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Anesthesia -Scott Newman & Janet King > Test 3 Notes: Janet > Flashcards

Flashcards in Test 3 Notes: Janet Deck (166):
1

Define induction

taking patient from a conscious to an unconscious state

2

2 Methods of induction

Injection
Inhalation

3

4 Benefits of ET intubation

Establish pt. airway
Prevent aspiration
IPPV
Decrease gas exposure to personnel

4

3 Types of ET tubes

Murphy tubes
Cole Tubes
Cuffless ET tubes

5

Cole Tube

Used for small animals & exotics
Skinny end inserted into trachea
Tie behind ears so wider part creates seal
Are easily dislodged

6

Murphy Tube

Beveled end (easier to insert)
Murphy eye (prevents complete blockage)
Cuff
Pilot line with balloon
Radiopaque strip

7

What are 3 benefits to using a cuffed ET tube

Prevents aspiration
Prevents leakage of gas to room
Prevents animal from breathing in room air

8

Cuffs do NOT ____, they create a ____

Hold the ET tube in place, they create a seal

9

How are ET tubes measured?

french scale= external diameter

10

How do you choose an ET tube size?

Use a chart based on weight
Palpate trachea
Measure tube diameter in comparison to nasal opening

11

How is the length of the ET tube measured?

From the tip of the nose to the thoracic inlet

12

What could happen if the ET tube is too long?

Endobronchial intubation
Increased resistance to respiration

13

How should a patient be restrained for placement of the ET tube?

Sternal recumbency
Restrainer holds top jaw
Extend neck and raise head
Intubator will pull tongue down to open mouth

14

Medical term for vocal folds

arytenoid cartilages

15

How do you restrain a ET tube?

Muzzle gauze
Rubberbands/ties
IV tubing

16

What is the best way to know the ET is in the trachea?

**To visualize it
-use fingers to feel for tube between vocal folds
-feel air with exhalation
-res. bag movement

17

How would you know the ET tube is NOT properly placed?

You hear vocalization

18

What are 2 ways to know how much air to use in cuff

Back pressure in syringe
Use pressure manometer

19

What numbers do you look at when using the pressure manometer to inflate the cuff?

Hear slight leak at 20cmH2O
No leak at 15cmH2O

20

What could happen if you over-inflated the cuff?

Compression of the tube
Pressure necrosis of trachea
Tracheal rupture/tear

21

Why are cats more difficult to intubate?

Small trachea diameter
Larynx sits deeper in neck (harder to visualize)
*Laryngospasms*
Vocal folds cover more of the glottis

22

How would you intubate a cat?

Using a stylet or by putting lidocaine on the vocal folds

23

How much lidocaine would you put on the vocal folds?

0.1ml
one drop on each vocal fold

24

Succinylcholine properties

For feline intubation
IV
Lasts 5-10min.
Relaxes jaw tone and prevents spasms

25

What is the instrument that depresses the base of the tongue and has a light source?

Laryngoscope

26

What are some complications associated with ET intubation?

Pressure necrosis of lining of trachea
Plugged ET tube (mucus plug)
Kinked tube
Stimulation of vagus nerve
Trauma
Animal could chew tube during recovery

27

How long do you leave the cuff inflated when extubating the patient?

Until you see 2 good swallows or you see signs of recovery

28

What do you do if the animal vomits with an ET tube in?

Deflate the cuff 1/2 way and remove (the cuff acts a squeegee)

29

How are ET tubes cleaned?

With dilute antiseptic (like chlorhexadine)
OK to submerge under water
Inflate cuff to remove all mucus
Use brush or pipe cleaner to clean inside
Rinse and hang to dry with cuff inflated

30

What should you be aware of if lasers are being used during surgery?

The laser mixed with the high oxygen could start a fire
Wrap ET tube with duct tape
Use a special laser safe ET tube

31

What is the Corneal reflex

touch cornea with sterile swab, animal should blink and withdraw eye, should be present during surgical plane, more common in equine

32

What is the Ear flick reflex

Gently touch hairs on inside of ear and look for "flick" could be absent or present during surgical plane
More reliable in cats

33

What is the Palpebral reflex

Gently tap medial canthus of the eye and observe blinking reflex
Should be gone during surgical plane

34

What is Jaw tone

Open jaw and observe muscle tone, should have some tone but mostly relaxed
Puppies and kittens have weak jaw tone

35

Eye position & Pupil size

Usually eyes will rotate ventromedial during surgical plane but can also be central
Pupils should be slightly dilated during surgical plane

36

10 Common vital signs to monitor during anesthesia

Heart rate
Pulse
ECG
Resp. rate
MM color
CRT
Temp
Blood pressure
O2 saturation
ETCO2

37

Stage 1

Voluntary excitement phase- induction
Immediately after admin of injectable or inhalant (usually rougher and longer)
Animal is conscious, but disoriented
HR & RR can be normal or increased
All reflexes present

38

Stage 2

Involuntary excitement phase
Begins with loss of consciousness, all reflexes present, animal is able to chew and swallow
May have rapid movement of limbs, vocalization, struggling etc.
Shorter stage 2 = better!

39

Stage 3, plane 1

Light plane of anesthesia
Can be intubated
Relaxed jaw tone
NOT able to withstand sx.

40

Stage 3, plane 2

Medium plane of anesthesia
Suitable for most surgical procedures
Slight response to surgical stimulation
Patient is unconscious and immobile

41

What is the normal RR during Stage 3, plane 2?

8-30rpm

42

Stage 3, plane 3

Deep plane of anesthesia
Significant depression of circulation and respirations
Excessively deep for most sx procedures
Good plane for very painful surgery
Marked muscle relaxation & slack jaw tone
NO surgical response

43

Stage 3, plane 4

Anesthetic overdose
Patient is too deep
Drop in HR, BP, CRT and pale MM

44

Stage 4

Death
CPCR necessary to save patient
Turn off vaporizer

45

What are the 6 injectable anesthetic agents?

Barbiturates
Cyclohexamines (dissociatives)
Propofol
Etomidate
Neuroleptanalgesia
Guaifenesin

46

What are the 2 main uses for Barbiturates?

Anticonvulsants (Pheno)
Euthanasia (Pento)

47

What is the ultra-short acting barbiturate?

Methohexital, thiopental
(death row drug)

48

Primary use of Phenobarbital

(Barbiturate)
Anticonvulsant

49

Primary use of Pentobarbital

(Barbiturate)
Euthanasia solution
ONLY DOUBLE THE ANESTHESIA DOSE!

50

Barbiturates properties

Controlled
NOT reversible
NO analgesia
IV admin only

51

4 effects of barbiturates

1.CNS depression
anti-convulsants
excitement during induction and recovery (Prolonged stage 2)

2.Potent respiratory depression
apnea with rapid admin or high doses
decreased RR and depth

3.Cardiovascular depression
decreased BP and cardiac output

4.Tissue irritation
IV admin only

52

What breeds have increased potency with barbiturates?

Sighthounds & lean animals

53

Thiopental properties

(Pentothal) -Barbiturate
Ultra-short acting
Used to be used as induction agent
No longer made in the US

54

Methohexital properties

(Brevital) -Barbiturate
Ultra-short acting
Best for use in sighthounds
Death row drug

55

What are the 2 Cyclohexamines?

Ketamine (Ketaset, Ketalar, Vetalar)
Tiletamine (in Telazol)

56

Cyclohexamine uses and properties

Induction agent
Controlled
NOT reversible
Some analgesia
IV or IM admin.

57

Cyclohexamine mode of action

CNS STIMULATION
Disrupts or scrambles nervous system pathways so they never make it to the brain
"Trance-like" anesthesia- appears awake, but immobile and unaware

58

CNS effects of Cyclohexamines

-Increased CSF, intracranial pressure, and intraocular pressure
-Lowers seizure threshold
-Increased sensitivity to sound
-Hallucinations

59

What drug combined with Cyclohexamines can help decrease the rough recovery?

Benzodiazepine tranquilizers

60

Cardiovascular effects of Cyclohexamines

Tachycardia
Combine with Glycopyrrolate instead of Atropine
Apneustic respirations

61

What are apneustic respirations

Breath holding, prolonged pause after inspiration

62

Other effects of Cyclohexamines

Catalepsy (increased muscle tone)
Spastic reflexes
Open, dilated eyes
Nystagmus (mainly cats)
Ptyalism (increased salivation)

63

What is ptyalism & what can help this?

Increased salivation
Anticholingergics can decrease this

64

How are Cyclohexamines metabolized?

Dogs- metabolized by the LIVER, then excreted

Cats- excreted by the KIDNEYS only

65

Ketamine general properties

Most common induction agent
Can be used for short procedures
Can squirt into the mouths of aggressive cats (takes 5-10mins)

66

Advantages of IV Ketamine

Faster onset and recovery
Decreased dose compared to IM
No tissue irritation

67

Advantages of IM ketamine

Can be used in wild/fractious animals
Longer duration of anesthesia

68

Duration of IV & IM Ketamine

IV= 3-10min.

IM= Dog: 20-30min, Cat: 30-60min.

69

What is the most common Ketamine combo?

Diazepam + Ketamine
(commonly mixed with tranquilizer or sedative)

70

What are the 3 advantages of Ketamine combos?

Increases muscle relaxation
Decreases potential for seizures
Smoother recovery

71

Ketamine-diazepam properties

Ket/Val
IV ONLY!
Very common
Can mix in the same syringe

72

Tiletamine properties

Newer dissociative, very similar to Ketamine
In Telazol
Can be given IV, IM, or SQ (very useful for aggressive pts.)

73

Tiletamine common combo

Tiletamine & zolazepam
(benzodiazepine tranquilizer)
Decreases risk of seizures
Increases muscle relaxation
Smoother recovery

74

Porpofol general properties

(Propo-flo) -No family
Common IV induction agent
Oil in water emulsion (shake well)
Milky white but is still given IV
NOT controlled
NO analgesia
NOT reversible
More expensive

75

Cardiovascular effects of Propofol

Hypotension immediately after injection due to vasodilation
-usually short duration in healthy patients
-IV fluids will minimize this

76

Respiratory effects of Propofol

Respiratory depression
-transient apnea if given rapidly

77

How should you give Propofol?

Slowly over 20-60seconds, titrate to effect
Monitor respirations carefully for a couple min.
Once respirations are good, turn on vaporizer

78

Why should you pre-oxygenate with Propofol?

Flow-by or mask patient
To increase the amount of oxygen saturated with hemoglobin

79

Propofol drug properties

Very short acting
Rapidly metabolized
Minimal hangover
Wide margin of safety

80

Duration of Propofol

Duration= 5-10min.
Complete recovery= 20-30min.

81

Propofol shelf-life

Limited, no preservatives
Ingredients support growth of bacteria
Use within 6 hours- Ok to extend to 24 hours

82

PropoFlo28 general info.

Newer formulation
Contains benzyl alcohol to minimize bacterial growth
Lasts 28 days

83

Muscle myoclonus with Propofol

Seizure like muscle twitch during anesthesia- no treatment required and not common

84

IV injection of ____ prior to Propofol can decrease induction amount by __%

Benzodiazepine tranquilizer
33%

85

Etomidate general properties

(Amidate) -No family
Rapid acting
Ultra short
NO analgesia
NOT controlled
NOT reversible
Very similar to propofol

86

Effects of Etomidate

Minimal cardio effects
Mild respiratory depression (transient apnea)
Wide margin of safety
Rapid loss of consciousness
Rapid, smooth recovery

87

Adverse effects of Etomidate

IV may cause pain/irritation in people
High doses/CRI can cause RBC lysis
Muscle rigidity/myoclonus- Benzos can minimize this

88

Etomidate endocrine effects

Suppression of adrenal-cortical axis for 6 hours in dogs and 3 hours in cats
Single induction doses usually not a issue

89

Etomidate should be avoided with what patients?

Hypoadrenocorticism patients
(Addison's Dz.)
vNa
^K

90

Neuroleptanalgesics

Combo of opioid and tranquilizer or sedative
Used to achieve increased sedation and analgesia

91

When can Neuroleptanalgesics be used as a induction drug?

Only with SICK/debilitated patients
Will NOT produce unconsciousness in a young, healthy patient

92

Guaifenesin general properties

(Glycerol guaiacolate- GG or GGE)
Muscle relaxant
Given to large animals to help induce or maintain anesthesia

93

Common Guaifenesin combos

Ketamine, Diazepam, Xylazine
(Triple drip: GKX)

94

How are liquid anesthetics delivered?

They are vaporized then delivered by carrier gas (Oxygen)

95

Diffusion of anesthetic gas

Gas crosses ALVEOLI then wants to travel to a place with less concentration so it goes to the BLOODSTREAM then the BRAIN becomes saturated due to high blood flow

96

How is the rate of diffusion of anesthetic gas controlled?

by a concentration gradient between the alveoli and bloodstream
(Goes from high to low concentration)

97

Concentration of gas in alveoli and blood during induction

Alveoli= increased concentration
Bloodstream= decreased concentration

98

How is depth of anesthesia determined?

Concentration of anesthetic in the brain

99

How is anesthesia maintained?

By insuring concentration of anesthetic in alveoli, blood, and brain is maintained

100

When recovering, how is the concentration reduced?

When the gas in the alveoli is reduced, the higher concentration in the blood will diffuse from blood stream to the alveoli
Then when the concentration of gas in the blood is less than the brain, it will diffuse from the brain, to the blood, to the alveoli

101

How long should animals receive 100% oxygen after the vaporizer is turned off?

5 minutes- creates a steep concentration gradient between the blood and alveoli

102

Precision vaporizers deliver inhalants as __ and are VOC. Meaning:

a %
VOC= vaporizer out of circuit
(Precision vaporizer)

103

What are the 6 inhalant anesthetics?

Iso
Sevo

Nitrous oxide
Methoxyflurane
Halothane
Desflurane

104

Nitrous oxide properties

Stil used in human medicine (laughing gas)
Wide margin of safety
NEVER used alone!

105

Nitrous oxide provides ____ & ____

Good analgesia & muscle relaxation

106

Color of Nitrous oxide cylinder

Blue

107

What 3 things does the patient breathe when using Nitrous oxide?

Oxygen
Nitrous
Anesthetic gas

108

Respiratory effects of inhalant anesthetics

Decreased RR and Tidal Volume
-can lead to respiratory acidosis and atelectasis

109

Cardiovascular effects of inhalant anesthetics

Cardiovascular depression
-Vasodilation, Bradycardia, Hypotension, Hypothermia...etc.
-Increases heart's sensitivity to epinephrine

110

What are the 3 physical properties of inhalant gases?

Vapor pressure
Solubility
MAC value

111

What does MAC stand for?

Minimum Alveolar Concentration

112

What does vapor pressure measure?

the tendency of anesthetic to go from liquid to gas

113

Inhalants with high vapor pressure want to ___. Low vapor pressure gasses want to ___.

Be a gas (evaporate readily)
Be a liquid (slow evaporation)

114

High vapor pressure agents must use a ____ vaporizer to carefully control the % being evaporated.

Precision (VOC)

115

2 other words for VIC & anesthetic agent used with this.

Vaporizer In Circuit
non-prescision
Methoxyflurane

116

What 3 anesthetic agents need a VOC/Precision vaporizer?

Isoflurane
Sevoflurane
Halothane

117

What does the Solubility coefficient measure?

The solubility of an anesthetic gas in rubber tubing, blood, fat, and other tissues

118

What does Solubility provide info on?

SPEED of induction, depth change, and recovery

119

High solubility would mean that it is ____ dissolved in "stuff" and low solubility would mean it ____.

Easily
Will not dissolve easily

120

Inhalants with ___ solubility will move rapidly to the brain because they don't want to ____.

Low
stay dissolved in blood, fat, etc.
(faster induction, depth changes, and recovery)

121

Inhalants with ___ solubility are slower, so they will ____.

High
be absorbed by tubing, blood, fat, tissues.
(slower induction, depth changes, and recovery)

122

List the 4 inhalant drugs from lowest to highest solubility. (Fastest to slowest)

Sevoflurane--fastest: low solubility
Isoflurane
Halothane
Methoxyflurane --slowest: high solubility

123

Inhalants with low solubility are best for what kind of induction?

Mask or chamber (faster= better)

124

Low solubility agents allow for ____ stage/plane changes and ____ recovery

Quick
Rapid

125

Define Minimum Alveolar Concentration

The minimum alveolar concentration (%) of gas that produces no response to surgical stimulation in 50% of patients

126

What is MAC measuring & this gives an indication of the ____

The % of gas in alveoli
Potency

127

The ____ the MAC the ____ the gas is.

Higher
Less potent
(more needed for sx)

128

The ____ the MAC the ____ the gas is.

Lower
More potent
(less needed for sx)

129

MAC x ___= light plane of anesthesia

1

130

MAC x ___= surgical plane of anesthesia

1.5

131

MAC x ___= deep anesthesia

2

132

List the inhalant agents from lowest to highest MAC

Methoxyflurane (most potent)
Halothane
Isoflurane
Sevoflurane (least potent)

133

Halothane vapor pressure & solubility

High vapor pressure
Medium solubility
-fairly rapid induction, depth change, and recovery
-popular with equine anesthesia

134

Adverse effects of Halothane

Sensitizes heart to epinephrine induced arrhythmias
Increases vagal tone
**Cardio depression
**Respiratory depression- could lead to Atelectesis

135

___% of Halothane is metabolized by the liver and the rest is eliminated through the ____

20%
respiratory tract

136

Effects of Halothane

-Fair muscle relaxation
-Slight analgesia
-Malignant hyperthermia

137

What is malignant hyperthermia

A rare, but often fatal disorder of thermoregulation
Results in increased temp. muscle rigidity, cardiac arrhythmias.
Can happen with any inhalant gas, but more common with Halothane

138

Isoflurane vapor pressure and solubility

High vapor pressure
Low solubility
-rapid induction, depth change, and recovery
-great for mask/chamber induction but can be irritating to mm

139

Isoflurane has ___ changes in depth of anesthesia (within ____ after vaporizer is changed)

Rapid
1-2 minutes

140

Isoflurane has ___ recovery (within ____ after gas is turned off) But don't turn off vaporizer until ____.

Rapid
1-2 minutes
Close to, or on last stitch

141

Isoflurane has a ____ MAC

Higher

142

Common induction % with Isoflurane=
Common maintenance %=

2.5%
1.5-2.5%
(Settings vary from patient to patient!)

143

____ has a wider margin of safety than Halothane & has little effect on the heart.

Isoflurane
**Cardiovascular depression
**Respiratory depression

144

How much Isoflurane is metabolized? (%)

0.2%
the rest is exhaled

145

Isoflurane has excellent ____ but little to no ____ post-op

Excellent muscle relaxation
Little or no analgesia post op
(give pre-emptive & post op analgesics to prevent windup)

146

3 Sevoflurane facts

Newest inhalant anesthetic
More expensive than Iso
Less pungent odor and less irritating to MM than Iso

147

Sevoflurane has ____ vapor pressure & ____ solubility

High vapor pressure & has the lowest solubility

148

Which gas is the fastest acting?

Sevoflurane- lowest solubility

149

When should you turn off your vaporizer when using Sevoflurane?

Not until surgery is COMPLETE!
Rapid recovery

150

Which gas has the highest MAC value?

Sevoflurane

151

Sevo requires ____ vaporizer settings because it is ____.

Higher
the least potent (High MAC)

152

How much (%) Sevo is metabolized?

3%
the rest is exhaled

153

Effects of Sevo

Greater effect on the heart than Iso, but still considered safe
Moderate muscle relaxation
Little to no analgesia post-op
Smoother recovery- cognitive/motor function
**Cardio depression
**Resp depression

154

Sevo has slightly more ____ than Iso

Respiratory depression
Decreased RR & Tidal Vol.

155

Sevo's manufacturer states that ____ & ____ return simultaneously which results in ____.

Cognitive & motor function
Smoother recovery

156

What is the only benefit of induction chambers?

Little physical restraint (good for feral patients)

157

What are the 4 disadvantages of induction chambers?

Only for small animals
Difficult to monitor patient in chamber (vitals)
No control of airway
Not a good induction method for brachys or animals with resp. or cardio. problems

158

What 2 things do you need when using an induction chamber?

1. Inlet for gas/oxygen
2. Outlet for scavenge
(fresh gas in, escaped gas to scavenge)

159

What is the induction chamber procedure?

1. Deliver 100% oxygen for about 5 min.
2. Gradually add inhalant anesthetic by 0.5% increments every 10 seconds

160

The induction chamber procedure uses ____ vaporizer settings for a ____ induction.

Higher
Faster

161

How can you tell if a patient is ready to be intubated when using a induction chamber?

Observe for loss of righting reflex
Shake the chamber or bang on the glass

162

What are 2 disadvantages of mask induction

Some animals resist the mask which leads to stress
Not recommended for brachys or pts. with respiratory problems (no control of airway)

163

When using mask induction and the animal is stressed what could happen?

Stress causes release of epinephrine which can predispose patient to cardiac arrhythmias

164

When does the mask induction technique work best?

When the patient is calm or sedated

165

Mask induction procedure

Hook up rebreathing tubing (can also use NRB)
Hook up tightest fitting mask to Y tubing
Deliver 100% oxygen
Gradually add inhalant increasing by 0.5% increments
When patient appears relaxed, turn off vaporizer, remove mask and intubate

166

Mask induction will need ____ vaporizer settings for a ____ induction

Higher
Faster