How Pressure Ulcers Form
Even a healthy person can begin to develop pressure ulcers in less than a day if left in one position. It helps to know where how pressure ulcers develop and what you can do to prevent them.
People who can’t move for long periods of time are at risk for pressure ulcers because oxygen and other nutrients can’t easily reach their cells. An immobile person with skin made fragile by age or disease is at even greater risk. This skin heals more slowly.
Shear and Friction
Two forces contribute to pressure ulcers. Opposite, but parallel, sliding motions (shear)—like bone moving down and skin up—compress blood vessels. Surfaces rubbing (friction) can also cause skin to break down.
Skin overfilled with fluid is fragile. And certain kinds of fluid—sweat, urine, or feces—can provide a medium for bacteria growth, delaying healing. Too much moisture carries another risk: it can increase friction.
Cells reproduce slowly if they are poorly nourished. They reproduce even more slowly in a person with an illness or tissue injury. Loss of body weight from poor nutrition makes tissue thin and fragile.