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Flashcards in General Anesthesia Deck (45):
1

What is anesthesia?

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

2

3 phases of general anesthesia

1. Induction
2. Maintenance
3. Emergence

3

1. Induction is what?
2. Most commonly used agent?

1. “Putting to sleep”
2. Most commonly used induction agent is Propofol

4

Propofol causes what? 3

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

5

Other agents for Induction? 2

1. Etomidate
2. Ketamine

6

Why isnt etomide used very often as an induction agent?

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

7

Ketamine: Used in which pts?
5

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

8

Maintenance
Use what? 2

inhaled (volatile) or IV anesthetics

9

Maintenance
1. Inhalation anesthetic agents 2 kinds?

2. IV anesthetic agents
2

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

10

1. Emergence is what?

2. Can result in what?

1. Waking up

2. Can result in autonomic hyper-responsiveness

11

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

2. What can blunt this response? 3

1.
-Tachycardia,
-hypertension,
-bronchospasm,
-laryngospasm

2.
-Short acting narcotics,
-beta blockers or
-lidocaine can blunt this autonomic response

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?

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

13

Propofol (Diprivan)
1. Advantages? 2

2. Disadvanatges? 2

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

14

Propofol (Diprivan) Adverse affects? 4

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

15

Ketamine (Ketalar)
1. MOA?

2. Frequently used in who?

3. Can also be used in who? 2

4. Onset?

5. Duration?

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

3. 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)

16

ANESTHESTIC GASES
are? 4

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

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

1. reversibility

2. back to the lungs

3. longer

4. Nitrous oxide and desflurane

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

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

19

What is MAC (minimum alveolar concentration)?

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)

20

What are the following MAC for these drugs:
1. Nitrous oxide?
2. Isoflurane?
3. Sevoflurane?
4. Desflurane?

1. 105%

2. 1.15%

3. 1.8%

4. 6.2%

21

Age is related to MAC how?

MAC decreases as a person ages

22

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

2. Causes what? 4

1. for onset and longer for emergence

2.
-tachycardia,
-peripheral vasodilation
-Airway irritation,
-coughing

23

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

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

24

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

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

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

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

26

Nitrous Oxide
1. Increases post-operative what?

2. Has ________ properties

1. nausea

2. analgesic

27

Advantages of Nitrous Oxide
7

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

28

Disadvantages of Nitrous oxide
4

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

29

Contraindications to potent inhaled anesthetic agents
2

1. Inability to tolerate the physiologic alterations produced

2. Malignant hyperthermia

30

NEUROMUSCULAR BLOCKING DRUGS

5

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

31

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

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

32

Acetylcholine (ACh)
Describe its role in muscle contraction? 3

ACh rapidly inactivated by what?

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)

33

2 Types of NMBDs? 2

1. Depolarizing
2. Nondepolarizing

34

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

1. Depolarizing
-Succinylcholine (Anectine)

2. Nondepolarizing
-Rocuronium (Zemuron)
-Vecuronium (Norcuron)
-Pancuronium (Pavulon)
-Cisatracurium (Nimbex)

35

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

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

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

1. at the motor endplate

2. slowly

3. butyrylcholinesterase to
-choline and
-succinylmonocholine

37

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

1. rapid control of the airway is necessary

2. (less than 1 minute)

3. (6-10 minutes)

38

Succinylcholine: Disadvantages
10

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

39

Nondepolarizing NMBDs
1. MOA?
2. fasciculations?

3. Nerve stimulation exhibits what?

4. Best clinical marker of strength is what?

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

40

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

1. Long-acting
-Pancurounium

2. Intermediate-acting
-Vecuronium
-Rocuronium,
-Cisatracurium

3. Short-acting
-Mivacurium

41

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

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

42

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

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

43

Describe the train of four?
5

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.

44

1. Reversal of NMBDs
with what?

2. What are these? 2

1. Acetylcholine esterase inhibitors

2. Neostigmine, edrophonium result in accumulation of Ach at the neuromuscular junction

45

Sugammadex
1. Advantage?
2. Reverses what? 2

1. No anticholinergic effects like those above

2. vecuronium and rocuronium