General Anesthesia

Front 1

What is Anesthesia?

Back 1

The state in which there is an absence of pain and movement in response to a surgical incision

Front 2

5 Element of Anesthesia

Back 2

Sedation
Analgesia
Amnesia
Attenuation of Autonomic Relexes
Immobility

Front 3

Ideal General Anesthetic
(4 characterisitcs)

Back 3

Rapid, smooth induction
Rapid, smooth recovery
Large Theapeutic Index
Minimal Adverse Effects

Front 4

Volatile anesthetics are selected on what Basis?

Back 4

Side effects

Front 5

Two Non Halogenated Inhalaltionals

Back 5

NO2
Xe

Front 6

One Halogenated Alkane

Back 6

Halothane

Front 7

Four Halogenated Ethers

Back 7

Sevoflurane
Enflurane
Isoflurane
Desflurane

Front 8

MAC definition

Back 8

i. MAC is minimum alveolar concentration of anesthetic at one atmosphere that produces immobilization in 50% of subjects exposed to noxious stimulus

Front 9

Meyer-Overton Rule

Back 9

Potency of gas as an anesthetic is proportional to its olive oil/gas partition coefficient
(MAC x oil/gas partition coeeff = 2.17 ATM)

Front 10

Exceptions to the Meyer-Overton Rule

Back 10

Anesthetic Enantiomers
Non-immobilizers

Front 11

How are synapses inhibited by Inhalationals?

Back 11

Hyperpolarization

Front 12

Two mechanisms of Anesthesia?
(which one is major in vertebrates?)

Back 12

Inhibit excitatory synapses**
Enhancing Inhibitory Synapses

Front 13

Action at GABAa receptors?

Back 13

Potentiation

Front 14

What receptor is modified to produce hyperpolarizing effect?
Which drugs modify this receptor?

Back 14

Background K+ channel is opened

All the ones we talked about

Front 15

GABAa channel is a _____ channel

Back 15

Chloride

Front 16

NO and Xe act on what kind of channel?

What is the mode of inhibition?

Back 16

NMDA type Glutamate receptors

Non-competitive

Front 17

Unitary Theory of Anesthesia

Back 17

All general anesthetics (volatile and intravenous) act through a common mechanism.
This theory is incorrect

Front 18

Major site of Anesthetic action?

Other Place an anesthetic can act?

Back 18

Post-synaptic NT receptor and Ion Channel?

Pre-synaptic vesicle fusion

Front 19

MAC response (unresponsiveness to painful stimulus) is produced where?

Back 19

Spinal Cord

Front 20

Hypothalamic activity Regarding wakefulness in normal state.

Back 20

LC releases NE which inhibits VLPO so it cannot release inhibitory GABA onto the TMN. Thus, TMN can thus activate the Cortex using Histamine.

Front 21

NREM sleep Hypothalamic action.

Back 21

LC releases NO NE so VLPO is unopposed.VLPO can thus release inhibitory GABA onto the TMN. Thus, TMN CANNOT activate the Cortex and will release no Histamine.

Front 22

Hypothalamic activity in Anesthesia with a GABA agonist.

Back 22

GABA agonist (Propofol, muscimol, Benzodiadepines) inhibits TMN so it cannot arouse cortex and releaes no histamine. GABA agonists will have no effect on the LC, so it will fire away as if the person was aroused.

Front 23

LC is located in the:
VLPO is located in the:
TMN is located in:

Back 23

PONS
Basal Forebrain
Rostral Hypothalamus

Front 24

Hypnotic effects of some anesthetics is mediated where?

Back 24

Hypothalamus

Front 25

Brain Partial P is proportional to and cannot exceed

Back 25

Alveolar Partial Pressure

Front 26

At Eqilibrium alveolar partial pressure is equal to:

Back 26

tissue partial pressure

Front 27

Partition coefficient=
1)definition
2) math

Back 27

1)ratio of concentrations when partial pressures are equal
2)[destination]/[source]

Front 28

Equation which describes tissue concentration in a tissue over time.

Back 28

c = 1 – e ^–kT or c = 1 – e ^–T/tau

k=F/V= (Rate of ventilation)/(FRC)
F=Va (= Rate of Ventilation)
V=FRC

Front 29

Blood uptake of a drug from gas in the lungs depends upon

Back 29

Blood gas partition coeffienct
CO
Pa-Pv

Front 30

How does brain uptake of a drug vary with CO

Back 30

Inversely because flow to head is constant, but increased CO will shunt blood to other organs that can steal drug from the circulation.

Front 31

Tissue uptake from blood depends upon

Back 31

Equilibrium concentration in the tissue
(partition coefficient)
Blood Flow

Front 32

Vessel rich group

Back 32

brain, heart, kidney, liver

Front 33

What patient could cause a pt. to wake up slowly?

Back 33

Obesity- fat is a drug resevoir.

Front 34

Metabolism of Inhaled anesthetics?


Caveat of methoxyfluane?

Back 34

80-100% through lungs-unchanged


Metabolism produces Fl- which can cause renal failure. (also done a small amount by sevoflurane and enflurane)

Front 35

Possible effect of Halothane metabolism?

Back 35

Hepatic Necrosis- Immune reaction

Front 36

How does length of anesthesia effect waking up?

Back 36

Longer anesthesia can allow more gas to accumulate in fat, which will leech out slowly. More prominent in fat soluble anesthetics (fluranes>halothane>NO2)

Front 37

How does Ventilation rate effect induction.

Back 37

Increased rate decreases induction time (Speeds induction)

Front 38

Circulatory Side effects of Volatile Anesthetics

Back 38

1)Dose dependant decrease in BP
2)HR (H decreases, I and D increases)
3) decrease baroreceptor setpoint
4) central vasodilation/inhibition of autoregulation (canRe lead to ICH)

Front 39

Respiratory Side effects of Volatile Anesthetics

Back 39

1) Bronchodilation
2)Increase in pCO2 (acidosis)
3)Depressed O2 chemoreceptor sensitivity
4) Pungency

Front 40

Other Side effects of Volatile Anesthetics

Back 40

Decreased RBF
Decreased Hepatic blood flow
Uterine relaxation (cant give during delivery but can give after)

Front 41

Three N20 specific side effects

Back 41

Megaloblastic Anemia
Bone Mrrow Depression
Teratogenesis

Front 42

Xenon:
1) side effect?
2) induction and recovery?
3) limit to use?

Back 42

1) none
2) both are rapid
3) limited availibility- rare element

Front 43

FIve Parenteral Anesthetics

Back 43

Thiobarbiurates
Etomidate
Propofol
Benzodiazepine
Ketamine

Front 44

Which Parenteral anesthetic acts on NMDA glutamatergic channels?
What anatomical site does it act on?

Back 44

Ketamine
Hippocampus

Front 45

Common feature of all parenterals

Back 45

produce sedation, but often need to supplement for other components of anesthesia (analgesia, attenuation of reflexes, amnesia, immobility)

Front 46

Thiobarbituates main use

Back 46

induction agent

Front 47

Thiobarbituates time scale
1) onset
2) length of effect

Back 47

1)8-10 sec
2) 10-12 minutes

Front 48

Thiobarbituates Side effects:

Back 48

1) CNS, Cardiac, and Respiratory Depressant (can cause hypotension)

Front 49

Thiobarbituates Effects on CNS bloodflow and resultant indication for usage.

Back 49

Thiobarbituates reduce CNS bloodflow and metabolism
Indicated for patients with increase intracranial pressure

Front 50

Thiobarbituates can induce crisis in a specific population......

Back 50

Patients with Acute Intermittent Poryphyria

Front 51

Etomidate main use:

Back 51

Induction agent

Front 52

Etomidate time scale:
Induction:
Length of effect

Back 52

1) seconds
2) 5-10 minutes

Front 53

Etomidate is particularly poor at this part of anesthesia

Back 53

Analgesia

Front 54

Why do we like Etomidate so much?

Back 54

Minimal cardiac or resp. side effects

Front 55

Etomidate CNS effect

Back 55

Decreses cerebral blood flow

Front 56

Etomidate use is limited by?

Back 56

Painful injection

Front 57

Etomidate Acts on?
potentiates or inhibits?

Back 57

B3 subunit of GABAa receptor
potentiates

Front 58

Etomidate major side effect?

Back 58

Adrenocortical Supression-- Addison's like disease

Front 59

Etomidate- Why does effcet terminate so quickly?

Back 59

Redistribution from brain to muscle and fat (same for thiobarbituates)

Front 60

Propofol- 2 main uses

Back 60

Induction Agent
Maintenance drug for short surgical procedures

Front 61

Propofol- CNS actions terminated by?

Back 61

Rapid redistribution

Front 62

Propofol-How fast to people awake after discontinuation of infusion?

Back 62

VERY quickly

Front 63

Propofol Side effects?

Back 63

CV and respiratory depression

Front 64

Propofol use limited by?

Back 64

Injection site pain

Front 65

Propofol- 2 useful side effects?

Back 65

Antiemetic
Post-operative euphoria

Front 66

Propofol Mechansim?

Back 66

Allosteric modulator of GABAa channels at B3 subunit

Front 67

Ketamine causes.....

Back 67

Catatonia
Amnesia
Analgesia (Excellent)

Front 68

Wierd thing about Ketamine

Back 68

Patients wont move spontaneously but can do so if ask.

Front 69

Side effects of Ketamine:

Back 69

Increased HR by Sympathetic stim
Hallucinations (bad in adults, good in kids)
NO respiratory or muscular effects.

Front 70

Ketamine effect on cerebral blood flow?

Back 70

Increased

Front 71

Ketmaine Acts on?

Back 71

PCP site on NMDA glutamatergic Channels

Front 72

Ketamine used in?

Back 72

Kids because they have good hallucinations rather than bad ones.
Patients in shock undergoing painful procedures.

Front 73

Only example of a Benzodiazepine which is water soluble and can be given IV.

Back 73

MIDAZOLAM

Front 74

Benzodiazepines- Particularly good at inducing what component of anesthesia?

Back 74

Amnesia

Front 75

Benzodiazepines- Lorazempam and Diazepam are given preoperatively for what purpose?

Back 75

Sedation and Anxiolysis

Front 76

Benzodiazepines- Mechanism?

Back 76

Partial Agonist of GABAa receptor

Front 77

All anesthetics that effect GABAa

Back 77

Halothane
-fluranes
Propofol
Etomidate
Barbiturates
Neurosteroids

Front 78

All anesthetics that DONT effect GABAa

Back 78

NO2
Ktamine
Xenon
Cyclopropane

Front 79

4 stages of anethesia

Back 79

1) amnesia and analgesia (lastf from administration to loss of conciousness)
2)Delirium (loss of conciousness to onset of regular breathing and disappearance of lid reflex)
3) Surgical anesthesia (lasts from regular pattern of breathing to cessation of respiration)
4) Overdose (cessation of respiration to circulatory failure)

Front 80

Why do we use polypharmacy?
Why is it dangerous?

Back 80

Lowers amount of any one drug given giving reduced toxicity

Can cause problems with drug interactions

Front 81

4 things one could give as anesthetic pre-medication

Back 81

1) Benzo- common
2) analgesic- Occasional
3) Anti-emetic-rare
4) Anticholinergics

Front 82

Why would one give anticholinergics before anesthesia?

Back 82

Dries airway secretions and allows airway manipulation.

Front 83

Induction agents?
1) 4 IV
2) 1 inhalational

Back 83

1) propofol, thiobarbiturates, etomidate,
ketamine
2) Sevflurane (not pungent)

Front 84

Why would one give muscle relaxants to an anesthesia patient?

Back 84

Relaxes Cords, easier intubation

Front 85

Delivery Systems control

Back 85

vaoporization of anesthetic
O2 delivery
CO2 removal

Front 86

Assesment of Anesthetic depth:
For halogenated anesthetics, depth varies with.....

Back 86

BP

Front 87

Things we might use to determine anesthetic depth

Back 87

BP- if using halogenated anesthetic
HR
RR
Respiratory compliance
Facial grimacing and lacrimation

Front 88

Assesment of Anesthetic Depth:
Bispectral index involves-

Back 88

Auditory invokes potential monitoring

Front 89

Recovery from Anesthesia:
2 steps and one we rarely use

Back 89

1) discontinuation of inhalant
2) reversal of non-depolarizing muscle relaxants
3) Narcotic antagonists- rarely used because it inhibits endogenous opiates.

Front 90

Selection of anesthetic is based upon____1(3 things)__ NOT____2_____

Back 90

1) side effects, pharmacokinetics, excretion
2) NOT primary effect

Front 91

Selecting an anesthetic- SHOCK
Avoid:
Use:

Back 91

Must support BP and maintain O2 saturation
Avoid: Barbiturates and halogens (depress BP) and N20 (Pt. need to be on high 02 concentration)
USE: Ketamine, etomidate, opitates, muscle relaxants

Front 92

Selecting an anesthetic- Neurosurgery
Avoid:
Use:

Back 92

Must avoid increased ICP
Avoid: Halogenated agents, ketamine
Use: Barbiturates, opiates, NO2, muscle relaxants

Front 93

Selecting an anesthetic- Thoracic Surgery
Avoid:
Use:

Back 93

Must maintain Oxygentation because you may be operating on a lung:
avoid: N20
Use: Halogenated agent in 100% O2

Front 94

Selecting an anesthetic- Liver Failure
Avoid:
Use:

Back 94

Inability to metabolize drugs
Avoid: Barbiturates,opiates, ketamine (metabolized by liver)
Use: Halogenated agents, N2O (excreted by lungs)

Front 95

Which IV anesthetics:
1) increase cerebral blood flow?
2) Decrease cerebral blood flow?

Back 95

1) Ketamine (And halogenateds)
2) Thiobarbiturates, Etomidate

Front 96

Which IV anesthetics:
1) cause card. and resp. depression?
2) Has minimal respiratory effects but increases HR and BP?
3) does not affect heart or respiration?

Back 96

1) Propofol, Thiobarbiturates
2) Ketamine
3) Etomidate

Front 97

Which IV anesthetics can be used for induction?

Back 97

Thiobarbiturates, etomidate, propofol, ketamine

Front 98

Wht two types of IV anesthetics can be combined to produce a "balanced anesthesia"?

Back 98

Narcotics and Barbiturates

Front 99

What IV agent lowers requirements for volatile anesthetics?

Back 99

narcotics

Front 100

Do narcotics affect BP?

Back 100

no

Front 101

Do narcotics
1)depress the respiratory system?
2) block autonomic reflexes?

Back 101

1)YES
2) no