Chapter 8 Wound Healing and Its Impact on Dressings and

Chapter 8

Wound Healing and Its

Impact on Dressings and

Postoperative Care長庚皮膚科 R2 劉人鳳2015.12.11

Chapter summary

Dressing – cover the wound, absorb drainage, moist environment

Moist environment– epithelial migration, angiogenesis, growth factors

retention, autolytic debridement, fibrinolysis, protection, voltage gradient

Acute wounds healing

Chronic wounds –relieve pain, promote autolytic debridement, decrease

frequency of changes

Dressings, skin grafts and skin substitutes

長庚皮膚科 R2 劉人鳳

Functions of Dressings

Table 8.1


Functions of Dressings -- Acute wounds

Heal in an orderly/timely fashion

Moist environment and occlusion -- 40% faster of healing than air exposed

Enhancement of epithelial migration: keratinocytes begin to migrate sooner

Stimulation of angiogenesis:

- angiogenesis-stimulating factors (TNF, heparin)

- steep oxygen gradient or hypoxia stimulates capillary growth


Functions of Dressings -- Acute wounds

Retention of growth factors: platelet derived growth factor (PDGF), basic

fibroblast growth factor (bFGF), transforming growth factor (TGF-b),

epidermal growth factor (EGF), interleukin IL-1

Facilitation of autolytic debridement: retained water and proteolytic enzymes

Protection of exogenous organisms: physical barrier; neutrophils,

lysozymes/globulins; inhibitory to bacteria growth by mildly acidic pH

Maintenance of voltage gradients: keratinocyte migration, increase

synthesis of growth factors


Functions of Dressings -- Chronic wounds

Chronic wounds – with underlying pathology (delay in the healing process)

Inhibitory to epithelialization, inhibit keratinocyte migration; fails to

stimulate DNA synthesis directly; considerably higher protease activity

Pain relief, painless wound debridement, containment of wound exudates,

reduction in the incidence of complications, and improved quality of life


Box 8.1


Non-adherent fabrics

Hydrophobic -- greater occlusive capability

Vaseline gauze (The Kendall Co, Mansfield, MA), Xeroform (The Kendall

Co), and Telfa (The Kendall Co)

Hydrophilic -- less occlusive, facilitate drainage of fluids and exudates

Xeroflo (The Kendall Co), Mepitel (Mö lnlycke Health Care, Gothenburg,

Sweden), Adaptic (Johnson & Johnson Medical, Arlington, TX), and N-

Terface (Winfield Laboratories, Dallas, TX)


Non-adherent fabrics: Absorptive dressings

Gauze is one of the most common

Secondary dressing to fix

Foam dressings and alginates: both absorptive and occlusive/moisture-

retentive dressings


Occlusive/moisture retentive

Moisture vapor transmission rate (MVTR) in 24 hrs

MVTR of intact normal skin: 200 g/m 2 per day

MVTR of wounded skin: 40X

MVTR of <35 g/m 2 per hour are defined as occlusive or moisture retentive.


Non-biologic

occlusive

dressings



Foam dressings

[Advantages]

Able to expand to conform to the size and shape of

the wound

Wounds with unusual configurations

Highly absorptive

Can be easily removed

[Disadvantages]

Opaque, require secondary dressing


Foam dressings

[Indications]

Partial-thickness wounds

Moderately to heavily exudative wounds and infected wounds

Pressure relief and cushion bony prominences

Secondary dressings for additional absorption

[Examples]

Allevyn (Smith & Nephew United, Largo, FL), Biopatch (Johnson & Johnson Medical), Curafoam (The Kendall Co), Flexzan (Dow B Hickam, Inc, Sugarland, TX), Hydrasorb (The Kendall Co), Lyofoam (ConvaTec, Princeton, NJ), Mepilex (Mö ln-lycke Health Care), Polymem (Ferris Corp, Burr Ridge, IL)

[Technique] 2 cm margin, tape or gauze for non-adhesive foam dressing長庚皮膚科 R2 劉人鳳

Film dressings

[Advantages]

Transparent, bacterial barrier

Self-adhesive

[Disadvantages]

Non-absorptive fluid collection frequent

dressing changes

Strip away newly formed epidermis on removal

Wrinkle easily, hard to handle

Contact dermatitis


Film dressings

[Indications]

Mildly exuding wounds, including lacerations, superficial surgical and burn wounds, donor sites, superficial ulcers, and catheter sites

Partial-thickness wounds with minimal exudates

Secondary dressings over alginates, foams, and hydrogels

NOT used in moderately to heavily exuding or infected wounds, sinus tracts, or cavities

[Examples]

Tegaderm (3M Healthcare, St Paul, MN), Bioclusive (Johnson & Johnson Medical), Blisterfilm(The Kendall Co), Polyskin II (Kendall Healthcare, Mansfield, MA), Mefilm (Mö lnlyckeHealth Care), Carrafilm (Carrington Lab, Irving, TX), and Transeal (DeRoyal, Powell, TN)

[Technique]

Intact periwound skin, 3–4 cm margin 長庚皮膚科 R2 劉人鳳

Hydrocolloids

[Advantages]

Absorbent, create bacterial and physical barrier

(waterproof)

Hydrophilic particles absorb and form a gel

autolytic debridement, enhance angiogenesis,

granulation tissue formation, and healing.

[Disadvantages]

Opaque, gel has unpleasant smell, expensive


Hydrocolloids

[Indications]

Partial- or full-thickness wounds, mildly to moderately exudative wounds (NOT actively infected)

Pressure ulcers, venous ulcers

Burn wounds (NOT 3rd degree) and donor sites

Acute surgical wounds

[Examples]

Duoderm (ConvaTec), NuDerm (Johnson & Johnson Medical), Comfeel (Coloplast, Minneapolis, MN), Hydrocol (Dow Hickam/Bertek), Cutinova (Smith & Nephew), Tegasorb (3M, Minneapolis, MN), Replicare (Smith & Nephew United), and Restore (Hollister, Libertyville, IL)

[Technique] >2 cm margin, daily ~ 3-7 days, ZnO for peri-wound skin長庚皮膚科 R2 劉人鳳

Hydrogels

[Advantages]

Semitransparent, soothing& cooling

effect

Do not adhere to wounds, hydrating

[Disadvantages]

Require secondary dressing, frequent

dressing changes


Hydrogels

[Indications]

Painful wounds

Partial-thickness wounds

Wounds after laser, dermabrasion or chemical peel

Donor sites

[Examples]

Vigilon (CR Bard, Murray Hill, NJ), Nu-gel (Johnson & Johnson Medical), Tegagel (3M), Flexi-Gel (Smith & Nephew), Curagel (The Kendall Co), Clear-Site (Conmed Corp, Utica, NY), Curafil (The Kendall Co), Curasol (Healthpoint), Carrasyn (Carrington Laborato-ries), Elasto-Gel (SW Technologies, North Kansas City, MO), Hypergel (Mö lnlycke Health Care), Normlgel (Mö lnlycke Health Care), SoloSite Wound Gel (Smith & Nephew), 2nd Skin (Spenco Medical, Ltd, Waco, TX), and Transigel (Smith & Nephew).

[Technique] changed every 3 days for necrotic wounds, 7 days for granulating wounds. Remove gently.


Alginates

[Advantages]

Highly absorbent

Hemostatic, do not adhere to wounds

Fewer dressing changes

[Disadvantages]

Require secondary dressing, gel has unpleasant

smell


Alginates

[Indications]

Highly exudative wounds

Deep wounds, sinuses and cavities (rope and ribbon forms)

Partial- or full-thickness wounds

After surgery

[Examples]

AlgiSite (Smith & Nephew), Algosteril (Johnson & Johnson Medical), Kaltostat (ConvaTec), Curasorb (The Kendall Co), Dermacea (The Kendall Co), Melgisorb (Mö lnlycke Health Care), SeaSorb (Coloplast, Holtedam, Denmark), Kalginate (DeRoyal), and Sorbsan (Dow B Hickam, Inc)

[Technique] at least 2 mm beyond the wound edges, secondary dressing is needed


Non-biologic

occlusive

dressings

NEWER NON-BIOLOGIC

DRESSINGS ARE CLASSIFIED

INTO 3 BASIC CATEGORIES


Hydrofibers

[Advantages]

Soft, absorbent

[Indications]

Moderately to heavily exuding wounds

Wounds that are prone to bleeding

Abrasions, lacerations, excisional wounds, pressure or leg ulcers, burns, and graft donor sites, wound cavities (hydrofiber ribbons)

[Examples] Aquacel


Collagen dressings

[Advantages]

Available as particles, sheets, or gels

Providing a collagen matrix for cellular migration

[Disadvantages]

Cause irritation or initially increase drainage

[Indications]

Moderately exudative wounds and recalcitrant ulcers

[Examples] Fibracol (Johnson & Johnson, Skillman, NJ), Medifil (Biocore Medical

Technologies, Inc, Silver Spring, MD), and Nugel collagen wound gel (Johnson &

Johnson Medical)


Hyaluronic acid dressings

[Advantages]

Biodegradable, absorbent

Accelerates granulation tissue formation and re-epithelialization

[Examples]

Hyalofil (ConvaTec)


Biologic

dressings: grafts


Biologic dressings: grafts

Grafts: local blood supply new blood supply from the recipient bed

Autografts: donor site to recipient site from the patient

Fractional skin harvesting: multiple full thickness cores of skin with small

diameter to minimize donor site morbidity

Allografts: donors of the same species -- cadaveric skin

Composite grafts: at least two different types of tissues, ex: skin and

cartilage



Biologic/biosynt

hetic dressings:

skin substitutes




Cultured epidermal grafts

Cultured epidermal autografts: serial subculture of human keratinocytes from the patient’s own skin large epidermal sheets sutured onto the

recipient’s tissue

Secondary dressing: mesh gauze for 7-10 days

Another outer dressing: absorb wound exudates, change QD or QOD

Disadvantages: require a 2–3-week period, fragile, lack a dermal

component. short-term stability


Cultured epidermal grafts

Cultured epidermal allografts: Neonatal foreskin

Growth factors release stimulate migration and multiplication of the

recipient’s keratinocytes

Donor sites, partial-thickness burns, chronic leg ulcers, epidermolysis

bullosa, and wounds resulting from tattoo removal



Dermal replacements

Cadaveric allograft skin, Biobrane (Smith and Nephew), EZ Derm (Mö lnlycke),

Oasis (Healthpoint), and Dermagraft (Shire Regenerative Medicine, St Helier,

Jersey)

Human cadaver skin -- acellular collagen dermal matrix and an intact basement membrane

Can be used alone or in combination with other grafts

AlloDerm (Life Cell Co, Woodlands, TX) --

• used in combination with STSGs

• burn wounds and dermal defects, and for periodontal, and plastic and

reconstructive surgery長庚皮膚科 R2 劉人鳳

Dermal replacements

Biobrane -- bilaminate biosynthetic material made up of silicone film and nylon fabric containing porcine collagen peptides

• pain relief, healing time, and absorption of exudates

EZ Derm -- porcine collagen chemically cross-linked using an aldehyde

• temporary coverage of partial-thickness wounds (burns and ulcers)

Oasis -- porcine small intestinal submucosa

• longer shelf-life, requiring a secondary dressing for additional protection

Integra (Integra LifeSciences Corp, Plainsboro, NJ) -- bovine collagen and chondroitin-6-sulfate covered by a synthetic silicone elastomer

• approved by FDA for burns (severe burns, insufficient skin available for an FTSG)


Dermal replacements

Dermagraft -- neonatal fibroblasts seeded on a 3D polyglactin

bioabsorbable mesh with no outer silicone membrane

• Full-thickness wounds, FDA approved for chronic diabetic ulcers

Avoiding the use of non-human tissue

Ready availability

Less chance of wound contracture and scarring

Mesh absorption in 60–90 days


Dermagraft



Composite skin substitutes

Contain both epidermal and dermal components

Apligraf (Organogenesis, Canton, MA; also known as Graftskin) --cultured human neonatal foreskin keratinocytes overlying fibroblasts

cultured on a dermal matrix of bovine type I collagen

• Lack immune cells no clinical rejection

• FDA-approved: venous leg ulcers or neuropathic diabetic foot ulcers


Apligraf


Composite skin substitutes

Bilayered cellular matrix (BCM) or OrCel (Forticell Bioscience Inc, New York,

NY) -- porous collagen sponge containing cultured keratinocytes and

fibroblasts derived from allogeneic cells harvested from neonatal foreskins

• FDA approved: split-thickness donor sites of burn; recessive dystrophic

epidermolysis bullosa


Cell therapies

For healing of chronic wounds

Solution containing cells is sprayed onto the wound bed

Do not require in-vitro tissue engineering (unlike skin substitutes)


Keratinocyte Spray

Spray-applied cell therapy

Growth-arrested allogeneic neonatal keratinocytes and

fibroblasts

Phase-2 double-blind randomized trial

Superiority of the active treatment over vehicle (p = 0.0446)

Lowest concentration and least frequent, administered

every 14 days showed the largest improvement (p = 0.0028)


Mesenchymal stem cells derived from

bone marrow

Bone marrow aspirate in vitro multipotent mesenchymal stem cells

A fibrin polymer spray system used to apply the cultured autologous stem

cells

Difficult-to-heal wounds

Chronic lower extremity wounds


Antimicrobial dressings

Silver-impregnated dressings

broad-spectrum action on bacteria, including against vancomycin-

resistant enterococci and methicillin-resistant Staphylococcus aureus

(MRSA)

• release antibacterial levels of silver for 3–7 days

against fungi and yeast

Aquacel Ag (ConvaTec), Contreet (Coloplast), Arglaes (Medline Industries,

Mundeline, IL), Acticoat (Smith & Nephew, London, UK), Silverlon

(Argentum Medical, Geneva, IL), and Silvasorb (AcryMed, Inc, Portland,

OR)


Antimicrobial dressings

Cadexomer iodine -- a slow-release formulation of iodine

broad-spectrum antibiotic coverage

significantly decrease the bacterial load on the wound surface

Iodosorb -- a cadexomer iodine ointment

antibacterial and an effective debriding agent

pressure, venous, and diabetic ulcers


DEBRIDEMENT


Autolytic debridement

The body’s own enzymes and moisture liquefy necrotic tissue

Selective and painless

Enhanced with dressings (films, hydrogels, and hydrocolloid dressings)

Should be monitored for infection (particularly with anaerobes)


Mechanical & Surgical debridement

Mechanical

Wet-to-dry dressings: moist dressing is applied to a wound and then

removed after drying

Non-selective (may traumatize healthy tissue), painful

Side-effects of infection with water-borne pathogens and tissue

maceration

Surgical

Rapid and selective

Significant amount of necrotic tissue


Enzymatic debridement

Proteolytic enzymes

Enhance granulation tissue formation and epithelialization

No large, high-quality, published randomized controlled trials comparing

the efficacy


Maggot therapy (biosurgery)

Lucilia sericata (green bottle fly) are the most commonly used maggots for

biosurgery

Secretion of proteolytic enzymes, digestion of necrotic tissue and bacteria,

increase in wound pH

Most efficacious in wounds infected with Gram-positive

bacteria, including MRSA


POSTOPERATIVE

CARE AND

WOUND CARE

ACUTE WOUNDS


Post-excision wounds healing by

primary intention

Simple low-or non-adherent gauze dressing secured with tape

Vaseline or Aquaphor ointment to make the patient more comfortable

Rarely require cleansing (care using saline )

1 week for sutured wounds to re-epithelialize

suture removal -- 4–6 days for the head and neck, 7 days for the upper

limbs, 10 days for the trunk and abdomen, and 14 days for the lower limbs


Liquid adhesive bandages

Minor lacerations and abrasions, partial-thickness wounds, shave

biopsies

Traumatic lacerations especially in pediatric patients

Nexcare (3M), Band-Aid brand (Johnson & Johnson Medical), and

New-Skin (Medtech, Inc, Irvington, NY)


Post-excision wounds healing by

secondary intention

“Shave” or tangential removal of skin

Randomized controlled trials -- white petrolatum is as safe and effective as

bacitracin with less risk for inducing allergy

Dressing -- left undisturbed for 48–72 h after surgery, to reduce incidental

trauma and contamination

Another alternative: occlusive dressings

• superficial wounds with minimal exudation -- films

• deeper wounds -- hydrogels or hydrocolloids

• highly exudative -- foams and alginates


Postoperative care in laser resurfacing


Postoperative care in laser resurfacing

Closed technique

Occlusive or semiocclusive dressing (such as Flexzan, Vigilon, 2nd Skin, N-

Terface)

More rapid epithelialization, less pain

Combination of the two approaches --

Closed technique being used for the first 48 h, then followed by the open

technique


Uncomplicated partial-thickness and

full-thickness wounds

Moisture-retentive occlusive dressings -- facilitate healing and relieve pain

Biologic and biosynthetic skin grafts and skin substitutes

STSGs, FTSGs

cultured epidermal autografts, AlloDerm, Integra, and Apligraf


POSTOPERATIVE

CARE AND

WOUND CARE

CHRONIC WOUNDS


Venous ulcers

The most common form of leg ulcers

Compression, edema reduction, and improvement of venous return

Bed rest

Leg elevation

• Elevate the affected leg 18 cm above the level of the heart, 2–4 h during the day and night

Compression devices

• occlusive arterial disease should be excluded

• recommended ankle pressure: 30–40 mmHg


Venous ulcers

Compression stockings

Difficult in elderly or arthritis patient

Compression bandages

Elastic bandages – the ACE type: reusable, but not self-adherent

• be applied in a spiral with 50% overlap between turns


Venous ulcers

Compression bandages

Unna boot –

• semirigid paste bandage, applied with foot at a 90° angle

• replaced weekly

• https://www.youtube.com/watch?v

=vrGjhDwd5Mo


https://www.youtube.com/watch?v=vrGjhDwd5Mo

Venous ulcers

Four-layer bandage –

• more flexible and absorbent than the Unna boot

• maintaining evenly distributed pressure

• long periods of time

• orthopedic wool layer, a crepe layer, an elastic layer applied in a figure-

of-eight pattern, and an elastic layer applied in a spiral pattern


Venous ulcers

Orthotic device –

• useful in patients who cannot tolerate other

compression modalities or who require

frequent dressing changes

Pneumatic compression –

• For patients unresponsive to conventional

compression bandages or stockings



Venous ulcers

Moisture-retentive dressings combined with compression therapy may produce more rapid healing rates initially

But long-term follow-up has failed to demonstrate any statistically significant advantage over compression therapy alone

Meshing of STSGs

Shave therapy (excision of ulcers with lipodermatosclerotic tissue) & meshed STSGs

FDA approved: Apligraf -- in combination with compression therapy, > 6 months


Arterial ulcers

Requires surgical re-establishment of an adequate vascular supply

Diabetes mellitus, cigarette smoking, hypertension, and hyperlipidemia

should be controlled

Moderate exercise may promote development of collateral circulation

Elevation of the head of the bed 10–15 cm improves gravity-dependent

arterial flow

Limbs should be kept warm

Good foot care


Diabetic foot ulcers

Good wound care –

• proper footwear, the correct antibiotics when needed, avoidance of weight bearing, pressure-relieving aids, debridement as necessary

• Aggressive revascularization

• Control of the serum glucose levels

Topical antibacterials

Saline-moistened gauze

Occlusive dressings such as hydrogels, hydrocolloids, and polymers

Dermagraft and Apligraf ; Bilayered Cellular Matrix


Pressure ulcers

Goal to enhances soft tissue viability and promotes healing of the pressure ulcers

Nutrition (espescially protein), immobility, comorbid disease, and protection from fecal or urine soiling

Debridement of devitalized tissue, wound cleansing, application of dressings

• Possible adjunctive therapy with electrical stimulation for stage III and IV unresponsive ulcers

• Alginates followed by hydrocolloid > hydrocolloid alone

• Foam dressings or wound fillers to eliminate dead space


OPTIMIZING OUTCOMES

Avoid leakage

Control pain

Prevent maceration: apply zinc oxide paste on the periwound area

Minimize odor: odor-absorbing dressings

Remove necrotic tissue

Ensure patient compliance

Check intrinsic factors

Keep wound moist, but not wet


PITFALLS AND THEIR MANAGEMENT

Infection: antibiotics, practice clean or aseptic techniques, irrigate under pressure, debride to remove necrotic tissue

Contact dermatitis

Seroma formation

Excessive pressure from dressing

Excessive granulation tissue: apply pressure, change dressing type, pare with curette, cauterize with silver nitrate

Pigmentary alteration

Milia or suture granuloma


PRACTICAL APPLICATIONS


SUMMARY

Extensive discussion of the different types of dressings currently available,

including their advantages, disadvantages, and indications

Reviews the technical aspects of applying some types of dressings as well

as specific dressings for venous ulcers and techniques for post laser

resurfacing care


“

”Thank You For Your Attention


Documents

Chapter 8 Wound Healing and Its Impact on Dressings and