Pressure injuries, often called bedsores or pressure ulcers, are localized areas of damage to the skin and underlying tissue. They develop as a result of sustained pressure or pressure combined with shear forces. Understanding these contributing factors is important for individuals and caregivers to enable earlier recognition and prevent complications.
Biological and Physiological Factors
An individual’s physical state plays a significant role in their susceptibility to pressure injuries. Limited movement, or immobility, is a primary concern because it prevents regular repositioning that naturally relieves pressure on bony areas. When a person cannot shift their weight independently, sustained pressure on areas like the sacrum, heels, or hips can compress blood vessels, restricting blood flow and oxygen delivery to the tissues. This lack of circulation can lead to tissue damage and open wounds.
Reduced ability to feel pain or discomfort, known as sensory perception impairment, further increases risk. Individuals with conditions affecting their sensory nerves may not receive the warning signals that prompt a change in position. This diminished sensation means they might remain in a compromising posture for extended periods, allowing tissue damage to progress unnoticed beneath the skin’s surface.
Poor nutrition and inadequate hydration also weaken the body’s defenses against skin breakdown. Insufficient protein intake, for example, hinders the repair of damaged tissues and the formation of new skin cells. Deficiencies in vitamins, particularly Vitamin C, and minerals like zinc, can impair collagen synthesis and wound healing. Dehydration reduces skin elasticity and turgor, making it more fragile and prone to injury from external forces.
The aging process alters skin structure, making older adults more vulnerable. As people age, their skin becomes thinner, loses elasticity, and contains less collagen and subcutaneous fat, which provide cushioning. This reduced protective layer means less tolerance for pressure and shear forces, increasing the likelihood of skin breakdown even with moderate external stress. The skin’s ability to repair itself also slows down with age, prolonging healing times.
Underlying medical conditions can increase the risk. Diabetes can impair circulation and nerve function (neuropathy), reducing blood flow to tissues and diminishing sensation, making individuals less aware of pressure. Vascular diseases compromise blood vessel integrity and flow, leading to inadequate oxygen and nutrient delivery. Neurological disorders, such as stroke or spinal cord injuries, result in paralysis or weakness, causing immobility and sensory loss. Anemia, characterized by a low red blood cell count, reduces the blood’s oxygen-carrying capacity, further compromising tissue oxygenation.
External and Environmental Influences
Forces originating outside the body also contribute significantly to the development of pressure injuries. Sustained pressure on specific body areas, especially over bony prominences like the heels, hips, or tailbone, compresses blood vessels. This compression restricts blood flow, depriving the underlying tissue of oxygen and nutrients, a condition known as ischemia. If this pressure continues for too long, cells begin to die, leading to tissue damage and a pressure injury.
Shear and friction are mechanical forces that can damage skin layers. Shear occurs when the skin remains stationary while the underlying bone and tissue move, often seen when a person slides down in a bed or chair; this stretches and tears blood vessels, disrupting blood flow to the skin. Friction is caused by two surfaces rubbing against each other, such as skin dragging across bed linens, which can abrade the outer layers of the skin. Both forces compromise skin integrity, making it easier for pressure injuries to form.
Excessive moisture on the skin from sources like incontinence, sweat, or wound drainage increases vulnerability. Prolonged exposure to moisture softens or “macerates” the skin, weakening its protective barrier and making it more fragile. This softened skin is then more easily damaged by pressure, shear, or friction, promoting skin breakdown and infection.
Medical devices can also exert localized pressure on the skin. Such items as urinary catheters, oxygen tubing, casts, or ill-fitting braces can press against the skin for extended periods. This continuous pressure can compromise blood flow to the underlying tissues, similar to the effects of prolonged body weight pressure.
Identifying High-Risk Individuals and Initial Indicators
Recognizing individuals who are at an elevated risk for pressure injuries is an important step in prevention. People who are bedridden, use a wheelchair for extended periods, or have limited mobility due to illness or injury are at higher risk. Individuals who appear confused, unresponsive, or have a diminished ability to communicate discomfort are also more vulnerable because they may not be able to reposition themselves or alert caregivers to developing issues. Those with a poor appetite, weight loss, or incontinence are at increased risk due to compromised nutritional status and moisture exposure.
Observing early changes in the skin is the first step in identifying a developing pressure injury. Initial indicators include:
Non-blanchable redness, where an area of skin remains red even when pressed with a finger, indicating underlying tissue damage.
The affected skin feeling warmer or cooler to the touch compared to surrounding areas, suggesting altered blood flow.
Changes in tissue consistency, such as feeling firm, boggy, or spongy when palpated, signaling early damage.
Localized pain, discomfort, or itching in the affected area, even before visible skin breakdown.