Clinical Skills: Local Anesthesia and Laceration Repair

Local Anesthesia

Blocks the conduction of nerve impulses

Effects are reversible and nonspecific

Can act on sensory nerves, temperature sensation, pain, touch, pressure, and motor

Most common forms of local anesthesia

topical, direct infiltration, regional blocks

Why anesthesia burns

Anesthetic solution are acidic

Once injected the pH normalizes

Buffer with bicarbonate- limits shelf-life, degrades epinephrine

Epinephrine decreases pH which makes burning worse

Epinephrine is included in anesthesia for

Decreases blood flow

Reduces systemic absorptions

Shortens onset

Extends duration of action

Doubles the duration of anesthesia with Lidocaine

Limited system absorptions allows for greater amounts to be used without a fear of toxic potential

Reasons why epinephrine should not be included in anesthesia

Decreases blood flow

Not be used for regions of the body supplied by a single vascular source

May cause necrosis

Regions of the body that can be affected by necrosis from epinephrine

Fingers, nose, penis, and toes

pinna of the ear can also be affected

Anesthetic in infection

Anesthetic solutions work best at physiologic pH

They are less effective in infected tissues than in healthy tissues

This is due to the infected tissue's metabolic acidosis from the infection, which decreases the tissue pH

Maximum amount of anesthetic calculation

dose (mg/kg) x (weight in kg/10) x (1/concentration of local anesthetic) = mL lidocaine

Maximal dose for lidocaine without epinephrine

3 mg/kg

Maximal dose for lidocaine with epinephrine

7 mg/kg

Anesthesia toxicity is due to

decreased clearance

Decreased hepatic blood flow and reduced enzyme function

Anesthesia toxicity patient considerations

those undergoing general anesthesia, taking propranolol, have congestive heart failure, cirrhosis, or hypothermia

Maximum dose of lidocaine for most average patients

30 cc of 1% Lidocaine

Topical anesthetic agents

benzocaine and lidocaine

Injectable anesthetic agents

lidocaine, bupivacaine

Local anesthetia indications

Elimination of pain with therapeutic modalities

Repair lacerations and minor surgery

Incision and drainage of abscesses

Removal of lesions, biopsies, nail removal

Contraindications to local anesthesia

True allergy

Severe liver disease

Severe renal disease

Severely unstable blood pressure

Untreated hyperthyroidism

Severe CAD

Epinephrine in local blocks

Narrow angle glaucoma

Anesthesia complications

Vasovagal reaction of patient due to injection fear

Local anesthesia complications

Not common

Bruising, edema, prolonged nerve damage

Systemic anesthesia complications

Hypotension, bradycardia, CNS depression, stimulation

How to prepare the patient for anesthesia injection

Talk to the patient

Reassure the patient

Have the patient supine

Engage in conversation to distract

Encourage them to take deep breaths

Reassure them through the procedure

May need conscious sedation for anxious patients or children

Cryo-anesthetics

Provide short period of decreased pain sensation

Ice, ethyl chloride, trichloromonofluoromethane,

Can use before an injection

Use for curettage of superficial lesion

Can burn if sprayed on skin too long

Topical anesthetics

Apply topically to mucous membrane or skin/wound

Best for highly vascular sites (face and scalp)

Takes approx. 15-20 minutes

Injection anesthesia

injected into the wound or surrounding tissue

use small 27-g needle

slowly inject

burns

Direct infiltration of wound

1.Enter from inside the wound

2.Start on side where innervation originates

3.Aspirate to ensure not in vessel

4.Inject then withdraw

5.Move the needle around the wound repeating

6.Repeat until all edges of the wound are anesthetized

Field block

Use when larger laceration and grossly contaminated wound

Use a 25 - 27-g needle, 11/4 to 2 inch needle

Insert needle and run parallel to the skin up to the hub

Slowly inject as you pull back

Repeat 3 additional times until you have squared the field

Digital block

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

Nail avulsion, paronychial drainage, repair of lac of digit

Lidocaine 1% w/o epi

Digital block: dorsal injection

1.Inject just distal to the web space in the middle of the digit. (lateral and medial sides)

2.After aspirating, inject 0.1 mL of anesthetic locally into the epidermis

3.Advance the needle to the bone, withdraw slightly, and then move dorsally, where 0.5 mL of anesthetic is injected after aspiration

4.Withdraw the needle again to the midline, advance to bone, and move ventrally, where another 0.5 to 1 mL of anesthetic is injected after aspiration

5.Withdraw the needle and repeat the whole procedure on the other side of the digit

Digital block: palmar inject

1.Hand placed in supinated position

2.Needle is introduced distal to the distal crease of the palm lined up with midline of the digit

3.After aspiration, inject 1 to 2 mL of anesthetic

Wound closure considerations

Reapproximate wound edges to facilitate wound healing and reduce the likelihood of infection

Timeframe for wounds to be closed within

18 hours of injury

Wound closure indications

time required for wound healing

likelihood of infection

amount of scar tissue

Repair loss of structure and/or function

Improve cosmetic appearance

Wound closure contraindications

Contaminated wounds

Presence of foreign bodies

Tendon, nerve, and/or artery involvement

Potential complications of wound closure

Infection

Scarring, including keloid formation

Loss of function and structure

Loss of a cosmetically desirable appearance

Wound dehiscence

Tetanus

Langer line

Lacerations that run parallel to these lines naturally reapproximate the skin edges

Lacerations that run at right angles to the tension lines tend to gape apart

Clean wounds

Incisions made during a surgical procedure in which aseptic techniques were followed, without involvement of the gastrointestinal, respiratory, or genitourinary tract; likelihood of infection is less than 2% and warrants routine primary closure

Clean-contaminated wounds

Similar to clean wounds, except that the gastrointestinal, respiratory, or genitourinary tract is involved

Contaminated wounds

Similar to clean and clean-contaminated, except there is gross spillage (e.g., bile, stool); traumatic wounds fall into this category

Infected wounds

Established infection before wound is made (e.g., incision and drainage of an abscess) or heavily contaminated wounds (e.g., gross spillage of stool)

Wound closure classification: primary intention

All layers are closed

Best chance for minimal scarring

Usually performed in clean and clean-contaminated wounds

Wound closure classification: secondary intention

The deep layers are closed, whereas superficial layers are left open to granulate on their own from the inside out

Often leaves a wide scar and requires frequent wound care, consisting of irrigation and assorted types of packing and dressings

Prolonged process

Reasons for use include excessive tissue loss and infection

Used for infected and contaminated wounds

Wound closure classification: third intention or delayed primary intention

The deep layers may be closed primarily, whereas the superficial layers are left open until reassessment on day 4 or 5 after initial closure, at which time the wound is inspected for signs of infection

If it looks clean and has begun to granulate, it is irrigated and closed

If it looks as if it may be infected, it is left open to heal by secondary intention

These wounds often arise initially from contaminated wounds

Patient preparation for wound closure

History

Physical Exam

Tetanus Vaccination History

Absorbable suture types

Gut, Monocryl, Vicryl

Absorbable suture absorption time is affected by

Material

Location of suture

Patient factors

Absorbable sutures are commonly used for

Deep tissue and tissues that heal rapidly

Small bowel anastomosis

Urinary or biliary tracts

Tying off small vessels near the skin

Closing of skin

Nonabsorbable suture types

silk, nylon, polypropylene

Nonabsorbable sutures are used to provide

long-term tissue support

Remain walled off by the body's inflammatory processes

Nonabsorbable sutures are used for

tissues that heal slowly

Fascia

Tendons

Closure of abdominal wall

Vascular anastomoses

Monofilament suture types

nylon and polypropylene

Monofilament sutures

Passes through tissue more easily than does braided suture. Disadvantage- has less tensile strength than a multifilament suture

Multifilament suture types

silk and ethibond

Multifilament sutures

Better flexibility, Disadvantage would be that it may harbor organisms more easily within the braid

Suture size

denoted by the number of zeros, and increases in number as the diameter of the suture decreases

Example 7-0 is smaller than 1-0

Natural suture material

made of natural fibers (e.g. silk or catgut). They are less frequently used, as they tend to provoke a greater tissue reaction

Natural suture materials commonly used for

securing surgical drains

Synthetic suture materials

comprised of man-made materials (e.g. PDS or nylon). They tend to be more predictable than natural sutures, particularly in their loss of tensile strength and absorption

Monofilament suture

a single stranded filament suture (e.g. nylon, PDS*, or prolene). They have a lower infection risk but also have poor knot security and ease of handling

Multifilament suture or braided suture

made of several filaments that are twisted together (e.g. braided silk or vicryl). They handle easier and hold their shape for good knot security, yet can harbor infections

Ideal suture needle

Rigid enough to resist distortion

Flexible enough to bend before breaking

Slim as possible to minimize trauma

Sharp enough to penetrate tissue with minimal resistance

Stable within a needle holder to permit accurate placement

Parts of a suture needle: swage

connects the needle to the suture

Parts of a suture needle: body or shaft

the region grasped by the needle holder

Parts of a suture needle: point

pierce the tissue

Suture needle body types: round (taper)

Friable tissue such as liver and kidney

Dilates rather than cuts

Suture needle body types: reverse cutting

Reverse cutting needles have a cutting surface on the convex edge

Cuts rather than dilates

Ideal for tough tissue such as tendon or subcuticular sutures

Reduced risk of cutting through tissue

Ideal for skin

Suture needle body types: cutting

Triangular in shape

3 cutting edges to penetrate tough tissue such as the skin and sternum

Have a cutting surface on the concave edge

Cuts rather than dilates

Creates weakness allowing suture tear out

Suture needle point types: sharp

Pierce and spread tissues with minimal cutting

Used in areas where leakage must be prevented

Suture needle point types: blunt

Used for abdominal wall closure, and in friable tissue,

Can potentially reduce the risk of blood-borne virus infection from needlestick injuries

Needle shape

vary in their curvature

Are described as the proportion of a circle completed

Most common needle curvatures used

¼, ⅜, ½, and ⅝

Instruments used for laceration repair

Scissors, tissue forceps, needle holder

Proper positions for laceration repair

Suture considerations: hairy region

Trim surrounding hair

Cutting the suture tails longer than usual

Use blue suture

Never shave an eyebrow

Suture considerations: lining up edges

Line up the hair and skin borders exactly to avoid misalignment

Align the vermilion border of the lips

Tattoos

If an incision has to be made, it is important to recognize and follow the natural skin tension lines

Staples

useful for long, linear lacerations of the scalp, trunk, and extremities because they can be applied quickly with the same ultimate cosmetic result as suture

How to apply staples

1.Use an assistant to evert the tissue edges of the laceration

2.Place staples over the approximated wound and firmly squeeze the trigger to deliver each staple

Follow up care after a laceration repair

Keep wound dry and clean

Elevate

Cold compress for 48 hours

Describe signs of infection

Wound check twice a day for signs of infection

Activity restriction

Pain medication

Return to clinic

Antibiotic considerations for wounds

Wounds > 12 hours old at initial presentation, especially those of the hands

Human or animal bites, including those caused by the patient's teeth

Crush wounds

Heavily contaminated wounds

Avascular areas, such as the cartilage of the ear

Joint spaces, tendon, or bone

Severe paronychia and felons

Wounds in patients with a history of valvular heart disease

Immunosuppressed patients

Antibiotic treatment for bite wounds

Augmentin - amoxicillin/clavulanate

Antibiotic treatment for MRSA

Clindamycin

Suture removal: days until removal