Anesthesiology - A Paradigm, Week 2 Lecture

Question 1

What is the common chemical derivative for all the volatiles that we use regularly today? How are they modified?

Answer 1

All of the volatiles that we use today are ether derived. They start with ether and modify it with different noble gases to create different properties.

Question 2

What is the idea behind balanced anesthesia?

Answer 2

Balanced anesthesia looks at the different components that make up an anesthetic state.

This paradigm is utilized to come up with the delivery of anesthesia in a way that balances multiple factors that effect patient comfort, care, safety.

Question 3

What are the 5 components of balanced anesthesia?

Answer 3

Amnesia
Hemodyamic control
Analgesia
NMB
Unconsciousness

Question 4

What is the goal of amnesia in balanced anesthesia?

Answer 4

Block (esp with sedatives) the transition of info from short-term memory to long-term memory, so that patients do not remember it (since they are unable to move short-term memory to long-term memory.

Question 5

What are the different types of memories that we want to block?

Answer 5

Declarative memory (explicit)
	-Memories that can be recalled without prompting. (Pt can recall specific events that happened after a long period of time.) 

Non-declarative memory (implicit)
-Non-specific recall can be induced by some sort of paired stimulus

Question 6

Describe anesthesia recall.

Answer 6

Formation of explicit/declarative memories even while under anesthesia. Recall of experience can be done WITHOUT prompting (very psychologically damaging) - Think Pavlovian conditioning.

Question 7

Describe ‘awareness under anesthesia’.

Answer 7

Formation of implicit/non-declarative memories even while under anesthesia. Memory recall can be induced by some sort of prompt (verbal or stimulus/cue) but not without prompting.

Can be psychologically damaging when paired with the appropriate stimulus.

Question 8

Describe consciousness briefly.

Answer 8

Consciousness: ability to interact with environment in a purposeful manner. (eg listen to commands)

Question 9

How do we monitor consciousness?

Answer 9

No truly reliable monitor has been developed to tell to us whether pt is unconscious, but a lot of this is based on our intuition. We monitor this based on a gradient of behavioral cues that has no clear cut boundaries

Question 10

What is the last sense to go and first sense to return during anesthesia?

Answer 10

Hearing

Question 11

Can patients respond while unconscious?

Answer 11

Yes! Patients can respond to sensory stimuli (example: reflex jerks) even unconscious.

Question 12

Can unconscious patients form memories under anesthesia?

Answer 12

Yep.

Question 13

What do we currently use to monitor depth of consciousness?

Answer 13

BIS monitor = most common one used for ‘depth of consciousness’ monitoring

Question 14

What are some problems with the monitoring method we currently use to measure depth of consciousness?

Answer 14

(BIS)

> Its based on probability and regression analysis

> We don’t have a gold standard measurement for what is unconscousness and what threshold represents inability to form memory

> Expensive

> Low-risk problem in anesthesia relative to other factors we worry about (doesn’t mean its not important just that incident rate of complications related is low)

Question 15

What is the highest % of inhalational H2O that we should ever administer to patients?

Answer 15

79%, We should never give patients a hypoxic mixture (less than room air O2, 21%)

Question 16

Goal of neuromuscular blockade.

Answer 16

Goal is to allow surgeon into areas that are otherwise tense and provide relaxation that will help the procedure proceed.

Also helps with intubation (relaxed muscles of the airway for tube placement)

Question 17

What is the ‘ceiling effect; of narcotics administration?

Answer 17

At the ceiling effect/dose, narcotic admin no longer increases analgesia but rather leads to more and more complications and negative side effects.

Question 18

What are physiological side effects of volatile anesthetics in the context of hemodynamic control?

Key point in terms of BP+HR control?

Answer 18

Too much volatiles =

• decreased effectiveness of smooth muscle in the vascular system (toxic vasodilatation);
• sympathetic nervous system depression
• cardiac contractility also effected (cardiac depression from higher and higher levels)

(due to volatile anesthetics being non-specific)

*Lower HR and BP from volatiles might not be purely due to analgesia, but a product of the side effects of volatiles on smooth muscles and sympathetic NS blunting

Question 19

What are the hemodynamic effects of an upright tilt position (either seated, reverse tredelenberg, etc..)?

Answer 19

Peripheral venous pooling –> decreased venous return –> decreased left ventricular filling –> increased left ventricular contractility (or decreased CO if this response is ablated/not well developed)

Ultimately leads to brady, hypotension, or both