Neuro Monitoring

Question 1

Effect of volatiles on BAEP latency and amplitude?

Answer 1

Increase latency and decrease amplitude (N2O has no effect on amplitude)

Question 2

Effect of volatiles on SSEP?

Answer 2

Increase latency and decrease amplitude

Question 3

Drugs that increase SSEP amplitude?

Answer 3

Ketamine and etomidate

Question 4

Which anesthetic drugs decrease or have no effect on SSEP latency?

Answer 4

None

Question 5

Propofol effect on SSEP?

Answer 5

Increase latency, no effect on amplitude

Question 6

Fentanyl effect on BAEP?

Answer 6

No change in latency or amplitude

Question 7

Two basic types of electrophysiologic brain monitors

Answer 7

Electroencephalogram (EEG) and evoked potentials (other monitors are derived from these)

Question 8

Main cells that contribute to EEG?

Answer 8

Vertically oriented pyramidal cells of the cortex

Question 9

Name of internationally recognized EEG pattern?

Answer 9

10:20 pattern

Question 10

Why is it important to apply EEG electrodes in standard placement?

Answer 10

So that recordings can be compared to others. Also, so that the brain can be compared against itself, such as comparing activity of two sides of the brain.

Question 11

Hz is a measure of what?

Answer 11

Frequency. 1 Hz means that an event repeats once per second.

Question 12

Names and values of different frequencies (example - alpha) of EEG?

Answer 12

delta 1-4 Hz, theta 4-7 Hz, alpha 8-13 Hz, beta >13 Hz

Question 13

Normal EEG amplitude?

Answer 13

20-200 microvolts

Question 14

What happens to EEG amplitude in stage 2?

Answer 14

Bursts are seen (sleep spindles)

Question 15

Types of EEG programs?

Answer 15

Spectral edge frequency, cerebral function analyzing monitor, bispectral monitor (BIS)

Question 16

Different types of evoked potentials?

Answer 16

somatosensory (SSEP), brainstem auditory (BAEP), motor (MEP), visual (VEP)

Question 17

What does latency mean in regard to evoked potentials?

Answer 17

The time delay from peripheral stimulation to central electrical activity

Question 18

Explain the Kety-Schmit method

Answer 18

A marker is injected into arterial blood to the brain, the amount of this marker is measured in venous blood from the brain and from it an extraction ratio can be determined.

Question 19

What is the Fick principal?

Answer 19

The amount of substance taken up or eliminated by an organ is equal to the difference between venous and arterial concentrations.

Question 20

What are some of the cerebral blood flow monitoring methods?

Answer 20

jugular venous bulb oximetry, jugular thermodilution, laser doppler flowmetry, thermal clearance, transcranial doppler ultrasonography, cerebral oximetry, radioactive tracer clearance

Question 21

How does jugular venous bulb oximetry work?

Answer 21

Measures arteriovenous oxygen difference (AVDO2)

Question 22

What is one main drawback of the jugular venous bulb oximetry test?

Answer 22

You cannot tell which areas of the brain are extracting O2.

Question 23

Jugular thermodilution measures what?

Answer 23

Speed of CBF

Question 24

Laser Doppler flowmetry measures what?

Answer 24

Movement of RBC’s in specific area of the brain

Question 25

Explain how the thermal clearance test works

Answer 25

Two gold plates attached to the cortex are used to measure temperature of CBF at different points. The less difference in temperature between the two plates correlates with a higher CBF.

Question 26

Transcranial Doppler ultrasonography measures what?

Answer 26

RBC velocity in large vessels

Question 27

What monitor is known as the "pulse ox of the brain?"

Answer 27

Cerebral oximetry

Question 28

What is a normal cerebral oximetry saturation?

Answer 28

65-75% (same as mixed venous O2 sat)

Question 29

Types of radiographic monitoring?

Answer 29

PET scanning, Functional Magnetic Resonance Imaging (FMRI)