Week 8- General Anesthesia

Question 1

Anesthesia, by the definition, is a change in the responses of an ____ _____ to ____ _______. Making a definitive link between anesthetic effects observed in vitro and the anesthetic state observed and defined in vivo is difficult.

Answer 1

intact animal

external stimuli

Question 2

T/F: There are multiple molecular mechanism that can produce clinical anesthesia.

Answer 2

True!

No structure-activity relationships are apparent among anesthetics. A wide variety of structurally unrelated compounds, ranging from steroids to elemental xenon, are capable of producing clinical anesthesia.

Question 3

Anesthetics work at very high concentrations in comparison to drugs, neurotransmitter and hormones; this implies that the have a very _____ ______ to the receptor and do not stay bound for long.

Answer 3

low affinity

this makes it much more difficult to observe and characterize than high affinity bonding. They stay bound to the receptor for very short periods of time.

Question 4

broadly defined as a drug-induced reversible depression of the CNS resulting in the loss of response to and perception of all external stimuli.

Answer 4

General Anesthesia

Question 5

Anesthesia is a collection of “component” changes in behavior or perception.
The components of an anesthetic state: (5)

Answer 5

A. unconsciousness
B. amnesia
C. analgesia
D. immobility
E. attenuation of autonomic responses to noxious stimuli

Question 6

One of the reasons why defining anesthesia is difficult?

Answer 6

our understanding of the mechanism of consciousness is amorphous

Question 7

T/F: MAC is additive.

Answer 7

True

** example running nitrous with sevo

Question 8

In order to study the pharmacology of anesthetic action, qualitative measures of anesthetic potency must be measure (T/F)

Answer 8

False!! quantitative

Question 9

why is there some difficulty in defining anesthesia?

Answer 9

MOA is not fully understood at this time

Question 10

General anesthesia is a collection of “component” changes in _______ & ___________

Answer 10

behavior & perception

Question 11

___________measures of anesthetic potency must be measured

Answer 11

Quantitative

Question 12

what is MAC (minimum alveolar concentration)

Answer 12

partial pressure of gas at which 50% of humans do not respond to surgical stimulation

Question 13

MAC = _____: Represents the average response of ___________, not the response of a single subject

Answer 13

Dose;

the whole population

Question 14

________ concentration of gas provides an index of the “free” concentration of drug required to produce anesthesia

Answer 14

end-tidal

Question 15

how does end-tidal concentration provide an index of the “free” concentration of drug required to produce anesthesia

Answer 15

the end-tidal gas concentration is in equilibrium with the free plasma concentration and BIS monitoring

Question 16

MAC only refers to the___________ of agent. NOT the _________ of other adjuncts that we have given

Answer 16

concentration

amount

Question 17

_________ has also become a standard of care in general anesthesia

Answer 17

BIS monitoring

Question 18

There is a linear relationship between the oil/gas partition coefficient and anesthetic potency (MAC)- theories regarding protein binding also satisfy the

Answer 18

Meyer-Overton Rule

Question 19

Unitary theory of anesthesia:

Answer 19

Since a wide variety of structurally unrelated compounds obey the Meyer-Overton Rule, it has been reasoned that all anesthetics are likely to act at the same molecular site.

Genetic data plainly demonstrates that the this unitary theory of anesthesia is not correct; no single mechanism is responsible for the effects of all general anesthetics

Question 20

More than 100yrs ago Meyer and Overton observed that the potency of gases as anesthetics was strongly correlated with their solubility in olive oil- this idea led to:

Answer 20

The unitary theory of anesthesia

Question 21

Anesthetic agents must disrupt the function of neurons mediating ________, __________, & __________

Answer 21

behavior, consciousness & memory

Question 22

Anesthesia alters neuronal communication by:

Answer 22

1. altering neuronal excitability- create a more negative rmp (resting membrane potential) = hyperpolarize the neuron which decreases the action potential.
2. synaptic transmission- widely considered to be the most likely subcellular site of general anesthetic action

**evidence suggest that some voltage gated calcium channels are sensitive to anesthetics and some sodium channels subtypes are inhibited by volatile anesthetics. This effect may be responsible for a reduction in neurotransmitter release at some synapses.

Question 23

widely considered to be the most likely subcellular site of general anesthetic action

Answer 23

synaptic transmission

Question 24

T/F: Many anesthetics potentiate GABA in CNS

Answer 24

True.

Question 25

GABA receptors are probable targets of anesthetics along with what other sites?

Answer 25

- Glycine - Neuronal nicotinic receptors - 5-HT3 receptors.

Question 26

Relevant targets for Amidate & Propofol

Answer 26

GABA activated ION Channels

Question 27

Where in the CNS do Anesthetics work?

Answer 27

- Suppress circuits in the spinal cord & brainstem - Induce immobility & disrupt autonomic homeostasis

Question 28

It is clear that all anesthetic effects cannot be localized to a specific anatomic site in the CNS. (T/F)

Answer 28

True

Question 29

T/F: Neurobiologic underpinnings of arousal and awareness are distributed across the **brainstem, subcortical, and cortical structures**. There is a single anatomic site responsible for anesthetic-induced unconsciousness.

Answer 29

False! ** There is no single anatomic site responsible for anesthetic-induced unconsciousness.

Question 30

Genetic data plainly demonstrates that the unitary theory of anesthesia is not correct because:

Answer 30

No single mechanism is responsible for the effects of all general anesthetics . Nor does a single mechanism account for all effects of a single anesthetic.

Question 31

Anesthetics have powerful and widespread effects on

Answer 31

synaptic transmission

Question 32

Volatile anesthetics directly reduce excitatory synaptic transmission of______ neurons

Answer 32

spinal

Question 33

Propofol depresses activity in______ horn neurons via GABAergic mechanism

Answer 33

ventral

Question 34

_______ suppresses interneurons of central pattern generators involved in coordinated movements

Answer 34

Isoflurane

Question 35

Anesthetics can alter descending, afferent, efferent & modulating limbs of ______ ______ for reacting to noxious stimulation

Answer 35

reflex arcs

Question 36

It is clear that all anesthetic actions cannot be localized to a specific site in the CNS- much evidence allows that different components of the anesthetic state are mediated by actions at ______ anatomic sites!

Answer 36

disparate

Question 37

Anesthetics exert profound effects on cardiopulmonary & thermoregulatory homeostatic circuitry without autonomic centers in the______ & _______

Answer 37

brainstem hypothalamus

Question 38

Inspiratory neurons in the________ drive **phrenic** motor neurons to activate diaphragmatic contraction

Answer 38

medulla

Question 39

______ suppresses the spontaneous activity of the inspiratory neurons to activate the diaphragm

Answer 39

Halothane

Question 40

Anesthetics also have an effect on the cardiovascular reflexes mediated by nuclei in the______

Answer 40

brainstem

Question 41

the __________ is a plausible target for suppression of memory formation

Answer 41

hippocampus **causes amnesia**

Question 42

Is a diffuse collection of **brainstem neurons** that mediate arousal

Answer 42

RETICULAR ACTIVATING SYSTEM (RAS)

Question 43

Is the major site for generating awareness of the external environment; primary sensory areas

Answer 43

cerebral cortex **Disruption feedback by anesthetics may contribute to impaired consciousness

Question 44

T or F: extubtion of trachea is a benign procedure

Answer 44

F - NOT benign

Question 45

Extubating Criteria: (8)

Answer 45

- **secretions cleared** - 5-sec head lift/sustained hand grasp - **adequate pain control** - minimal expiratory concentration of IA - Vc > or = 10 ml/kg - Negative inspiratory pressure >20 cmH20 - Vt > 6 cc/kg - sustained tetany

Question 46

PACU report should include (7)

Answer 46

- List ABX given - Amount of narcotic - Make sure RN comfy with pt - Pt allergies - Any med rxns (reactions) - Report before you leave - Airway difficulties (intubation/extubation)

Question 47

most stimulating part of D&C

Answer 47

dilation

Question 48

during D&C, when can you usually turn off N2O

Answer 48

when they begin suction

Question 49

Suction D&C for a woman that had a missed AB at 10weeks but has reflux; and a BMI of 48 -- what position

Answer 49

Lithotomy position in steep Trendelenburg

Question 50

LMA should not be used if?

Answer 50

- Prone surgery - Muscle relaxants used - Sx over 2 hours - Insufflated belly (ex. Lapararoscopic) - BMI > 50

Question 51

Designed a classification system used to define relative risk prior to conscious sedation and surgical anesthesia

Answer 51

American Society of Anesthesiologists (ASA)

Question 52

Class I ASA

Answer 52

Class 1: Normal healthy patient

Question 53

Class II ASA

Answer 53

Patient with mild systemic disease (no functional limitations)

Question 54

Class III ASA

Answer 54

Class 3: Patient with severe systemic disease (some functional limitations)

Question 55

Class IV ASA

Answer 55

Class 4: Patient with severe systemic disease that is a constant threat to life (**functionally incapacitated**)

Question 56

Class V ASA

Answer 56

Class 5: Moribund patient who is not expected to survive without the operation

Question 57

Class VI ASA

Answer 57

Class 6: Brain-dead patient whose organs are being removed for donor purpose.

Question 58

E - ASA

Answer 58

If the procedure is an emergency the physical status is followed by an “E”

Question 59

SAB

Answer 59

Subarachnoid block (this is a spinal)

Question 60

PAW

Answer 60

PAW- peak airway pressure

Question 61

IntrathecaL

Answer 61

inside the dura

Question 62

Epidural

Answer 62

outside of the dura, In the epidural space (which is a potential space)

Question 63

GSW

Answer 63

gun shot wound

Question 64

BBSE

Answer 64

Bilateral breath sounds equal (a fast way to chart lung sounds that are clear

Question 65

One of the reasons why defining anesthesia is difficult?

Answer 65

our understanding of the mechanism of consciousness is amorphous