Anesthesia

Question 1

Physiology

Answer 1

How the major organs of the body work

Question 2

Pathophysiology

Answer 2

How disease affect the body

Question 3

Order of pain processing

Answer 3

1. Transduction - thermal, chemical, or mechanical stimuli are converted into an action potential
2. Transmission - action potential travels through 1st, 2nd, and 3rd order neurons
3. Modulation - inhibition or augmentation of the afferent or efferent pain signals
4. Perception - final pathway; integration of painful input into the somatosensory and limbic cortices

Question 4

Allodynia

Answer 4

A painful response to a normally innocuous stimulus

Question 5

Hyperalgesia

Answer 5

An increased response to painful stimuli

Question 6

A 55 year old man has severe pain on gentle touching of the arm. Six months ago, the median nerve was damaged. What is the term that defines this phenomenon?

Answer 6

The question states “gentle,” which can be interpreted as an innocuous stimulus. However, the man is responding to it painfully. This is an example of allodynia

Question 7

Analgesia definition

Answer 7

It is the absence of pain while conscious. These drugs are painkillers

Question 8

What type of analgesia are NSAIDs (Nonsteroidal anti-inflammatory drugs)? What enzymes do they normally target? Give 4 examples of NSAIDs

Answer 8

Non-opiate analgesia

They target COX-1 and COX-2 enzymes depending on what the drug is selective for

Ex. Ibuprofen (Advil), Aspirin, Naproxen (Aleve), Steroid

Question 9

What type of analgesia is Acetaminophen (Paracetamol)? What enzyme do they normally target? Do they have a high or low therapeutic index (TI)?

Answer 9

Non-opiate analgesia

Blocks COX-3 in the brain

They have a high TI. This means that an individual would have to take a lot of pills to feel toxic side effects

Question 10

MOA of opiate analgesia

Answer 10

1. They block neurotransmitter release by inhibiting Ca2+ influx into the presynaptic terminal
2. Open K+ channels, which hyperpolarizes neurons and inhibits spike activity

Question 11

What type of analgesia is Fentanyl? Do they have a high or low TI?

Answer 11

Opiate analgesia - it is a cheap synthetic opioid

It has a low TI - very potent and fast acting

Question 12

A 35 year old female is 4 days post surgery for motor vehicle accident injury? The surgeon prescribed her Hydromorphone (Dilaudid). While she takes acetaminophen, naproxen and hydromorphone, her brother teases her and says, “Why do you take so many? It’s not good to mix drugs!” Is this true?

Answer 12

No - it is good to approach the injury through multimodal analgesia because pain comes from multiple sources. This gives the drugs a chance to attach multiple pathways, such as COX-1, COX-2, etc.

Question 13

True or False: Prior to 2013, more people died of heroin overdose than prescription opiates.

Answer 13

False - most overdoses were due to prescribed medication. This is because the Sackler family pushed prescription medicine to patients

Question 14

True or False: In 2017, more people died of heroin overdose than prescription opiates

Answer 14

True - in 2017, synthetic fentanyl was introduced and laced into heroin → more deaths from heroin that was laced with fentanyl

Question 15

Definition, example, MOA of local anaesthetic

Answer 15

Anaesthetic that blocks a part of the body (regional anesthesia)

Ex. Lidocaine

MOA: Na+ channel blocker and prevents the propagation of nerve action

Question 16

What is an epidural and what are its uses?

Answer 16

Form of regional anesthesia that involves injection of local anesthetic and/or opiates into epidural space

Uses: continuous analgesia - labor pain, post operative pain after abdomen or chest surgery

Question 17

Side effects of Lidocaine/Cocaine

Answer 17

Seizures, arrythma, complete heart block

Question 18

A 46 year old female visits her dentist for a tooth extraction. The dentist administers lidocaine.
* What is the mechanism of action of lidocaine?
* What is the advantage of adding vasoconstrictors (e.g. epinephrine) to local anesthetics?
* What are some signs and symptoms of local anesthetic toxicity?

Answer 18

1. Blocks sodium channels
2. Reduce circulation of drug - keeps localized
3. Cardiac arrhythmia-> heart block

Question 19

Light Sedation. Give the:
- Responsiveness
- Airway
- Respiration/Ventilation
- Cardiovascular Function

Answer 19

• Normal response to verbal commands
• Unaffected airway
• Spontaneous breathing
• Normal cardiovascular function

Question 20

Deep sedation. Give the:
- Responsiveness
- Airway
- Respiration/Ventilation
- Cardiovascular Function

Answer 20

• Purposeful response to pain
• Mildly collapsed airway (but no intervention required)
• Slow/deep breathing, supplemental O2 required
• Bradycardia/hypotension, body able to compensate

Question 21

General anesthesia. Give the:
- Responsiveness
- Airway
- Respiration/Ventilation
- Cardiovascular Function

Answer 21

• No response to pain
• Breathing device required to keep airway open
• Inadequate respiration (requires assisted/medical ventilation)
• Impaired cardiovascular function requiring pharmacological support

Question 22

Goals of general anesthesia

Answer 22

Amnesia, analgesia, anesthesia

Question 23

How is anesthesia achieved?

Answer 23

Upregulating inhibitory pathways
Downregulating excitatory pathways

Question 24

Excitatory neurotransmitter examples

Answer 24

Acetylcholine (nicotinic)
NMDA
Glutamate

Question 25

Inhibitory neurotransmitter examples

Answer 25

GABA Glycine *most important are GABA chloride channels

Question 26

Context sensitive half-time

Answer 26

Time for [blood plasma] of a drug to decline by one half after an infusion has been stopped

Question 27

What can you interpret from context-sensitive half time?

Answer 27

Lower context sensitive half time = shorter acting regardless duration of action = better predictable and fast offset pharmacokinetic