Pressure Sores, Pressure Ulcers or Decubitus Ulcers


Spinal Cord Injury Pressure Sores

Pressure sores must be taken seriously, if left unchecked a pressure sore can lead to amputation or in the worst case scenario, death. Even when well cared for a pressure sore can still become infected such as was the case with Christopher Reeve in October 2004. Christopher had the best care and was looked after by dedicated staff at Northern Westchester Hospital but still his sore became severely infected, resulting in a serious systemic infection. This in turn led to a heart attack and coma from which he did not recover. Check yourself for red marks and sores daily, it should be a routine which is as second nature as brushing your teeth.

Causes of Pressure Sores

A pressure sore, also known as a bed sore is an injury to the skin and the tissue under it. A pressure sore develops when the blood supplying the tissue with oxygen and nutrients is unable to circulate, and the tissue no longer receiving oxygen and nutrients dies. The oxygen and nutrients are essential to maintain healthy tissue. Sitting in the same position for a prolonged period of time can start the process of tissue breakdown by excessively loading the skin and underlying tissue. Friction and shearing forces applied to the skin and increased moisture on the skin surface can also increase the incidence of pressure sore development.

Shear stress occurs when a force is applied in the plane of the skin surface. Friction occurs when there is displacement between the skin and the supporting surface. For example, a patient with spinal cord injury who tilts up in bed from a supine position induces shear stresses in the sacral region over the bone. When there is slip between the skin and the bed, friction is induced. A similar situation can occur during a transfer from the bed to a wheelchair where the individual slides from one surface to another without creating sufficient lift through the arms for the buttocks to clear the surfaces.

Shear and friction forces on the skin can cause the skin layers between the epidermis and dermis to separate resulting in a blister. An adaptive response of the skin to frictional loading is the development of calluses. Calluses are even thickening’s of the layer of the epidermis which form in response to repeated frictional loads. There is much variability in individual response, with some people tending to blister in response to slight friction, while others immediately develop a callus. Damp skin tends to blister, while dry skin tends to develop callosities. An explanation is that the damp skin produces higher friction, above the breakdown threshold for the skin compared with frictional forces induced in dry skin.

People who smoke are also at an increased risk of developing a pressure sore due to reduced blood flow to the skin. Nicotine is a vasoconstrictor and reduces blood flow to the skin. Those who are overweight or diabetic are also at increased risk.

In elderly people who have sustained a spinal cord injury age is also a contributing factor to the formation of pressure sores. The thickness of skin decreases with age. As a result of a reduction in elastin, the elastic range of the skin is decreased. Collagen, proteoglycan, and water content, as well as blood supply, have all been shown to decrease with age, indicating a general atrophy of the skin and underlying tissue. This in turn makes the skin more fragile and more susceptible to loading, friction and shearing forces resulting in skin breakdown.

Prevention of Pressure Sores

A person who has been paralysed may not feel a pressure sore developing, therefore it is essential to change position on regular intervals to allow the circulation of blood throughout pressured areas. Normally as an able bodied person if the seating position is uncomfortable, messages from nerves in the skin will be sent via the spinal cord to the brain to indicate discomfort initiating a change in posture. However, in a person with a spinal cord injury these sensory messages are blocked at the level of injury, and the paralysed person may not be aware the skin is at risk of breakdown.

Following the early stages of a spinal cord injury an individual on bed rest will need turning from side to side by nursing staff to relieve prolonged pressure. Patients at high risk of pressure sore formation may be placed on mattresses designed to cyclically change the distribution of pressure. Whilst on bed rest the main areas most at risk of developing pressure sores are the heal and ankle areas of the foot, the inner areas of the knee joints, the natal cleft of the buttock area, the exterior of the hip bone known as the trochanter, the wrists, elbows and scapulae (shoulder blade).

Once a patient is able to sit up in a wheelchair, custom designed gel and pneumatic wheelchair cushions help distribute the load more evenly. Further, patients in wheelchairs are taught to conduct pressure releases regularly to prevent skin break down. These "pressure releases" may be in the form of pressure lifts for paraplegics or weight shifts for tetraplegics (quadriplegics). For all spinal cord injury patients, the sacral and ischial tuberosity regions are subjected to the largest pressures during sitting.

It is interesting to note that skin tolerance for sustained loading pressures typically increases over time with monitored increases in pressure durations. It is desirable to induce a rehabilitation process that involves adaptation of skin tissues rather than merely preventing breakdown. It is this program in the rehabilitation phase following a spinal cord injury which helps an individual gradually increase the period of time being able to sit in a wheelchair. Over time the deep tissues on load bearing areas change becoming more fibrous in nature, and more resistant to load bearing.

Types of Pressure Sore

Pressure sores are also be referred to as pressure ulcers or decubitus ulcers. The damage from a pressure sore will range from slight discolouration of the skin (stage 1) to open sores that go all the way to the bone (severe). The affected area may feel warmer than the surrounding tissue. In light-skinned people, the discolouration may appear as dark purple or red. In darker-skinned people, the discolouration will appear darker than the surrounding tissue.

Stage One Pressure Sore

How to recognise: Skin is not broken but is red or discoloured. The redness or change in colour does not fade within 30 minutes after pressure is removed. The hardness or firmness (with an edge you can feel) is called induration and is one of the most common signs of a stage I pressure ulcer.

NEVER massage over a pressure ulcer like this. It will increase the damage and can cause it to progress to an open (stage II or deeper) pressure ulcer.

Stage Two Pressure Sore

How to recognise: The epidermis or topmost layer of the skin is broken, creating a shallow open sore. Drainage may or may not be present.

Stage Three Pressure Sore

How to recognise: The break in the skin extends through the dermis (second skin layer) into the subcutaneous and fat tissue. The wound is deeper than in Stage Two.

Stage Four Pressure Sore

How to recognise: The breakdown extends into the muscle and can extend as far down as the bone. Usually lots of dead tissue and drainage are present.

Stage 4 pressure sore extending down to the bone.