Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

APEX > Unit 5 > Flashcards

Unit 5 Flashcards

1
Q

Alpha fibers

A

alpha-skeletal muscle motor, proprioception
Beta- touch, pressure
Gamma- Skeletal muscle tone
Delta- fast pain, temp, touch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Beta fibers

A

Preganglionc ANS fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

C fibers

A

Sympathetic- postganglionic ANS fibers

Dorsal root- slow pain, temp, touch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Block onset

A
  1. B
  2. C
  3. A gamma and A delta
  4. A alpha and a beta
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

VGNaC

A

1 alpha unit
2 betas
Resting (-70 mV): closed
Active (-70 to +35 mV): opens, Na flows outside to inside
Inactive (+35 to -70 mV): closed, inactivation gate until membrane potential reestablished
LA can bind in active and inactive phases- more frequent depol means more time for blockade (use dependent or phasic blockade)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Resting membrane potential

A

-70
3 Na+ out and 2 K+ in

LAs do not impact resting membrane potential or threshold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Mechanism of action LA

A

Weak bases
After injection LA dissociates into uncharge base and ionized, conjugate acid
PKa’s higher than 7.4= > 50% will exist as ionized conjugate acid
Uncharged base enters cell and becomes ionized due to acidic ECF
Only ionized, conjugate acid binds to LA binding site on alpha subunit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

LA molecule construction

A

Benzene ring- lipophilic
Intermediate chain- ester or amide (has NH in it)
Tertiary amine- hydrophilic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Ester LA’s

A

No i before Caine suffix
Benzocaine, cocaine, chloroprocaine, procaine, tetracaine
Pseudocholinesterase metabolism
Low allergic potential- cross sensitivity if allergy happens, due to PABA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Amide type

A

I before suffix Caine
Articaine, bupivicaine, etidocaine, lidocaine, mepivicaine, ropivicaine
Hepatic/P450 metabolism
Extremely rare allergies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Onset of action

A

PKA- closer to pH of blood= larger fraction uncharged and able to cross and get to receptor

Dose- give large dose of chlorprocaine cause isn’t very potent even with high pKa
Concentration- higher concentration onset’s quicker

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Potency

A

Lipid solubility- can get inside drug and be available to bind to receptor

Intrinsic vasodilating effect- cocaine, chloroprocaine, and ropi dont vasodilate, lido does

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Duration of action

A

Protein binding- tissue reservoir to extend DOA, preferably bind to alpha a acid glycoprotein but can bind to albumin

Lipid solubility
Intrinsic vasodilating effect
Addition of vasoconstrictors- prolongs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Amide pKa

A

Bupivacaine- 8.1
Ropivacaine- 8.1
Lido- 7.9
Prilocaine- 7.9

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Ester pKa’s

A

Procaine- 8.9
Chloroprocaine- 8.7
Tetracaine- 8.5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

PKa and LA

A

Degree of ionization increases as pKA gets further from physiologic pH
Faster onset at pKa close to blood (except chloroprocaine)

17
Q

Benzocaine

A

PKa 3.5

Unionized at pH yet i has anesthetic activity

18
Q

Site of LA and uptake

A 
I Think Illogical Imposters Can’t Educate But Fabulous Schools Should
IV
Tracheal 
Interpleural
Intercostal
Caudal
Epidural
Brachial plexus
Femoral
Sciatic
Subcutaneous
19
Q

Amide max doses

A

Bupivicaine 2.5mg/kg, 175mg, with epi 3mg/kg, 175mg
Lidocaine 4.5 mg/kg, 300 mg, with epi mg/kg, 500mg
Ropivicaine 5 mg/kg, 200 mg
Mepivicaine 7 mg/kg, 400mg

20
Q

Ester max doses

A

Procaine 7mg/kg, 350-600mg

Chloroprocaine 11mg/kg, 800mg

21
Q

Lidocaine toxicity

A 
1-5mcg/mL- analgesia
5-10mcg/mL- tinnitus, perioral numbness, skeletal muscle twitching, restlessness, vertigo, blurred vision, hotn, myocardial depression
10-15mcg/mL- seizures
15-25mcg/mL-  coma, respiratory arrest
>25mcg/mL- cardiovascular collapse
22
Q

CNS factors that increase LAST risk

A

Hypercarbia
Hyperkalemia- raises membrane potential and makes depolarization more likely
Metabolic acidosis- ion trapping in brain

23
Q

LA cardiac affinity

A

Bupivacaine>levobupivacaine>ropivacaine>lidocaine

Bupi risk increased with pregnancy, beta blockers, ca channel blockers, dig

24
Q

Cocaine toxicity

A

Inhibits NE reuptake into nerve terminal- vasoconstrictive properties
SNS stim increases risk
Avoid with MAOIs, TCAs, sympathomimetic drugs
Beware of beta blockade due to unopposed alpha 1 stimulation
Nitro is best but use labetolol or beta blocker with alpha mixed in

25
Q

Lipid emulsion for LAST

A

Bolus 20% 1.5mL/kg (lean body mass) over one minute
Infusion 0.25 mL/kg/min
Can repeat bolus up to 2 more times and increase infusion to 0.5
Infusion goes 10min after hemodynamic stability
Max dose 10mL/kg in 1st 30 min

26
Q

Lipid MOA

A

Lipid sink- reservoir to sequester LA
Metabolic- increases fatty acid metabolism
Inotropic effect- increased Ca influx
Membrane effect- impairs binding to VgNaC

27
Q

Avoid in LAST treatment

A

Beta blockers and Ca blockers

28
Q

Tumescent anesthesia

A

PE most common causes of death
Solution of sodium chloride, lido, epi, and bicarb
Max lido dose 55mg/kg
Peaks at 12 hours and eliminated in 36 hours

29
Q

Methemoglobinemia

A

Fe2+ on hemoglobin oxides to ferric form Fe3+-forms methemoglobin
Decreases O2 carrying capacity and shifts curve to L
Causes- benzocaine, cetacaine, prilocaine, EMLA, nitroprusside, nitroglycerin, sulfa, phenytoin

30
Q

Methemoglobinemia S/S

A 
Hypoxia
Cyanosis- with normal PaO2
Chocolate colored blood
Tachycardia
Tachypnea
Mental status changes
Coma/death
31
Q

Methemoglobinemia treatment

A

Methylene blue: 1-2 mg/kg over 5 min, max dose 7-8 mg/kg
Metabolized and reduces methemoglobin to hemoglobin
Neonates at high risk

32
Q

EMLA

A

50/50 lido and prilocaine
Analgesia in 1 hour, max effect 2-3 hrs
Only to intact skin
Infants and kids have risk of methemoglobin

33
Q

EMLA dosing

A

0-3 months or < 5 kg- 1 g, 10 cmsquared
3-12 months or >5kg- 2 g, 20cmsquared
1-6 years or >10kg- 10g, 100cmsquared
7-12 years or >20kg- 20g, 200cmsquared

34
Q

Prolong duration of action

A

Epi- alpha 1 agonist, works better on intermediate action LAs
Decadron- acts on steroid receptor
Dextran- decreases uptake of LAs

35
Q

provide supplemental analgesia

A

Clonidine- alpha 2 agonism in brain and SC
Epi- alpha 2 agonism
Opioids- spinal and epidural

36
Q

Drugs that shorten onset time

A

Sodium bicarb
Increases number of lipid soluble molecules
Increasing fraction of nonionized base

37
Q

Drugs that improve diffusion through tissues

A 
Hyaluronidase
Hinders spread of substances through tissues 
Used in ophthalmic blocks
Reduces hematoma size
Allergy potential

APEX (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions