Neuro Monitoring

Question 1

detects decreases in perfusion and ultimately ischemia based on reductions in electrical brain activity

Answer 1

EEG

Question 2

CBF average

Answer 2

50 mL/100 gm/min but can vary regionally from 30-300 mL/100 gm/min

Question 3

CBF < 25 mL/100 gm/min =

Answer 3

slowing of EEG

Question 4

CBF ≈ 15-20 mL/100 gm/min =

Answer 4

isoelectric EEG (internal cell)

Question 5

CBF < 10 mL/100 gm/min =

Answer 5

↓ cell integrity, irreversible injury

Question 6

CPP of this will show EEG changes

Answer 6

CPP < 50 torr

Question 7

CPP of this shows ↓ cell integrity, irreversible damage

Answer 7

CPP < 25 tor

Question 8

what does an EEG monitor?

Answer 8

electrical signals of the cerebral cortex

Question 9

Readings of EEG can be misinterpreted with what 4 pathologies?

Answer 9

hypothermia,
hypercapnia,
electrolyte imbalance,
volatile anesthetic agents resemble ischemic ∆s

Question 10

affects brain focally and asymmetrically

Answer 10

ischemia

Question 11

affects brain symmetrically

Answer 11

anesthesia

Question 12

Major rhythm seen in normal
resting relaxed awake adults. stops in eye
opening and mental exertion.

Answer 12

alpha 8-12 htz

Question 13

Fast activity, alert, eyes open,

concentrating, anxious or busy thinking.

Answer 13

Beta - 13-40 Hz

Question 14

Slow activity, considered abnormal
in awake adults. Can indicate encephalopathy,
subcortical lesions, Normal in young children.

Answer 14

Theta - 4-7 Hz

Question 15

slowest frequency and highest
amplitude. Subcortical lesions and
encephalopathy, hydrocephalus. Normal in babies.

Answer 15

Delta - 1-3 Hz

Question 16

Anesthetic effects on EEG Barbiturates and Benzodiazepines

Answer 16

accentuate frequency then

decrease it.

Question 17

Opioids Anesthetic effects on EEG

Answer 17

slow frequency, increase amplitude

Question 18

Inhalation anesthetics effects on EEG

Answer 18

both frequency and amplitude are reduced

Question 19

flat line EEG associated with anesthesia

indicative of decreased metabolic oxygen demands and neuroprotective qualities.

Answer 19

Isoelectric state:

Question 20

conscious recall or

remembering exact events of previous experiences

Answer 20

Explicit (conscious) memory

Question 21

movement and ability
to respond to commands without specific conscious
recall of events (some call awareness w/o recall)

Answer 21

Implicit (unconscious) memory

Question 22

also known as “recall” is defined as a
consciousness(explicit memory) under general
anesthesia with subsequent recall of the experienced
events

Answer 22

awareness

Question 23

paralysis of un-anesthetized patients
occurring when patients are given NMB prior to
anesthesia (out of sequence, mislabeling)

Answer 23

Awake paralysis

Question 24

risk factors for awareness

Answer 24

< 60 y.o., ASA 1-2, female, elective surgery

Question 25

3 primary reasons for awareness?

Answer 25

1. light anesthesia 2. pt requires an increased level of anesthetic 3. anesthetic delivery problems

Question 26

Signs of “Light” Anesthesia and possible | awareness/recall [none reliable]

Answer 26

``` • Minor patient movement • Tearing and sweating • Autonomic nervous system changes –Tachycardia –Hypertension –Increased respiratory rate and depth if spontaneous respiration ```

Question 27

drugs that Mask physiological responses to light anesthesia

Answer 27

–Amphetamines –Beta blockers –Calcium channel blockers -NMB

Question 28

what vitamin interferes with anesthesia levels?

Answer 28

vit C

Question 29

Reducing the Risks of Awareness Claims

Answer 29

- premedicate with amnestic drugs - benzo, scopalamine | - MAC >.7 monitoring expired

Question 30

Quantitative EEG index assessing level of | consciousness during sedation or anesthesia

Answer 30

Patient State Analyzer Array PSArray

Question 31

what regions of brain does PSArray monitor?

Answer 31

Analyzes anterior and posterior and bilateral | regions of the brain

Question 32

Analysis of raw EEG data to derive a formula-driven | numerical value indicative of level of consciousness

Answer 32

BIS

Question 33

3 things BIS takes into account?

Answer 33

–Amount of slow wave content (beta ratio) –Amount of bicoherence of all frequency pairs –Amount of burst suppression present (ratio)

Question 34

General anesthesia is a BIS reading of

Answer 34

40-60

Question 35

BIS value of 0 represents

Answer 35

flat line EEG

Question 36

BIS value > | 70 is associated with

Answer 36

increased probability of | recall

Question 37

Arguments against relying on BIS

Answer 37

``` hypothermia shivering unipolar cautery ketamine and N2O head trauma patient position ```

Question 38

Electrical signals produced in response to | various stimuli by the nervous system to monitor neuronal pathway

Answer 38

Evoked Potentials

Question 39

4 types of evoked potentials

Answer 39

somatosensory (SSEP), motor | MEP), auditory (BAEP), and visual (VEP

Question 40

how t general anesthetics affect Evoked Potential Monitoring

Answer 40

inhibit neurotransmission of impulses

Question 41

produce a dose-dependent increase | in SSEP latency and decrease in amplitude

Answer 41

volatiles

Question 42

IV anesthetics affect SSEP ___ inhaled anesthetics

Answer 42

less than

Question 43

meds that increase SSEP amplitude

Answer 43

Etomidate and Ketamine

Question 44

have little to no affect on SSEP amplitude

Answer 44

opioids

Question 45

nitrous affect on SSEP amplitude?

Answer 45

60% decreased SSEP, but had no effect on latency

Question 46

decrease SSEP

Answer 46

reduction in blood flow

Question 47

Assesses corticospinal tracts that are not monitored by SSEP

Answer 47

Motor Evoked Potentials (MEP)

Question 48

Monitors motor response to nerve stimulation.

Answer 48

EMG

Question 49

Damage to the sensory pathway will display a

Answer 49

decreased | signal amplitude and an increased latency

Question 50

optimal MAC?

Answer 50

0.5-0.7 MAC

Question 51

valuable indicators of depth of anesthesia.

Answer 51

The rate, rhythm, and muscles used for respiration

Question 52

explain ether eye signs

Answer 52

The gaze becomes disconjugate during stage II and becomes congruent again when stage III is entered.

Question 53

No substantive changes in respiration, heart rate, pupillary activity, reflexes or muscle tone.

Answer 53

Stage I: Analgesia and Disorientation

Question 54

Respiration: irregular, breath holding/apnea, gasping. Reflexes: hyperactive. Muscle Tone: hyperactive, often thrashing extremities.

Answer 54

Stage II: Delirium, Agitation, and Excitement

Question 55

``` Medullary Paralysis (Moribund) Progressive cardiovascular collapse ```

Answer 55

stage IV