APEX: MISC MONITORS Flashcards

1
Q

Best describes the CEREBRAL OXIMETRY

A

A greater than 25% change from baseline suggests a REDUCTION in CEREBRAL OXYGENATION

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2
Q

Cerebral oximetry is a

A

noninvasive technique that utilizes near infrared spectroscopy NIRS to measure regional (NOT GLOBAL) cerebral oxygenation

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3
Q

What is cerebral oximetry based on

A

The principle that decrease cerebral oxygen delivery lead to increase cerebral oxygen extraction and decrease venous hgb saturation

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4
Q

Cerebral oximetry sensor is placed where

A

Patient’s scale over the frontral lobe

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5
Q

Cerebral oximetry contains a light emiting

A

Diode and 2 light sensor: surface photodetector and a DEEP photodetector

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6
Q

The infrared light in cerebral oximetry follos

A

Elliptical pathway from the emitting diode –>scalp –> skull –> brain–> skull –> scalp–> Photodetectors

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7
Q

Cerebral oximetry relies on the facts that

A

Cerebral blood volume is 1 part arterial and 3 parts venous. 75% of the blood in the brain is on the venous side of circulation

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8
Q

Can NIRS detect pulsatile blood flow?

A

no

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9
Q

Since NIRS does not have ability to detect pulsatile BF, it is primarily a measure of what?

A

Venous oxyhemoglobin saturation and Oxygen extraction.

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10
Q

Can contaminate the signal of NIRS

A

Scalp hypoxia , may falsely interpret it as brain ischemia

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11
Q

EEG waves from high to low frequency (BAT-D)

A

Beta
Alpha
Theta
Delta

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12
Q

EEG measures the difference between

A

Electrical potentials in multiple regions of the brain.

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13
Q

EEG Provides information about electrical activity of the

A

Cerebral cortex

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14
Q

EEG provide little information about the

A

Subcortical structures, spinal cord and the cranial and peripheral nerves.

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15
Q

High Frequency low voltage waves

A

beta waves

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16
Q

Beta waves associated with

A

Awake mental stimulation and LIGHT ANESTHESIA

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17
Q

Beta frequencies

A

13-30 cycles/sec

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18
Q

Alpha waves associated with

A

Awake but RESTFUL STATE WITH EYES CLOSED.

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19
Q

Alpha frequencies

A

8-12 cycles/second

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20
Q

Theta waves frequencies

A

4-7 cycles/second

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21
Q

Theta wave associated with

A

GA

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22
Q

Waves associated with children during normal sleep

A

Theta waves

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23
Q

Delta waves associated with

A

GA, DEEP SLEEP, brain ischemia or injury

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24
Q

Burst suppression is associated with

A

GA, hypothermia, CBP, Cerebral ischemia (especially if its UNILATERAL burst suppression)

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25
Q

Isoelectricity is

A

absence of electrical activity

Associated with very deep anesthesia and death.

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26
Q

How brain waves change during anesthesia? Induction

A

Increased beta wave activity

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27
Q

How brain waves change during anesthesia? light anesthesia

A

Increased beta wave activity

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28
Q

Waves the predominate during GA

A

Theta and beta

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29
Q

Produces burst suppresion

A

Deep anesthesia

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30
Q

At what MAC does GA cause complete suppresion or isoelectricity?

A

1.5-2.0 MAC

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31
Q

Nitrous and EEG

A

When administered alone, Increases beta wave activity

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32
Q

Can increase EPILEPTIFORM EEG activity

A

Sevoflurane

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33
Q

Can cause myoclonus

A

Etomidate

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34
Q

Can cause myoclonus but this is not associated with epeleptiform EEG activity

A

Etomidate

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35
Q

Ketamine on EEG

A

Increase high frequency cortical activity and may confuse EEG interpretation - the patient may be deeper than the EEG SUGGESTS>

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36
Q

When does burst suppresion occur with temp

A

hypothermia, especially with CPB

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37
Q

This kind of burst suppresion suggest cerebral ischemia

A

Unilateral burst suppression .

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38
Q

EEG usefulness for infarction?

A

EEG provides a sensitive measure of brain tissue at risk of infarction

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39
Q

The brain requires an

A

Adequate perfusion pressure to provide a steady supply of oxygen and glucose.

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40
Q

In the absence of these substrates the brain is unable to maintain its electrical function

A

Oxygen

Glucose.

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41
Q

You are seeing the development of new delta waves during anesthetic maintenance may signify

A

that brain is at risk for ISCHEMIA

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42
Q

Circumstance that mimic cerebral ischemia:

A

Deep anesthesia
Hypothermia
Hypocarbia

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43
Q

EEG monitoring useful during the following neck procedure:

A

Carotid endarterctomy

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44
Q

EEG monitoring useful during these brain surgeries

A

AV malformations
Cerebral aneurysm
Epilepsy dx and tx

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45
Q

EEG monitoring useful for other procedures

A

ASsessment of barbiturate coma
Deliberate hypotension
CPB
Coma and death.

46
Q

Bispectral index monitor with ketamine

A

Ketamine falsely elevates the BIS value

47
Q

BIS and burst suppresion

A

Burst suppresion begins at a BIS value of 20

48
Q

While most general anesthetics reduce HIGH FREQUENCY EEG activity , Ketamine

A

Increases them

49
Q

There is a

A

20-30 secong lag between measuring the EEG and computing BIS value.

50
Q

Patient safety index monitor is similar to BIS in what ways?

A

Measures EEG, runs the data through an algorithm and displays the number that indicates the level of anesthetic depth.

51
Q

Unlike BIS, the patient safety monitor target for GA is

A

40-60

52
Q

Unlike BIS, the patient safety monitor target for PSA is

A

25-50

53
Q

BIS number are from

A

0-100

54
Q

BIS number of 100

A

Fully awake

55
Q

BIS NUMBER of 80

A

Light-moderate sedation

56
Q

BIS 40-60

A

General Anesthesia

57
Q

BIS number associated with low probability of explicit recall

A

40-60

58
Q

BIS 40

A

Deep hypnotic state

59
Q

BIS 20

A

Burst suppression

60
Q

BIS 0

A

Absence of cerebral activity .

61
Q

As the anesthesia becomes deeper, the EEG waveforms exhibits a (FLAH)

A

Lower frequency

HIGHER AMPLITUDE

62
Q

2 exceptions that can interfere with BIS value

A

Nitrous oxide

63
Q

Limitations of BIS

A

There is a 20-30 second lag between measuring the EEG and computing BIS value.

64
Q

Can impair the accuracy of the BIS

A
Hypothermia
EMG interference (increase muscle tone)
65
Q

BIS and children

A

less accurate with children.

66
Q

Data to suggest that a BIS value < 40 for more than 5 minutes correlates with

A

INCREASED 5 year mortality

67
Q

Patient safety index monitor target range of GA

A

25-50

68
Q

Function of the LINE ISOLATION MONITOR

A

ALarm sounds when the OR power supply becomes grounded.

69
Q

The electrical supply in the OR is

A

NOt grounded

70
Q

Why is LIM alerting the OR staff that the power supply is grounded important?

A

Because a second electrical fault can lead to an electric shock

71
Q

Does the line isolation monitor protect the patient from microshock?

A

no

72
Q

Does the line isolation monitor Isolate the electrical equipment from the ground?

A

No

73
Q

Does the line isolation monitor cut off the power supply to a piece of equipment that has become grounded?

A

no

74
Q

Electricity obeys this law

A

Ohm’s => Voltage (driving pressure) = Current (flow) x Impedance (resistance)

75
Q

To receive a shock, a person must be

A

part of and complete an electrical circuit.

76
Q

For current to flow there has to be

A

voltage pressure across an impedance (resistance)

77
Q

If a closed circuit exists,

A

then exposure to a live electricity source provides an elctromotive force (voltage) that pushes the current through an impedance (resistance). The impedance can be you or the patient.

78
Q

An electric current that enters the body will exit the body

A

Along the path of least resistance.

79
Q

Consequences of electrical injury?

A

Cardiac arrythmias
Nerve injury - muscle contraction and diaphragmatic paralysis
Thermal injury ( damage to internal organs)

80
Q

Macroshock is a

A

Larger amount of current that is applied to the external surface of the body

81
Q

The impedance of the skin offers a _____Resistance, so it takes a _____ current to induce vfib

A

HIGH ; larger

82
Q

Microshock is a

A

Smaller amount of current that is applied DIRECTLY to the myocardium

83
Q

With microshock to the myocardium, the high resistance of the skin is bypassed, therefore it takes a

A

Significantly smaller amount of current to induce vfib.

84
Q

Things that increases the patient’s susceptibilty to microshock?

A

Central line
PAC
Pacing wires.

85
Q

What is the MAXIMUM allowable current leak in the OR

A

10 MicroAmps (10mA)

86
Q

What is the current that will lead to VFIB

A

100 microamps

87
Q

Threshold for touch perception of electrical shock

A

1 milliAmp

88
Q

Maximum current for a HARMLESS electrical shock

A

5 milliAmp

89
Q

Let go current occuring before sustained contraction

A

10-20mA

90
Q

Loss of consciousness current

A

50 mA

91
Q

The electrical systems in the OR are designed to reduce the risk of electric shock because

A

The OR power supply is not grounded

The equipment is grounded.

92
Q

The absence of grounding in the OR provides a

A

Second layer of protection against electrical shock

93
Q

For an electrical shock to occur in the OR there must be faults in the system?

A

After the 1st fault, the OR power supply become grounded, there is NO COMPLETED CIRCUIT and there IS NO SHOCK
after the 2nd fault, the circuit is complete and an ELECTRIC SHOCK occurs

94
Q

The line isolation monitor assesses the

A

integritiy of the ungrounded power system in the OR. It tells you when the OR becomes grounded and how much current could potentially flow through you or a patient if a second fault occurs.

95
Q

The primary purpose of the LIM is to

A

Alert the OR staff of the first fault (this means that OR has become grounded)

96
Q

Does LIM protect from macro or microshock?

A

no

97
Q

IF the LIM alarm sounds, what should be done?

A

The LAST PIECE OF EQUIPMENT THAT WAS PLUGGED IN SHOULD BE UNPLUGGED>

98
Q

The LIM will alarm when

A

2-5 milliAMps of leak current is detected.

99
Q

All electrical devices

A

leak a small amount of current.

100
Q

If the sum of all the currents exceeds 2-5 mA, what happens to the LIM ?

A

the alarm will sound, however, there is no risk of electric shock in this situatio and no corrective actiion is required

101
Q

Electrocautery on PM function

A

Suppress

102
Q

If the operative site is near a PM or ICD

A

The bipolar cautery is useful

103
Q

Is a return pad required?

A

Because the current flows from one tip of the instrument to the other, no return pad is required.

104
Q

On a monopolar electrocautery unit, what is needed?

A

Return pad

105
Q

What is a return pad necessary for a monopolar electrocautery unit?

A

Because the return pad provides a location for the electrical current to exit the body . if the pad is too small or does not make good contact with the patient, the electrical current will find another way to exit the body such as EKG pads, jewelry, temp probes, or anything else with conductive properties.

106
Q

The surgical electrocautery device delivers

A

HIGH FREQUENCY current (500000-1million hz) that is used to cut, coagulate, dissect or destroy tissue.

107
Q

Risk with surgical electrocautery device?

A

Vfib

108
Q

Energy pathway for monopolar electrocautery

A

Electrosurgical generator –> Active cable –> Active electrode –> Return pad –> return cable.

109
Q

To prevent burn at the return pad site, the entire surface of the return electrode should

A

be in direct contact with the patient’s skin.

110
Q

Return pad should NOT be placed where

A

bony prominences or metal implants.

111
Q

The electrolyte gel on the return pad should be inspected for

A

Dryness.

112
Q

If the gel of the electrolyte gel dries out what happens?

A

The Electrical current wont have a direct path to the return electrode and will find another way to exit the body.