Unrelieved pressure on the skin squeezes tiny blood vessels, which supply the skin with nutrients and oxygen. When skin is starved of nutrients and oxygen for too long, the tissue dies and a pressure ulcer forms. Skin reddening that disappears after pressure is removed is normal and not a pressure ulcer.

Where Pressure Ulcers Form
Pressure ulcers form where bone causes the greatest force on the skin and tissue and squeezes them against an outside surface. This may be where bony parts of the body press against other body parts, a mattress, or a chair. In persons who must stay in bed, most pressure ulcers form on the lower back below the waist (sacrum), the hip bone (trochanter), and on the heels. In people in chairs or wheelchairs, the exact spot where pressure ulcers form depends on the sitting position. Pressure ulcers can also form on the knees, ankles, shoulder blades, back of the head, and spine.
Nerves normally tell the body when to move to relieve pressure on the skin. Persons in bed who are unable to move may get pressure ulcers after as little as 1-2 hours. Persons who sit in chairs and who cannot move can get pressure ulcers in even less time because the force on the skin is greater.

5 Ways to Prevent Pressure Sores
The following steps for prevention are based on research, professional judgment, and practice. These steps can also keep pressure ulcers from getting worse. Some steps apply to all prevention efforts; others apply only in specific conditions. It may help to talk to a nurse or doctor about which steps are right for your resident.

1 Taking Care of the Skin

Residents’ skin should be inspected at least once a day. Pay special attention to any reddened areas that remain after you have changed positions and the pressure has been relieved. Pay special attention to pressure points. The goal is to find and correct problems before pressure ulcers form. Skin should be cleaned as soon as it is soiled. A soft cloth or sponge should be used to reduce injury to skin.
A bath should be given when needed for comfort or cleanliness. If a daily bath or shower is preferred or necessary, additional measures should be taken to minimize irritation and prevent dry skin. When bathing or showering, warm (not hot) water and a mild soap should be used.

To prevent dry skin:

• Use creams or oils on your skin.
• Avoid cold or dry air.
• Minimize moisture from urine or stool, perspiration, or wound drainage. Often urine leaks can be treated.

When moisture cannot be controlled:

• Pads or briefs that absorb urine and have a quick drying surface that keeps moisture away from the skin should be used.
• A cream or ointment to protect skin from urine, stool, or wound drainage may be helpful.

2 Protect skin from injury

Avoid massaging skin over bony parts of the body. Massage may squeeze and damage the tissue under the skin and make you more likely to get pressure ulcers. Limit pressure over bony parts by changing positions or having your caregiver change your position.

• If resident is in bed, their position should be changed at least every 2 hours.
• If resident is in a chair, their position should be changed at least every hour. Reduce friction (rubbing) by making sure you are lifting, rather than dragging, during repositioning. Friction can rub off the top layer of skin and damage blood vessels under the skin. Avoid use of donut-shape (ring) cushions. Donut-shape cushions can increase risk of getting a pressure ulcer by reducing blood flow and causing tissue to swell.

3 Bed Confinement

• A special mattress that contains foam, air, gel, or water helps to prevent pressure ulcers. The cost and effectiveness of these products vary greatly. Talk to your residents’ health care provider about the best mattress.
• The head of the bed should be raised as little and for as short a time as possible if consistent with medical conditions and other restrictions. When the head of the bed is raised more than 30 degrees, skin may slide over the bed surface, damaging skin and tiny blood vessels.
• Pillows or wedges should be used to keep knees or ankles from touching each other.
• Avoid lying resident directly on hip bone (trochanter) when lying on side. Also, a position that spreads weight and pressure more evenly should be chosen -- pillows may also help.
• If resident is completely immobile, pillows should be put under legs from midcalf to ankle to keep heels off the bed. Never place pillows behind the knee.

4 In wheel chair or chair

• Foam, gel, or air cushions should be used to relieve pressure. Ask health care provider which is best. Avoid donut-shape cushions because they reduce blood flow and cause tissue to swell, which can increase your risk of getting a pressure ulcer.
• Avoid allowing the resident to sit without moving or being moved for an extended period of time.
• Good posture and comfort is important.

5 Eating well & Exercise

• Make sure resident is eating a balanced diet. Protein and calories are very important. Healthy skin is less likely to be damaged.
• If he/she is unable to eat a normal diet, talk to their health care provider about nutritional supplements that may be desirable.
• Improve ability to move
• A rehabilitation program can help some persons regain movement and independence.