Test 1 part III (CM)

Question 1

What is the oxygen saturation of blood at the proximal pulmonary artery (measured by PAC)? Reflects average O2 saturation of blood returning to heart

Answer 1

SvO2

Question 2

What is a normal SvO2?

Answer 2

65-80%

Question 3

What conditions cause an increase in SvO2?

Answer 3

1. left to right shunts
2. hypothermia
3. sepsis
4. cyanide toxicity
5. wedged PAC
6. increase in CO

Question 4

What conditions cause a decrease in SvO2?

Answer 4

1. hyperthermia
2. shivering
3. seizures
4. reduced pulmonary transport of oxygen
5. hemorrhage
6. decreased CO

Question 5

Transcutaneous monitoring of the adequacy of oxygenation specific to the brain → O2 supply vs demand within a region of the brain

Answer 5

Cerebral Oximetry

Question 6

You have to monitor a core temperature with what kinds of anesthesia?

Answer 6

GA > 30 min and RA with anticipated temperature changes

Question 7

What is normothermia?

Answer 7

37 C

Question 8

What is hypothermia?

Answer 8

< 36 C

Question 9

What is hyperthermia?

Answer 9

> 38 C

Question 10

How does hypothermia occur?

Answer 10

A redistribution of lower-temp blood from vasodilated periphery

Question 11

How does hyperthermia occur?

Answer 11

1. Genetic predisposition to MH
2. Infection
3. drugs inhibit sweating
4. recreational drugs

Question 12

What are the core temperature monitoring sites?

Answer 12

Tympanic membrane, PA, distal esophagus, nasopharynx

Question 13

Core temperature is estimated using which sites?

Answer 13

oral, axillary, rectal, bladder

Question 14

Do rectal and skin temperatures increase with malignant hyperthermia?

Answer 14

No

Question 15

The transfer of body heat to a cooler environment, all surfaces absorb heat from surroundings

Answer 15

Radiation

Question 16

Heat transfer via Sweating (rare), surgical wounds/cleansing, respiratory (expire warm, moist air), transcutaneous evaporation (peds!)

Answer 16

evaporation

Question 17

Heat loss from direct contact with surfaces (OR table), negligible

Answer 17

Conduction

Question 18

Heat loss to cool air, “wind chill” factor

Answer 18

Convection

Question 19

What are the top two ways a patient can become hypothermic in the OR?

Answer 19

1. Radiation (majority of heat loss)
2. Convection (2nd most important contributor)

Question 20

What adverse outcomes are associated with hypothermia?

Answer 20

1. Increased M&M, prolonged PACU stay, increased perioperative costs
2. Increased O2 consumption
3. Inc Risk CV events
4. Sickling w sickle cell dz
5. Impaired coagulation
6. Decreased drug metabolism
7. Reduced MAC volatile anesthetic agents (by 5% per 1C)
8. Wound infection
9. Delayed healing d/t impaired immune function

Question 21

What are risk factors for hypothermia?

Answer 21

High physical status, lengthy procedure (>3hr), geriatrics, lean body mass, failure to monitor, combined anesthetic technique (GA + RA)

Question 22

What are ways to prevent hypothermia in the OR?

Answer 22

Warming before induction can reduce redistribution hypothermia.
1. Preoperative cutaneous warming (warming blanket)
2. airway heating/humidification (HME esp in peds)
3. warm IV fluids
4. warm ambient OR temp (>23C)
5. cutaneous heating

Question 23

Which is better: Prevention of hypothermia or active rewarming?

Answer 23

Prevention of hypothermia

Question 24

What is the benchmark for adequate recovery from NMB?

Answer 24

Adductor pollicis TOF ratio >0.9

Question 25

What is the most common site for monitoring NMB (TOF)?

Answer 25

Ulnar Nerve (gold standard) Can also use other peripheral, superficial nerves: median, posterior tibial, common peroneal, facial

Question 26

Occurs when each of the successive twitch responses from T1 through T4 become smaller

Answer 26

Fade

Question 27

Fade exists with what kinds of blocks?

Answer 27

1. Non-depolarizing block 2. Phase 2 Depolarizing Block

Question 28

Comparing the size of T4 twitch to T1 switch provides what?

Answer 28

Train of Four Ratio (TOFR)

Question 29

Which is the first "organ" to have onset of NMB?

Answer 29

1. Eye muscles 2. Extremities 3. Trunk 4. Abdominal Muscles 5. Diaphragm Recovery from NMB is the same order in reverse

Question 30

Which organ is the most resistant to NMB, but recovers the quickest?

Answer 30

Diaphragm

Question 31

A method that administers one single supramaximal stimuli (0.1 to 1 hertz (Hz) for 0.1 to 0.2 milliseconds (ms)), most useful at onset of NMB (induction of anesthesia), must have comparison twitch response prior, indicates 100% NMB if no movement detected.

Answer 31

Single Twitch

Question 32

4 supramaximal stimuli (2 Hz for 2 sec) are given every 0.5 sec, # of twitches correlates with degree of NMB

Answer 32

Train of Four

Question 33

If you have 3/4 twitches, what % block do you have?

Answer 33

75-80%

Question 34

If you have 2/4 twitches, what % block do you have?

Answer 34

80-85%

Question 35

If you have 1/4 twitches, what % block do you have?

Answer 35

90-95%

Question 36

If you have 0/4 twitches, what % block do you have?

Answer 36

100% block

Question 37

Intraoperatively, what degree of NMB do you want (how many twitches)?

Answer 37

85% to 95% or 1 to 2 twitches

Question 38

Assesses the degree of NMB when there is no response to a single supramaximal twitch or TOF (deep NMB is present). This method involves administering 5s of tetanic stimulation, followed by a single supramaximal twitch or TOF. If no response, an intense blockade remains. If response is seen with the single twitch or TOF, then there is some recovery from NMB.

Answer 38

Post tetanic Stimulation

Question 39

Method that consists of two short bursts of a 50-Hz tetanus separated by 0.75 seconds. -improves the ability to detect residual paralysis during recovery. -Normal response is 2 contractions of equal intensity -Partial NMB is present if 2nd response is weaker than the 1st (fade) - comparable to TOFR <0.6

Answer 39

Double Burst Stimulation

Question 40

The high frequency delivery of a supramaximal stimulus. Normal response is contraction. -Non-depolarizing and Phase 2 Depolarizing blocks yield a non-sustained response (Fade). If fade is present, a clinically significant block remains. -Painful and may cause muscle fatigue -TOF 4/4 with sustained tetany > 5 sec indicates adequate NMB reversal

Answer 40

Tetanic Stimulation