Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

SRNA4TopicsAnesthesia > VALLEY: CNS MONITORING > Flashcards

VALLEY: CNS MONITORING Flashcards

1
Q

4 indications for EEG monitoring during anesthesia

A
  1. carotid endartercetomy
  2. CPB procedures
  3. Cerebrovascular surgery
  4. When burst suppression is desirable for cerebral protection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

2 indications for EEG monitoring in ICU

A

Barbiturate coma for patients with TBI

When subclinical seizures are suspected.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How many mV are generated by EEG signals

A

0.1 mV which is 100 microVolts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

EEG waves are

A

Alpha
Beta
Delta
Theta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

EEG waves are categorized based on

A

Frequency and amplitude

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Lowest frequency wave and range

A

Delta waves (0-4Hz)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Greatest amplitude waves in the EEG

A

Delta waves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Slighly lower amplitude than delta waves

A

Theta waves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Theta waves frequency

A

Theta 4-7 Hz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Alpha waves are typically recorded over the

A

posterior aspect of the head during awake, alert, but relaxed activities.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Alpha waves amplitude

A

have an intermediate amplitude
Alpha < Delta =Theta
Alpha > Beta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Alpha Waves frequency

A

frequency range of 8- 12 Hz.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Waves are the highest frequency

A

beta (> 12 Hz),

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Lowest amplitude waveforms

A

Beta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Are recorded predominantly over the frontal areas of the head

A

Beta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Delta waves are seen when?

A

Delta waves (0-4 Hz) are seen in the sleeping adult, but are considered abnormal in the awake adult.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Delta waves seen which pathology

A

Delta waves are also seen in encephalopathy, deep

coma, and deep anesthesia.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Theta waves are seen in

A 
Theta waves (4-7 Hz) are seen in sleep and in deep
anesthesia.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Prominent alpha wave activity (7-12 Hz) is characteristic of

A

awake, alert, but relaxed activities.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

An ‘eyes closed’ resting alpha pattern is the

A

baseline awake pattern used when anesthetic effects on the EEG are described

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Are characteristic of aroused, attentive, active thinking

A

Beta waves (> 12 Hz)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What happens to the electroencephalography (EEG) waveforms as anesthetic depth increases?

A

Increasing depth of anesthesia from the awake state is characterized by increased amplitude and synchrony in the EEG waveforms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

As anesthetic depth increases, what happens ?

A

periods of electrical silence occupy greater proportions of the electroencephalogram (EEG).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is Electrical silence in the EEG

A

period of electrical silence in an EEG is called an isoelectric EEG pattern.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What MAC correlates with an isoelectric EEG pattern?

A

An isoelectric pattern dominates the EEG in the range of 1.5 to 2.0 MAC.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

During certain surgical procedures, maximal suppression of cerebral metabolic rate is desirable why?

A

to protect the brain during an ischemic insult

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

During certain surgical procedures, maximal suppression of cerebral metabolic rate is desirable to protect the brain
during an ischemic insult. Under such circumstances, the anesthetic agent can be

A

titrated against the EEG until the desired effect is achieved

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Typically Typically, instead of an isoelectric EEG, the goal is a state called

A

called burst suppression.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Characterize “burst suppression” on the electroencephalogram

A

(EEG) burst suppression is characterized by periods
of isoelectric EEG punctuated by “bursts” of EEG activity. The “burst” is high-frequency activity and the “suppression” is O.S· to several-second periods of isoelectric activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

The electroencephalogram {EEG) is occasionally used during cerebrovascular surgery to confirm

A

adequate cerebral oxygenation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Identify four conditions o agents that can produce EEG changes mimicking cerebral ischemia (HEMA)

A

(1) hypothermia,
(2) electrolyte disturbances,
(3) marked hypocapnia, and
(4) anesthetic agents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

When would you use sensory evoked potential monitoring?

A

The primary application of sensory evoked potential monitoring (somatosensory, brainstem auditory, visual) is to assess continually the function and integrity of neural pathways

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Monitor the spinal cord or or cranial nerve II {visual).

A

somatosensory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Monitor cranial nerve VIII

A

(brainstem auditory),

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Evoked potentials are used during

A

resection of spinal cord tumors, corrective surgery of the spine and cranial tumor resection.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

How are somatosensory evoked potentials elicited?

A

by electrically stimulating tibial, ulnar or radial nerves.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

SSEP neurons excited are

A

Low threshold sensory neurons (those that carry touch and pressure sensations) are excited

38
Q

What is the value of somatosensory evoked potential monitoring?

A

monitor the integrity of the posterior (dorsal) spinal cord where the sensory tracts (cuneatus and gracilis) of the dorsal-lemniscal system are located.

39
Q

Somatosensory evoked potential (SSEP} monitoring assesses the integrity of which region of spinal cord: dorsal, lateral, or ventral?

A

SSEP monitoring assesses the integrity of the dorsal cord.

40
Q

Where are recording electrodes placed for somatosensory evoked potential monitoring if the tibial nerves are stimulated bilaterally?

A

recorded from electrodes placed between the ears on the scalp. The crucial electrode is placed midway
between each ear.

41
Q

For SSEPs , where is the crucial electrode placed

A

Midway between each ear.

42
Q

What happens to the somatosensory evoked potential (SSEP) when the patient undergoing laminectomy is paralyzed with a muscle relaxant?

A

Nothing. Neuromuscular blockade will not alter transmission of action potentials in the sensory tracts.

43
Q

SSEPs: All anesthetic agents except muscle relaxants

A

depress SSEPs to a varying degree.

44
Q

How are evoked potentials altered by volatile anesthetics?

A

Volatile anesthetics, especially high concentrations (> 1 MAC), produce dose-dependent increases in latency and decreases in amplitude of evoked potentials.

45
Q 
Which volatile inhalational agent LEAST depresses the amplitude and increases the latency of the somatosensory
evoked potential (SSEP)?
A

Halothane

46
Q

Which volatile inhalational agent MOST depresses the

amplitude and increases the latency of the SSEP?

A

Enflurane

47
Q

How does nitrous oxide affect latency and amplitude of the somatosensory evoked potential?

A

Nitrous oxide causes a decrease in amplitude without a change in latency of the somatosensory evoked potential when used alone or when added to opioid or volatile anesthetics.

48
Q

List 5 physiologic factors that may alter sensory evoked potentials (SEPs).

A

(l) temperature. (2) hypotension, (3) hypoxia, (4) hypocarbia, and (5) • isovolemic hemodilution.

49
Q

Which physiologic factor has the greatest effect on sensory evoked potentials?

A

altered temperature affects SEPs the most, whereas

50
Q

Which physiologic factor has the least effect on sensory evoked potentials?

A

hemodilution affects SEPs the least

51
Q

SEP : Hypothermia will

A

increase latency and decrease amplitude of SEPs (latency

increases by 1 ms for each 1 ° C decrease in temperature)

52
Q

SEP: Hyperthermia will

A

decrease amplitude by up to 15%.

53
Q

SEPs are lost at which temperature

A

42C.

54
Q

MAP and SEP

A

With a mean arterial pressure less than 40 mm-Hg. there

is a progressive decrease in amplitude ofSEPs.

55
Q

A decrease in SEP amplitude is seen with hypoxia, probably due to

A

alterations in blood flow

56
Q

With an ETC02 S 25 mm-Hg, SEP.

A

latency increases

57
Q

SEP latency does not increase until the hematocrit is

A

less than 15%

58
Q

SEP amplitude does not decrease until the hematocrit is

A

less than 7%.

59
Q

Flow through what spinal arterial vessel(s) is monitored by somatosensory evoked potentials (SSEPs)?

A

SSEPs monitor flow through the posterior spinal arteries

60
Q

Arterial blood is delivered to the spinal cord via

A
  • one anterior spinal artery
  • two posterior spinal arteries and small segmental (radicular} arteries that augment flow to the anterior and posterior arteries
61
Q

The major source of blood for the spinal cord is

A

the anterior and posterior arteries.

62
Q

SSEPs monitor sensory action potentials, which ascend in tracts located in the, so

A

posterior cord

63
Q

Posterior cord ischemia resulting from hypoperfusion of the posterior spinal arteries would result in _____latency and ______amplitude of the SSEP

A

increased latency and decreased amplitude of the SSEP

64
Q

Brainstem auditory evoked potential monitoring is useful during operations involving what cranial nerve?

A

Cranial nerve VIII.

65
Q

Is brainstem auditory evoked potential monitoring appropriate for surgery for acoustic neuroma? Why or why not?

A

Yes it is appropriate, since cranial nerve VIII carries acoustic messages.

66
Q

Monitoring of what evoked potential may be useful during pituitary surgery?

A

Visual evoked potential monitoring may be used during pituitary surgery to assess direct compression of, or compromise of the blood supply to, the optic nerve and optic chiasm.

67
Q

What evoked potential (somatosensory, brainstem auditory, or visual) is monitored during transsphenoidal surgery?

A

Visual evoked potential monitoring may be employed for transsphenoidal surgery if the tumor is large and involves the optic nerves (cranial nerve II)

68
Q

Multiple drugs used in the perioperative period can influence the ability to accurately monitor

A

sensory-evoked responses (SER; e.g. somatosensory,

visual, and brainstem (auditory) evoked potentials).

69
Q

Inhalational agents, including nitrous oxide, generally have

A

more depressant effect on evoked

potentials than equipotent doses of intravenous agents.

70
Q

Propofol and thiopental

A

attenuate the amplitude of virtually all evoked potential modalities but do not obliterate them.

71
Q

Opioids and benzodiazepines on evoked potentials

A

Opioids and benzodiazepines have negligible effects on the recording of all evoked potentials

72
Q

2 drugs that have been reported to enhance the quality of signals in patients with weak baseline somatosensory evoked potential (SSEP) signals.

A

Ketamine and etomidate

73
Q

Rank the three major sensory-evoke responses-somatosensory (SSEP). visual (YEP), and brainstem/auditory
(BAPE)-based upon sensitivity to anesthetic agents

A

Visual are Very
Somatosensory are Somewhat, and
Brainstem are Barely sensitive.

74
Q

Brainstem auditory evoked potentials (BAEP) are generally very resistant to alteration by anything other than structural pathology in the brainstem. What operating room environmental variable will decrease latency and prolong interpeak intervals in BAEPs?

A

Mild hypothermia has been associated with decreased latency and prolonged interpeak intervals during brainstem auditory evoked potentials

75
Q

Where are motor evoked potentials stimulated?

A

Motor evoked potentials (MEPs) are stimulated over or in the motor region of the cerebral cortex.

76
Q

MEPs, How are they stimulated?

A

by transcranial electrical stimulation (teMEP), transcranial magnetic stimulation (tmMEP) or by direct stimulation of the motor cortex with an electrode

77
Q

Where may motor evoked potentials be monitored?

A

(1) the spinal cord, (2) a peripheral nerve, or (3) the involved muscle.

78
Q

T/F Neither sensory evoked potentials (SEPs} nor motor evoked potentials (MEPs) can be recorded at the site of stimulation.

A

True

79
Q

What is the wake-up test, and how is it performed?

A

The wake-up test is used to assess integrity of the spinal motor pathways, which are found in the anterior (ventral) cord. It is performed by lightening the anesthetic depth. The patient is asked to squeeze a hand and move
his/her feet and toes. After these maneuvers are performed, anesthesia is quickly deepened

80
Q

Where is the spinal motor pathway found

A

Anterior (ventral) cord

81
Q

The wake-up test monitors what region of spinal cord {dorsal, lateral, or ventral}?

A

The wake-up test monitors ventral cord, which is supplied by the anterior spinal artery

82
Q

During the wake up test, When the patient is awakened, he or she is asked to

A

squeeze the anesthetists hand and move his or her feet and toes.

83
Q

Motor tracts are found in the____Cord.

A

ventral cord

84
Q

Recall that the somatosensory evoked potential

monitors the _____cord.

A

dorsal

85
Q

What complications can occur during the wake-up test?

A

Extubation in the prone position,
Recall of intraoperative events (incidence, 0-20%), Myocardial ischemia, self- injury,
Dislodgement of instrumentation, and air embolus from open sinuses if the patient is breathing spontaneously and inhales vigorously.

86
Q

What agents will not alter bispectral index (BIS} monitoring?

A

the BIS is not affected by opioids or analgesics. Nitrous oxide alone will have no effect on BIS.

87
Q

Agent that may affect BIS

A

Ketamine has minimal effect on BIS, and may slightly increase BIS transiently

88
Q

What is cerebral oximetry?

A

Cerebral oximetry is a noninvasive monitor used to measure regional blood hemoglobin saturation (rS02) via near-infrared optical spectroscopy (NIRS).

89
Q

Cerebral oximetry used for patients

A

Technology is similar to that of pulse oximetry and can be used for patients at risk for stroke

90
Q

Briefly describe the technique of cerebral oximetry via near-infrared optical spectroscopy (NIRS).

A

To measure regional hemoglobin oxygen saturation (rS02) via trans cranial near-infrared spectroscopy (NIRS). an infrared light source contained in a self-adhesive patch is affixed to the forehead.Because the human skull is
translucent to infrared light, photons are transmitted through the skull and underlying tissues to the outer layers of the cerebral cortex. Adjacent sensors separate photons reflected from the skin, muscle, skull, and dura from those
of the brain tissue. NIRS measures all hemoglobin, pulsatile and nonpulsatile, in a mixed microvascular bed.

91
Q

NIRS measures

A

all hemoglobin, pulsatile and nonpulsatile, in a mixed microvascular bed.

92
Q

Cerebral oximetry has the advantage that it may be used

during

A

nonpulsatile CPB and circulatory arrest

SRNA4TopicsAnesthesia (47 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions