Brainscape's Knowledge GenomeTM

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


See full index

Patho/Phys 3 > IONM > Flashcards

IONM Flashcards

1
Q

The afferent input for somatosensory evoked poten tials (SSEPs) is carried through which spinal cord tract?
A. Spinocerebellar
B. Spinothalamic
C. Dorsal columns
D. Corticospinal

A

C. Dorsal Columns

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

Which of the following intravenous anesthetics is con traindicated in patients with intracranial hypertension?
A. Propofol
B. Fentanyl
C. Ketamine
D. All are acceptable

A

C. Ketamine

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

A 14-year-old girl with severe scoliosis is to undergo spine surgery. Anesthesia is maintained with fentanyl, N2O 50% in O2, vecuronium, and isoflurane. Neu rologic function of the spinal cord is monitored by SSEPs. In reference to the SSEP waveform, spinal cord ischemia would be manifested as
A. Increased amplitude and increased latency
B. Decreased amplitude and increased latency
C. Decreased amplitude and decreased latency
D. Increased amplitude and decreased latency

A

B. Decreased amplitude and increased latency

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

Which of the following is the MOST sensitive means of detecting venous air embolism (VAE)?
A. Electroencephalography (EEG)
B. Pulmonary artery catheter
C. Transesophageal echocardiography
D. Right atrial catheterization

A

C. Transesophageal echocardiography

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

Administration of vecuronium during spinal surgery may interfere with monitoring of
A. Dorsal columns
B. Corticospinal tract
C. Electrocorticography
D. Bispectral index

A

B. Corticospinal tract

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

A 13-year-old boy is anesthetized with 0.5% isoflu rane, 50% N2O, and fentanyl for scoliosis repair. So matosensory evoked potentials (SSEP) monitoring is conducted during the procedure. Which of the fol lowing structures is NOT involved in conveyance of the stimulus from the posterior tibial nerve to the ce rebral cortex?
A. Corticospinal tract
B. Medial lemniscus
C. Brain stem
D. Internal capsule

A

A. Corticospinal tract

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

A 19-year-old woman is undergoing surgery for a Har rington rod placement. General anesthesia is adminis tered with desflurane, nitrous oxide, and fentanyl. After completion of spinal instrumentation, a wake-up test is undertaken. Four thumb twitches are present when the nerve stimulator attached to the ulnar nerve is activated. The volatile anesthetic and nitrous oxide have been dis continued for 10 minutes when the patient is asked to move her hands and feet. After repeated commands, the patient still does not move her hands or feet. The most appropriate intervention at this time would be
A. 3 mg neostigmine plus 0.6 mg glycopyrrolate IV
B. 20μg naloxone IV
C. 0.1 mg flumazenil IV
D. Reduce the distraction on the rods

A

B. 20μg naloxone IV

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

Which of the following pharmacologic agents would have the LEAST effect on somatosensory evoked potentials?
A. Isoflurane
B. Nitrous oxide
C. Vecuronium
D. Etomidate

A

C. Vecuronium

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

Which of the following pharmacologic agents would have the LEAST effect on transcranial motor evoked potentials (MEPs)?
A. Isoflurane
B. Nitrous oxide
C. Etomidate
D. Fentanyl

A

D. Fentanyl

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

Ketamine
A. Decreases cerebral blood flow (CBF)
B. Augments the CO2 responsiveness of the cerebral vasculature
C. Reduces cerebral metabolic rate (CMR)
D. Increases cerebral blood volume (CBV)

A

D. Increases cerebral blood volume (CBV)

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

Etomidate does all of the following EXCEPT
A. Abolishes CO2 reactivity
B. Reduces CMRO2
C. Increases both SSEP amplitude and latency
D. Reduces CBF

A

A. Abolishes CO2 reactivity

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

What are the evoked potential modalities in IONM?

A

SSEP (somatosensory evoked potentials)
BAEP (brainstem auditory evoked potentials)
TcMEP (transcranial motor evoked potentials)
VEP (visual evoked potential)

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

What are the two types of electromyography?

A

Spontaneous and triggered

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

What can cause IONM changes intraoperatively?

A

Iatrogenic injury
surgical maneuvers
ischemia
malpositioning

-anesthetics can mimic this changes

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

Anesthetic agents work on the nervous system by altering __________ excitability via changes in _________ synaptic function or _________ conduction

A

Anesthetic agents work on the nervous system by altering neuronal excitability via changes in synaptic function or axonal conduction

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

More synapses = ___________(more/less) sensitive

A

More sensitive

The effect an anesthetic has on modality increase with the number of synapses present in the specific pathway being monitored

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

EEG y-axis records __________?

A

Voltage

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

EEG x-axis records _________?

A

Time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

EEG is used to identify what two things?

A

Decreased CBF states
Intraoperative seizures

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

What anesthetics are EEG sensitive to?

A

Potential inhalation agents
Barbiturates
Propofol
Benzos

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

What is burst suppression useful for?

A

Neuroprotection when there is a need to reduce CBF (clip) or when CBF is inadvertently reduced (rupture)

22
Q

What can rule out anesthetic changes to an EEG versus something physiologically significant?

A

Anesthesia produces global suppression of EEG

Surgical maneuvers, ischemia, and malpositionig produce focal EEG changes (not 100% of the time)

23
Q

Evoked potentials (EP) stimulate nerves and record from _________ and _________ nervous systems

A

Stimulate nerves and record from the peripheral and central nervous systems

24
Q

What is the goal of IONM of evoked potentials?

A

Monitor response latencies and amplitude for changes from the baseline established early in the procedure

25
Q

What nerves does SSEP stimulate?

A

Peripheral nerves in wrist, ankles, body, neck and head

26
Q

SSEP sends signals through what part of the spinal cord?

A

Dorsal column medial lemniscus pathway to the brain

27
Q

For SSEP what should potent inhalational agents be limited to?

A

0.5-1 MAC
Stability important

28
Q

N2O _____________ (increases/reduces) SSEP cortical amplitude and _______________ (increases/reduces) latency when used alone or in combination with halogenated agents or opioids.

A

N2O reduces SSEP cortical amplitude and increases latency when used alone or in combination with halogenated agents or opioids.

29
Q

What inhalational agent produces more profound changes in cortical SSEPs and MEPs than any other agent?

A

N2O

N2O is context sensitive and actual effects vary depending on other anesthetic agents already being delivered

30
Q

Where are transcranial motor evoked potentials (TcMEP) stimulated?

A

Primary Motor Cortex

31
Q

Where are TcMEPs recorded from?

A

Distal extremities (arms, legs, and occasionally the face)

32
Q

TcMEP latencies reflect the time it takes for the impulses to traverse the what spinal tract?

A

Corticospinal tract

UE are earlier than LE

33
Q

When are TcMEPs standardly offered?

A

Any cervical procedure in a patient with myelopathy or spinal cord injury (trauma)
Any thoracic spine procedure
Any intramedullary spinal cord tumor cases
Any thoracic aortic aneurysm cases (TEVAR)
Any cerebral aneurysm cases
Selective post-fossa/foramen magnum cases

34
Q

What three things can affect TcMEP?

A

Blood pressure (low BP)
Temperature (low temp)
Anesthesia (TIVA with no muscle relaxant preferred)

35
Q

What medication most adversely affects TcMEP?

A

MUSCLE RELAXANT

Consider Sugammadex if patient does not have 4/4 twitches, avoid redosing

36
Q

The Corticospinal tract is susceptible to anesthetic agents at what 3 sites?

A

Motor cortex

Anterior horn cells

Neuromuscular junction

37
Q

What should you ALWAYS have when doing TcMEP?

A

SOFT BITE BLOCK

High voltage stimulation of motor cortex required to produce CMAPs in distal extremities produces a strong jaw clench

38
Q

What is the effect of opioids on SSEPs and TcMEPs

A

less prominent than with inhalational agents

Produce minimal changes, though some transient depression of amplitude and increase of latency in cortical responses depending on delivery method. Spinal application produces minimal change

39
Q

Precedex effect on IONM

A

Good supplement, decreases need for opioids/barbituates/propofol

Can be problematic when >/= 0.5mcg/kg/hr with high propofol rates (creates higher stimulation threshold)

AVOID boluses which can decrease TcMEP amplitude

40
Q

Ketamine effect on IONM

A

Enhances cortical SSEP/TcMEP amplitude

Minimal subcortical/peripheral SSEP response

Contraindicated in intracranial pathology due to increased ICP/hallucinations

Avoid boluses when monitoring TcMEP

41
Q

Etomidate effect on IONM

A

Increases amplitude of cortical SSEPs and TcMEPs

Increased myoclonus (increased cortical excitability)

42
Q

Propofol effect on IONM

A

Induction bolus reduces cortical SSEP/TcMEP amplitude but with rapid recovery

Ideal agent for infusion in conjunction with other TIVA agents to avoid inhaled agents

43
Q

What is the best anesthetic for SSEP monitoring

A

Inhalational agent no greater than 1.0 MAC preferred

Muscle relaxant is acceptable (and encouraged)

Notify Neurophysiology when giving bolus of Propofol, narcotic, Ketamine

Prefer no Nitrous Oxide, if needed - less than 50% is typically acceptable case by case basis

Infusions of remifentanil, precedex, and propofol are acceptable

44
Q

What is the best anesthetic for SSEP/Lower extremity EMG (lumbar fusion)

A

Inhalational agent no greater than 1.0 MAC preferred

Muscle relaxant can be given at the beginning of the procedure (surgeon will want complete paralysis to last through the exposure part of the procedure)

At least 2/4 twitches are needed to record EMG when requested by Neurophysiology or surgeon (usually during decompression/instrumentation parts of the procedure).

4/4 twitches will be needed to test the pedicle screws

Notify Neurophysiology when giving bolus of Propofol, narcotic, Ketamine

Infusions of remifentanil, precedex, and propofol are acceptable

Prefer no Nitrous Oxide, if needed - less than 50% is typically acceptable case by case basis

45
Q

What is the best anesthetic method for cranial nerve EMG

A

Muscle relaxant can often be given at the beginning of the procedure for intubation/positioning (succinylcholine and small doses of rocuronium to get through positioning are typically acceptable)

4/4 twitches are needed to record cranial nerve EMG.

46
Q

What medication should be avoided completed any case with EMG from the start (thyroidectomy, parotidectomy, XLIF, MVD7)

A

Non-depolarizing muscle relaxant should not be given at induction or any time during the procedure (succinylcholine is acceptable for intubation)

47
Q

What is the best anesthetic method for any case with TcMEP?

A

TIVA strongly preferred (no inhalational agent or Nitrous Oxide) - Remifentanil and propofol best

Precedex infusions should be kept less than 0.5mcg/kg/hr (causes increased threshold of stimulation throughout the case requiring higher and higher stimulation intensity)

Prefer no muscle relaxant to be used, though surgeons sometimes do request muscle relaxant for exposure. No muscle relaxant can be used when actually recording TcMEP (4/4 strong twitches)

Avoid boluses of Propofol or narcotic when TcMEP is being collected frequently

Soft Bite-block required prior to any TcMEP data collection

48
Q

What anesthetic method is best for any case with EEG?

A

Inhalational agent no greater than 1.0 MAC preferred

Notify Neurophysiology when giving bolus of

Propofol, narcotics, benzos, or barbiturates

Prefer no Nitrous Oxide, if needed - less than 50% is typically acceptable case by case basis

49
Q

What anesthetic method is best for VEP?

A

TIVA strongly preferred (no inhalational agent or Nitrous Oxide) - Remifentanil and propofol best

Propofol should be run at the lowest infusion rate that Anesthesia is comfortable running

Precedex infusions should be kept less than 0.5mcg/kg/hr (can help reduce propofol requirement)

  • Rarely used in Intraoperative Neuromonitoring
50
Q

What IONM does not have any anesthesia restrictions?

A

BSER (brainstem auditory evoked potentials)

51
Q

Cheat sheet for how anesthetic agents affect SSEP and MEP

A

Patho/Phys 3 (4 decks)

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