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Monitors & Equipment > Apex- Miscellaneous Monitors (TOF/BIS/EEG/Electricity) > Flashcards

Apex- Miscellaneous Monitors (TOF/BIS/EEG/Electricity) Flashcards

1
Q

What is the BEST method of assessing a deep neuromuscular block?

A. Sustained tetany
B. Post-tetanic count
C. Double Burst Stimulation
D. TOF

A

B. Post-tetanic count

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2
Q

TOF delivers a series of 4 twitches over how many seconds
at how many Hz
with how many second intervals

A

2 seconds
2Hz
-0.5 secondintervals

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3
Q

Clinical recovery from NMB is achieved when the TOF ratio is > what

when is a reversal indicated with

A

> 0.9

< 0.9

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4
Q

Tetanus should be delivered over how many seconds at how many Hz

A

5 seconds
50Hz

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5
Q

DBS delivers two short bursts of _ Hz _ seconds apart

A

50 Hz
0.75 seconds apart

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6
Q

T/f: it is easier to detect fade with TOF compared to DBS

A

false - easier with DBS

think ur just comparing 2 instead of 4

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7
Q

TOF ratio of 0.9 = how many receptors still blocked?

A

75% blocked, 25% recovered

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8
Q

TOF wont be accurate for up to how long after tetanus assessment?

A

6 minutes

bc tetnus can cause post-tetanic potentiation
-flood the synaptic cleft with ACH that has been stored

its innacute bc ur testing the backup supply, now theres no acetylcholine to be had

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9
Q

A single twitch delivers a stimulus ranging from what to what Hz

A

0.1-1Hz

TOF = 2 hz

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10
Q

What % of Nm receptors must be blocked to lose T1

what does it mean to lose T1

A

90%

means there are no twitches

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11
Q

How many post-tetanic twitches suggest T1 will return at any moment

A

6-10

less than this suggests return of T1 is further away

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12
Q

Fade occurs when the T4/T1 ratio is less than what

A

1.0

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13
Q

What’s the advantage of DBS

A

it’s easier to detect fade with DBS than with TOF

but impairs TOF for up to 6 mins after

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14
Q

Select the statement that BEST describes cerebral ox

A. It’s invasive
B. a >/= 25% change from baseline suggests a reduction in cerebral oxygenation
C. It monitors arterial o2 sat in the cerebral blood
D. It monitors global cerebral oxygenation

A

B.

Cerebral ox is a noninvasive technique that uses near-infrared spectroscopy (NIRS) to measure regional (not global) cerebral oxygenation

based on the prinicple that decreased cerebral o2 delivery > increased cerebral o2 extration > decreased venous hemoglobin saturation

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15
Q

T/F: cerebral ox uses near infrared spectroscopy (NIRS)

what is it measuring

A

true

regional cerebral oxygenation (not global)

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16
Q

A change of what % or greater with cerebral ox suggests a reduction in CBF

A

25% or greater

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17
Q

Does cerebral ox measure arterial or venous o2 in the brain

A

venous

decreased o2 delivery = increased o2 exctraction = decreased venous hgb oxygenation

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18
Q

T/F- cerebral ox cannot detect pulsatile blood

A

true -

it measures venous o2 sat in the brain

measures venous oxyhemoglobin and o2 extraction

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19
Q

what equipment measures venous o2 sat in the brain

A

cerebral ox

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20
Q

What % of the blood in the brain is on the VENOUS side of ciruclation

A

75%

1 part artial, 3 parts venous

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21
Q

T/F: a decrease in cerebral o2 delivery will result in dereased o2 extraction

A

false

decreaed delivery will result in increased o2 extraction and decreased venous hgb sat

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22
Q

T/F- scalp hypoxia can be misinterpreted as brain ischemia

A

true

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23
Q

Rank the EEG waveforms from Highest to lowest frequency

Delta
Beta
Alpha
Theta

A
  1. Beta
  2. Alpha
  3. Theta
  4. Delta
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24
Q

Where does EEG provide information regarding electrical activity

what does it not provide great info about

A

in the cerebral cortex

subcortical structures, spinal cord, or peripheral nerves

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25
During anesthesia, the EEG waveforms typically change in what 2 ways:
1. they become slower (lower frequency) 2. they become taller (higher amplitude) ## Footnote slow, low > freak out big peak > slow, low > freak out big peak
26
anesthesia causes EEG waves of (higher/lower) frequency and (higher/lower) amplitude
lower frequency higher amplitude ## Footnote slow, low > freak out big peak > slow, low > freak out big peak
27
How does nitrous alone affect EEG
increae beta activity
28
which inhalational gent can increase epileptiform EEG activity
sevo
29
T/F: etomidate is not associated with epileptiform EEG activity
True
30
How does ketamine effect EEG activity
- confuses it, may falsely increase activity - pt deeper than they appear on EEG
31
Burst suppression occurs with what 2 things
deep anesthesia and hypothermia
32
what EEG waveform is suggestive of cerebral ischemia
UNILATERAL burst suppression
33
Complete EEG supression (isoelectricity) occurs what what MAC
1.5-2 MAC
34
when would EEG monitoring be useful | 3 examples
when cerebral oxygenation is at risk ## Footnote CEA, deliverate hypotension, barbituate coma
35
Which brain waves occur in an awake but restful state with eyes closed
alpha | 8-12 cycles/sec
36
label
37
T/F: induction of GA is associated with increased beta wave activity
True ## Footnote beta waves = awake waves , high freq, low voltage just think of it as the SNS stage 2 freakout before they actually go to sleep
38
Which kind of brain waves predominate during GA
Theta and Delta ## Footnote Theta = 4-7 cycles /sec Delta = < 4 cycles per sec (can also be assoc with brain ischemia or injury)
39
The development of what kind of waves during anesthetic maintenance might signify that the brain is at risk for ischemia
new delta waves
40
what 3 circumstances can mimic cerebral ischemia
1. deep anesthesia 2. hypothermia 3. hypocarbia
41
Alpha, Beta, Theta, or Delta waves: Light anesthesia
Beta
42
Alpha, Beta, Theta, or Delta waves: Normal sleep in kids
Theta
43
Alpha, Beta, Theta, or Delta waves: Deep sleep
Delta
44
Alpha, Beta, Theta, or Delta waves: Mental stimulation
Beta
45
Alpha, Beta, Theta, or Delta waves: GA
Theta and Delta
46
Alpha, Beta, Theta, or Delta waves: Brain ischemia
Delta
47
Alpha, Beta, Theta, or Delta waves: Awake
Beta
48
T/F: Ketamine falsely elevates the BIS value
True
49
Burst suppression begins at a BIS value of what
20
50
T/F: there is no lag time between measuring EEG and computing the BIS value
False: 20-30 second lag ## Footnote some people argue that titrating your anesthetic to the BIS is akin to driving using only your rear view mirrow
51
BIS target for GA vs Patient safety index target for GA
BIS = 40-60 PSI = 25-50 ## Footnote both measure EEG, run data through an algorithm, and display a number to indicate the level of anesthetic depth
52
What is the bispectral index monitor and how does it work?
BIS - uses a computer algorithm that translates raw EEG data into a number between 0-100
53
BIS number of what = moderate sedation
80
54
BIS deep hypnoti state number
40 ## Footnote GA 40-60
55
4 things that influence BIS
1. hypothermia 2. EMG interference (increased muscle tone) 3. encephalopathy 4. ketamine
56
T/F- as a sole agent, nitrous oxide does not reduce the BIS reading
true
57
how does nitrous affect high frequency vs low frequency activity | BIS
increases amplitude of high freq activity reduces amplitude of low freq activity
58
T/F: ketamine increases low frequency activity
False - increases high frequency activity ## Footnote can produce a BIS value that is higher than the level of sedation/anesthesia one would otherwise suggest
59
T/F: BIS is less accurate in kids
True
60
Select the statement that MOST accurately describes the function of the line isolation monitor: A. If a piece of equipment becomes grounded, it cuts off the power supply to that piece of equipment B. It protects the patient from microshock C. The alarm sounds when the OR power supply becomes grounded D. It isolates electrical equipment from the ground
C
61
T/F: the electrical supply in the OR is NOT grounded
TRUE ## Footnote the line isolation monitor is to alert the OR staff when the power supply becomes grounded >an issue bc a second electrical fault can lead to an electric shock
62
T/F: The line isolation monitor protects the patient from microshock
False | Line Isolation **monitor** ## Footnote the line isolation monitor is to alert the OR staff when the power supply becomes grounded >an issue bc a second electrical fault can lead to an electric shock
63
T/F: The line isolation monior isolates the electrical equipment from the ground
False | Line isolation **monitor** ## Footnote the line isolation monitor is to alert the OR staff when the power supply becomes grounded >an issue bc a second electrical fault can lead to an electric shock
64
T/F: the line isolation monitor cuts off the power supply to a piece of equipment that has become grounded
False | Line isolation **monitor** ## Footnote the line isolation monitor is to alert the OR staff when the power supply becomes grounded >an issue bc a second electrical fault can lead to an electric shock
65
The OR power supply (is/is not) grounded and the equipment (is/is not grounded)
power supply = grounded equipment = not grounded ## Footnote on the first fault, the OR power supply becomes grounded - no completed circuit, no shock second fault - circuit is complete and electric shock occurs
66
The line isolation monitor assesses the integrity of hte (grounded/ungrounded) power in the OR
the ungrounded power system
67
The line isolation monitor alarms if the sum of all currents exceeds what ## Footnote what should you do if it alarms?
2-5mA ## Footnote unplug the last piece of equipment that was plugged in (most common reason why it alarms)
68
Max allowable current leak in the OR
10 MICROamps ## Footnote microshock voltage for vfib is 100 MICROAMPS; so the allowable current leak is ssignifiantly lower
69
Macroshock for VFIB | microshock ## Footnote why are they different?
100mA | 100 MICROAMPS ## Footnote bc the surface of the skin offers a high resistance, so it takes a larger current to induce vfib microshock is a current applied directly to the myocardium- no skin to be bypassed, a lot less voltage needed
70
Macroshock vs microshock
macroshock = current applied to outside of body microshock - current applied directly to myocardium ## Footnote skin offers high resistance, so larger current is required for macroshock
71
threshold for touch perception of electrical shock | max current for a harmless electrical shock ## Footnote "let go" current before sustained contraction
1mA | 5mA ## Footnote 10-20mA
72
what voltage does LOC occur at
50mV
73
For an electric shock to occur in the OR, there must be how many faults in the system
Two ## Footnote After the first fault, the OR power supply becomes grounded. There is no completed circuit and no shock After the second fault, the circuit is complete and electric shock occurs -when your at home, an electric shock can occur with teh first fault since the power outlet is already grounded , the circuit is complete and electric schok occurs
74
What is required to supply ungrounded power to the OR
an isolation transfomer ## Footnote conceptually, you can think of this as a device that sits between the power coming from the power company and the OR
75
T/F- the isolation transformer can tell usif theres a problem
false - the line isolation monitor is needed to assess the integrity of the ungrounded power system
76
Does the LIM protect you from macro or microshock
no- neither - it's primary purpose is to alert the staff of the first fault, meaning OR has become grounded, and if a second fault occurs, someone could get electrocuted
77
Max allowable current leak in the OR vs when the LIM will alarm
max leak = 10 milliamps LIM alarms at 2-5mA ## Footnote *all electrical devices leak a small amount o current but if the sum of all the currents exxceeds 2-5mA, the alarm will sound,
78
Do central lines and PACs increase the risk of microshock or macroshock
microshock- direct line to the heart, only 100milliaps required to produce vfib compared to 100mA for microshock thru the skin
79
T/F: the return pas (bovie pad) grounds the patient
NO - grounded the patient is bad gounded pt = complete circuit = shock
80
What happens if the return pad fails
pt is at risk for burns ## Footnote if too small or doesnt make good contact with skin- the current will find another way to exit the body > EKG pads/Jewelery/temp probes or anything else with conductive properties
81
Why doesnt the bovie/electrocautery unit (ESU) provide a risk of vfib?
bc it uses a high-freuqency current that have low tissue penetration and dont affect excitable cells | 500,000 - 1 million Hz ## Footnote used to cut, coagulate, dissect, or destroy tissue so they can destroy tissue but not penetrate it well? sure
82
what does the return pad actually do?
It provides an exit point for the current by providing a low impedance surface area for the electrical current to exit the body thru and return to the generator
83
Why is there no need for a return pad if using a bipolar ESU
bc the electrical current is not dispersed throughout the patient's body since the ESU (forcepts) contain the active and return electrodes
84
Why shouldn't the bovie return pad be placed over bony porminences or metal implants
bc it needs to be in direct contact with the patietn's skin to prevent burns
85
what are the risks associated with the presence of body jewelry when the ESU is in use
it can cause a burn by reconcentrating the electrical current from the ESU
86
what if the pt has a piercing on the right that wont come out and surgery is being done on the left- where should hte bovie pad be placed
on the left - dont place it in a place wehre jewelry would be in the direct path
87
T/F: if somone cant get their metal jewelry out, they could use a capacitive-coupled return electrode instead
FALSE - this increases the burn risk
88
If jewelry cont come out, it should be taped to the skin so that the largest surface area of contact esists between the jewelry and the skin
True | ex. belly button ringshould be taped flat agaisnt skin ## Footnote this ocnfuses me
89
if somone tells you they cant get their jewelry out, what are your thoughts
1. are we using bovie 2. where is the jewerluy in relation to the surgical site 3. place the return pad away from it 4. tape it
90
What is the real name for the "grounding pad"
the return pad or return electrode
91
why is the return pad so large?
bc a large, low impedance surface area is needed for the electrical current to exit the body and return to the power generator
92
When assessing train-of-four, what degree of post-junctional nicotinic receptor blockade is consistent with teh disappearance of T4?
80%
93
Cerebral oximetry: A. Requires pulsatile flow B. Measures venous oxygen saturation in cerebral blood C. Monitors global cerebral oxygenation D. Is an invasive monitoring technique
B. | uses near infrared spectroscopy (NIRS) ## Footnote decreased o2 delivery = increased o2 extraction = decreased venous hgb sat >/= 25% change from baseline = concern
94
Match: Voltage, current, and impedance with: CO, BP, and SVR
Voltage = BP Current = CO Impedance = SVR
95
What is the minimum macroshock current required to produce vfib (enter answer in mA) | What about minimum microshock and answer in microamps
100mA | 100 microamps

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