Exam 2 - ANESTHESIA

Question 1

General Anesthetics - effects (2) and forms (2)

Answer 1

• depress CNS to produce loss of conciousness, loss of responsiveness to sensory stimuli, including pain and relaxation of muscles
• either volatile liquids (injected) or gas vaporized in O2 (inhaled)

Question 2

General Anesthesia involves (5 - RAISA)

Answer 2

1) analgesia (opiods)
2) amnesia (barbituates)
3) inhibition of reflexes (variety of drugs)
4) skeletal muscle relaxation (NMJ blocking agents)
5) rapid hypnosis (barbituates, others)

Question 3

How do we produce balanced anesthesia?

Answer 3

-use combination of drugs to reduce requirement for inhaled anesthetics, reduce dose of barbituates, NMJ blockers, etc

Question 4

Stages of General Anesthesia

Answer 4

• Stage I = analgesia
• Stage II = excitement
• Stage III = surgical anesthesia (Plane 1-4)
• Stage IV = imminent death

Question 5

Inhaled General Anesthetics – gas

Answer 5

• Nitrous oxide
• common side effects: dizziness, drowsiness, apnea, euphoria, vomiting
• serious: malignant hyperthermia, apea, cyanosis

Question 6

Inhaled General Anesthetics – volatile liquid

Answer 6

• the -fluranes
• common: dizziness, nausea, vomiting
• serious: myocardial depression, marked hypotension, pulmonary vasoconstriction, hepatotoxicity

Question 7

MAC

Answer 7

=Minimum Alveolar Concentration

• how dosage expressed
• concentration of which 50% pts don’t move during surgery (% of gas mixture or % of 760 mmHg pressure)
• an index of potency of inhaled GA
• steep dose-response curve, inversely proportional to anesthetic potency

Question 8

MAC affected by ____

Answer 8

• Age (lower in elderly) *major determining factor of dose, esp after 80
• NOT by sex, height, weight

Question 9

If 90% air, 10% anesthetic, MAC = ?

Answer 9

1MAC = 10%

Question 10

If 80% air, 20% anesthetic, MAC = ?

Answer 10

1MAC = 20%

Question 11

The higher the % required, the ____ the drug.

Answer 11

LESS potent

Question 12

Stage I

Answer 12

• Analgesia stage

- loss of pain

Question 13

Stage II

Answer 13

• Excitement stage

- excitement and hyperactivity

Question 14

Stage III

Answer 14

-surgical anesthesia stage

Question 15

Stage IV

Answer 15

• imminent death stage

- paralysis of medulla

Question 16

Percent of MAC = 0.64

Answer 16

-loss of awareness

Question 17

Percent of MAC = 1.00

Answer 17

Anesthesia

Question 18

Perfect of MAC = 1.2

Answer 18

Surgical anethesia (want to maintain slightly above)

Question 19

MOA - Lipophilicity

Answer 19

-extremely lipophilic, so solubility disrupts lipid bilayer of cell membrane, thus increasing threshold to fire

Question 20

Myer-Overton Principle

Answer 20

-the more lipid soluble the agent, the more potent anesthetic

Question 21

MAC is influenced by ___ (3)`

Answer 21

1. Pulmonary ventilation – the more rapidly the air is exchanged, the more rapidly anesthesia will be achieved
2. Pulmonary blood flow – faster blood flow = takes longer to increase blood concentration. slower blood flow (decreased blood volume or BP) = more rapid induction of anesthesia
3. Water solubility – less water soluble = build up rapidly in alveoli and approach concentration necessary for unconsciousness. more water soluble = first mixes in watery blood reservoir before sufficient concentration reached in alveolus

Question 22

Phamacological Effects (5)

Answer 22

1. block flow of sodium into neurons
2. enhance inhibitory action of GABA (*general CNS depressant response)
3. Delay impulses, reduced neural activity
4. produces unconsciousness
5. produces lack of responsiveness to painful stimuli

Question 23

Intravenous anesthetics – uses (5)

Answer 23

1. used in situations that require short duration anesthesia (outpatient surgery)
2. to supplement inhalation anesthetics
3. primarily used as adjuncts to inhalational agents
4. administered first
5. rapidly induce unconsciousness

Question 24

IV Anesthetics – types (5)

Answer 24

1. Barbituate
2. Benzodiazepines
3. Opiods
4. Propofol
5. Ketamine

Question 25

Barbiturate

Answer 25

- thripental | - rapid onset, potent, NO analgesia

Question 26

Benzodiazepines

Answer 26

- lam/pam | - produce sedation and amnesia but NO analgesia

Question 27

Opiods

Answer 27

- Fentanyl | - good analgesia, for intra-operative pain

Question 28

Propofol

Answer 28

-commonly used for sedation during procedures or in ICU

Question 29

Ketamine

Answer 29

-rarely used in adults, good analgesia, produces delusions

Question 30

Techniques for applying local anesthetics (5)

Answer 30

- topical - nerve block - infiltration - spinal - epidural

Question 31

Local Anesthetics - MOA

Answer 31

- amides and esters - stop axonal conduction - block Na channels - cause rapid sensation loss in limited part of body

Question 32

Local Anesthetics - contraindications

Answer 32

-cardiovascular conditions -- they have antiarrythmic properties

Question 33

What is co-administered with locals?

Answer 33

-vasoconstrictors (NE) to limit absorption and concentrate at injection site

Question 34

Topical Anesthetics

Answer 34

- applied to skin or mucous membrane - Benzocaine is major drug - relieve pain from minor burns, irritation, itching - also given to numb area before injection - SE = skin irritation, hypersensitivity reactions

Question 35

Muscle Relaxants -- Groups (2)

Answer 35

1. Neuromuscular blockers (NMJ) - used in ICU to cause paralysis and as adjunct to anesthesia 2. Spasmolytics - to reduce spasticity in variety of neuro disorders

Question 36

NMJ Blockers -- uses (3)

Answer 36

- relax skeletal mus during surgery - reduce intensity of spasms in electrically induced convulsions - manage pts who are fighting mechanical ventilation

Question 37

NMJ Blockers -- Non-Depolarizing

Answer 37

- (-curonim's) block action of AcH.at NMJ - don't cross BBB, no CNS action - can be reversed with anticholinesterases (-stigmines)

Question 38

NMJ Blockers -- Depolarizing

Answer 38

- succinyl choline - causes excessive depolarization which desensitizes muscles, renders them unresponsive - acts as agonist but stays locally, broken down by cholinesterase - RAPID effect

Question 39

Spasticity

Answer 39

- increase in tonic stretch reflexes - increased flexor ms spasm - reflex arc involvement - higher center involvement (UMN)

Question 40

Universally used adjunct to GA

Answer 40

- Atropine | - dry shit up, prevent bradycardia

Question 41

Bacloven

Answer 41

central spasmolytic - GABA analog - good for addictions, DT in alchys - used for para/quadriplegic with SCI due to MS or trauma

Question 42

Diazepam (Valium)

Answer 42

- central spasmolytic - effective for acute spasm and chronic spasticity - good for spinal cord lesion (transection) and CP

Question 43

Peripheral Spasmolytic

Answer 43

- Dantrolene - similar effects to central drugs, but works directly on ms by inhibiting calcium release - most effective for spasticity with cerebral origin (MS, CP) and acute things like malignant hyperthermia