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KM (Spring 2024) Anesthesia Pharm ** > Local Anesthetics II (Exam IV) > Flashcards

Local Anesthetics II (Exam IV) Flashcards

(94 cards)

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1
Q

What is the average pKa of local anesthetics?

A

8

S42

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2
Q

What is the function of the Alkalinization of LA Solutions?

What are the benefits of alkalinization?

A

Alkalinization increases the percentage of lipid-soluble or non-ionized forms.

  • Faster onset of action
  • Speeds onset of peripheral and epidural blocks by 3 to 5 mins.
  • Enhances the depth
  • Increase the spread (i.e., epidural)

S42

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3
Q

Regarding weak bases, the pKa is ________ pH.

A

before

ex. pKa 9, pH 7 → 9 - 7 = +2

S44

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4
Q

Regarding weak acids, the pKa is ________ pH.

A

after

ex. pKa 9, pH 7 → 7 - 9 = -2

S44

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5
Q

Nicely negative numbers are _________.

A

non-ionized

S44

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6
Q

If Drug V (weak base) has a pKa of 9.1, will the drug be more ionized or nonionized at physiological pH?

A

pKa - pH
9.1 - 7.4 = +1.7

Drug V will be more ionized at physiological pH.

Weak Bases, pKa before pH
Weak Acids, pKa afterpH

S44

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7
Q

If the pKa of LA (a weak base) is at 4.5, will the drug be more ionized or nonionized at physiological pH?

A

pKa - pH
4.5 - 7.4 = -2.9

LA will be more non-ionized at physiological pH.

Weak Bases, pKa before pH
Weak Acids, pKa afterpH

S44

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8
Q

LA1’s pKa is 9.2, and LA2’s pKa is 7.5. Which of the following are correct when placed in physiological pH? Select 2 answers.

A. LA2 has more non-ionized components
B. LA1 has more ionized components
C. LA2 has more ionized components
D. LA1 has more non-ionized components

A

B and C

LA1
9.2 - 7.4 = +1.8 (ionized)

LA2
7.5 - 7.4 = +0.1 (ionized)

Weak Bases, pKa before pH
Weak Acids, pKa afterpH

S45

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9
Q

What adjuvant medications prolong the duration of local anesthetics?

A
  • Dexmedetomidine
  • Magnesium
  • Clonidine
  • Ketamine
  • Dexamethasone

S46

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10
Q

What will be the results of combining LA Chloroprocaine & Bupivacaine?

A
  • Produce a rapid onset
  • Tachyphylaxis (bupivacaine)

S47

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11
Q

What is added to 30 mL of LA to alkalinize the drug?

A

1 mL of 8.4% Sodium Bicarbonate

This will increase the non-ionized form of LA.
Make sure the mixture does not contain any precipitate.

S47

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12
Q

Combining local anesthetics and getting toxic effects is a synergistic process. T/F ?

A

False. Additive. (1+1 =2)

S47

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13
Q

Compare the onset of action between chloroprocaine and bupivacaine.

A

Chloroprocaine: Rapid
Bupivacaine: Slow

S48

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14
Q

What vasoconstrictors can be utilized with local anesthetics?

A
  1. Epinephrine
  2. Phenylephrine

S49

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15
Q

Why is it important to use vasoconstrictors with LA?

A

The duration of action of a LA is proportional to the time the drug is in contact with nerve fibers.

For this reason, epinephrine may be added to LA solutions to produce vasoconstriction, which limits systemic absorption and maintains the drug concentration in the vicinity of the nerve fibers to be anesthetized.

FIX THIS FLASHCARD

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16
Q

What are the results of using vasoconstrictors with LA?

A
  • Produce vasoconstriction
  • Increased neuronal uptake of LA
  • α-adrenergic effects may have some degree of analgesia
  • No effect on the onset rate of LA
  • Enhanced cardiac irritability with inhaled anesthetics
  • Systemic absorption → HTN (tachycardia)

S49 FIX SLIDE

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17
Q

What is epinephrine 1:200,000 mean?

Convert that to mcg/mL.

A

1:200,000 means 1 gram of epinephrine is dissolved in 200,000 mL of solvent.

  • 1g/200,000 mL
  • 1000mg/200,000 mL
  • 1 mg/200 mL
  • 1000 mcg/200 mL
  • 10 mcg/2 mL
  • 5 mcg/mL

S51

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18
Q

Compute 1:500,000 to mcg/mL

A

2 mcg/mL

  • 1 g/500,000 mL
  • 1000 mg/500,000 mL
  • 1 mg /500 mL
  • 1000 mcg/500 mL
  • 10 mcg/5 mL
  • 2 mcg/mL

Shortcut: 1,000,000 divided by the solvent number. 1 million/500,000 = 2 mcg/mL

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19
Q

How much epinephrine or phenylephrine is given with bupivacaine or lidocaine for a subarachnoid block (SAB)?

A
  • 0.2 mg Epi
  • 2 mg Phenylephrine
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20
Q

Compute 1:500,000 Epi to mcg/mL

A

1,000,000/ 500,000=2

2 mcg/mL

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21
Q

Compute 1:10,000 Epi to mcg/mL

A

1,000,000/ 10,000 = 100

100 mcg/mL

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22
Q

Compute 1:1000 Epi to mcg/mL

A

1,000,000/ 1000 = 1000

1000 mcg/mL

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23
Q

0.25% equates to how many mg per mL ?

A

2.5 mg/mL

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24
Q

0.5% equates to how many milligrams per milliliter?

A

5 mg/mL

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25
1% equates to how many milligrams per mL ?
10 mg/mL
26
2% equates to how many milligrams per mL ?
20 mg/mL *2% lidocaine is the most common concentration used in the OR*
27
4% equates to how many milligrams per mL ?
40 mg/mL ## Footnote S52
28
Your surgeon injected 20 mLs of Bupivacaine 0.25% with 1:200,000 of Epi. What are the total mgs for Bupivacaine and the total mcgs for Epinephrine?
Bupivacaine: 0.25% = 2.5 mgs/mL 2.5 mgs x 20 mLs = 50 mgs total Epinephrine: 1:200,000 = 5 mcg/mL 5 mcg x 20 mLs = 100 mcg total ## Footnote S53
29
What is the Lidocaine Recommended Max Single Dose for Spinal?
100 mg
30
Mepivacaine Recommended Max Single Dose Mepivacaine Recommended Max Single Dose with/Epi Mepivacaine Recommended Max Single Dose for Spinal
400 mg 500 mg w/ Epi 100 mg ## Footnote S58
31
Prilocaine Recommended Max Single Dose
600 mg
32
Bupivacaine Recommended Max Single Dose Bupivacaine Recommended Max Single Dose with/Epi Bupivacaine Recommended Max Single Dose for Spinal
175 mg 225 mg w/ Epi 20 mg
33
112.5 mg of Bupivacaine with Epi and 250 mg of Lidocaine with Epi were given during surgery. What are the percentages of each LA based on the recommended max single dose in mg?
Max single dose of Bupivacaine with Epi: 225 mg 112.5/225 = 50% Max single dose of Lidocaine with Epi: 500 mg 250/500 = 50% ## Footnote S59
34
Where are topical anesthetics applicable?
Applicable on the mucous membranes of the nose, mouth, tracheobronchial tree, esophagus, or GU tract. ## Footnote S60
35
Which anesthetic has localized vasoconstriction that will decrease blood loss and improve surgical visualization?
Cocaine (4-10%) ## Footnote S60
36
Which anesthetic is great with surface anesthesia?
Lidocaine (2-4%) ## Footnote S60
37
Lidocaine inhalation does not alter airway resistance, but does cause ______.
vasodilation ## Footnote S60
38
Which local anesthetics are not effective for topical anesthesia?
Procaine and Chloroprocaine *These drugs do not penetrate mucous membranes as effectively as cocaine or lidocaine.* ## Footnote S60
39
What is does LTA stand for?
* Lidocaine tracheal anesthesia * Localized tracheal anesthesia ## Footnote S61
40
What is the % of Lidocaine for LTA? And is this added to the total Lidocaine count?
4 mL of 4% YES! It will be added with total Lidocaine ## Footnote S61
41
Eutectic Mixture of LA (EMLA) contains what two local anesthetics? Dose: Onset:
Lidocaine 2.5% + Prilocaine 2.5% = 5% LA Dose: 1 to 2 g/ 10 cm2 area Onset: 45 mins ## Footnote S62
42
EMLA has to be applied for ______ hours before skin graft.
2 hours ## Footnote S62
43
EMLA can be applied for 10 minutes before any of these procedures:
- Cautery of genital warts - Venipuncture, lumbar puncture - Arterial cannulation (Nitroglycerine) - Myringotomy ## Footnote S62
44
What considerations should one have when using EMLA ?
* Caution with methemoglobinemia * No open skin wounds * No amide allergy patients ## Footnote S63
45
Other Topical Anesthesia Preparations besides EMLA
* Amethocaine (EMLA-like) * Tetracaine 4% Gel * Lidocaine 7% * Tetracaine 7% ## Footnote S63
46
What is considered local infiltration with LA?
Extravascular placement of LA (subcutaneous injection) ## Footnote S64
47
What LAs are used on inguinal operative sites?
* Lidocaine 1% or 2% * Ropivacaine 0.25% * Bupivacaine 0.25% ## Footnote S64
48
What are the contraindications of using epinephrine on LA for local infiltrations?
* Not intracutaneously or into tissues at end arteries * Fingers, toes, ears, nose, penis *Can cause necrosis.* | d/t vasoconstiction ischemia ## Footnote S64
49
How is Peripheral Nerve Block achieved? MOA?
Achieved by LA injection into tissues surrounding individual peripheral nerves or nerve plexuses. MOA: diffusion from outer mantle to central core of nerve along a concentration gradient. *** Smallest sensory and ANS fibers first, then larger motor and proprioceptive axons.*** ## Footnote S65
50
What area (proximal or distal) is affected first with local anesthetic administration?
The proximal area (site of LA administration) is affected first and then distal. ## Footnote S65
51
When the peripheral nerve block is wearing off, what comes back first? Proximal or Distal?
Proximal comes back first & then distal. ## Footnote S65
52
Peripheral Nerve Block onset of action is dependent on the local anesthetic's _________.
pK ## Footnote S66
53
The duration of a peripheral nerve block depends on the _____ of the local anesthetic.
dose ## Footnote S66
54
What are the benefits of a continuous infusion block?
* Improved pain control * Less nausea * Greater satisfaction * Additives are used with continuous infusion blocks (ie: Ketolorac, Ketamine, Decadron) ## Footnote S66
55
slide 67
56
Slide 68
57
Slide 70
58
What is a Regional Bier Block?
Bier Block IV injection of LA into an extremity isolated from the rest of the systemic circulation with a tourniquet. Sensation and muscle tone return dependent on tourniquet release ## Footnote S71
59
What LA is commonly used in Bier Block?
Lidocaine ## Footnote S71
60
What are the steps to performing a Bier Block?
IV start Exsanguination Double cuff LA injection IV D/C ## Footnote S72
61
What is the sequence of blockades for a segmental block in Neuraxial Anesthesia?
1. SNS (Myelinated preganglionic B fibers) 2. Sensory (Myelinated A, B fibers, unmyelinated C fibers) 3. Motor (Myelinated A-δ and unmyelinated C fibers) ## Footnote S73
62
Which of the following will be the last sign associated with injection of an anesthetic for neuraxial blockade? A. NIBP B. Heart Rate C. Cold Alcohol Pad D. Leg Movement
D. Leg Movement | we're assessing motor blockade ## Footnote Clinical Scenario
63
How is a Spinal Anesthesia Block (SAB) produced?
Subarachnoid local anesthetic injection ## Footnote S74
64
What is used for confirmation of a Spinal Anesthesia Block (SAB)?
CSF ## Footnote S74
65
What is the principal site of action for sub arachnoid block?
Preganglionic fiber
66
For SAB, the _______ effect is on the same level of denervation.
sensory ## Footnote S74
67
For SAB, the _______ effect is 2 spinal segments cephalad of the sensory block. For SAB, the _______ effect is 2 spinal segments below the sensory block. ## Footnote S74
SNS Motor
68
If the sensory block is at T5, where is the SNS block?
T3 *This SNS block will trigger an asystole event.* ## Footnote S74
69
What dermatomes correspond with our cardiac accelerator?
T1 to T4 ## Footnote S74
70
Clinical Scenario Slide: If the assessed sensory level after SAB is T6 ( Top of Xiphoid Process), what are the blocked SNS and motor levels?
SNS Block: T4 Motor Block: T8 ## Footnote S74
71
What are the most common local anesthetics used in SABs ?
- Bupivacaine - Levobupivacaine - Lidocaine - Ropivacaine - Tetracaine ## Footnote S76
72
What factors affect SAB dosage?
* **Height of patient** (volume of subarachnoid space) * **Segmental level** of anesthesia desired * **Duration** of anesthesia desired ## Footnote S76
73
For SAB, _____ is more important than _______ of drug (%) or the ______ (mLs) of the solution injection.
Dose; Concentration ; volume ## Footnote S77
74
What is the dose of bupivacaine for the scenario below? 5 ft tall patient = _____mL of 0.75% Bupivacaine + ______ mL for every inch above…. 2 cc total ( 1½ hours to 2 hours)
1 mL 0.1 mL *For someone who is 5'5", you will give 1.5 mL of bupivacaine for a SAB.* ## Footnote S77
75
What dose of 0.75% bupivacaine would be indicated for a 6'7" patient undergoing a SAB?
2.9mL 1mL for 5ft tall 1.9mL for other 19inches ## Footnote Clinical question
76
For SAB, the _________ of LA is important in determining the spread of the drug.
specific gravity ## Footnote S77
77
What can be added to LA so that its specific gravity can increase? What can be added to LA so that its specific gravity can decrease?
Glucose added → hyperbaric solution. Distilled water added → hypobaric solution ## Footnote S77
78
Which side will you want to position a right-hip arthroplasty patient on if they receive a hyperbaric LA solution?
Right side lying, the hyperbaric solution will "sink." ## Footnote S77
79
Which side will you want to position a right-hip arthroplasty patient on if they receive a hypobaric LA solution?
Left side lying, the hypobaric solution will "float". ## Footnote S77
80
The most common LA used in Epidural Anesthesia.
Lidocaine *Good diffusion through tissue and safer* ## Footnote S79
81
What is the onset of epidural anesthesia?
Onset: 15 to 30 minutes ## Footnote S79
82
Epi 1:200,000 with ___________ offers no advantage in an epidural block.
Bupivacaine ## Footnote S79
83
Can epidural anesthesia cross the placental barrier with OB and C-section patients?
Yes ## Footnote S80
84
What is the difference between SAB and epidural blocks?
Epidural blocks have No differential zone of SNS, sensory, and motor blockade. ## Footnote S80
85
What is considered an acceptable additive to both epidural and SAB to produce a synergistic effect?
Opioids ## Footnote S80
86
Clinical Scenario
## Footnote S81
87
What is Tumescent?
Subcutaneous infiltration of large volume (5L or more) ## Footnote S82
88
What makes up the tumescent solution?
* Diluted Lidocaine (0.05% to 0.1%) * Epinephrine 1:100,000 ## Footnote S82
89
What causes the tumescent effect?
The taunt stretching of overlying blanched skin d/t large volume → Tumescent Effect *Fat can be aspirated without blood loss and provide prolonged post-op analgesia.* ## Footnote S82
90
Where is tumescent usually administered?
* Thigh * Abdomen * Hips * Buttocks ## Footnote S83
91
When is the plasma peak for tumescent anesthesia?
12 to 14 hours s/p injection. ## Footnote S84
92
What is the dose for Regional Anesthesia Lidocaine with Epi?
7 mg/kg ## Footnote S83
93
Highly diluted Lidocaine with Epi Tumescent dose.
35 to 55 mg/kg ## Footnote S83
94
What is the theory with the Tissue Buffering System?
1 gram of SQ can absorb up to 1 mg of Lidocaine

KM (Spring 2024) Anesthesia Pharm ** (101 decks)

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