Local Anesthesia/ Nail Bed Injuries Flashcards
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
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?
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
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
5
Q
Order of blockade in anesthesia
A
Pain Cold Warmth Touch Deep pressure Motor Recovery occurs in reverse order
6
Q
Duration of cocaine
A
Med
7
Q
Max dosage of cocaine
A
N/A
8
Q
Duration of procaine
A
Short
9
Q
Max dosage of procaine
A
7 mg/kg
10
Q
Duration of tetracaine
A
N/A
11
Q
Max dosage of tetracaine
A
N/A
12
Q
Duration of benzocaine
A
N/A
13
Q
Max dosage of benzocaine
A
N/A
14
Q
Duration of chloroprocaine
A
Short (15-30 mins)
15
Q
Max dosage of chloroprocaine
A
800 mg; 1000 mg
16
Q
Duration of lidocaine
A
Med (30-60 min)
17
Q
Max dosage of lidocaine
A
4.5 mg/kg; 7 mg/kg
18
Q
Duration of bupivacaine
A
Long (120-240 mins)
19
Q
Max dosage of bupivacaine
A
2.5 mg/kg (with epi)
20
Q
Duration of mepivicaine
A
Med (45-90 min)
21
Q
Max dosage of mepivicaine
A
7 mg/kg to max of 400
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
Max dosage of prilocaine
500 mg; 600 mg
26
Central nervous system toxicity of anesthesia: initial sx
```
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
CNS toxicity in higher doses
```
Muscle twitching
Convulsions
Unconsciousness/coma
Respiratory depression/arrest
CV depression/collapse
```
28
Direct cardiac effects of anesthesia
```
Myocardial depression (tetracaine, etidocaine, bupivacaine)
Cardiac dysrhythmias (bupivacaine)
Cardiotoxicity in pregnancy? (may be based on bat rat studies)
```
29
Peripheral CV effects of anesthesia
Vasodilate at low doses
| Vasoconstrict at higher doses
30
Range of CV effects
```
CP
SOB
Palpitations
Lightheadedness
Diaphoresis
Hypotension
Syncope
```
31
Hematological toxicity
```
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
Lidocaine
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
Lidocaine concentrations
```
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
Lidocaine with epi
Helps limit bleeding in field
| Slows the rate of medication washout from field
35
Lidocaine without epi
NEVER inject epi into distal appendages
-Ears, nose, fingers, toes, penis
If you inject epi by mistake, use nitro paste
36
Bupivacaine
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
Topical anesthetics
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
How to properly apply topical anesthetics
Tear off a piece of cotton ball enough to cover wound
Completely saturate
Put on wound with tape
39
Medication choice
Never underestimate the power of distraction, esp in children!
Having a child watch TV works the best
40
Allergies
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
Local infiltration
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
Method- local infiltration- supplies
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
Method-local infiltration- injection
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
Field block
```
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
What should you avoid in a field block?
Sternocleidomastoid
46
Digital block
```
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
Subungual hematoma
Trauma to nail results in bleeding under nail plate
| Bleeding separates nail plate from nail bed
48
Trephination
Use of a small, usually hollow, instrument to make a hole in a solid surface
49
Preparation for subungual hematoma
```
Skin prep
Trephine
-Electrocautery
-18g needle or scalpel
-Heated paperclip?
Anesthesia?
Gloves, eye protection
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50
CIs to trephination
Severe crush injury
| Underlying fx?
51
Indications for nail plate removal
```
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
Preparation for nail plate removal
Skin prep
Anesthesia
Hemostats, iris scissors
Gloves, eye protection
53
Steps for nail plate removal
```
Use hemostats to lift nail
Scissors may be needed to undermine
If underlying matrix is destroyed, nail will not grow back
-Phenol/alcohol
-Electrocautery
```
