Inhalation Agents

Front 1

Desflurane at > __% atm can cause airway irritation. You should therefore avoid Des for...

Back 1

>6 % will cause airway irritation.

Best to induce with other agent or use <6%.

Front 2

The less soluble the anesthx, the ______ induction and emergence.

Back 2

FASTER

Front 3

______ may react with ______ to form Compound A. Why do we care?

Back 3

SEVO may react with SODA LIME (CO2 absorbent) to form Coumpound A. Metabolites of Compound A are nephrotoxic.

Front 4

Only ____ is not metabolized at all in the body.

Back 4

Xenon

Front 5

All inhaled anesthx may have ______ activity on CNS occasionally.

Back 5

Stimulating

Front 6

Guedel's Signs and Stages developed by observing pt's on what drug?

Back 6

Diethyl ether

Front 7

Stage I: Analgesia

Back 7

Initial analgesia, later amnesia

Front 8

Stage II: Excitement

Back 8

Delirium, amnesia, irregular RR and TV, vomiting possible, struggling pt.

Ideally pt will pass through II quickly.

Front 9

Stage III: Surgical Anesthesia

Back 9

BEGINS with recurrence of regular respiration

ENDS with cessation of breathing.

Has 4 planes:

1) Regular resp, swallowing, absent lid reflex.

2) Pupils central & fixed, RR regular, BIS ~30.

3) Loss of accessory muscle use for respiration, shallow breathing; assist respiration, laryngeal depression.

4) Only diaphragmatic respiratory effort, pupils large and central, carinal depression.

Front 10

In plane 1 of Guedel's stage III, absent lid reflex means you can start to _____ the patient.

Back 10

Positive pressure ventilate

Front 11

In Plane 2 of Guedel's Stage III, you can put in _____.

Back 11

Oral airway.

Front 12

Stage III of Guedel's: which plane can you intubate?

Back 12

Plane 2-3 good for intubation.

Front 13

T/F.... Plane 4 of Guedel's Stage III is unnecessarily deep.

Back 13

True. Plane 4 is "too deep."

That's what she said... hahaha

Front 14

Guedel's Stage IV: Stage of Medullary depression.

Back 14

Spontaneous respiration ceases

Severe depression of vasomotor center in medulla and respiratory center

Need full circulatory and respiratory support otherwise death is imminent

*Anesthesia crisis!

Front 15

Inhalation agents, except ______, are colorless liquids at room temp.

Back 15

except Desflurane

Front 16

Halothane uses the preservative ______.

Which prevents decomposition caused by _____

Back 16

Thymol 0.01%

Decomposition when exposed to light.

**Thymol residue can impair vaporizer's accuracy.

Front 17

Population with largest risk for Halothane hepatitis...

Back 17

Kids with many surgeries/exposures to Halothane.

Front 18

Which agent has lowest B:G PC?

Which agent has the highest vapor pressure?

Back 18

Desflurane 0.42 B:G

Desflurane 669 mmHg

Front 19

Agents in order of MAC potency?

Why is this important?

With regards to Desflurane, what does its MAC tell you?

Back 19

Halothane 0.75 %

Isoflurance 1.15 %

Sevoflurane 2.05%

Desflurane 7%

Lower the MAC (vol%), the less agent needed to induce, which leave more room for O2 in gas mixture.

Desflurane of 7% significant because significant airway irritation at conc >6%. Bad induction agents unless using N2O concurrently.

Front 20

Easy to differentiate structure of Halothane from other agents because....

Back 20

NOT an ether (No -C-O-C-). A halogen.

Front 21

6 factors influencing speed of action of Inh agents.

Back 21

1) Inspired Anesthesia pp

2) Gas Flow rate

3) Alveolar pp

4) Anesth Solubility (very soluble = slower onset)

5) Ventilation -- Increased ventilation increases rate of rise of FA/FI

6) Cardiac Output -- Decreased CO accelerates the rate of rise (less blood rushing agent away from alveoli).

Front 22

Order of FA/FI for agents "wash in"

Back 22

Fastest to slowest:

Desflurane, Sevoflurane, Isoflurane, Halothane.

Front 23

Cheapest agent ______

Most expensive agent_____

Back 23

Halothane cheapest (0.24 AWP/mL)

Sevoflurane most expensive (1.08 AWP/mL)

Front 24

Why do we want fresh gas flows as low as possible?

Back 24

1) Saves gas

2) Keeps patient hydrated.

Front 25

Despite ______ having highest AWP/mL, calculating the "per MAC hour" of the agents shows that due to potency it is more economical than _____.

Back 25

SEVOFLURANE has highest AWP/mL, but DESFLURANE has higher price "per MAC hr," which is a better calculation for determining true cost.

Des: $19.17 per MAC hr
Sevo: $14.14 per MAC hr

Front 26

Define vapor pressure...

Back 26

When evaporation of a liquid in a container equals the amount of vapor returning to liquid form (equilibrium).

Front 27

Boiling point is...

Back 27

Temp at which vapor pressure = atmospheric pressure

Front 28

Variable-bypass Vaporizer

Back 28

Setting of concentration dial determines ratio of flow that goes thru bypass chamber vs vaporizing chamber.

Front 29

_______ in high doses has been known to show seizure activity on EEG.

Back 29

Desflurane

Front 30

Deflurane is unique because has....

Back 30

Completely fluorinated ether molecule.

Front 31

Desflurane has a high vapor pressure, requiring...

Back 31

a heated, pressurized vaporizer.

Front 32

Induction dose of Desflurane...

Back 32

6-10% with Air/O2

5-8% with N2O

Front 33

Desflurane may cause coughing/airway irritation. May be beneficial to induce patient how?

Back 33

Induce with LESS irritating agent, then switch to Desflurane.

Front 34

Maintenance dose of Desflurane?

Back 34

5-7%.

Front 35

When using a TEC 6 vaporizer, if FGF increases, machine does what?

Back 35

Increases working Pressure proportionally.

Front 36

TEC 6 easy because user just has to....

Back 36

Determine concentration setting on a dial and machine will adjust for variables like FGF to deliver constant concentration.

Front 37

_______ may lead to coronary artery steal sydrome! Which can cause ____ or __.

Back 37

Isoflurane

Can cause ischemia or MI.

Front 38

Why avoid isoflurane in patients with aortic valve stenosis?

Back 38

These pts cannot tolerate the decrease in SVR.

Front 39

Induction dose of Isoflurane

Back 39

3-4% in Air/O2

1.5 - 3 % in 65% N2O

Front 40

Maintenance dose of Isoflurane

Back 40

1- 2.5%

Front 41

Isoflurane known to cause coughing and _____.

Back 41

apneic periods.

Front 42

Which agent should not be used in low flow systems? Why?

FGF should be = or > ___

Back 42

Sevoflurane -- it degrades to compound A.

2 L per minute

Front 43

_____ is formed when sevoflurane reacts with CO2 absorbents. This is a concern because its metabolites are ______.

Back 43

Compound A

Nephrotoxins

Front 44

Sevoflurane does not _____, a big reason why it is replacing halothane for ________ in _____ patients.

Back 44

DOES NOT cause airway irritation.

Replacing halothane for mask inductions in pediatric patients.

Front 45

Sevoflurane induction doses:

Back 45

1.5 - 3 % in Air/O2

0.7 - 2% in 65% N2O

Front 46

Sevoflurane maintenance dose:

Back 46

0.4 - 2 %

Front 47

2 agents that lower B/P d/t negative inotropy

Back 47

Halothane and Enflurane

Front 48

Desflurane, Isoflurane, and Sevoflurane all lower B/P via

Back 48

Decreased SVR

Front 49

Two agents that produce dose dependent increase in HR

Back 49

Isoflurane & Desflurane

Front 50

Effects of inhaled anesthx on:

CBF
ICP
CMR

Back 50

Inc CBF
Inc ICP
Dec CMR

Front 51

Sevoflurane maintenance dose:

Back 51

0.4 - 2 %

Front 52

2 agents that lower B/P d/t negative inotropy

Back 52

Halothane and Enflurane

Front 53

Desflurane, Isoflurane, and Sevoflurane all lower B/P via

Back 53

Decreased SVR

Front 54

Two agents that produce dose dependent increase in HR

Back 54

Isoflurane & Desflurane

Front 55

Effects of inhaled anesthx on:

CBF
ICP
CMR

Back 55

Inc CBF
Inc ICP
Dec CMR

Front 56

Inhaled anestx effects on:

RBF
GFR

Back 56

Dec RBF
Dec GFR

Front 57

___ doses of Isoflurane and ___ doses of desflurane cause increased HR.

Back 57

Low Iso
High Des

Front 58

2 agents that have NO significant change in HR

Back 58

Halothane and Sevo

Front 59

What can you give to pts to blunt Increased HR seen with Iso and Des?

Back 59

Opioids

Front 60

Cardiac dysrhymias are of concern when _____ used in combination with catecholamines like Epi.

Back 60

Halothane

Front 61

1 agent that causes drop in cardiac output d/t decrease in myocardial contractility.

Back 61

Halothane

Front 62

HPV: hypoxia causes...

_____ in small pulmonary arteries and ______ in systemic arteries.

Back 62

Constriction in small PAs

Dilation in systemic arteries.

Front 63

Ultimately, HPV reduces flow of desaturated blood thru _________ areas of the lung.

Back 63

underventilated

Front 64

HPV works by sensing changes in O2 tension in what two areas?

Back 64

1) Type 1 cells of carotid body

2) Pulm vascular smooth muscle cells

Front 65

HPV in systemic arteries:

Hypoxia causes inc current through _____________ and vasodilation.

Back 65

ATP-dependent K+ channels

Front 66

HPV: pulmonary arteries --

Hypoxia inhibits _________ current and causes __________

Back 66

K+ current

vasoconstriction

Front 67

Which agent blunts HPV the worst?

Back 67

Halothane

Front 68

Shunt __to___ has significant effect on wash-in.

Has larger effect on which type of agents?

Back 68

R-to-L

Greater effect on poorly soluble agents

Front 69

R-to-L shunt limits the increase in agent pp in the pulmonary vein because (2 reasons):

Back 69

1) Increase in ventilation does not substantially affect wash-in of less soluble agent

2) shunted blood slows the rate of rise of Pv.

Front 70

All inh agents offer some sort of cardioprotection, how?

Back 70

Improve O2 supply/demand or embracing coronary collateral circulation.

Front 71

Anesthetic Induced Preconditioning (APC) ultimately results in increased:

Back 71

Resistance to injury.

Works because tissues remember previous exposure to volatile anestx and triggers a cascade leading to end-effector responsible for resisting injury

Front 72

w/regards to APC, volatile anestx may:

Back 72

1) Generate reactive oxygen species (ROS)

2) Facilitate K(ATP) channel opening

Front 73

Of critical importance in APC, preservation of ________ protects against ischemia.

Back 73

mitochondrial bioenergetic function

Front 74

Volatile anesthetics enhance ischemic protection by ______

Back 74

... prolonging openings of ion channels!

Front 75

Inh agents affects on:

RR
TV
MV
PaCO2

Back 75

INC resp rate

d/t DEC tidal volume

yields DEC min vent &

INC PaCO2

Front 76

Inh. agents suppress ______ in brain, diminishing CNS response to PaCO2 during inh. anesthesia.

Back 76

Medullary vent. center

Front 77

Inh depress vent response to hypoxemia, which is mediated by ______

Back 77

Carotid bodies

Front 78

Inh anestx blunt ____________ of hypoxemia + hypercapnia on stimulation of ventilation.

Back 78

synergistic effects

Front 79

3 agents cause dose-dependent decrease in airway resistance.

Back 79

Isoflurane
Sevo
Halothane

Front 80

_______ Used to treat status asthmaticus that does not respond to conventional therapy.

Back 80

Halothane

Front 81

Volatile anestx are potent bronchodilators d/t....

Back 81

decrease of IC Ca++ concentration and decreased Ca++ sensitivity.

Front 82

All inh agents _______ FRC.

Back 82

Decrease

Front 83

Inh effects on:

RBF
UO
GFR

Back 83

Dec RBF
Dec UO
Dec GFR

Front 84

Inh. agents _____ hepatic blood flow

Back 84

Decrease hepatic blood flow

Front 85

In neurosurg case: use ____% MAC. Why?

Best option is to use propofol + narcotics to avoid ______.

Back 85

50% MAC in neurosurg d/t increased CBF and CBV

Prop + narcs better as it does not block SSEP.

Front 86

With regards to metabolism, ______ is most stable agent

Back 86

Desflurane

Front 87

Halothane hepatitis causes ________ in children.

Back 87

Liver necrosis

Front 88

Inh. agents cause uterine _______ and _____ uterine contractility.

Back 88

uterine vasodilation &

decrease in uterine contractility

Front 89

All inh. agents cross _____

Back 89

placenta

Front 90

Uterine relaxation produced by inh agents may be helpful for...

Back 90

... removal of retained placenta.

Front 91

Uterine vasodilation from inh agents of concern d/t...

Back 91

... increased blood loss during obstetric surgery or delivery.

Front 92

____ does not change uterine contractility during vaginal delivery.

Back 92

N2O

Front 93

Volatile anesthx _____ action of NMB agents.

Back 93

Potentiate

Front 94

3 agents that produce significant skeletal muscle relaxation

Back 94

Isoflurane
Des
Sevo

Front 95

____ produces no skel muscle relaxation and may actually cause muscle rigidity, especially in combo with _____

Back 95

N2O

in combo with opioids

Front 96

T/F

Sevoflurane has been shown to cause significant nephrotoxicity in humans.

Back 96

False... no evidence in humans yet. Still must maintain high FGF to prevent it.

Front 97

Significant parts of Sevo metabolism...

Back 97

Compound A

May lead to F- ion, which is nephrotoxic metabolite

End result: proximal tubular necrosis.