused, or unresponsive following carotid occlusion during CEA, what should the anesthesiologist do?

Answer 58

Assume cerebral ischemia is the culprit and increase BP to 20% over baseline SBP

Question 59

What is stump pressure?

Answer 59

The pressure in the internal carotid artery measured distal to the cross clamp supposed to reflex collateral blood flow through the circle of Willis should be greater than 50

Question 60

Usually if there is a discrete epileptic focus, it is located in which lobe?

Answer 60

temporal Temporal lobectomy with amygdalohippocampectomy is the most common surgery to treat epilepsy

Question 61

If a patient has a seizure during an awake craniotomy, what should be done?

Answer 61

Poor cold saline over the brain surface Give 20mg propofol

Question 62

In spinal surgeries, MAP should be kept greater than:

Answer 62

85