Lecture 14: Inhalant Anesthesia Flashcards

1
Q

What is MAC value

A

Minimum alveolar concentration of an inhaled anesthetic in the alveoli that will produce immobility in 50% of tested population during a surgical incision

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

MAC is a measure of ___ and is used for comparing anesthetics

A

Potency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the percentages of anesthesia machine gases: iso, O2, and CO2

A

Iso: 2%
O2: 94%
CO2: 5%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

95% of patients should hold still at MAC of ___

A

1.2%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

100% of patients should hold still at MAC of __

A

1.5%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are some factors that decrease MAC

A

Pregnancy, hypercapnia (PaCO2 >95), hypoxemia (PaO2 <40), hypotension (MAP <50), hyponatremia, systemic disease, hypothermia, increasing age, drugs that suppress CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are some factors that increase MAC

A

Hyperthermia, hypernatremia, CNS stimulants, hyperthyroidism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are some factors that increase alveolar concentration

A

Higher inspired concentration, greater ventilation rate, poor solubility in blood and peripheral tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What factors lower alveolar concentration

A

High CO and high solubility

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How can we asses CNS

A

Palpebral reflex, jaw tone, eye position

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is ideal eye position, palpebral reflex, and muscle tone for surgery

A

Eyes: Ventral
Absent palpebral
Muscle tone- relaxed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the depth of anesthesia if eyes are central, medial canthus palpebral present and relaxed to strong muscle tone

A

Too light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is depth of anesthesia if eye positions are central, palpebral is absent and muscle tone is relaxed

A

Too deep

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Isoflurane can cause ___in swine

A

Malignant hyperthermia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Which is more potent iso or sevo

A

Isoflurane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Raising the ___partial pressure of an inhalant is key to get the patient anesthetized

A

Alveolar

17
Q

How does elimination of anesthetic occur

A

Pulmonary exchange

18
Q

What are the cardiovascular effects of sevoflurane, Isoflurane, desflurane

A

Reduce systemic vascular resistance and maintain CO

Isoflurane and desflurane increase SNS, increase HR and CO2

19
Q

Which inhalant has the least effects on HR

A

Sevoflurane

20
Q

BP= ___x___

A

CO X SVR

21
Q

Inhalants cause a dose dependent ___in BP

A

Decrease

22
Q

Which inhalants are most likely to cause decrease BP

A

Isoflurane and sevoflurane&raquo_space;>desflurane

23
Q

What is the treatment for hypotension caused by inhalants

A
  1. Decrease inhalant concentration
  2. Add drugs that don’t depress CVS: fentanyl, lidocaine, ketamine, local anesthesia
  3. IV fluids
24
Q

What are the respiratory side effects of inhalants

A

Decrease ventilators response to CO2 and hypoxemia

Decrease TV
Respiratory rates increase

25
Q

If ventilation is suppressed what do you do to inhalant concentration

A

Decrease

26
Q

If ventilation is increased what do you do to inhalant concentration

A

Increase

27
Q

What do inhalants do to CNS

A

Reversible dose related unresponsiveness, immobility, unconsciousness, amnesia

28
Q

What do inhalants NOT do to CNS

A

No analgesia

29
Q

How does Isoflurane affect seizure activity

A

Suppresses seizure activity

30
Q

How do inhalants affect cerebral metabolism

A

Decrease it, decrease cerebral oxygen consumption

31
Q

What do inhalants do to ICP

A

Increase it

32
Q

What should MAC be at if patient as increase ICP

A

Less than 1 MAC

33
Q

Ex: 13yr boxer comes in with acute head tilt, vomiting, seizures

Scheduled for brain MRI what will you maintain anesthesia with

A
  1. Propofol CRI
  2. Sevoflurane <1 MAC
34
Q

What are the effects of inhalants on the liver

A

Decrease BF and oxygen

35
Q

Which inhalant promotes best liver BF

A

Isoflurane- least % is metabolized by liver

36
Q

What are the effects of inhalants on kidneys

A

Decrease BF, GFR, and urine

37
Q

Effects of inhalants on the kidneys is influenced by what

A

Hydration status, hemodynamics during anesthesia

38
Q

What are the effects of inhalants on skeletal muscle- especially swine and what is tx

A

Malignant hyperthermia
Tx: dantrolene