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Emergency Med > Local Anesthesia/ Nail Bed Injuries > Flashcards

Local Anesthesia/ Nail Bed Injuries Flashcards

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1
Q

Why local anesthesia

A 
Increased pt comfort and satisfaction
Steady field to work in
Easier to clean and remodel wound
-Some wounds need to be trimmed more to make it aesthetically pleasing
May help keep blood out of field
Improved pain control after procedure
PTS EXPECT IT
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2
Q

Why NOT local anesthesia?

A

Increased risk of infection
Toxicity concerns
Allergy concerns
May increase amt of blood in field
It hurts
-Medicine can burn, poke with initial injection
-Will it take longer and cause more pain to anesthetize?

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3
Q

Local anesthesia physiology

A

Reversibly block conduction of nerve fibers
Prevent increase of permeability of nerve cell membranes to Na+ ions, decreasing rate of depolarization
-Bind intracellular receptor on Na+ channel- inhibit influx
-Does not change resting or threshold potential

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4
Q

Esters

A 
Cocaine
Procaine (Novocaine)
Tetracaine (Pontocaine)
Chloroprocaine
Benzocaine
Not used much anymore except tetracaine in ophthalmology
Do not use tetracaine in open wounds
Benzocaine can be found in OTC topical preparations
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5
Q

Order of blockade in anesthesia

A 
Pain
Cold
Warmth
Touch
Deep pressure
Motor
Recovery occurs in reverse order
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6
Q

Duration of cocaine

A

Med

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7
Q

Max dosage of cocaine

A

N/A

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8
Q

Duration of procaine

A

Short

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9
Q

Max dosage of procaine

A

7 mg/kg

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10
Q

Duration of tetracaine

A

N/A

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11
Q

Max dosage of tetracaine

A

N/A

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12
Q

Duration of benzocaine

A

N/A

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13
Q

Max dosage of benzocaine

A

N/A

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14
Q

Duration of chloroprocaine

A

Short (15-30 mins)

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15
Q

Max dosage of chloroprocaine

A

800 mg; 1000 mg

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16
Q

Duration of lidocaine

A

Med (30-60 min)

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17
Q

Max dosage of lidocaine

A

4.5 mg/kg; 7 mg/kg

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18
Q

Duration of bupivacaine

A

Long (120-240 mins)

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19
Q

Max dosage of bupivacaine

A

2.5 mg/kg (with epi)

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20
Q

Duration of mepivicaine

A

Med (45-90 min)

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21
Q

Max dosage of mepivicaine

A

7 mg/kg to max of 400

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22
Q

Duration of etidocaine

A

Long (120-180 min)

23
Q

Max dosage of etidocaine

A

6 mg/kg; 8 mg/kg

24
Q

Duration of prilocaine

A

Med (30-90 min)

25
Q

Max dosage of prilocaine

A

500 mg; 600 mg

26
Q

Central nervous system toxicity of anesthesia: initial sx

A 
Perioral tingling/numbness
Metallic taste
Lightheaded/dizzy
Visual/auditory hallucinations
-Tinnitus, difficulty focusing
Disorientation/drowsiness
Instruct pts before you start so they can let you know during the procedure
27
Q

CNS toxicity in higher doses

A 
Muscle twitching
Convulsions
Unconsciousness/coma
Respiratory depression/arrest
CV depression/collapse
28
Q

Direct cardiac effects of anesthesia

A 
Myocardial depression (tetracaine, etidocaine, bupivacaine)
Cardiac dysrhythmias (bupivacaine)
Cardiotoxicity in pregnancy? (may be based on bat rat studies)
29
Q

Peripheral CV effects of anesthesia

A

Vasodilate at low doses

Vasoconstrict at higher doses

30
Q

Range of CV effects

A 
CP
SOB
Palpitations
Lightheadedness
Diaphoresis
Hypotension
Syncope
31
Q

Hematological toxicity

A 
Metabolite of procaine (also seen with lidocaine and benzocaine) oxydizes hemoglobin to methemoglobin
-Methemoglobin is same substance found in carbon monoxide poisoning
Cyanosis
Cutaneous discoloration (gray)
Tachypnea/dyspnea
Exercise intolerance/fatigue
Dizziness and syncope
Weakness
32
Q

Lidocaine

A

Rapid onset (1-2 mins to peak)
Relatively short duration of action (~1 hr)
Acidic, so burns briefly on injection
-Can buffer (10:1 lido: sodium bicarb)
- Bicarb causes anesthesia to be taken up more quickly

33
Q

Lidocaine concentrations

A 
1%
-Most commonly used
2%
-Allows you to use less medicine (small spaces)
-Sometimes used for nerve blocks
-Good for ears and peds
Both come with and without epi
34
Q

Lidocaine with epi

A

Helps limit bleeding in field

Slows the rate of medication washout from field

35
Q

Lidocaine without epi

A

NEVER inject epi into distal appendages
-Ears, nose, fingers, toes, penis
If you inject epi by mistake, use nitro paste

36
Q

Bupivacaine

A

0.25%, 0.5%; with and without epi
Slower onset (5-10 mins to peak)
Longer acting (~4 hrs and up)
Commonly used for nerve blocks
Sometimes mixed with lidocaine to provide rapid onset with longer duration
Has been shown to reduce residual pain, even after it has worn off

37
Q

Topical anesthetics

A

LET/LAT, EMLA cream
-EMLA cream is combo of lidocaine/prilocaine
Avoid pain associated with injection
Avoid wound margin distortion
Take time to work (20-45 mins)
May not work as well in older children and adults
Don’t work if not applied properly

38
Q

How to properly apply topical anesthetics

A

Tear off a piece of cotton ball enough to cover wound
Completely saturate
Put on wound with tape

39
Q

Medication choice

A

Never underestimate the power of distraction, esp in children!
Having a child watch TV works the best

40
Q

Allergies

A

Lidocaine and Novocaine are in different classes of anesthetics, so an allergy to Novocaine usually does not indicate an allergy to lidocaine
Lidocaine and bupivacaine are in the same class
Many lidocaine allergies area actually reactions to the preservative in the multi-dose vials
In a pinch, can use non-traditional anesthesia
-Ice or injection with Benadryl or even saline will all provide some degree of anesthesia

41
Q

Local infiltration

A

Most commonly used method
quick and simple, easily mastered
Provides immediate anesthesia to localized area
Tends to distort wound margins
Usually requires multiple injections
Can turn localized infection into blood-borne infection

42
Q

Method- local infiltration- supplies

A

Use small syringe (no greater than 5 mL)
Use long, thin needle (27 gauge, 1 1/4 inch) except on very small or facial wounds
Draw up more than you’ll need- this may require use of multiple syringes
Orient yourself with the wound so that you can work comfortably
-Try to work with the wound pointing away from you

43
Q

Method-local infiltration- injection

A

If injecting through skin, prep area with EtOH
Less painful to insert needle into subcutaneous tissue from inside wound
Try to start on the proximal aspect of wound
Insert needle fully, aspirate to check for blood, and inject SLOWLY as you withdraw the needle
Repeat as needed (both sides of wound) and check for numbness

44
Q

Field block

A 
Similar to local infiltration, except done few inches away from wound
-Avoids wound margin distortion
-Avoids injection through infection
-Good for ears, abscesses
Relatively easy to master
infiltrate a perimeter around wound site
Field inside perimeter should be numb
45
Q

What should you avoid in a field block?

A

Sternocleidomastoid

46
Q

Digital block

A 
Often performed for pt comfort
-Good alternative for pain meds or for procedures other than wound repairs
Same benefits as field block
Relatively easy to master
Uses less medicine
-Usually 1-4 mL is all you need
Long-acting anesthetic often best
After injection, allow 10-15 mins for anesthesia to set up before procedure
47
Q

Subungual hematoma

A

Trauma to nail results in bleeding under nail plate

Bleeding separates nail plate from nail bed

48
Q

Trephination

A

Use of a small, usually hollow, instrument to make a hole in a solid surface

49
Q

Preparation for subungual hematoma

A 
Skin prep
Trephine
-Electrocautery
-18g needle or scalpel
-Heated paperclip?
Anesthesia?
Gloves, eye protection
50
Q

CIs to trephination

A

Severe crush injury

Underlying fx?

51
Q

Indications for nail plate removal

A 
Severe crush injury, fracturing plate
-If repair needed: 6-0 or 7-0 absorbable monofilament
Severe injury with intact plate?
Subungual abscess
Ingrown nail?
52
Q

Preparation for nail plate removal

A

Skin prep
Anesthesia
Hemostats, iris scissors
Gloves, eye protection

53
Q

Steps for nail plate removal

A 
Use hemostats to lift nail
Scissors may be needed to undermine
If underlying matrix is destroyed, nail will not grow back
-Phenol/alcohol
-Electrocautery

Emergency Med (11 decks)

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