1. PHARMACOLOGY: WOUND DRESSINGS September 11, 2012
Renan B. Navarro, MD

2. DIFFERENT CLASSIFICATIONS
Primary / Secondary dressings Passive / Active / Interactive dressings Moisture-retentive (occlusive / semi-occlusive) Semirigid

3. 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

4. Primary & Secondary Dressings

5. (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

6. 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

7. 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

9. 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

10. MOISTURE-RETENTIVE DRESSINGS
(OCCLUSIVE / SEMI-OCCLUSIVE) 1. Hydrogel (occlusive / semi- occlusive) - Amorphous gel % water or glycerin based - non-adhesive - permeable to gas and water

11. 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

12. 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

13. 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

14. 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

15. 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

16. 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

17. 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 

18. 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

19. 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

20. Hydrocolloid wafer dressing (occlusive or semi-occlusive)
Advantages
Moisture retentive
Encourage autolytic debridement
Impermeable to urine, stool and bacteria
Provide thermal insulation
Waterproof

21. 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

22. Semipermeable foams (semi-occlusive)
-made of polyurethane foam *Hydrophilic inside & Hydrophobic outside

23. Semipermeable foams (semi-occlusive)
Common Uses
Moderate-maximum exudates
Burns
Skin Grafts
Donor Sites
Ostomy sites
Pressure ulcers
Venous insufficiency
Neuropathic ulcers

24. 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

25. 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

26. 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

27. 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

28. Calcium alginate (occlusive)
Common Uses
Absorbs mod. - highly exudating wounds
Venous insufficiency ulcers
Tunneling wounds
Swabs used to probe, fill and
measure wound depth

29. 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

30. Foam dressings (semi-occlusive)
absorbent dressings that may be adhesive or non- adhesive, 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

31. 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

32. Foam dressings (semi-occlusive)

33. 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, cost- effective, may be used as primary or secondary dressing.- 1. Standard Gauze (not impregnated) 2. Impregnated Gauze

34. Standard Gauze dressings
Standard Gauze (not impregnated)
sterile / non-sterile
woven (from yarn) / non-woven (synthetic)
maybe used as primary or secondary wound dressings

35. 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

36. 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

37. 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

38. 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

39. 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

40. 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 non-infected 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

41. Impregnated Gauze Dressings

42.  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.

43. Unna’s boot

44. 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

45. Total contact walking cast

46. 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

47. 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

48. Summary For dry / dessicated wound For minimal exudating wound
Wet to wet
Hydrogel
Continuous moist
Transparent film
For minimal exudating wound
Wet to dry
Hydrocolloid

49. For moderate to maximum exudating
Dry to dry
Calcium alginate, semipermeable foams
For highly exudating
Calcium alginate
Semipermeable dressing

50. THE END