Understanding the primary causes of pressure ulcers
Pressure ulcers, also known as bedsores or pressure sores, are injuries to the skin and underlying tissue caused by prolonged pressure on the skin. This constant pressure restricts blood flow to the affected area, depriving the tissue of essential oxygen and nutrients and causing it to break down. While anyone can develop a pressure ulcer under the right circumstances, some individuals are far more vulnerable due to intrinsic and extrinsic factors.
Key intrinsic risk factors
Intrinsic factors relate to a person's individual health and physiology. Understanding these can help identify those most susceptible.
Immobility and reduced activity
This is the single most significant risk factor. The body's natural impulse is to shift position to relieve pressure, but individuals who are bedridden, wheelchair-bound, or otherwise unable to move freely cannot do this. Common causes include:
- Chronic illness: Conditions that cause general weakness or fatigue.
- Neurological disorders: Spinal cord injuries, paralysis, and dementia can limit a person's ability to move or sense the need to move.
- Post-surgery recovery: Patients recovering from major surgery may be restricted to bed for extended periods.
- Coma or unconsciousness: An unconscious person cannot adjust their position at all.
Incontinence and excessive moisture
Skin that is frequently moist from sweat, urine, or feces becomes softened and more fragile, a condition known as maceration. This makes it more susceptible to damage from pressure, friction, and shear forces.
- Urinary and fecal incontinence: Continuous exposure to waste can irritate and break down the skin.
- Excessive perspiration: Perspiration trapped against the skin for long periods can also contribute to maceration.
Poor nutrition and hydration
Proper nourishment is essential for maintaining healthy skin and tissue integrity. Deficiencies can make the skin more vulnerable to breakdown and slow the healing process.
- Malnutrition: Lack of sufficient calories, protein, and nutrients like Vitamin C and zinc can weaken the skin.
- Dehydration: Inadequate fluid intake can compromise skin elasticity and overall health.
Sensory perception impairment
Individuals with a diminished ability to feel pain, discomfort, or pressure are unable to recognize the warning signs of a developing pressure ulcer. This is a common issue for people with:
- Neurological conditions: Such as spinal cord injuries, nerve damage, or diabetic neuropathy.
- Advanced dementia or altered consciousness: A person may simply not be aware of their discomfort or the need to move.
Advanced age
As people age, their skin naturally becomes thinner and more fragile. Other age-related factors contribute to increased risk, such as:
- Reduced fat and muscle padding: Less cushioning is available over bony prominences.
- Slower wound healing: The body's ability to repair tissue damage decreases with age.
Key extrinsic risk factors
Extrinsic factors relate to a person's environment and care. They include the mechanical forces that directly damage tissue.
Pressure
This is the most direct cause. Sustained pressure on a part of the body, especially over a bony prominence, restricts blood flow. The force of pressure, combined with the duration, determines the risk.
Friction
Friction occurs when the skin rubs against a surface, like bedding or clothing. It can strip the top layers of skin, making it more vulnerable to breakdown. This often happens when a person is moved or repositioned incorrectly.
Shear
Shear force is a combination of pressure and friction. It happens when skin stays in place, but underlying tissue and bone move, pulling and stretching the blood vessels. A common example is when the head of a bed is elevated and a person slides down, causing the skin over the tailbone to remain stationary while the underlying bone shifts.
Medical conditions that increase risk
Several health conditions can indirectly increase a person's risk of pressure ulcers by affecting circulation, sensation, and overall health.
Diabetes
Long-term diabetes can cause nerve damage (neuropathy), reducing a person's ability to feel pain and pressure. It also impairs blood circulation, slowing wound healing and making tissue more susceptible to injury.
Cardiovascular and vascular disease
Conditions like peripheral arterial disease that compromise blood flow can starve tissues of oxygen, greatly increasing the risk of breakdown even with minimal pressure.
Multiple comorbidities and polypharmacy
Patients with multiple chronic conditions often have complex health needs that increase their overall frailty. The use of multiple medications (polypharmacy) can also contribute by affecting mental status or skin integrity.
Comparison of risk factors in different settings
Here is a table comparing common risk factors for pressure ulcers, highlighting how they may differ based on the care setting.
| Risk Factor | Hospital Setting | Long-Term Care (Nursing Home) | Home Care |
|---|---|---|---|
| Immobility | Common due to acute illness, surgery, or injury; duration can be short-term. | Sustained immobility is often due to chronic conditions like dementia or paralysis. | Varies greatly based on the individual's condition and caregiver support. |
| Incontinence | Often managed closely by staff, but frequent assessment is critical. | High prevalence among elderly residents requires consistent management. | Dependent on caregiver availability and diligence, and patient's baseline health. |
| Nutrition | Acute malnutrition is common; tube feeding may be necessary. | Chronic malnutrition and dehydration can be persistent issues. | Highly dependent on the individual's ability to eat and family caregiver support. |
| Sensory Perception | Assessment is routine; staff are trained to look for signs. | Regular risk assessments using tools like the Braden Scale are standard. | Patient or caregiver must be vigilant; less formal assessment may occur. |
| Medical Conditions | Acute conditions like infection or heart failure increase short-term risk. | Chronic, degenerative conditions are prevalent and increase long-term risk. | Managed by visiting healthcare professionals and family caregivers. |
Prevention and care for at-risk individuals
For those at risk, preventing pressure ulcers is always easier and safer than treating them. Effective strategies include:
- Frequent repositioning: At least every two hours for bedridden patients and every 15–30 minutes for wheelchair users.
- Use of pressure-relieving equipment: Specialized mattresses, overlays, and cushions redistribute pressure away from vulnerable areas.
- Daily skin inspection: Regularly checking the skin, especially over bony areas, for signs of redness, warmth, or discoloration.
- Maintaining good nutrition: A diet rich in protein, vitamins, and minerals, along with adequate hydration, is essential for skin health and repair.
- Managing incontinence: Promptly cleaning and drying the skin after incontinence episodes and using barrier creams to protect fragile skin.
Conclusion
Identifying who is at risk of pressure ulcers requires a thorough understanding of an individual's intrinsic health factors and their environment. From advanced age and limited mobility to poor nutrition and chronic illness, a combination of issues often contribute to the problem. By implementing a proactive prevention strategy focused on repositioning, nutritional support, and vigilant skin care, the risk can be significantly reduced for even the most vulnerable individuals.
For more detailed guidance on prevention techniques and caring for fragile skin, visit the National Institutes of Health website. For example, their guide for patients on pressure ulcers is a valuable resource that expands on the importance of proactive care and skin management (https://www.ncbi.nlm.nih.gov/books/NBK2650/).
