Pressure Injuries (Bedsores)

What Are Pressure Injuries?

Pressure injuries occur when excessive pressure is applied to a specific area for too long, cutting off blood flow to the skin and underlying tissues. Without adequate blood supply, the tissue becomes starved of oxygen and nutrients, leading to damage and potentially an open wound.

Let's imagine you are sitting on a hard bench, engrossed in a sporting event or captivating movie. What you are watching is so good that you lose track of time and hardly take notice of anything else going on. As things come to an end, you get up and notice soreness in a couple of areas on your rear end, maybe even with an associated red mark or two. Well, that soreness and redness is a pressure injury in its mildest form. This is the effect of all your body weight resting on one or two of your gluteal bones for too long. The skin and subcutaneous tissue of your buttocks, unfortunately, get caught between the weight of your body and the hard bench below. Blood vessels leading to the area get crushed, cutting off blood flow to the skin and subcutaneous tissue.

The Physics of Pressure

Pressure is greatest when distributed over small areas. Remember that equation from school: P = F/A (Pressure equals Force divided by Area).

To bring that equation to life, imagine you're pushing your open hand down on the surface of a table. Go ahead, push hard. No problem, right? You might even be able to support much of your body weight on that hand. That is because the force is spread over a large surface area between the palm of your hand and the table, reducing the pressure.

But press your index finger against a corner of that same table. Well, now, that's a different story, isn't it? The pressure suddenly becomes very intense. It's because all that force is now focused on a very small area, causing the pressure (and pain) to shoot up intensely.

This focused, intense pressure is precisely why pressure ulcers tend to occur in areas where the body weight is concentrated on small, bony prominences. When body weight is focused on small bony areas like the heel or the tailbone, the skin, fat, and muscle in the area are caught between the bone and the surface the body is on. The tissues are deformed and the blood vessels leading to these areas are pressed closed.

In able-bodied folks, feedback loops in the brain subconsciously tell us when it's time to shift our weight to relieve pressure. Those little shifts we barely acknowledge are our bodies protecting themselves from pressure injuries. With weakness or impaired mobility, these feedback loops get ignored, leading to sustained pressure and tissue damage.

Understanding Shear Forces

Another important concept in the development of pressure injuries is 'shear.' Shear occurs when there is a combination of pressure and friction, or when the skin moves in one direction while the underlying tissues move in the opposite direction.

It is like when you drag a heavy object across the floor, and it causes a rug burn. Imagine sliding down in bed or in a chair - your skin stays relatively in place against the sheets or seat, but your bones and deeper tissues shift downward. This creates a shearing force that stretches and tears blood vessels and tissues.

Shear forces can further damage already vulnerable skin and contribute to the development of pressure injuries. This is why proper lifting and transferring techniques are so important for physically limited individuals.

Avoid raising the head of the bed higher than 30 degrees for extended periods, as this can create shear forces that damage tissue. Use positioning aids to prevent sliding down in bed.

Skin Aging and Pressure Injury Risk

Age-related skin changes significantly increase the risk of pressure injuries. As the skin's collagen and elastin fibers diminish with age, there is a loss of elasticity and firmness. The skin becomes thinner and more fragile, making it prone to bruising and damage.

Profound changes occur to skin with aging beyond just wrinkles and age spots:

• Reduced melanocytes (pigment cells)

• Fewer sweat glands

• Subcutaneous fat layer becomes thinner

• Decreased blood vessel density

• Slower cell turnover and healing

As skin ages, it requires increased care and attention to maintain its health and integrity. Understanding the structure and function of the skin is important in preventing chronic wounds. A cornerstone of wound care and prevention is diligent skin care.

Regular bathing clears the skin of dead cells, dirt, and debris. Drinking water to stay well hydrated gives the skin volume, strength, and suppleness. Use your favorite moisturizer at least once daily, particularly after bathing, to trap moisture against the skin. Even small cracks caused by dryness can set the stage for cellulitis, infection, and wound formation.

Common Pressure Points

Pressure injuries most commonly develop over bony prominences where there's less natural cushioning between bone and skin. The most vulnerable areas include:

• Heels - one of the most common sites

• Sacrum and coccyx (tailbone area)

• Hips and sides of the pelvis

• Shoulder blades

• Back of the head (less common but possible)

• Elbows and ankles

These areas are at highest risk because they bear the most pressure when lying down or sitting for extended periods.

Use a mirror or ask a caregiver to check pressure points daily, especially if you have limited mobility or reduced sensation.

Stages of Pressure Injuries

Pressure injuries are classified into stages based on the depth of tissue damage. Understanding these stages helps with proper treatment planning. Note: The descriptions below may be more noticeable in fair-skinned individuals, and the detection of early stage pressure injury may be more subtle in people with darker skin.

Think of an apple to understand pressure injury stages:

• Stage 1: The apple peel is discolored but intact

• Stage 2: There's a small break in the peel, like a scrape

• Stage 3: Take a bite out of the apple, but not all the way to the core - the wound goes through the peel (skin) and into the flesh (fatty tissue)

• Stage 4: Bite deeper, reaching the core (muscle or bone) - the wound is severe, exposing deeper tissues

• Deep Tissue: A bruised apple - damage to the inner flesh without visible breaks in the peel

• Unstageable: An apple that has sat out too long, brown and mushy in spots - the dead tissue on the surface makes it impossible to assess the damage below

The Critical Role of Offloading

The single most important intervention for pressure injury healing is eliminating pressure on the affected area. No matter how good the wound dressing or treatment, if pressure continues, the wound cannot heal.

Offloading strategies include:

• Repositioning every 2 hours when in bed

• Using the 30-degree side-lying position to avoid direct pressure on the sacrum

• Heel protection devices that keep heels completely off the bed surface

• Pressure-redistribution mattresses or overlays

• Special cushions for wheelchair users

• Body wedges and positioning aids

Imagine trying to repair a road while heavy trucks keep driving over it. The repair crew can't make progress if damage continues. The same is true for pressure injuries - healing requires removing the source of damage first.

Nutrition: Fueling the Healing Process

Proper nutrition is absolutely critical for pressure injury healing. Your body needs adequate calories, protein, and specific nutrients to repair damaged tissue.

Key nutritional considerations:

• Protein: The building blocks for new tissue formation. Aim for lean meats, fish, eggs, beans, and dairy products.

• Calories: Sufficient energy to power the healing process. Think of calories as the 'worker bees' of your body's construction crew.

• Vitamin C: Essential for collagen synthesis. Found in citrus fruits, strawberries, and leafy greens.

• Vitamin A: Promotes new cell growth. Found in carrots, sweet potatoes, and spinach.

• Zinc: Vital for cell division and wound closure. Present in seafood, nuts, and whole grains.

• Hydration: Proper water intake supports blood circulation and nutrient delivery to the wound site.

If you have difficulty eating enough, ask your healthcare provider about nutritional supplements specifically formulated for wound healing.