Wound healing basics only

1. WOUND HEALING

2. Definition
• Wound is a discontinuity or break in the surface
epithelium with loss of function and integrity.

3. Wound v/s Ulcer
• Wound is a discontinuity
or break in the surface
epithelium.
• Ulcer is discontinuity of the
skin or mucous membrane
which occurs due to
microscopic death of the
tissue.

4. Classification
Surgical Wound Classification
Class I/Clean:
Class II/Clean-Contaminated: Gastrointestinal, respiratory or
Genitourinary tracts.

5. Class III/Contaminated: Bullet, knife blade or other pointy
infected objects or large amounts of
spillage from the GI tract into the
wound.
Class IV/Dirty-Infected Traumatic wounds from a dirty source
where the treatment was delayed, infected
surgical wounds or any wound that has
been exposed to pus or fecal matter.

6. Classification
Acute Wound
• No underlying pathology
Chronic Wound

7. Classification
Closed wound
• Contusion: Soft tissue
injury without break in
the skin.
• Abrasion: Epidermis is
scraped off exposing the
dermis.
• Hematoma: Collection
of blood following injury.
Open wound
• Incised: Sharp object
• Lacerated: Blunt object
• Penetration: Sharp object
• Crushed: Blunt object

9. Factors Affecting Wound Healing
Local Factors Systemic Factors
•Oxygenation
•Infection
•Foreign body
•Venous sufficiency
•Age and gender
•Sex hormones
•Stress
•Ischemia
•Diseases: diabetes, keloids, fibrosis,
hereditary healing disorders, jaundice,
uremia
•Obesity
•Medications: glucocorticoid steroids,
non-steroidal anti-inflammatory drugs,
chemotherapy
•Alcoholism and smoking
•Immunocompromised conditions: cancer,
radiation therapy, AIDS
•Nutrition

10. Oxygenation
• It prevents wounds from infection, induces angiogenesis, increases keratinocyte
differentiation, migration, and re-epithelialization, enhances fibroblast
proliferation and collagen synthesis, and promotes wound contraction.
• Superoxide production is a key factor for oxidative killing pathogens.
• Tissue oxygen tensions 30 to 50 mm hg normal, 5-20 mm hg in chronic wounds.
• Temporary hypoxia after injury triggers wound healing, but prolonged or chronic
hypoxia delays wound healing.
• Cytokines that are produced in response to hypoxia include PDGF, TGF-β, VEGF,
tumor necrosis factor-α (TNF-α), and endothelin-1, and are crucial promoters of
cell proliferation, migration and chemotaxis, and angiogenesis in wound healing.
1. Bishop, 2008; Rodriguez et al., 2008
2. Tandara and Mustoe, 2004

11. Infection
• Micro organism which are present over skin gain access to
underlying tissue.
• The presence of micro organism there is prolongation of
inflammatory phase of wound healing, due to cytokines.
• Prolonged inflammation causes increased level of matrix
metalloproteases (MMPs), a family of proteases that can
degrade the ECM.
• It cause growth factors that appears in chronic wounds to be
rapidly degraded.
• Edwards and Harding, 2004; Menke et al., 2007

12. Age
• Age causes delayed wound healing due to delayed T-cell
infiltration into the wound area with alterations in chemokine
production and reduced macrophage phagocytic capacity.
• Characteristic age-related changes, including enhanced platelet
aggregation, increased secretion of inflammatory mediators,
delayed infiltration of macrophages and lymphocytes,
impaired macrophage function, decreased secretion of growth
factors, delayed re-epithelialization, delayed angiogenesis and
collagen deposition, reduced collagen turnover and
remodeling, and decreased wound strength.

13. Age
• Estrogen can improve the age-related
impairment in healing in both men and
women, while androgens regulate cutaneous
wound healing negatively.
• Gosain and DiPietro, 2004
• Swift et al., 2001
• Gilliver et al., 2007

14. Hyperglycemia
• Inadequate bacterial clearance and delayed or
impaired repair in individuals with diabetes
due to disregulated cellular functions.
• Loots et al., 1998; Sibbald and Woo, 2008

15. Glucocorticoids
• Inhibit wound repair via global anti-inflammatory effects
and suppression of cellular wound responses, including
fibroblast proliferation and collagen synthesis.
• Systemic steroids cause wounds to heal with incomplete
granulation tissue and reduced wound contraction.
• Franz et al., 2007

16. Alcohol
• Short term alcohol exposure results in
suppressed pro inflammatory cytokines,
decreased neutrophil recruitment and phagocytic
function.
• Greiffenstein and Molina, 2008

17. Smoking
• Nicotine increases blood viscosity caused by decreasing
fibrinolytic activity and augmentation of platelet
adhesiveness.
• Carbon monoxide causes tissue hypoxia, decreases fraction
of oxygenated hemoglobin.
• In proliferative phase of wound healing, smoking decreases
fibroblast migration and proliferation, reduced wound
contraction, hindered epithelial regeneration, decreased
extracellular matrix production, and upset in the balance of
proteases
• Siana et al., 1989; Jensen et al., 1991; Ahn et al., 2008

18. Immunocompromised
• Cytotoxic drugs interfere with cell proliferation
and may cause neutropenia.
• Decreased CD 4 T cells, promotes wound
infection.

19. Nutrition
• Protein Aim for 1.0-1.5g/kg/day .Inadequate intake inhibits normal protein synthesis
and wound healing. The immune response is diminished and there is a delay in matrix
formation.
• Energy Aim for 30kcal/kg/day. An adequate energy intake is essential to prevent dietary
and tissue protein being used as a source of energy rather than for wound healing.
• Fluid Aim for 30-35ml/kg/day . Adequate fluids are required to prevent skin dehydration.
• Vitamin C Aim for 60mg per day. Vitamin C is required for collagen synthesis and aids iron
absorption.
• Vitamin A Promotes epithelialisation and granulation of healing wounds.
• Vitamin B Complex Co-factor for enzyme systems in protein, fat and carbohydrate
metabolism.
• Zinc Deficiency is associated with collagen synthesis, epithelialisation and cell
proliferation.
• Iron Anaemia will result in decreased transport of oxygen to damaged tissue and may
delay wound healing.
• Copper Is necessary for collagen formation and essential for red blood cells formation.

20. Mechanism of wound healing

24. Inflammatory phase

25. Proliferative phase
• Epithelial proliferation and migration over the
provisional matrix.
• In inflammatory phase, fibroblast and
endothelial cells are most prominent cells
which support capillary growth, collagen
formation, and the formation of granulation
tissue at the site of injury.

26. Remodeling phase
• Remodeling to the architecture that
approaches that of the normal tissue.
• Wound also undergoes physical contraction
which is mediated by myofibroblasts.

27. Assessment for wound healing
• Step 1: Does the wound need cleansing?
• Step 2 : Measure wound length, width, depth and undermining. (Do not
estimate)
Use a scale such as: - tracing, disposable ruler for length and/or
width wound swab stick, wound probe for depth and/or undermining
• Step 3: What tissue type and levels of exudate does the wound have?
Dressing choice must accommodate tissue type, exudate level,
odour, expected wear time, peri-wound skin, area to be dressed, pain at
dressing change and patients needs.
• Step 4: Document in wound chart.
A wound chart must be completed for every patient/client with
a wound.

30. Diagnosis of clinical infection
• Swabbing: Swab to be taken from deep
surface after cleaning the wound with sterile
water.

31. Healing By Primary Or Secondary
Intention
• Primary intention: The edges of the wound can
be brought together, eg a surgical wound. The
first three phases of healing are usually short but
scar maturation may take a few months.
• Secondary intention: The edges of a wound
cannot be approximated, e.g a leg ulcer. This type
of wound heals by proliferation and wound
contraction.
• Tertiary intention: Delayed primary closure

32. Moist
• Moist environment in chronic wound healing causes
enhancement of autolytic debridement and
reduction in pain during wear and on removal of
dressings.
• Excess moisture causes maceration of surrounding
skin.
• Ischemic wounds worsen
• Hollinworth, 2005

33. Wound Care
• Wound dressing: daily cleansing of exudate, slough, visible
contaminants.
• A Study comparing the effectiveness of antibacterial solutions to
tap water, normal sodium chloride 0.9% and distilled water have
found no difference in lowering bacterial count and no
increased incidents of infection.
• Antiseptic solutions have been reported to cause tissue damage
and hinder the healing process and are unlikely to be effective.
• One study found the infection rate lowest in wounds cleansed
with tap water.
• (Hellewell et al. 1997).
• (Dire & Welsh 1990; Rodeheaver et al. 1982)

34. Wound Care
• Wound bed dressing: exudate management
• Anti microbial dressing: for infected wounds
• Peri wound skin: Keep dry without exudate

35. Characteristics of the Ideal Wound
Dressing
• To maintain high humidity at the wound dressing
interface
• To remove excess exudate
• To allow gaseous exchange
• To provide thermal insulation
• To be impermeable to bacteria
• To be free of particles and toxic wound contaminants
• To allow removal without causing trauma to the
wound.
Turner 1982

36. Povidone Iodine
• Povidone Iodine: Acts as a sporicidal treatment for wide range of
bacterial, protozoal and fungal organisms in superficial wounds and skin loss
injuries.
Used as primary wound contact layer
Check wound daily
Dressing should be changed only when distinctive orange-brown colour
changes to white; this indicates that povidone-iodine has been used up.

37. Silver Dressings
• Silver dressing: Interference with bacterial electron
transport, binding to DNA of bacteria and their spores, so
impairing cell replication
Cell membrane interaction – structural and receptor
function damage.
Should be changed when saturated with exudate, but can
be left in situ for up to seven days.

38. Honey dressing
• Honey dressing: · Has osmotic properties, producing an
environment which promotes autolytic debridement.
Can help control wound mal-odour, antibacterial properties
through
• Low concentrations of hydrogen peroxide
• High sugar content/high osmolarity draws lymph fluid from
beneath the wounds surface.
• providing protease enzymes at the wound interface.
• Debrides slough, rehydrates necrosis.

39. Charcoal dressing
• Charcoal dressing: Activated charcoal dressing
used as both primary (not in dry wound) and secondary dressings,
Polyamide coating prevents adherence to wound.
Use as a secondary dressing in low exudate wounds to prevent
adherence to wound.

40. Hydrogel amorphous
• Hydrogel amorphous:
Constituents: Betaine – a surfactant to clean and remove
wound debris and biofilm
Polyhexanide (PHMB) – an antimicrobial agent
• Apply gel to all areas of wound bed. Apply secondary dressing
products as required.

41. Larval (Maggot) Therapy
• Maggot therapy is widely used for the management of infected or necrotic wounds.
• Benefits to patients
• Rapid wound debridement, Elimination of infection, Reduced healing times
• Prevention of amputation, Reduce some wound related pain, Eliminate unpleasant
odours
• Decrease number of hospital / clinic visits
• Prevent the need for hospital admission, Significant savings in treatment costs
• Reduced bed occupancy for the treatment of infected wounds , Decreased antibiotic
usage
a) Types of Wounds Suitable for Maggot Therapy
• Maggot therapy is suitable for most types of wounds which contain adherent slough
or necrotic tissue and also for wounds that are clinically infected and not
responding to antibiotic therapy
b) Maggot therapy is most useful when:
• A wound needs to be cleaned quickly, A wound is full of devitalised tissue, The
patient is not suitable for surgical debridement due to anaesthetic risk, but would
benefit from rapid wound cleansing.

42. Larval (Maggot) Therapy

43. BioFOAM® dressings
• BioFOAM® dressings consist of maggots that are enclosed in net
pouches. The dressings contain pieces of hydrophilic polyurethane
foam and this encourages activity in the LarvE® by providing a
favourable environment.
• Dressing has to be reassessed after 5 days.

44. Negative Pressure Wound Therapy
• Applies controlled, localized pressure to help draw wounds
closed. Helps remove interstitial fluid allowing tissue
decompression and enhanced blood flow. Promotes
granulation formation. Removes infectious material. Provides
a closed, moist wound healing environment.

45. • Platelet reach plasma
• Glutamin

46. Care Of The Surrounding Skin
• Dry skin which may break down and provide a portal
for infection
• Maceration caused by poor management of exudate
• Contact sensitivity to dressing.
The principles of good skin care depend on:
• Keeping the skin clean and dry