Advanced Wound Care

Pressure Ulcers Overview

Pressure ulcers are localized areas of tissue ischemia or skin breakdown. They are caused when soft tissue (the skin) is compressed between a bony prominence (like a hip) and an external surface (like a mattress) for a prolonged period of time. If left untreated, these ulcers progress through increasingly destructive stages, eventually producing necrosis or tissue death.

A staging system measures destruction by classifying wounds according to the tissue layers involved. To carefully evaluate the amount of tissue damage, other factors such as undermining, slough, eschar and sinus tract development, must be considered.

Definitions by the National Pressure Ulcer Advisory Panel (NPUAP):

Stage I An observable pressure related alteration of intact skin whose indicators as compared to the adjacent or opposite area on the body may include changes in one or more of the following: skin temperature (warmth or coolness), tissue consistency (firm or boggy feel) and/or sensation (pain, itching). The ulcer appears as a defined area of persistent redness in lightly pigmented skin, whereas in darker skin tones, the ulcer may appear with persistent red, blue or purple hues.
Stage II Partial loss of skin thickness involving epidermis and/or dermis. The ulcer is superficial and presents clinically (appears) as an abrasion, blister or shallow crater.
Stage III Full thickness skin loss involving damage or necrosis of subcutaneous tissue that may extend down to (but not through) the underlying fascia. The ulcer presents clinically as a deep crater with or without undermining adjacent tissue.
Stage IV Full thickness skin loss with extensive destruction; tissue necrosis; or damage to muscle, bone or supporting structures (e.g. tendon, joint capsule). Note: Undermining and sinus tracts may also be associated with Stage IV pressure ulcers.
A healing wound is in the process of reconstruction. The base of a healing Stage III or Stage IV wound is filled with granulation tissue, so as a Stage III pressure ulcer heals, it must be carefully observed and protected to prevent re-occurrence.

Primary Causes and Effects of Skin Breakdown

Pressure: Unrelieved pressure is the primary cause of pressure ulcers and skin breakdown.

The effects of excessive pressure on soft tissue depend on:
• the intensity of the pressure (how heavy the patient is, for example)
• how long pressure is applied
• how well the tissues tolerate pressure

A key variable is capillary closing pressure , the pressure at which small blood vessels close. This level of pressure can vary dramatically from patient to patient.

Shear is caused by tissue layers sliding against each other. This can cause disruption or angulation of blood vessels, usually at the fascia level.

Shearing forces account for the high incidence of sacral ulcers. When a patient's head is elevated, the skeletal frame slides toward the foot of the bed while the sacral skin adhere (by friction) to the bed linen. Sliding produces stretching and angulation of the arteries that supply the skin.

Friction is surface skin damage caused by skin rubbing against another surface. An example is sliding a patient up in bed. The skin rubbing against the sheet causes friction, and the resulting "burn" or abrasion exposes the skin to bacterial invasion and infection.

Treatment Planning and Intervention Recognizing and relieving pressure will help:

• prevent skin breakdown
• reduce the healing time of existing ulcers
• lower the cost of treatment
• reduce pain and discomfort to the patient

Pressure reducing devices. These devices offer an effective way to reduce interface pressure below what is encountered with a standard mattress. They cannot provide pressures consistently less than 25-32 mm/Hg, so they may have to be used with a turning schedule. Examples of such devices include:

• foam mattresses
• gel/water mattresses
• static air mattresses
• foam overlays

Pressure relief devices. These consistently reduce pressure below 25-32 mm/Hg. Examples include:

• low air-loss therapy beds
• alternating pressure mattresses
• dynamic mattress systems
• air fluidized therapy systems

Corrective Steps To reduce the effects of shearing, the plan of care should include the following specific nursing steps:

• do not elevate the head of the bed for prolonged periods
• use care in placing and removing bed pans
• use patient handling techniques and tools to reduce friction (such as heel protectors, an over-bed trapeze, transparent dressings, and a mattress with a low friction covering)

Methods to protect the skin from excessive moisture should also be included in the plan of care. Some helpful supplies include:

• skin cleansers
• moisturizers
• lubricating sprays and ointments
• ointment barriers
• skin sealants
• incontinence devices

Wound Care Healing occurs faster in wounds which are kept moist because epidermal cells can migrate only across a moist surface. In a dry wound, these cells are forced to tunnel down to a moist layer, then secrete collagenase to lift the scab away from the wound surface in order to migrate. Therefore, the goals of topical wound treatment include:

• provide adequate circulation/oxygenation to the wound
• remove necrotic (dead) tissue
• eliminate large amounts of exudate*
• eradicate clinical infection
• obliterate dead spaces or voids
• maintain a clean, moist wound surface

Information contained herein is intended to provide general information on basic aspects of Wound Management. This is not intended as a substitute for a detailed, individualized treatment and prevention protocol. Please consult a licensed, qualified caregiver as individual circumstances may vary. Information is subject to change without notice.

Devitalized (dead) tissue must be removed from a wound for effective healing to occur. This tissue can be removed three ways: surgically, mechanically or chemically.

Surgical debridement provides rapid, effective removal of necrotic tissue. Mechanical debridement can be accomplished with whirlpool treatments, wet-to-dry dressings and other means. Enzymatic agents which chemically break down necrotic tissue also can be used.