A WOUND IS A DISRUPTION OF NORMAL ANATOMIC STRUCTURE

AND FUNCTION

Wounds can be classified in many ways, by acute or chronic, by cause (e.g., pressure,

trauma, venous leg ulcer, diabetic foot ulcer), by the depth of tissue involvement, or other characteristics such as closure (primary or

secondary intention)

Wound depth is classified by the initial level of tissue destruction evident in the wound:

superficial, partial-thickness, or full-thickness

Descriptions of wounds must includethe nature of the wound, ie whether it is a bruise, abrasion or laceration etc

the wound dimensions, eg length, width, depth etc. It is helpful to take a photograph of the wound with an indication of dimension (eg a tape measure placed next to the wound), and for measurements to be taken of the wound as it appears first, and then with wound edges drawn together (if it is a laceration etc)

the position of the wound in relation to fixed anatomical landmarks, eg distance from the midline, below the clavicle etc

the height of the wound from the heel (ie ground level) - this is particularly important in cases where pedestrians have been struck by motor vehicles

THE MAIN TYPES OF WOUNDS

abrasions bruises/ contusions

lacerations incised wounds

punches kicks

bite marks defence injuries

ACUTE WOUNDS

When a surgeon makes an incision or the skin is otherwise cut, an acute wound is created. By definition, an acute wound is acquired as a result of trauma or an operative procedure and proceeds normally in a timely fashion along the healing

pathway with at least external manifestations of healing apparent in the early postoperative period without

complications. Acute wounds are usually successfully managed with local wound care. Surgically created wounds

include all incisions, excisions, and wounds that were surgically debrided. Nonsurgical wounds include all skin

lesions that occurred as a result of trauma (e.g., burns, falls), as a result of an underlying condition (e.g., leg ulcers), or as a

combination of both

CHRONIC WOUNDS

Wounds that fail to heal in the anticipated time frame and often reoccur are considered chronic wounds. These wounds

are visible evidence of an underlying condition such as extended pressure on the tissues, poor circulation, or even

poor nutrition. Pressure ulcers, venous leg ulcers, and diabetic foot ulcers are examples of chronic wounds. Successful management of chronic wounds demands

treatment of the whole person, meticulous local wound care, an understanding of the wound healing process, a working knowledge of modern wound dressings, and correction and

management of the patient’s underlying condition

LEG ULCER - ARTERIAL

LEG ULCERS - MIXED AETIOLOGY

CLEAN WOUNDSAn uninfected operative wound in which no inflammation is encountered and the respiratory, alimentary, genital, or

uninfected urinary tracts are not entered. In addition, clean wounds are primarily closed and, if necessary, drained with closed drainage. Operative incisional wounds that

follow nonpenetrating (blunt) trauma should be included in this category if they meet the criteria

CLEAN WOUND

CLEAN-CONTAMINATED WOUNDS

Operative wounds in which the respiratory, alimentary, genital, or urinary tracts are entered under controlled

conditions and without unusual contamination. Specifically, operations involving the biliary tract, appendix, vagina, and

oropharynx are included in this category provided no evidence of infection or major break in technique is encountered

CONTAMINATED WOUNDSIncludes open, fresh, accidental wounds. In addition, operations

with major breaks in sterile technique (e.g., open cardiac massage) or gross spillage from the gastrointestinal tract, and

incisions in which acute, nonpurulent inflammation is encountered are included in this category

DIRTY OR INFECTED WOUNDS Includes old traumatic wounds with retained or devitalized tissue and those that involve existing clinical infection or perforated viscera. This definition suggests that the organisms causing postoperative infection

were present in the operative field before the operation

INFECTED WOUND

INFECTED WOUNDS

FOR THE PURPOSES OF DRESSING SELECTION, WOUNDS MAY BE

CLASSIFIED

Black and necrotic - covered with a hard dry layer of dead skin

Sloughy/necrotic - covered or filled with a soft yellow slough

Clean and granulating with significant amount of tissue loss

Epithelialising

BLACK NECROTIC WOUNDDead dehydrated tissue, easily recognisable by a black or brownish

appearance. Necrotic areas may completely cover a wound, forming a dry eschar or, alternatively, may present as small patches in the base or

margins of a wound bed

SLOUGHY WOUNDSlough is the formation of a viscous, predominantly yellow layer of

tissue

GRANULATING WOUNDGranular appearance, glossy red and bleeds easily

EPITHELIALISING WOUND

CAVITY WOUNDA cavity wound can be acute or chronic, eg a dehisced surgical wound or a

pressure ulcer. They may be present with a wound bed of differing tissue type ie clean, infected, sloughy, granulating, or a combination. The tissue type and amount

of exudate will affect treatment

The terms superficial, partial-thickness, and full-thickness refer to wound depth

The deeper a wound, the more tissue that needs to be replaced or repaired and

the longer it will take to heal

SUPERFICIAL WOUNDS

When a wound is superficial, as is the case in most abrasions and blisters, only the epidermis is affected and

has to be replaced. A truly superficial wound does not bleed and heals within a few days

PARTIAL-THICKNESS WOUNDS

A partial-thickness wound does bleed, because the epidermis and part of the dermis are no longer present or have been

affected. If left uncovered, a blood clot will cover the wound and a scab will form. The missing tissue will then be replaced, followed by regeneration of the epidermis. A partial-thickness

wound can take from several days to several weeks to heal, depending on the patient and the wound treatments chosen

FULL-THICKNESS WOUNDS

A full-thickness wound involves the epidermis and the dermis. The underlying fatty tissue, bones, muscles, or tendons may

also be damaged. If full-thickness wounds cannot be sutured, the healing process will create new tissue to fill the wound,

followed by regeneration of the epidermis. The full-thickness wound takes substantially longer to heal than does a partial-

thickness wound, sometimes as long as several months

.

HAIR FOLLICLES GROW MORE THAN HAIR

One of the most important differences between partial-thickness and deep, full-thickness wounds is that in partial-thickness

wounds not all hair follicles have been destroyed. Because hair follicles are surrounded by epidermal cells, small islands of

epidermis remain in the wound bed of partial-thickness wounds. Thus, even though the epidermis may have been destroyed, the

"islands" of epidermal cells in the wound bed will help the wound replace the epidermis more quickly than in a full-

thickness wound, where the epidermal cells have to migrate in from the edges of the wound

Wound assessment should include an evaluation of the skin surrounding the wound. Whether acute or chronic, sutured or not

sutured, the condition of the periwound skin provides vital information relating to the status of the wound. When the periwound

skin is red, it may be the result of prolonged pressure; it may indicate ongoing or chronic inflammation or irritation from contact with feces or urine; or it may merely be evidence of increased blood

supply to the area as part of the early healing process. Redness, tenderness, warmth, and swelling of the surrounding skin are also the classic clinical signs of an infection. If the surrounding skin is

light colored but pink, it may be newly formed epithelium. However, if the skin is white or gray, it is likely that maceration has

occurred. In addition to looking for signs of maceration, inflammation, and infection in leg ulcers, look at the surrounding

skin for information about the etiology of the wound itself

WOUND BEDTo evaluate the condition of the wound bed, assess for:

Necrotic tissue (usually black and hard, sometimes soft with a tinge of yellow) Fibrinous tissue or slough (yellowish and threadlike denatured proteins that cannot be removed when rinsing) Granulation tissue (red, beefy tissue that may bleed easily)

Note whether or not there is any debris or other foreign materials (e.g., suture remnants) and quantify your findings

Other wound characteristics that should be assessed include the odor of the wound and the amount, and color and consistency of exudate

WOUND HEALING

The process of wound healing involves three overlapping phases:

Inflammation – involves scab formation and infiltration of

damaged tissue by white blood cells. These are responsible for removing dead tissue and ingesting bacteria

Proliferation – involves development of granulation tissue, contraction of the wound and growth of epithelial cells under the

dried scab Maturation – wound becomes less vascular and is strengthened by

the rearrangement of collagen fibres.

FACTORS AFFECTING WOUND HEALINGAge

The physiological changes that occur with ageing place the older patient at higher risk of poor wound healing. Reduced skin elasticity and collagen replacement influence healing. The immune system also declines with age making older patients more susceptible to infection. Older people can also present with other chronic diseases, which affect their circulation and oxygenation to the wound bed

DehydrationThis leads to an electrolyte imbalance and impaired cellular

function. It is a particular problem in patients with burns and fistulae

Hand WashingEffective hand washing greatly reduces the risk of transferring

pathogenic organisms from one patient to another by direct contact or by contamination of inanimate objects that are shared

InfectionInfection has been defined as the deposition and multiplication of organisms in tissue with an associated host reaction. If the host reaction is small or negligible then the organism is described as colonising the wound rather than infecting it. It is important to distinguish between colonisation and infection since colonised

wounds will heal without the need for antibiotics

PREVENT/CONTROL INFECTION

All wounds are contaminated with a variety of microorganisms; however, most chronic wounds do not become infected. When

pathogenic microorganisms invade the tissues, at least one or two of these classic symptoms of infection can be observed: erythema,

warmth, swelling, and/or odor, purulent exudate, and fever

When an infection is suspected, the wound should be cultured. Currently, researchers have not decided which culture method is most likely to lead to identifying the infection-causing organism. Some favor obtaining a biopsy, others suggest that wound fluid

aspiration is the method of choice, and a third group maintains that swab cultures are reliable

In most instances, a course of systemic antibiotics, based on the results of the culture, will result in elimination of the infection. Attaining sufficiently high concentrations of medication in the

tissues that have been invaded by the pathogenic microorganism may not be possible when using topical antibiotic ointments only

Why some wounds become infected when others do not depends on a variety of factors including: the type of wound, the type of organism involved, the wound environment, and the patient's

general medical condition and immunological status. For example, acute wounds are more susceptible to infection than chronic wounds.

In addition to debridement, adhering to the basic principles of infection control and reducing further wound contamination will

help minimize the risk of infection

Finally, providing a wound environment that prevents desiccation (which results in the formation of nonviable tissues), and retains the

body's natural defense mechanisms (i.e., white blood cells and macrophages), has also been shown to reduce the rate of wound

infections

OPTIMIZE EXUDATE CONTROL; REMOVE NECROTIC TISSUE OR FOREIGN BODIES

A wound that contains dead tissue or foreign matter is more likely to become infected than one that does not. Bacteria thrive in the

presence of dead tissue. It is postulated that once bacteria have colonized dead or foreign materials, they are less susceptible to host

defense mechanisms and antibiotic therapy. Thus, in order to prevent infection, dead tissue or foreign matter must be removed

Loose particles and nonadherent fibrinous materials can often be removed through cleansing. The recommended maximum amount of pressure to cleanse wounds is 5-15 pound per square inch, which can

be delivered using a 18-20 gauges angiocath and a 30-35 mL syringe. Is it important to differentiate between solutions designed

as skin cleansers and wound cleansers and to select only those cleansing agents specifically designed for use in wounds.

Antiseptics as well as many cleansing agents (e.g., povidone iodine, chlorhexidine, etc.) have been found to be toxic to skin cells in

commonly used concentrations

Dry, necrotic tissue cannot usually be removed by cleansing alone. When necrotic tissue is present, it has to be debrided. There are four basic methods for debriding wounds. Each method of debridement

has its own specific advantages and disadvantages

METHODS OF DEBRIDEMENT

Mechanical Wet or moist dressings applied and removed when dry Direct scrubbing action with a brush, a sponge, or woven gauze Pulsatile lavage Whirlpool Slow and painful Nonselective (removes healthy tissue as well)

Surgical Using a scalpel, scissors, or forceps to remove dead tissue Quick, effective, and selective if performed by a qualified and skilled professionalMay result in blood loss

Enzymatic Enzymatic debriding agent applied under a dressing Easy to perform Selective Prescription required Some agents may need moisture to work; some may damage surrounding skin Discontinue when dead tissue has been dissolved

Autolytic Moisture retentive dressing is applied, retaining endogenous enzymes Selective Easy to perform Painless Does not harm healthy tissue

PREVENT PREMATURE WOUND CLOSURE

Prevention of premature wound closure is particularly important when caring for dehisced surgical wounds or wounds with sinus tracts and undermining. The healing process should be closely

monitored to ensure the wound is healing "from the bottom up." Lightly packing the wound with a dressing that will retain moisture

helps prevent premature wound closure

PROMOTE GRANULATION AND CONTRACTION

Granulation tissue, a red, beefy-looking tissue that replaces the lost dermis, consists of new blood vessels and fibroblasts to make

collagen. Cells can neither live, nor replicate in a dry environment; thus, granulation tissue formation is facilitated when the wound is kept moist. In addition, some dressings have been shown to retain

growth factors that stimulate fibroblasts

PROMOTE RE-EPITHELIALIZATION

Re-epithelialization, the process by which epidermal cells proliferate and migrate across the wound bed, is also facilitated in the presence of moisture. In the presence of eschar, epidermal cells must travel down and under the eschar before they can migrate across moist

dermal tissues, lengthening the time required for re-epithelialization. Wounds covered with moisture retentive dressings re-epithelialize faster than wounds covered with gauze-type dressings or wounds

that are left exposed to the air