Miscellaneous topics Flashcards

1
Q

What is the BEST method of minimizing intraoperative heat loss?
a. forced air warmer
b. circulating water mattress
c. warm blankets
d. fluid warmer

A

a. forced air warmer

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2
Q

Hypothermia is defined as a core body temperature less than

A

36 degrees C

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3
Q

Who has the greatest risk of developing perioperative hypothermia?

A

patients at extremes of age

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4
Q

What are the four mechanisms of heat transfer?

A

radiation
convection
evaporation
conduction

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5
Q

What two mechanisms of heat transfer are most significant?

A

radiation (most)
convection (second most)

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6
Q

Perioperative events contributing to heat loss include

A

drug-induced vasodilation
impaired shivering
cold operating room
cold OR table
administration of room temperature fluids and cold blood products
core to peripheral temperature redistribution
re-calibration of the hypothalamic set point

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7
Q

After induction of anesthesia, heat loss occurs in three stages:

A
  1. heat redistributes from the core (torso) to the periphery (extremities)
  2. heat transfer to environment exceeds heat production
  3. heat transfer approximates heat production (new equilibrium)
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8
Q

What is the afferent limb of temperature regulation?

A

thermoreceptors located in the skin, deep tissue, and spinal cord

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9
Q

What is the control center of temperature regulation?

A

hypothalamus (preoptic region)
brainstem

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10
Q

What is the efferent response to “too cold” of a body temperature?

A

vasoconstriction
piloerection
shivering
non-shivering thermogenesis

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11
Q

What is the efferent response to “too hot” of a body temperature?

A

vasodilation
diaphoresis

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12
Q

What is radiation?

A

heat follows a temperature gradient and thus, the patient is warmer than the environment so heat is lost through the form of infrared radiation

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13
Q

__________ reduces radiant heat loss.

A

Covering the patient

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14
Q

What is convection?

A

it’s the transfer of heat by the movement of matter

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15
Q

____________-increases the amount of heat lost to convection.

A

Laminar flow

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16
Q

Water can be lost by evaporation from

A

respiration
wounds
and exposure of internal organs during surgery

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17
Q

What is conduction?

A

heat is lost when the patient comes into direct contact with a cooler object

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18
Q

What is the least significant source of heat loss in the OR?

A

conduction

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19
Q

Which temperature monitoring site offers the BEST combination of accuracy and safety over an extended period of time?
a. rectal
b. esophageal
c. tympanic membrane
d. pulmonary artery

A

b. esophageal

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20
Q

Perioperative hypothermia increases the risk of

A

morbidity and mortality

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21
Q

Shivering increases oxygen consumption by up to

A

400-500%

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22
Q

Shivering increases the risk of

A

myocardial ischemia and infarction

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23
Q

Pharmacologic modalities used to treat postoperative shivering include

A

meperidine, clonidine, dexmedetomidine

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24
Q

What are times when perioperative hypothermia can improve outcomes?

A

stroke
cardiopulmonary bypass
aortic cross-clamping
cardiac arrest
cerebral aneurysm clipping
traumatic brain injury
carotid endarterectomy

25
Q

Esophageal temperature should be measured in the

A

distal 1/3rd to 1/4th of the esophagus

26
Q

How far should the esophageal temperature probe be inserted?

A

38-42 cm past the incisors

27
Q

Skin temperature ____ with core body temperature

A

does not correlate

28
Q

Pharmacologic consequences of perioperative hypothermia include

A

slowed drug metabolism
increased solubility of volatile agents
prolongs things

29
Q

Perioperative hypothermia can result in

A

myocardial ischemia and dysrhythmias
decreased O2 available to tissues
surgical site infection (d/t vasoconstriction & decreased Tissue PO2)
increased blood loss
risk of sickle cell crises

30
Q

Oxygen consumption is reduced by ________ for every 1 degree C reduction in body temperature

A

5-7%

31
Q

Where is the ideal position of a nasopharynx temperature probe?

A

sensor contacts posterior nasopharyngeal wall posterior to the soft palate

32
Q

What is the risk of using a rectal temperature?

A

risk of bowel perforation

33
Q

What is the risk of bladder temperature?

A

risk of UTI
-don’t use during GU procedures

34
Q

What will reduce the accuracy of temperature measurement at the esophagus?

A

probe positioned in the proximal esophagus

35
Q

What will reduce the accuracy of temperature measurement at the bladder?

A

inadequate UOP

36
Q

What will reduce the accuracy of temperature measurement at the nasopharynx?

A

leakage of inspiratory gas (if present)

37
Q

What will reduce the accuracy of temperature measurement at the rectum?

A

cool blood in lower extremities and insulation by stool

38
Q

What will reduce the accuracy of temperature measurement in the pulmonary artery?

A

open chest

39
Q

Anesthetic considerations for removal of vocal cord papilloma with a carbon dioxide laser include:
a. reducing the FiO2 by adding nitrous oxide
b. applying reflective tape to a red rubber endotracheal tube
c. using amber goggles
d. adding saline instead of air to the cuff of the ETT

A

d. adding saline instead of air

40
Q

What are the three ingredients required to produce a fire?

A
  1. ignition source
  2. oxidizer
  3. fuel
41
Q

Examples of ignition sources include

A

electrosurgical cautery
laser

42
Q

Examples of oxidizers include

A

oxygen
nitrous oxide

43
Q

Examples of fuel include

A

endotracheal tube
drapes
surgical supplies

44
Q

Immediate steps to take when an airway fire is present include:

A
  1. stop ventilation and remove ETT
  2. stop the flow of all airway gases
  3. remove other flammable material from the airway
  4. pour water or saline into the airway
  5. if the fire isn’t extinguished on the first attempt, use a Co2 fire extinguisher
45
Q

Steps to take after an airway fire is controlled:

A
  1. re-establish ventilation by mask. avoid supplemental O2 or nitrous oxide
  2. check ETT for damage- fragments may remain in the patient’s airway
  3. perform bronchoscopy to inspect for airway injury or retained fragments
46
Q

Laser safety considerations include:

A

use <30% FiO2
do not use N2O
use a laser resistant ETT. remember all cuffs are vulnerable
fill the cuff with saline
protect the patient’s eyes

47
Q

What kind of goggles does a CO2 laser require?

A

Clear goggles

48
Q

What type of goggles does a Ruby laser require?

A

Red

49
Q

What type of goggles does an Argon laser require?

A

Amber

50
Q

What type of goggles does a Nd:YAG laser require?

A

Green goggles

51
Q

The best way to protect yourself from fine particulates created from tissue vaporization?

A

a smoke evacuator
high-efficiency masks

52
Q

Laser light differs from ordinary light because it is:

A
  1. monochromatic (a single wavelength)
  2. coherent (oscillates in the same phase)
  3. collimated (exists as a narrow parallel beam)
53
Q

Lasers with short wavelengths absorb __________ water and penetrate____________ into tissue

A

less; deeper

54
Q

Which laser has the shortest wavelength?

A

Argon

55
Q

Which laser is used for vocal cord and oropharyngeal surgery?

A

CO2 laser

56
Q

Which laser is used for tumor debulking?

A

Nd:YAC

57
Q

Which laser is used for vascular lesions?

A

argon

58
Q

Which laser has the longest wavelength?

A

CO2

59
Q

Which laser is used for retinal surgery?

A

Ruby