Wounds & Dressings Flashcards
(18 cards)
What is the definition of a wound?
Any defect or damage in the skin caused by physical, chemical, thermal and disease factors.
Outline the 6 types of open wounds?
- Incisions
- Lacerations - Rough irregular wounds, caused by crushing or ripping forces
- Abrasions - Superficial wounds
- Puncture
- Penetration
- Avulsion - When the integrity of any tissue is compromised
Outline the 3 types of closed wounds.
Contusions (bruises): Caused by blunt force trauma, DMG tissues under skin
Hematoma: Caused by DMG to blood vessel, resulting in blood accumulating under the skin
Crushing injuries: Caused by blunt force, a pressure injury over a long period of time
Describe the acute and chronic wound repair process.
Acute Wound: Heal completely w/ minimal scarring, typically w/in 8-12 weeks
Chronic Wounds: Injury taking >12 weeks to heal, often recurring & heavily contaminated. Possilbe repeated trauma or underlying condition.
3 wound healing phases - 8
1) Inflammatory Phase
1. Bleeding occurs at site to remove toxic waste then activates vasoconstriction
2. Clotting Mechanism elicited by platelets, resulting in coagulation & fibrin network the formation
3. Inflammation causes vasodilation & phagocytosis - causing release of histamine & serotonin.
4. phagocytes enter wound, engulfing dead cells.
5. Platelets are liberated & form aggregates.
2) Proliferative Phase
6. Migrating cells provide continuous source of growth factors for stimulating capillary production & fibroplasia.
7. Fibroplasia results in formation of collagen bed to fill the defect
3) Remodelling Phase:
8. Collagen released to wound site & matures, with X-links forming, providing strength & stability to the collagen, helping the wound contract
What is the microvasculature typically like in normal tissue?
In normal tissue the microvasculature is stable & covered by pericytes with inactivated fibroblasts occupying the surrounding connective tissue.
Outline the microvasculature during wound healing - 3
- Fibroblasts or Pricytes activate & differentiate into myofibroblasts
- However, pericytes may migrate from vasculature & enter the wound bed.
- Signals & matrix from the wound microenvironment may cause pericytes to become more contractile & matrix depositing
Outline petroleum impregnated dressings - 3
- For clean, healthy wounds with minimal granulation bed or wounds with no need for debridement, granulation & contraction
- Best use at early stages of wound repair for shallow wounds
- Increases wound contraction but delays epithelialization
First- and second-degree burns,
Abrasions, grafts, venous ulcers, pressure ulcers,
Nail extractions, eczema, staples, surgical incisions,
Lacerations, reconstructive procedures and suture lines.
Outline hydrogel dressings. - 2
- Sheets for shallow wounds and gels for cavities.
- Both suitable for rehydration of hard eschar & necrotic wounds as they:
Donate moisture
Permits autolytic debridement
Increases collagenase activity in burns
Promotes granulation and epithelialization
Promotes contraction
Outline hydrocolloid wound dressings - 2
- Early to mid-repair phase of healing, can also reduce pain in wounds.
- Encourages also angiogenesis in acute wounds.
hydrocolloid wound dressings action - 6
Action:
1. Occlusive to semi-occlusive
2. Highly absorbent
3. Promotes moist wound healing
4. Promotes autolysis to debride wounds that are sloughy and necrotic.
5. Promotes granulation (may cause hyper granulation)
6. Adhesiveness may reduce contraction
Foam dressings & indications - 6
- A non-adherent dressing - can absorb large amounts of exudates
Indications
2. Inflammatory or repair phase of healing
3. Deep wounds with mild to moderate exudates
4. Decubital ulcers
5. Can be used at any stage of healing
6. Best used after granulation, to encourage epithelialization and contraction.
Alginate dressings - 7
- good gel-forming & film-forming properties & encourages wound healing.
- Best early repair phase of wound healing (after contamination & necrotic tissue removed).
- Best for moderate to highly exuding wounds.
- Highly absorptive, encourages epithelialization.
- Promotes autolytic debridement & granulation
(undergoes spontaneous & mild gelling in presence of divalent cations such as Ca). - Encourages clotting cascade in a bleeding wound.
- Indications: Burns, shearing/avulsion injuries & Cavity wounds
Film dressings - 4
- Important role as both primary and secondary dressings.
- comfortable & resistant to shear & tear.
- Prevent bacterial colonisation but do not absorb exudate.
- Vapour permeable - allows fluid to evaporate while keeping the wound moist
What are the pros & cons of using natural polymers in wound healing - 6
Adv: Biocompatibility, biodegradability & hydrophilicity
Dis: Batch to batch variability, large heterogeneity, prone to high biodegradability
Collagen in wound healing - 5
- Promotes healing via attachment & migration.
- Its high thrombogenicity has led to its application as a haemostatic agent.
- Causes blood clotting through a pathway similar to physiological haemostasis.
- Dry collagen physically adsorb blood cells & effectively adhere them to the wound site, providing mechanical strength.
- ‘Colgel’ (collagen powder): Effective in blood loss reduction in the patients undergoing cardiac operations.
Chitin in wound healing - 4
- Bioactive in slightly acidic media, depolymerises to release b-1-4-linked-D-glucosamine which initiates fibroblast proliferation & aids collagen deposition during the wound healing.
- has haemostatic properties.
- involved in rapid mobilization of platelet & RBCs to injured site
- helps in vasoconstriction & activates blood clotting factors, responsible for blood clotting.
In addition to aiding the healing process it is:
Biodegradable,
Biocompatible,
Non-toxic,
Bio-adhesive,
Bioactive,
Non-antigenic
Antimicrobial
What are the pros and cons of synthetic polymers - 3
Adv:
Overcome the shortcomings of the natural polymers.
Synthesized & modified in a controlled manner (constant and homogenous physical and chemical properties and stability).
Dis:
Biologically inert, so no therapeutic advantage as seen with natural polymers.
