local anesthesia

Question 1

provides a REVERSIBLE blockade of nerves leading to loss of pain

Answer 1

local anesthesia

Question 2

Types of local anesthesia

Answer 2

topical and regional

Question 3

Two main categories of local anesthesia

Answer 3

 Esters
 Amides
 A simple way to remember if an agent is an esther or amine is that all the amine will have two “i’s” (lidocaine and bupivacaine) and their generic name whereas esters
(procaine and tetracaine) will only have one “i”.

Question 4

Benzocaine
Cocaine
Procaine (Novocaine)
Tetracaine
Cause far more allergic reactions due it’s conversion PABA(Para-
amino-benzoic acid)

Answer 4

Esters

Question 5

Lidocaine
Mepivacaine
Bupivacaine
Dibucaine
Prilocaine

Answer 5

amides

Question 6

Bind and block the conduction of
action potentials
This affect is reversible and
nonspecific

Answer 6

local anesthetics

Question 7

Nerve fiber diameter

Answer 7

The larger the diameter the more anesthetic needed

Question 8

Vascularity of the Location

Answer 8

 Highly vascularized areas remove the local much faster
 Most locals are vasodilators except cocaine

Question 9

Solution and tissue pH

Answer 9

 Most local are acidic but are neutralized upon injection leading to the burning sensation
 Less affective in infected tissue

Question 10

Higher concentrations lead to shorter onset

Answer 10

concentration

Question 11

Increasing the dose leads to more effective blockade but also increases side effects

Answer 11

total dose

Question 12

LOCAL ANESTHETICS
CONTRAINDICATIONS

Answer 12

*Allergic reaction (ester causes most)
*Severely unstable BP
*Severe liver disease (metabolism) –
amides are metabolized by the liver
(increases system toxicity)
*Severe renal disease
*Mental instability

Question 13

indications of local anesthetics

Answer 13

Minor surgical procedures
Lacerations
Incision and drainage
Removal of lesions, biopsies, and nail
removal

Question 14

biggest contraindications of epinephrine

Answer 14

Absolute
 Untreated hyperthyroidism or
pheochromocytoma*
 Administration to single, dependent blood supply –> Fingers, toes, penis, nose, and pinna of the ear“

Question 15

still used to
anesthetize adult nasal mucosa
Only under a trained
professional
No children or infants

Answer 15

cocaine

Question 16

an be added to a local anesthetic
solution to prolong its duration of action, to assist with hemostasis by local vasoconstriction, and slowly absorption of the local anesthetic

Answer 16

epinephrine

Question 17

complications of lidocaine

Answer 17

Anxiety
Local
 Bruising
 Edema
 Infection
 Nerve damage
 Temporary motor nerve paralysis
 Toxicity 70kg 31.5mg of 1% lidocaine

Question 17

COMPLICATIONS
Systemic

Answer 17

 Hypotension
 Bradycardia
 CNS depression, stimulation to include
slurred speech, drowsiness, disorientation,
tremor, restlessness, weakness, seizures,
paralysis, coma, respiratory failure, and
cardiac dysrhythmias

Question 18

complications of epinephrine

Answer 18

More common with bupivacaine
Cardiac dysrhythmias
Increased BP
Anxiety
Cardiac arrest
Cerebral hemorrhage
Ischemia if used in areas of single end artery flow

Question 19

allergies

Answer 19

Esters convert to PABA:
 Those patients allergic to benzocaine a para aminobenzoic acid (PABA) tend to be
more sensitive to thiazides, sulfonylureas, sulfonamides, paraphenylenediamine and
PABA preparations
Usually amides are good substitution - There is no cross reactivity
between an amide and an ester

Question 20

injection anesthetics
 Rapid onset
 Direct wound infiltration is approx. 20-30 min
- most common

Answer 20

lidocaine with or without epi

Question 21

injection anesthetics
 6-10 for onset
 Lasts about 30-60 min

Answer 21

mepivacaine

Question 22

injection anesthetics
 8-12 min for onset
 Lasts 4x longer than lidocaine – used in the OR

Answer 22

bupivacaine

Question 23

injection anesthetics
 May be used for an allergic reaction to either an amide or ester
 Infiltration of wounds lasts about 30 min
 Painful

Answer 23

diphenhydramine

Question 24

injection tips

Answer 24

1. Warm and or buffer the local anesthetic agent 2. Inject the local anesthetic agents slowly 3.Inject open wounds through the wound edges and not through the intact skin except when the wound is grossly contaminated 4. Infiltrate subdermal to minimize pain 5. Do not totally withdraw the needle after infiltration if possible 6.Leave the tip of the needle within the skin and redirect the needles to prevent excessive skin punctures

Question 25

PATIENT PREP

Answer 25

Place the pt in a supine position – the most common reaction is vasovagal response or syncope Reassurance, conversation, informing the patient of each step Warming the local anesthetic - can use a blanket or warming bath

Question 26

DIRECT INFILTRATION OF WOUNDS

Answer 26

Minimally contaminated wounds Injection is between the dermis and the subcutaneous fat Begin by injecting the side where the sensory innervation originates and then proceed distally

Question 27

INJECTION

Answer 27

27 or 30 gauge needle  Decreases the speed of injection – rapid injection increases pain 1-3ml syringe Shorter needle length is adequate for punch biopsies Longer lengths for larger excisions, wound infiltration, field and digital blocks

Question 28

DIRECT INFILTRATION

Answer 28

Once the needle is inserted, aspirate...then inject if no blood return Reposition the needle in the area Aspirate and proceed Repeat Anytime blood is aspirated with the needle until clear

Question 29

TOPICAL ANESTHESIA pros

Answer 29

 No injection  No distortion of anatomy  Easy *Easy to use and decrease the need for sedationTOPICAL ANESTHESIA Invasive procedures can cause significant anxiety in patients both young and old Noninvasive anesthesia has been shown to decrease pain and anxiety surrounding procedures (ex: lumbar puncture, IV access, and laceration repair *Less painful to apply *Do not distort wound margins *Decrease infection rate *Easy to use and decrease the need for sedation

Question 30

TOPICAL ANESTHESIA Wound closure

Answer 30

 Works better on the highly vascular face and scalp  Should be limited to wounds of 5cm or < to avoid systemic absorption

Question 31

Contraindications of topical anesthesia

Answer 31

Allergy Mucous membranes – (careful administration due to rapid absorption) Class 1 anti-arrhythmic (relative) Mexiletine and tocainide

Question 32

TOPICAL ANESTHETIC COMBINATIONS

Answer 32

 TAC (20-30min)  Tetracaine, adrenaline and cocaine  EMLA (60min)  Eutectic mixtures of lidocaine and prilocaine  LET (15-30min)  Lidocaine, epinephrine, and tetracaine

Question 33

For intact skin – use of superficial anesthesia  EMLA (50% lidocaine and 50% prilocaine)  RLA-Max (4% lidocaine)  About 2-3ml is sufficient to achieve complete anesthesia

Answer 33

topical anesthesia

Question 34

steps of topical application

Answer 34

1.Debride any blood clots 2.Saturate the gauze sponge or cotton with anesthetic 3.Fold the saturated sponge on the wound and tape in place 4. Apply pressure for 15-20 minutes 5.Remove the cream before the start of the procedure

Question 35

local anesthetic is infiltrated around the border of the surgical field, leaving the operative area undisturbed

Answer 35

field block

Question 36

anesthetic is injected directly adjacent to the nerve supplying the surgical field.

Answer 36

nerve block

Question 37

anesthetizes the nerves supplying the skin in the operative field Local anesthetic solution is infiltrated around the border of the surgical field Lasts longer than local infiltration Does not cause swelling in the surgical field or obscure local anatomy

Answer 37

field block

Question 38

The needle is inserted at two points, and anesthetic solution is injected along four lines (walls) that surround the area to be anesthetized. The shape of the anesthetic field can be modified by changing the number and direction of the anesthetic walls

Answer 38

field block

Question 39

most commonly used meds for digital block

Answer 39

* 1% lidocaine w/o epi * 1% mepivacaine w/o epi * 2% lidocaine w/o epi

Question 40

digital block is Recommended for procedures distal to the mid-proximal phalanx of the digit

Answer 40

* Nail avulsion * Paronychial drainage * Lacerations of the digit * Fractures

Question 41

digital block steps

Answer 41

1. Inject anesthetic just distal to the web space in the middle of the digit 2. Aspirate, if no blood, then inject 0.1ml of anesthetic locally into the dermis 3. Advance the needle to the bone, withdraw slightly and move dorsally to inject 0.5ml after aspiratin 4. Withdraw the needle to the midline, advance to bone and move ventrally. Aspirate and inject another 0.5ml to 1ml of anesthetic 5. Withdraw the needle and repeat on the other sid

Question 42

Local anesthetic is injected into the hematoma between the fractured bone fragments Indicated for fractures that require manipulation and closed reduction Contraindications include open fracture, cellulitis, and neurovascular deficit, or vascular deficit Aseptic technique with subcutaneous wheal, aspirate once in fracture site, and inject Can also be used for intra articular fracture dislocations (ankle, shoulder)

Answer 42

hematoma block - fractures

Question 43

follow up

Answer 43

Instruct the patient to notify you or the office if rash or inflammation, unusual skin coloration, itching, prolonged pain, or if sensation does not return to the area.