N2Wk4- 10-5 Inhalation Anesthetics

Front 1

What are the commonly utilized inhalational anesthetics?

Back 1

1. Nitrous Oxide (N2O)
2. Halothane (HAL)- one of the earliest
3. Isoflurane (ISO)
4. Desflurane (DES)
5. Sevoflurane (SEVO)
6. Enflurane (EN)

Front 2

What is 3 goal anesthetic therapy "balanced anesthesia"?

Back 2

1. Analgesia
 Opioids (fentanyl, morphine, hydromorphone, etc…)
2. Amnesia- Benzodiazepines (midazolam, lorazepam, diazepam, etc…)
3. Anesthesia (incl. immobility)- Neuromuscular blockers (vecuronium, pancuronium,
rocuronium, etc…)
Must use in combination with other drugs

Front 3

In Anesthesia we have stages (4 describe them)

Back 3

1. Stage of analgesia- w/o amnesia
2. Stage of excitement- can be delirious respiration irregular possible n/v
3. Stage of surgical anethesia- return of regular respirations
4. stage of medullary depression- apnea present

Front 4

MOA of inhalational anesthetics

Back 4

Stereochemically bind to and activate the inhibitory GABAa receptor in brain (Specifically, affecting receptors’ Cl- channels
resulting in enhanced inhibition of neurotransmitter
release and depressed CNS activity)

Front 5

Describe the big picture of pharmacokinetics aspects in anesthetics

Back 5

Basic Steps:liquid to gas to lungs to blood to brain
1. “Volatile” gases – each needing a vaporizer to convert the liquid into a gas (inhalational)
2. Not commonly used alone (balance anesthesia)
3. Gas flow from flowmeters (02, N20) mixes with volatile anesthetic
4. Mixture enters inspiratory limb of the breathing circuit and passes via trachea to the alveoli
5. An alveolar concentration of gas will build in lungs and pass into arterial blood
6. Gas molecules in arterial blood are transferred to various tissues (Brain, Fat, Muscle)

Front 6

Component to uptake of anesthetic and onset of activity
Solubility explain

Back 6

Expressed in "partition coefficients"
Each coefficient is a ratio of concentration of anesthetic gas in 2 phases (locales)
• Blood:Gas (bolded)
• Brain:Blood
• Fat:Blood

Front 7

Greater the solubility in inhaled anesthetics mean?

Back 7

greater the solubility the longer the drug gets stuck in the blood longer before it works (think of a dam filling until it has enough to overflow)

Front 8

Lower the number blood:gass partition coefficients= less soluble what does that mean for putting a person to sleep

Back 8

lower solubility (blood:gass partition coefficients) means faster action

Front 9

Which Inhalation anesthetics are most to least soluble for blood:gas?

Back 9

1. Desflurane (DES)
2. Nitrous Oxide (N2O)
3. Sevoflurane (SEVO)
4. Isoflurane (ISO)
5. Enflurane (EN)
6. Halothane (HAL)- one of the earlies

Front 10

How can ventilation be manipulated for drugs actions?

Back 10

greater rate and depth of ventilation the faster the onset of anesthesia induction

Front 11

FA means what?

Back 11

FA (Fraction alveolar gas) includes all the following
1. Blood:Gas partition coefficient
2. Anesthetic Concentration (second gas effect)
3. Pulmonary Ventilation (rate/depth)
4. Pulmonary Blood Flow

Front 12

FI means what?

Back 12

FI (Fraction Inspired Gas Conc.) includes the following
1. Fresh gas flow rate
2. Breathing circuit volume
3. Breathing circuit absorption

Front 13

What are the key summarative elements in inhaled anesthetics

Back 13

FA and FI

Front 14

Class anesthetic Curve relates what?

Back 14

how quickly the drug works and fades off
FA/FI over time

Front 15

Why is NO faster than desflurane even though it is more soluble than desflurane?

Back 15

2nd gas effect- some of the effects in the body cause it to be processed faster

Front 16

All are inhaled anesthetics eliminated?
Relation to when you get gas out and solubility of drug.

Back 16

lungs
- great solubility = longer it takes to wake you up

Front 17

Unique SE of halothatne?

Back 17

H and H halothane hepatitis

Front 18

Minimum Alveolar Concentration (MAC): also mean?

Back 18

1 atm put 50% of pts and non purposefull immobility in pts

"POTENCY"- minimum concentration to effect 50% pts

Front 19

What is the MAC of NO?

Back 19

very high- which means you need high concentration to get 50% to sleep
Halothane has lowest MAC

Front 20

For Dose response concentrations what information does it give us on the slope of dose- response curve

Back 20

nothing because the curve is very steep i.e. 1.1-1.5 MAC can have 90-95% of patients appropriately

Front 21

What systems are physiologically effected by inhaled anesthetics

Back 21

Physiological Effects of Inhaled Anesthetics:
 There are common (and unique) physiological effects of the inhaled agents on the following systems:
 Cardiovascular
 Respiratory
 Cerebral
 Kidney
 Liver
 Uterine

Front 22

In general what do inhaled anesthetics do to Cardiovascular system
What do all inhaled anesthetics do to MAP (mean arterial pressure)- which drug is exception

Back 22

depress BP, but increase HR- the fluranes will not dramatically reduce Cardiac Outpul

- decrease except NO

Front 23

Right Atrial Pressure (RAP) & Cardiac Output (CO):

Back 23

Most increase RAP and decrease CO
Watch out for Enflurane and Halothane have the greatest CO depression

Front 24

Respiratory effect of inhaled anesthetics:
a. total volume
b. respiratory rate

Back 24

a. decrease TV to varying
degrees (mild, moderate; severe
b. All inhaled anesthetics increase RR to varying degrees (mild, moderate; severe

Front 25

Respiratory effect of inhaled anesthetics:
a. minute volume (MV)
b. Bronchodilation (which drug for asthma) Which is bad for asthma?

Back 25

a. All inhaled anesthetics decrease MV to varying degrees (mild, moderate; severe)
b. some are potent dilators sevoflurane- asthmatics
Desflurane bad for asthma

Front 26

What do inhaled anesthetics do to ability to secretions reflux

Back 26

Can’t easily clear own airway
 Risk of atelectasis & pulmonary infection

- anticholinergics administered to stop

Front 27

Pungent smelling drug inhaled anesthetics

Back 27

Desflurane

Sevoflurane has a pleasant smell

Front 28

What are the drugs effects on cerebral functions

Back 28

 All agents decrease cerebral metabolic rate
 The more soluble agents increase CBF (cerebral blood flow) secondary to reduced CVR (cerebral vascular resistance) leading to increased intra-cranial pressure (ICP)

Front 29

Kidney liver and uterine effects of inhaled anesthetics

Back 29

Decrease hepatic, decreased GFR and RBF
enhance neuromuscular blockade

Front 30

SE's of Sevoflurane

Back 30

renal toxicity secondary to Compound A can get around it by increasing flow rate

Front 31

What does amplitude of ventilation have to do with induction of anesthetic effect?

Back 31

The greater the rate & depth of ventilation the faster the onset of anesthesia induction

Front 32

What does the increase in cardiac output (pulmonary blood flow) do to rate of onset of anethesia

Back 32

slower onset of induction

Front 33

With inh anethetics what is the relationship of blood flow and the rate of onset?

Back 33

faster blood flow... the slower the onset of the anesthesia induction