General Anesthesia

Question 1

What is anesthesia?

Answer 1

A combination of amnesia, analgesia and muscle relaxation to allow the performance of surgery or other procedures.

Question 2

3 phases of general anesthesia

Answer 2

1. Induction
2. Maintenance
3. Emergence

Question 3

1. Induction is what?

2. Most commonly used agent?

Answer 3

1. “Putting to sleep”

2. Most commonly used induction agent is Propofol

Question 4

Propofol causes what? 3

Answer 4

1. Drop in BP and
2. cardiac output,
3. antiemetic properties

Question 5

Other agents for Induction? 2

Answer 5

1. Etomidate

2. Ketamine

Question 6

Why isnt etomide used very often as an induction agent?

Answer 6

Doesn’t cause vasodilation, higher rate of post op nausea, inhibits the biosynthesis of cortisol, use is limited due to increased risk of death by 2.5X

Question 7

Ketamine: Used in which pts?

5

Answer 7

1. hemodynamic instability,
2. cardiac stimulant,
3. significant analgesia,
4. bronchodilation,
5. hallucinations

Question 8

Maintenance

Use what? 2

Answer 8

inhaled (volatile) or IV anesthetics

Question 9

Maintenance
1. Inhalation anesthetic agents 2 kinds?

2. IV anesthetic agents
   2

Answer 9

1. Inhalation anesthetic agents
   Volatile anesthetic agents:
   -Sevoflurane and desflurane
   -Nitrous oxide: can be used in combo with volatile gases
2. IV anesthetic agents
   - Propofol and
   - remifentanil

Question 10

1. Emergence is what?

2. Can result in what?

Answer 10

1. Waking up

2. Can result in autonomic hyper-responsiveness

Question 11

Emergence:
1. Can result in autonomic hyper-responsiveness. This causes? 4

2. What can blunt this response? 3

Answer 11

1. • Tachycardia,
   • hypertension,
   • bronchospasm,
   • laryngospasm
2. • Short acting narcotics,
   • beta blockers or
   • lidocaine can blunt this autonomic response

Question 12

Propofol (Diprivan)

1. What kind of agent?
2. Metabolized where?
3. Excreted where?
4. So it can be used for what?
5. What kinds of surgery is it used for?
6. ONset of action? Clearance?
   Reversibility?
7. Onset?
8. Duration?

Answer 12

1. Non-barbiturate hypnotic agent
2. Rapidly metabolized in the liver and
3. excreted in the urine,
4. so it can be used for long durations of anesthesia
5. Used for
   - general surgery,
   - cardiac surgery,
   - neurosurgery, and
   - pediatric surgery
6. • Rapid onset of action (distribution two to four minutes),
   • rapid clearance, and
   • reversibility of effect once the drip is shut off
7. Onset 40 sec
8. Duration 1-3 hours

Question 13

Propofol (Diprivan)
1. Advantages? 2

2. Disadvanatges? 2

Answer 13

1. • Some anti-emetic effect so less nausea and vomiting associated with use
   • Clear-headedness during recovery

Milky looking solution (emulsion)

2. • Weaker amnestic effect than Midazolam (Versed)
   • No analgesic effect

Question 14

Propofol (Diprivan) Adverse affects? 4

Answer 14

1. Can support rapid growth of microorganisms
2. Hypotensive (administer slowly)
3. May cause hypertonia and movement
4. Respiratory depression

Question 15

Ketamine (Ketalar)
1. MOA?

2. Frequently used in who?
3. Can also be used in who? 2
4. Onset?
5. Duration?

Answer 15

1. Affects the senses, and produces a dissociative anesthesia (catatonia, amnesia, analgesia) in which the patient may appear awake and reactive, but cannot respond to sensory stimuli
2. Frequently used in pediatric patients because anesthesia and analgesia can be achieved with an intramuscular injection
3. Also used in
   - high-risk geriatric patients
   - and in shock cases, because it also provides cardiac stimulation
4. Rapid onset (30 sec)
5. Short duration (5-10 minutes)

Question 16

ANESTHESTIC GASES

are? 4

Answer 16

1. Isoflurane (Forane)
2. Desfluorane (Suprane)
3. Sevofluorane (Ultane)
4. Nitrous oxide

Question 17

Anesthetic Gases
1. An important property of anesthetics is what?

2. Once the anesthetic gas is turned off, the blood stream brings the gas where and it is eliminated here?
3. The more soluble the gas is in blood, the _____ it takes to eliminate
4. Which are the shortest-acting anesthetic gases because they are the least soluble in blood ? 2

Answer 17

1. reversibility
2. back to the lungs
3. longer
4. Nitrous oxide and desflurane

Question 18

How do inhaled anesthetics work?
1. Inhaled anesthetics act in different ways at the level of the what?

2. Disrupt normal synaptic transmission by what? 3

Answer 18

1. CNS

2.
-interfering with the release of neurotransmitters from presynaptic nerve terminal (enhance or depress excitatory or inhibitory transmission)

• Alter the re-uptake of neurotransmitters
• Change the binding of neurotransmitters to the post-synaptic receptor sites

Question 19

What is MAC (minimum alveolar concentration)?

Answer 19

The inhaled anesthetic concentration (steady state) at which 50% of patients move in response to a standard midline abdominal incision (37 C, 30-55yo, 1 atm)

Question 20

What are the following MAC for these drugs:

1. Nitrous oxide?
2. Isoflurane?
3. Sevoflurane?
4. Desflurane?

Answer 20

1. 105%
2. 1.15%
3. 1.8%
4. 6.2%

Question 21

Age is related to MAC how?

Answer 21

MAC decreases as a person ages

Question 22

Isoflurane
1. Higher blood-gas solubility so takes longer what? 2

2. Causes what? 4

Answer 22

1. for onset and longer for emergence
2. • tachycardia,
   • peripheral vasodilation
   • Airway irritation,
   • coughing

Question 23

Desflurane

1. Requires what for use?
2. Causes? 4
3. Not used for?
4. Onset and offset?

Answer 23

1. Requires a heated-pressurized vaporizer for delivery
2. Causes
   -tachycardia
   -peripheral vasodilation
   Least well-tolerated on the airway—can
   -cause coughing,
   -bronchospasm
3. Not used for mask induction
4. Fastest onset and off-set of volatiles

Question 24

Sevoflurane

1. Advantage?
2. Causes?
3. Mask induction?
4. Onset and emergence?

Answer 24

1. Does not cause tachycardia
2. Causes peripheral vasodilation
3. Well-tolerated for mask induction
4. Fast onset and quick awakening

Question 25

MAC is 105% 1. How does this affect administration? 2. Nitrous oxide diffuses into air containing cavities how? 3. What can all increase in size when nitrous oxide is being used? 6

Answer 25

1. therefore nitrous oxide alone, cannot provide anesthesia 2. 34 times faster than nitrogen can leave that space 3. - Bowel, - middle ear, - pneumothorax, - pneumocranium, - pneumo-peritoneum, or - cuffs of endotracheal tubes

Question 26

Nitrous Oxide 1. Increases post-operative what? 2. Has ________ properties

Answer 26

1. nausea | 2. analgesic

Question 27

Advantages of Nitrous Oxide | 7

Answer 27

1. Inexpensive 2. Readily available 3. Odorless/slightly sweet 4. Limited effect 5. No special equipment 6. Sympathomimetic 7. Will not cause malignant hyperthermia

Question 28

Disadvantages of Nitrous oxide | 4

Answer 28

1. High MAC/Limits FIO2 2. Sympathomimetic 3. Methionine synthetase inhibitor 4. Expands air-filled spaces

Question 29

Contraindications to potent inhaled anesthetic agents | 2

Answer 29

1. Inability to tolerate the physiologic alterations produced 2. Malignant hyperthermia

Question 30

NEUROMUSCULAR BLOCKING DRUGS 5

Answer 30

1. Succinylcholine (Anectine) 2. Rocuronium (Zemuron) 3. Vecuronium (Norcuron) 4. Pancuronium (Pavulon) 5. Cisatracurium (Nimbex)

Question 31

Neuromuscular Blocking Drugs (NMBDs) Produce immobility needed for? 3

Answer 31

1. Endotracheal intubation 2. Surgical immobility/relaxation(e.g. abdominal) 3. Mechanical ventilation

Question 32

Acetylcholine (ACh) Describe its role in muscle contraction? 3 ACh rapidly inactivated by what?

Answer 32

1. Released into the synaptic cleft and binds to nicotinic cholinergic receptors 2. Opens ion channels which causes depolarization along the muscle 3. Muscle contraction acetylcholinesterase (AChE)

Question 33

2 Types of NMBDs? 2

Answer 33

1. Depolarizing | 2. Nondepolarizing

Question 34

What are the types of Depolarizing (1) and Nondepolarizing (4) NMBD?

Answer 34

1. Depolarizing - Succinylcholine (Anectine) 2. Nondepolarizing - Rocuronium (Zemuron) - Vecuronium (Norcuron) - Pancuronium (Pavulon) - Cisatracurium (Nimbex)

Question 35

Depolarizing agents 1. Cause what? 2. Paralysis is due to?

Answer 35

1. Causes brief twitches or fasciculations, followed by flaccid paralysis 2. Paralysis is due to depolarization of the nerve terminal and the nerve being in a refractory state because the membrane is depolarized

Question 36

Succinylcholine (“Anectine”) 1. Causes depolarization where? 2. In contrast to ACh, succinylcholine ______ dissociates from the ACh receptors, resulting in an inactive state 3. Broken down by what and into what? 2

Answer 36

1. at the motor endplate 2. slowly 3. butyrylcholinesterase to - choline and - succinylmonocholine

Question 37

Succinylcholine (“Anectine”) 1. Often the agent of choice when? 2. Rapid onset: How fast? 3. Short duration: how long?

Answer 37

1. rapid control of the airway is necessary 2. (less than 1 minute) 3. (6-10 minutes)

Question 38

Succinylcholine: Disadvantages | 10

Answer 38

1. Cardiac dysrhythmias 2. Sinus bradycardia 3. Myalgias 4. Myoglobinuria 5. Hyperkalemia 6. Patient restrictions (e.g. children) 7. Masseter spasm 8. Malignant hyperthermia trigger 9. Possible increases in intraocular, gastric, and intracranial pressures 10. Dependent upon normal butyrylcholinesterase

Question 39

Nondepolarizing NMBDs 1. MOA? 2. fasciculations? 3. Nerve stimulation exhibits what? 4. Best clinical marker of strength is what?

Answer 39

1. Reversible competition between drug and ACh binding site 2. No fasciculations 3. a fade in train-of-four or tetany 4. is sustained head-lift

Question 40

Nondepolarizing agents 1. Long acting? 2. Intermediate acting? 3 3. SHort acting? 1

Answer 40

1. Long-acting - Pancurounium 2. Intermediate-acting - Vecuronium - Rocuronium, - Cisatracurium 3. Short-acting - Mivacurium

Question 41

``` Nondepolarizing NMBDs Describe the onset and duration for the following: 1. Rocuronium 2. Vecuronium 3. Pancuronium 4. Cisatracurium ```

Answer 41

1. 1-1.5 35 2. 1.5-2 40 3. 2-3 60 4. 2.5-3 25

Question 42

``` Nondepolarizing NMBDs Describe the metabolism and SE for the following: 1. Rocuronium 2. Vecuronium 3. Pancuronium 4. Cisatracurium ```

Answer 42

1. Hepatic None 2. Hepatic None 3. Renal Vagolytic 4. Other None

Question 43

Describe the train of four? | 5

Answer 43

1. When 4 twitches are seen, 0-75% of the receptors are blocked. 2. When 3 twitches are seen, at least 75% of the receptors are blocked. 3. When 2 twitches are seen, 80% of the receptors are blocked. 4. When 1 twitch is seen, 90% of the receptors are blocked. 5. When no twitches are seen, 100% of receptors are blocked.

Question 44

1. Reversal of NMBDs with what? 2. What are these? 2

Answer 44

1. Acetylcholine esterase inhibitors | 2. Neostigmine, edrophonium result in accumulation of Ach at the neuromuscular junction

Question 45

Sugammadex 1. Advantage? 2. Reverses what? 2

Answer 45

1. No anticholinergic effects like those above | 2. vecuronium and rocuronium