Miscellaneous monitors and equipment

Question 1

TOF delivers a series of 4 twitches. At what Hz and at what second intervals? For how long?

Answer 1

2 Hz
0.5
2 seconds

Question 2

Tetanus delvers how much stimuli? For how long?

Answer 2

50 Hz
5 second

Question 3

Is TOF or tetany more sensitive for recovery?

Answer 3

Tetany

Question 4

For how long after tetany test will TOF not be accurate?

Answer 4

6 min!!!!

Question 5

Double burst stimulation delivers how many short bursts at how many Hz how many sec apart?

Answer 5

2 shorts bursts
of 50 Hz
0.75 sec apart

Question 6

To perform post tetanic how many Hz should be delivered and for how long

Answer 6

50 Hz
for 5 sec

*Followed by series of single twitches

Question 7

What does more post tetanic twitches mean when you had 0 twitches without tetany mean?

Answer 7

6-10 suggests T1 will return at any moment

Question 8

What does fewer post tetanic twitches mean when you had 0 twitches without tetany mean?

Answer 8

The return of T1 is further away. This is a very deep block.

Question 9

Cerebral oximetry uses __ to measure cerebral oxygenation.

Answer 9

near infrared spectroscopy

Question 10

Cerebral oxygenation measures arterial or venous oxygenation?

Answer 10

venous.

Cannot measure pulsatile flow

Question 11

How does Cerebral Oximetry tell you O2 to the brain is low without measuring arterial sat?

Answer 11

Indirectly. Since it monitors the venous oxygen saturation. Decreased venous sat would be due to increased O2 consumption due to decreased arterial O2.

Question 12

What % of blood in the brain is venous?

Answer 12

75%! That is why cerebral oximetry is accurate

Question 13

What % change in cerebral oxygenation suggests a reduction in cerebral oxygenation?

Answer 13

> 25 %

Question 14

EEG provides information on what portion of the brain?

Answer 14

Cerebral cortex

Question 14

What are beta waves associated with

Answer 14

awake mental stimulation and “light” anesthesia

Question 15

What are alpha waves associated with

Answer 15

Awake but restful state with eyes closed

Question 16

What are theta waves associated with

Answer 16

General anesthesia and children during normal sleep

Question 17

What are delta waves associated with

Answer 17

GA
Deep sleep
Brain ischemia or injury

Question 18

What is burst suppression associated with?

Answer 18

GA
Hypothermia
Cardiopulm bypass
cerebral ischemia (especially if it is unilateral burst suppression)

Question 19

What does isoelectricity indicate on EEG?

Answer 19

Very deep anesthesia
Brain death

Question 20

At what MAC does GA cause complete suppression or isoelectricity?

Answer 20

1.5-2 MAC

Question 21

N2O alone increases _ wave activity

Answer 21

beta

Question 22

Which volatile can increase epileptiform EEG activity?

Answer 22

Sevo

Question 23

The patient may be more deeply anesthetized than the EEG suggests when which drug is being used?

Answer 23

Ketamine

Question 24

How does BIS work?

Answer 24

Uses a computer algorithm to convert the EEG number to a number between 0 and 100.

Question 25

As the level of anesthesia becomes deeper, the EEG waveforms exhibit what change to frequency and amplitude?

Answer 25

Lower frequency Higher amplitude

Question 26

What does Ketamine do to BIS?

Answer 26

Ketamine increases high frequency activity This can produce a BIS value that is higher than the level of sedation/anesthesia would otherwise suggest.

Question 27

Lag time between measuring EEG and computing BIS value

Answer 27

30 sec

Question 28

There is SOME research to say that a BIS value < __ for more than 5 min correlates with an increased 5 year mortality, but other studies have failed to replicate these results.

Answer 28

40

Question 29

Target range for GA using patient safety index monitor

Answer 29

25-50

Question 30

Electricity obeys Ohm's Law. What is that?

Answer 30

Voltage = Current x Impedance

Question 31

Microshock vs macroshock. What is macroshock?

Answer 31

When a shock is applied to the external surface of the body, the skin is a big barrier so it takes a larger current to induce V FIB

Question 32

What is microshock?

Answer 32

A smaller amount of current than macroshock. Applied directly to the myocardium. Since the high resistance of the skin is bypassed, it takes a significantly smaller amount of current to induce V FIB.

Question 33

What does a central line, PAC catheter, or pacing wires have to do with susceptibility to microshock?

Answer 33

Provides a direct conductive pathway to the heart

Question 34

The electrical systems in the OR are designed to reduce the risk of electric shock. Which of the 2 is grounded and which is not grounded?

Answer 34

OR power supply: not grounded Equipment: grounded

Question 35

What is an isolation transformer?

Answer 35

Required to supply underground power to the OR. Think of it as a device that sits b/w the power coming from the power company and the OR

Question 36

The isolation transformer only works under what circumstances?

Answer 36

The equipment connected to it is functioning properly

Question 37

What monitor tells you if the equipment connected to the isolation transformer is functioning properly

Answer 37

Line isolation monitor

Question 38

Describe monopolar electrocautery

Answer 38

One active electrode Think: one wire in, one big pad out Electricity travels through the patients body to a return pad

Question 39

Describe bipolar electrocautery

Answer 39

Electricity flows only between the 2 tips of the cautery device, not to the patient. No grounding pad needed. Used for delicate areas like in neuro and ENT. One side of the tip has active electrode and the other has the return electrode.

Question 40

What risk does the patient have if the return electrode malfunctions. Why?

Answer 40

Burns. Because if the current cant exit through return pad it will exit the patient through EKG electrodes, temp probe, metal components of the surgical table.

Question 41

Where should return pad be placed to prevent burns at the return pad site?

Answer 41

Entire surface of the return electrode should be in direct contact with the patients skin It should not be placed over bony prominences or metal implants **The return pad should always have gel on it, if it goes dry because its old that can be a problem and wont allow current to exit **

Question 42

Problem with O2 and electrocautery

Answer 42

The electrocautery can emit sparks and cause a fire, particularly in an oxygen rich environment.

Question 43

Why should jewelry be removed for surgery?

Answer 43

Can cause a burn when monopolar ESU is being used

Question 44

Is it ok to do surgery with metal jelwery?

Answer 44

Yes if unable to get it off or patient refuses so long as the site of surgery is far from the jewelry, jewelry should not be in direct path b/w ESU and return pad. Jewelry should be taped to skin.