The most important factor in pressure ulcer prevention is reducing the pressure at the skin interface. These include the occiput, scapula, elbow, heel and sacrum. To relieve that pressure before it creates an ulcer, it is essential to turn the patient every two hours. This allows the pressure to be redistributed to other body areas and provides blood flow to the previously compromised tissues. Turning a patient slightly sideways and placing a pillow or wedge under the patient's back, provides relief to a sacral ulcer while not exerting full pressure on the hips.
Pillows can also be place beneath the feet or between the knees to redistribute pressure.
They do not necessarily reduce pressure to a level below 32mmHg. Static - these devices only shift when the patient moves. Dynamic - these devices use energy to automatically shift the air. A static air mattress is inflated to one level and remains constant. A dynamic air mattress uses energy to continually shift the pressure levels.