PHARMACOLOGY:
WOUND DRESSINGS
September 11, 2012
Renan B. Navarro, MD
DIFFERENT CLASSIFICATIONS
Primary / Secondary dressings
Passive / Active / Interactive dressings
Moisture-retentive (occlusive / semi-occlusive)
Semirigid
DIFFERENT CLASSIFICATIONS
(Primary / Secondary)
Primary dressing
-also called contact layer
-comes into direct contact with the wound
- Ex. Band aid
Secondary Dressing
-is placed over a primary dressing to provide
increased protection
- Ex. Self-adhesive elastic Bandage
Primary & Secondary Dressings
(Passive / Active / Interactive Dressings)
Passive dressing- for protection, as
protective dressing
Active dressing- promotes healing
through the creation of a moist wound
environment
Interactive dressing - not only creates a
moist wound environment but interacts
with the wound bed components to
further enhance wound healing
Interactive Dressing
Enhanced wound healing due to:
• reduce colonization count
• reduce the level of exudates
• improves wound bed moisture retention
• improves wound collagen matrix
• removes cellular products
• provides protection for the epithelial bed
Interactive anti-microbial dressings
- contain broad spectrum antimicrobials
• silver dressings – silver is an antimicrobial
• dressings with Polyhexamethylene Biguanide (PHMB)
- antimicrobial that destroys pathogens (non-irritating to skin)
• dressings with Cademoxer iodine
- destroy pathogens while absorbing excess exudates preventing wound
infection
• bacteriostatic foam dressings – inhibit bacteria
• honey-based dressing
WHY MOIST WOUND HEALING?
•
• moist wounds heal faster than dry wounds
• prevent scab or crust formation over the wound
bed, it eliminates the energy and time for the
body to break this down;
• reduce travel time for keratinocytes as they
easily migrate across the moist wound bed
• traps enzymes at the wound bed facilitating
autolytic debridement
• preserves growth factors and promotes
collagen synthesis
MOISTURE-RETENTIVE DRESSINGS
(OCCLUSIVE / SEMI-OCCLUSIVE)
1. Hydrogel (occlusive / semi- occlusive)
- Amorphous gel.
- 80-90% water or glycerin based
- non-adhesive
- permeable to gas and water
1. Hydrogel (occlusive / semi- occlusive)
Common Uses
• Min-mod. exudating wounds
• Use to soften eschar and provide moist
environment to dry wounds
• Wounds with 50% granulation
• Padding for splints and total casts
1. Hydrogel (occlusive / semi- occlusive)
Advantages
• Moisture retentive
• Encourage autolytic debridement
• Reduce pressure
• Non- or minimally adherent
Disadvantages
• May dehydrate
• Require secondary dressing
• Not used on infected wounds
2. Transparent films (occlusive or semi-occlusive)
• Hydrates dry wounds as well but is nonselective.
• Allows air but not fluids.
• waterproof sheet made of clear polyurethane, adhesive
coating on one side, highly elastic and conformable to
body contours
• transparency allows visualization of wound bed,
• semi-permeable films - permeable to water vapor gases
like oxygen and carbon dioxide, impermeable to bacteria
and water
• for minor burns and scalds, simple wounds, partial
thickness wounds, donor sites,
• <50% granulation
2. Transparent films (occlusive or semi-occlusive)
Common Uses
• Superficial wounds
• Donor graft sites
• Over intravenous catheters to allow
bathing/whirlpool
• Over wounds for ultrasound
treatment
2. Transparent films (occlusive or semi-occlusive)
Advantages
• Moisture retentive
• Encourage autolytic debridement
• Reduce friction
• Allow visualization of wound bed
• Waterproof
• Cheaper
Disadvantages
• May traumatize periwound upon removal
• Difficult to apply especially on larger areas
• Not used on infected wounds
Hydrocolloid wafer dressing
(occlusive or semi-occlusive)
• consisting of a combination of gel forming polymers
that absorb exudates slowly
• provide thermal insulation and are impermeable to
water and bacteria
• conforms to body shape
• available in paste, granules, and powder for cavities
• used for partial and full thickness wounds
Hydrocolloid wafer dressing
(occlusive or semi-occlusive)
• for pressure ulcers, burns donor sites and
venous insufficiency ulcers, and small cavity
wounds (paste, powder or granules are used)
• absorb fluid slowly so they are not suitable for
bleeding wounds or heavily draining wounds
• should not be used in dry wounds, wounds
with minimal drainage, or on wounds with
exposed tendons and fascia
Hydrocolloid wafer dressing
(occlusive or semi-occlusive)
• because of the occlusive nature, hydrocolloids
are used only on patients with good skin
integrity
• contain hydrophilic colloidal particles
• Absorb exudate slowly by swelling into a gel
like mass
Hydrocolloid wafer dressing
(occlusive or semi-occlusive)
Common Uses
• Min-moderate exudates
• Granular and necrotic wounds
• Minor burns
• Pressure ulcers
• Venous insufficiency
• Periwound to attach adhesive
tape in the case of large wounds
Hydrocolloid wafer dressing
(occlusive or semi-occlusive)
Advantages
• Moisture retentive
• Encourage autolytic debridement
• Impermeable to urine, stool and bacteria
• Provide thermal insulation
• Waterproof
Hydrocolloid wafer dressing
(occlusive or semi-occlusive)
Disadvantages
• May traumatize fragile periwound upon
removal
• Leave residue within wound bed
• May cause hypergranulation
• May roll in areas of friction
• Not uses on infected wounds
Semipermeable foams (semi-occlusive)
-made of polyurethane foam
*Hydrophilic inside & Hydrophobic outside
Semipermeable foams (semi-occlusive)
Common Uses
•
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Moderate-maximum exudates
Burns
Skin Grafts
Donor Sites
Ostomy sites
Pressure ulcers
Venous insufficiency
Neuropathic ulcers
Semipermeable foams (semi-occlusive)
Advantages
• Moisture retentive
• Encourage autolytic debridement
• Thermal insulation
• Provide cushioning
Disadvantages
• May traumatize periwound upon removal
• May roll in areas of friction
• Not used on infected wounds unless changed
daily
Calcium alginate (occlusive)
• From brown sea weeds converted into
calcium/sodium salts
• are made from natural polysaccharide fibers
derived from processed seaweed
• highly absorbent and conforms to any shape
• because they have no adhesive properties,
secondary dressings must be used
• available in many forms and shapes and capable
of absorbing a large amount of exudate
• when the dressing comes into contact with the
wound exudate, alginate forms a gel-like
substance
Calcium alginate (occlusive)
• since it does not adhere to the wound site, pain
and trauma in changing dressings are much less
• the gel is easily removed from the wound site by
irrigation
• ideal for moderate to heavy draining wounds, for
venous insufficiency ulcers, pressure ulcers,
diabetic ulcers, surgical wounds, donor sites, and
first and second degree burns
Calcium alginate (occlusive)
• ideal primary dressings for infected wounds
• can be used for granular and slough covered
wounds
• unsuitable for dry and minimally draining
wounds.
• unsuitable for full thickness third degree burns
• should not be used for wounds with exposed
tendons or bones
Calcium alginate (occlusive)
Common Uses
• Absorbs mod. - highly exudating wounds
• Venous insufficiency ulcers
• Tunneling wounds
• Swabs used to probe, fill and
measure wound depth
Calcium alginate (occlusive)
Advantages
• Encourage autolytic debridement
• Highly absorbent
• Used on infected and uninfected wounds
• Biocompatible
Disadvantages
• Require secondary dressing
• Used with extreme caution with exposed
tendon, capsule, bone to prevent desiccation
Foam dressings (semi-occlusive)
• absorbent dressings that may be adhesive or nonadhesive, and may be used as primary or
secondary dressing
• formed from polymers such as polyurethane
• are able to trap moisture and permeable to gas
• absorb exudate and promote gaseous exchange
and thermal insulation
Foam dressings (semi-occlusive)
• maybe removed without adding trauma to frail
skin
• conforms to the shape
• for granulating or sloughed-covered partial and
full-thickness with minimal to heavy exudates,
minor burns, post-op sites, diabetic ulcers, and
venous insufficiency ulcers, used under
compression bandaging for amorphous hydrogels
and alginates
• for infected wounds, foams should be changed
daily
Foam dressings (semi-occlusive)
GAUZE DRESSINGS
(non-occlusive dressings allow all the moisture
to escape from the surface of the wound
leading to drying of the wound.)
The most readily available dressing, costeffective, may be used as primary or
secondary dressing.1. Standard Gauze (not impregnated)
2. Impregnated Gauze
Standard Gauze dressings
Standard Gauze (not impregnated)
• sterile / non-sterile
• woven (from yarn) / non-woven (synthetic)
• maybe used as primary or secondary wound
dressings
Standard Gauze dressings
Common Uses
• Wound which requires frequent change = 6 hrs
• For wounds with <50% granulation
• Infected & non-infected wounds
• Highly exudating wounds
• Provide cushioning
Standard Gauze dressings
Limitations
• Costly
• May adhere to wound bed
• Highly permeable
• Higher infection rate than occlusive dressings
• Readily available
• Wet to dry – Min. exud. wounds
• Continuous dry – Mod.&max. exud.
• Continuous moist – Dry wounds
Impregnated Gauze Dressings
• woven or non-woven materials
• substances such as iodinated agents,
petrolatum, chlorhexadine gluconate (CHG),
bismuth tribromophenate (BTP), water,
aqueous saline, or other agents have been
incorporated into the dressing material by the
manufacturer.
• when left at the wound to dry they are called
wet to dry dressings - sometimes used for
mechanical debridement--not universally
done
Impregnated Gauze Dressings
• a moist dressing maybe allowed to adhere to
the necrotic tissue as it dries out to allow
debridement; drawbacks:
1. non-selective because granulation tissue may
also be removed with the necrotic tissue
2. fibers of the gauze may remain on the wound
causing infection
3. the gauze dries out on the wound causing a
painful change of dressing
Impregnated Gauze Dressings
• Gauze is impregnated with solution that
promotes healing such as antiseptic, hydrogel or
hypertonic saline solution. This requires a
secondary dressing.
• Hypertonic solutions are infused with sodium
chloride that reeks moisture away from wounds
- dependent on wound moisture to moisten and thus, not
appropriate for dry to minimally draining wounds or dry
wounds covered with eschar
Impregnated Gauze Dressings
Impregnated gauze dressings- maybe as a
contact layer for granulating wounds, helps
exposed tendons from dehydrating
– ideal for burns, and wounds infected or noninfected of any size and shape
– if used for non- draining or minimally draining
wounds, a topical agent should be applied to the
wound bed to maintain a moist environment or
the gauze may be moistened with normal saline
– for heavily draining wounds would need additional
layers should be used to aid in absorption
Impregnated Gauze Dressings
SEMIRIGID DRESSINGS
(for wounds in legs of ambulatory people)
1. Unna’s boot- for leg wounds (ulcers, sores, edema)
-compression gauze containing zinc oxide paste and
other substances
- pliable nonstretchable dressing impregnated with
ointments
Ex. Zinc oxide, calamine and gelatin
-inexpensive means of covering the wounds
-provides compression and supports the calf pump to
empty venous blood from the lower ext.
Unna’s boot
2. Total contact walking cast
• A fiberglass shell with a bar on the bottom
• Used to treat ulcers (serious, deep sores) on a
person's foot.
• Protects the skin on the person's foot.
• has only a small amount of padding around
the rest of the foot
• Assist edema control
• Allows weight bearing
Total contact
walking cast
3. Posterior walking splint
• for patients with fragile skin
• a total contact cast that is
bivalved to allow it to be
removed for frequent monitoring
of skin and wound
4. Profore
• Four layer compression bandage system used for
venous leg ulcers
• consist of a cotton , crepe and 2 compression layers
• Can be left in place for up to a week
Summary
• For dry / dessicated wound
– Wet to wet
– Hydrogel
– Continuous moist
– Transparent film
• For minimal exudating wound
– Wet to dry
– Hydrocolloid
– Transparent film
• For moderate to maximum exudating
– Dry to dry
– Calcium alginate, semipermeable foams
• For highly exudating
– Calcium alginate
– Semipermeable dressing
THE END