1.1 Classification of wounds, principles of wound treatment Flashcards
What is a wound?
- disruption of normal anatomical relations intentionally (surgical wounds) or unintentionally (traumatic wounds)
- damage to the structure and function of epithelium and/or underlying tissues due to mechanical, chemical, thermal, electric current or radiation
Description of a wound
- type of wound and location
- thickness, stage of healing and size
- describe any undermining, tunneling or sinus tracts using clock system (12 o’clock is always the patient’s head)
- undermining: tissue destruction underlying intact skin along wound margins
- tunnelling: pathway that can extend in any direction, resulting in dead space
- sinus tract: a drainage pathway from a deep focus of acute infection through tissue and/or bone to an opening on the surface - odor and exudate
- types of tissue present in the wound bed
- wound edges: definition, attachment, character (epibolic, macerated, fibrotic, callused)
- surrounding tissue (color, edema, pallor, lesions)
- pain
- interventions for healing and factors that would affect healing (ie. diabetes)
- current topical treatments
Wound classification by depth of penetration
- superficial: epidermis only
- partial thickness: reaches the dermis
- full thickness: reaches subcutaneous adipose tissue
- deep wound: penetrates subcutaneous adipose tissue and beyond
Wound classification by severity
- simple: involves skin and subcutaneous tissues
- complicated: injuries to vessels, nerves, organs
- special: diabetic foot, decubitus, chronic ulcers
Wound classification by contamination
- sterile: wound made under sterile conditions, likely to heal w/o complications
- contaminated: result of accidental injury, there are pathogenic organisms and foreign bodies in the wound
- colonized: chronic wound, number of organisms present, very difficult to heal
- infected: pathogenic organisms present and multiplying showing clinical signs of infection (yellow, oozing pus with pain and redness)
Wound classification by time
Acute
- an injury to the skin that occurs suddenly rather than over time
- it heals at a predictable and expected rate according to the normal wound healing process
Chronic
- a non-healing wound that persist
- example: diabetic foot in which there is a loss of sensation because of neuropathy and decreased vascularity leading to foot ulcers that cannot heal properly (high risk of infection)
What are the mechanical open wounds?
- incisions: caused by clean, sharp-edged object (surgical)
- lacerations: caused by blunt trauma, may appear linear
- abrasions/grazes: epidermis is scraped off, caused by a sliding fall on rough surface
- avulsions: a body structure is forcibly detached from its insertion – a type of amputation where the extremity is pulled off
- punture wounds: caused by an object puncturing the skin
- penetration wounds: caused by an object, such as a knife, entering and coming out from the skin
- gunshot wound: caused by a bullet driving into or through the body (“through and through” wounds have an entry and exit wound)
- animal bites: partially closed wounds with a mixture of microbial organisms
What are the mechanical closed wounds?
closed wounds: skin is intact and the underlying tissue is not directly exposed to the external environment
- contrusions: common in sports injuries; caused by direct blunt trauma on small blood vessels, muscle and underlying tissue; presents as painful bruises
- crush injuries: caused by external high pressure force that squeezes part of the body b/w two surfaces
- hematomas: collection of blood in a limited space due to damaged small vessels; presents as painful, spongy, rubbery lump-like lesion
What are the non-mechanical wounds?
Thermic injury/burn wounds
- a burn is a type of injury to the flesh or skin caused by heat, chemicals, electricity, friction, or radiation
- classification by degree:
- 1st degree: hyperemia only
- 2nd degree: blistering and damage to the epidermis
- 3rd degree: damage to all skin layers, blackened areas
What is wound healing and its phases?
- wound healing is the process of the body trying to achieve anatomical integrity of the injured tissue to restore full function – it involves epithelial regeneration and formation of CT scar
- phases: hemostasis/coagulation; inflammation; migration/proliferation; and remodeling
What happens in the hemostasis/coagulation phase of wound healing?
- injury leads to transient neurogenic vasoconstriction and vasoactive substances are released (ie. serotonin)
- this leads to permanent vasodilation and then the release of clotting factors, platelets and fibrin for the formation of a blood clot
What happens during the inflammatory phase of wound healing?
- removal of initial clot, necrotic tissue and any bacteria present in the wound cavity but in case of large number of bacteria, a clinical infection will occur
- PMNs, platelets and macrophages are the main players: macrophages produce TGF-β which stimulates IL-1 and fibroblast proliferation –> IL-1 induces fever, promotes homeostasis and activates T-cells
- active matrix metalloproteinase (MMP) enzymes work together with the leukocytes to degrade matrix proteins in necrotic tissue, remonving the tiessue that is no longer viable
- this phase lasts 4-6 days, leaving the wound edematous and erythematous
What happens during the proliferative phase of wound healing?
- angiogenesis: from pre-existing vessels and the mobilization of endothelial precursor cells – mediated by VEGF and FGF-2
- granulation tissue: fibroblasts lay down collagen mesh and reticular cells will synthesize elastic fibers, forming granulation tissue (provides foundation for re-epithelialization
- re-epithelialization: keratinocytes migrate across wound margins to cover the granulation tissue and reform epithelial layer
- ECM deposition: scar formation; fibroblasts migrate to synthesize collagen and granulation tissue accumulates CT matrix to eventually form a scar
What happens during the remodeling phase of wound healing?
- inflammatory cells and fibroblasts disappear so the vascularity and cellularity decreases
- myofibroblasts contract the wound and give tensile strength
- collagen is cross-linked and the wound scar gradually flattens and becomes less prominent and pale
- destroyed tissue is replaced with scar tissue
Describe wound healing by primary intention
- complete healing without infection with restoration of anatomical structures and functions
- usually seen in acute wounds. when wounds are closed with sutures, staples, adhesives
- wound edges can be approximated
- shot wounds, bite wounds and deep puncture wounds are never healed by primary intention
