​Thinking Differently About the Causes of Pressure Injury Part 1: Overview

Posted by Nurse Linda in Daily Dose on June 08, 2022 # Health

A pressure injury is an issue for individuals with paralysis from any disease or trauma. Individuals with less sensation are at the highest risk; however, individuals with sensation also have the risk of developing a pressure injury as well. Suppose you have sensation issues on just one side of your body. In that case, you can develop pressure injury in areas where sensation is challenged and body areas where sensation is present if moving is difficult. Individuals with diabetes or poor circulation can develop pressure injury as sensations and responses may not be messaged well to the brain.

Pressure injury can even affect individuals who have complete sensation. It is often seen under casts, prosthesis, and equipment that have rubbed. Some people get a pressure injury from shoes that rub their feet. Changes in body metabolism can increase the risk of pressure injuries such as dehydration, malnutrition, and skin texture and integrity changes. Wet skin from incontinence, sweat, or poorly drying after bathing can lead to pressure injury.

Other words for pressure injury include pressure sore, bedsore, decubitus ulcer or decub, skin breakdown or ‘a spot’. Pressure injury (P.I.) is the current choice of name in healthcare today. This occurs when pressure from inside the body pushes on blood vessels disrupting circulation or blood flow to the inner tissue. You may not know when a pressure injury begins because you cannot see it forming. Individuals will first notice a pressure injury starting with the outer skin changing color from lack of circulation inside the body. But the injury has already been created inside the body. Many compare a pressure injury to an iceberg, you see a bit of it on top of the skin, but there is much, much more going on underneath the surface of the skin.

A pressure injury is often caused by a hard pointy bone being pressed on internal blood vessels, blocking blood flow. These include arteries, veins, and capillaries. Arteries carry oxygen and nutrients from the blood to the cells of the body. These are the largest and have the thickest blood vessels' walls. The heart’s greatest pumping pressure of blood is directly through the arteries. Pressure in the arteries depends on how your heart beats and the resistance of the artery wall. Arteries can become thicker and less elastic with cardiac issues such as atherosclerosis (hardening of the arteries), so failure or rupture can occur with artery changes which increase pressure injury risk.

Veins have less pressure as they carry blood away from the cells of the body, returning the blood to pick up oxygen from the heart. The arteries and veins connect to each other by capillaries. This is where the switch from carrying blood to the cells to carrying blood away from the cells occurs. Capillaries are the smallest and most delicate blood vessels. It takes very little pressure for a short amount of time to compress the capillaries, which can quickly collapse, interrupting blood flow. Lack of blood flow to the cells of the body leads to little or no oxygenation or nutrients delivered to the cells causing them to die. When the capillaries fail, veins and arteries quickly follow, leading to pressure injury.

Pressure injuries are the results of this interruption in body circulation. The signs of a pressure injury on the outside of the body are changes in skin tone, swelling, pain or referred pain, tenderness, changes in skin temperature including feeling cooler or warmer to touch than the surrounding area, skin loss, pus, odor, and drainage.

By the time you see changes in your skin, a pressure injury already has a good grip inside your body. Pressure injuries are classified in stages. Stage one is a change in pigmentation on the outside of your body. The change in pigmentation may be darker or white (ashy) in individuals with more melanin in their skin. Individuals with less melanin may have a pink, red, or purple area. Noticing this change, especially over a pointy bone or boney prominence, is critical as more damage is below the surface of the skin in your tissues, so stage one should be taken very seriously.

Stage two is the change in pigmentation, but also the skin surface may be blistered or even open if the top layer of skin is removed. If the skin is intact, keep it as it is. Opening the skin can lead to infection. If the skin is open on its own, keep the area covered to prevent infection with a nonstick bandage. You do not want the skin to be removed by changing a bandage that has stuck to this delicate top layer. The top layer of skin is very resilient and can heal quickly if pressure is no longer applied to the area. However, healing the pressure injury inside the body will take more time.

Stage three is a deep wound, including an opening where you can see the fat that is under your skin. The wound may be infected, contain pus, have drainage, and may have a foul odor. This wound needs to be covered to prevent infection or further infection and to contain drainage until you can see a health professional for further instruction.

Stage four is a very deep wound, down to the bone. You may see the bone when you look inside the opening. It is very prone to infection. Infection in the bone is life-threatening.

Unstageable wounds are open, but you see a white, black, or yellow covering when you look inside the wound. This is the body’s way of temporarily closing the wound, but it can be the source of infection, or infection can be under the covering. Since you cannot see inside the wound, the stage cannot be estimated. Do not disturb this injury. Instead, get instructions on how to care for this wound.

Removing pressure in the area of injury is the way to allow the body to heal. This means not sitting, laying or otherwise allowing any pressure. Do not rub this area or press it, as this adds more pressure from the outside of the body and the pressure already present inside the body.

In addition to pressure, skin can be disrupted by mechanical causes of shearing, friction, and by moisture. Shearing occurs when layers of the skin are separated deep within the body, disrupting blood flow. You may not see this injury as it is within the body, but it sets up a scenario for pressure injury to develop. This happens when people are transferring and dragging their bodies instead of picking them up off a surface. One layer of tissue sticks to the surface, but internal layers move with the transfer. This causes the connection of layers to separate, including damage to the capillaries.

Friction is a separation of the surface level of skin from the layer immediately below it. This injury looks like a red mark anywhere on the skin. This is sometimes called a ‘rug burn,’ but the source can be from sheets, clothing, or any other surface.

Moisture is another skin injury that is not particularly pressure-based. When skin is wet for too long, it becomes macerated, or the outer layer can be affected. Some moisture on the skin is very caustic such as urine, stool and even sweat. Enzymes in these body waste products can erode the surface of the skin over time. Shear, friction, and moisture can set the scene for the development of pressure injuries.

You are the first defense against pressure injury. If you have a sensation and you feel something is rubbing your skin, immediately look at the area and what is causing the irritation. For instance, if a cast is rubbing, bring it to the attention of your healthcare provider, something may not be padded correctly, or perhaps there is edema or deceased edema (like fluid resolving after a bone fracture) that has changed the effectiveness of the cast padding.

If you have a brace, splint, or other equipment that is rubbing your body, immediately get an adjustment or additional padding to protect your skin. That means making a same-day appointment for correction. Do not wait or attempt to form a callus, as this is a patch of dry skin that will crack and allow infection to enter your body.

Skin inspections must be done frequently if you have sensation or if your sensation is challenged. This is critical to detecting a pressure injury. A change in pigmentation is the first notation of damage that is much more significant than what you see. Early detection of skin changes leads to faster healing by staying off the area and natural healing of the skin that a scar that has no elasticity. You are the person who is living in your body. It is your responsibility to check your skin and become familiar with the normal look of your skin. Others, such as caregivers, can look with you, but you need to know your skin as caregivers can change, become ill or are absent for a day. Take a photo with your private phone for a recording of how your skin looks in its natural state or if you see a spot that concerns you.

Repeating critical information, if you detect a skin issue, be sure to stay off the area which eliminates any additional pressure. Do not poke or press the area. Do not massage the area. These actions just add more pressure. Healing a ‘spot’ is much easier and with better results than attempting to close an area that will leave a scar. Scars are not elastic like skin. Individuals who have a pressure injury are much more susceptible to a second pressure injury in the same location.

Pressure injury can occur in situations outside of your control. Practicing good skin care, pressure releases, nutrition, hydration, hygiene and use of pressure dispersing equipment can help reduce your risks. Nurse Linda

Pediatric Consideration:

Children’s skin is so new and healthy that individuals often overlook the risk for pressure injury, but it is present. Sensation issues will not alert them to discomfort, so checking their skin when sitting and laying as well as when using assistive devices falls to the caregiver. Be sure to include the child or teen in looking at their skin and transitioning them to independence in this activity as they are ready and able.

Often children like to ‘free’ play on the floor or carpet. The use of long pants, long sleeves and socks can help prevent shearing and friction injury. Monitoring bowel and bladder programs also help with moisture reduction. Nurse Linda

Linda Schultz is a leader, teacher, and provider of rehabilitation nursing for over 30 years. In fact, Nurse Linda worked closely with Christopher Reeve on his recovery and has been advocating for the Reeve Foundation ever since.

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