Inhaled anesthetics

Question 1

What are the side effect of N2O?

Answer 1

Postop N/V
Inhibits B12-dependent enzymes –> pernicious anemia and CI in pregnancy
Pulmonary HTN
Second gas effect

Question 2

What are the effects of N2O?

Answer 2

Does NOT drop BP
Minimal changes in CV
No change in minute ventilation 
Increased ICP, CBF and O2 consumption of brain
Decreased renal/hepatic flow
Increase SNS
Analgesia

Question 3

What is the MAC of N2O?

Answer 3

105%

Question 4

When is N2O contraindicated?

Answer 4

Air embolus, Intracranial air, pulm. HTN, pregnancy, pneumothorax, GI obstruction

Question 5

Of the 4 main inhaled anesthetics, which one is analgesic?

Answer 5

N2O

Question 6

What is the MAC of Isoflurane?

Answer 6

1.2

Question 7

Which inhaled anesthetic has the lowest blood/gas and fat/gas ratio?

Answer 7

Desflurane

Question 8

What are the 3 volatile inhaled anesthetics?

Answer 8

Desflurane, isoflurane, sevoflurane

Question 9

What two inhaled anesthetics are not irritants to the airway?

Answer 9

N2O and Sevoflurane

Question 10

What do all 3 volatile inhaled anesthetics do to the HR and BP?

Answer 10

Drop the BP

Increase the HR

Question 11

Which inhaled anesthetic has the fastest induction and emergence?

Answer 11

desflurane because has low solubility

Question 12

Why are isoflurane and desflurane only used for maintenance?

Answer 12

Because they are irritants to the airway and may cause cough or laryngospasm

Question 13

Which inhaled anesthetic is associated with carbon monoxide poisioning?

Answer 13

Desflurane

Question 14

Which inhaled anesthetic is associated with the accumulation of vinyl compound A?

Answer 14

Sevoflurane - compound A is renal toxic

Question 15

What are the effects of isoflurane on CV?

Answer 15

decreased SVR
Increased HR
May cause coronary steal syndrome if rapid increase (increase HR and BP)

Question 16

What are the pulmonary effects of isoflurane?

Answer 16

Rapid shallow breaths that cause a decrease in minute ventilation
Increase partial pressure of CO2
Normal response to hypoxia and hypercarbia is abolished

Question 17

What are the cerebral effects of isoflurane?

Answer 17

Increased CBF and ICP

Question 18

What are the renal effects of isoflurane?

Answer 18

Decreased RBF

Question 19

What are the CV effects of desflurane?

Answer 19

Decreased BP/SVR
Increased HR
Rapid increase –> release of catecholamines

Question 20

What are the pulmonary effects of desflurane?

Answer 20

Rapid shallow breaths that cause a decrease in minute ventilation
Increase partial pressure of CO2
Irritant to upper airway

Question 21

What are the cerebral effects of desflurane?

Answer 21

Increased CBF and ICP

Question 22

What inhaled anesthetic is the most lipid soluble?

Answer 22

Methoxyflurane

Question 23

What inhaled anesthetic is responsible for causing vasopressin-resistant high output renal failure?

Answer 23

methoxyflurane with metabolite fluoride

Question 24

Which inhaled anesthetic causes no change in SVR?

Answer 24

Halothane

Question 25

What are the CV effects of sevoflurane?

Answer 25

Slight decrease in myocardial contractility, BP, and SVR so slight decrease in CO because no increase in HR.

Question 26

What are the pulmonary effects of sevoflurane?

Answer 26

Potent bronchodilator Rapid shallow breaths that cause a decrease in minute ventilation Increase partial pressure of CO2

Question 27

What are the renal effects of sevo?

Answer 27

Reduces RBF proportionate to decrease in BP

Question 28

What are the CV effects of Halothane?

Answer 28

direct myocardial depressant depresses baroreflex receptors so no reflex tachy CO increases sensitizes heart to catecholamines

Question 29

What are the pulmonary effects of halothane?

Answer 29

Potent bronchodilator (inhibits release of intracellular calcium) Rapid shallow breaths that cause a decrease in minute ventilation Increase partial pressure of CO2

Question 30

What are the CV effects of methoxyflurane?

Answer 30

HR rises CO decreases Decreased cardiac contractility

Question 31

What are the CV effects of enflurane?

Answer 31

Direct myocardial depressant Decreased SVR CO drops significant

Question 32

What are the cerebral effects of enflurane?

Answer 32

Deep anesthesia level and hypocapnia cause EEG changes from high voltage, high frequecy to spike-and-wave pattern, then epileptic form.

Question 33

What is the MOA of thiopental, phenobarbital, thiamylal, and methohexital?

Answer 33

Inhibits presynaptic excitatory NTs Increases postsynaptic sensitivity to GABA Stimulates GABA receptors Chloride channels open longer

Question 34

Why are lower induction doses required for the elderly?

Answer 34

1. Decreased binding protein 2. Decreased volume of central compartmen 3. Decreased hepatic blood flow

Question 35

Which agents can potentiate the effects of barbs?

Answer 35

BZDs, narcotics, EtOH, H1 blockers

Question 36

What is the MOA of BZDs?

Answer 36

Increased frequency of Chloride channels opening | Facilitates GABA binding

Question 37

Which BZDs are well absorbed from the GI tract?

Answer 37

Diazepam and lorazepam

Question 38

Which BZDs are well absorbed via the IM route?

Answer 38

Midazolam and lorazepam

Question 39

What is a possible side effect of a barb?

Answer 39

Acute intermitent porphyria by induction of aminolevulinic acid synthetase

Question 40

What are the cerebral effects of barbs?

Answer 40

``` Depression of central vasomotor center in the brain Vasoconstriction Decreased CBF and ICP Decreased O2 consumption Protection against global ischemia ```

Question 41

What are the CV effects of barbs?

Answer 41

vasodilation and increased HR

Question 42

What are the pulmonary effects of barbs?

Answer 42

Decreased tidal volume and minute ventilation | Blunted response to hypoxia and hypercapnia

Question 43

The release of what is associated with morphine and meperidine?

Answer 43

histamine

Question 44

What are the pulmonary effects of opioids?

Answer 44

Increase PCO2 Blunted response to hypercapnia Chest wall rigidity

Question 45

What are the CV effects of ketamine?

Answer 45

Increased BP, SVR, HR and CO due to increase SNS

Question 46

What are the pulmonary effects of ketamine?

Answer 46

``` potent bronchodilator Increased secretions (prevent with glycopyrrolate) ```

Question 47

What are the cerebral effects of ketamine?

Answer 47

Increased O2 consumption, CBF and ICP

Question 48

What are some side effects of ketamine?

Answer 48

dissociation analgesia nystagmus Ileus/constipation

Question 49

What are the side effects of etomidate?

Answer 49

Inhibition of B-11 hydroxylase and adrenocortical suppression myoclonus seizures

Question 50

What is unique about etomidate?

Answer 50

little change on the heart. It is the DOC when CV stability is in question

Question 51

What is the CV effects of propofol?

Answer 51

Myocardial depression | Vasodilation

Question 52

What are the benefits of propofol?

Answer 52

Rapid Induction and emergence | Antipruritic and antiemetic

Question 53

How are BZDs metabolized?

Answer 53

By the liver into water soluble glucoronides

Question 54

What is the MOA of ketamine?

Answer 54

NMDA receptor antagonist | Causes dissociation of the thalamus from the cerebrum

Question 55

What does ketamine do to CO?

Answer 55

Increases CO

Question 56

What is the MOA of etomidate?

Answer 56

Depresses the RAS by enhancing GABA affinity for its receptor.

Question 57

What is the MOA of propofol?

Answer 57

modulates GABA receptors