By Ginny Paleg, PT
Sarah was admitted to the hospital for a large sacral decubitus. She is 14 years old and has spina bifida. This is her second admission for a decubitus ulcer this year. How can we ensure that this scenario will not repeat itself? The chief cause of decubiti is constant sustained pressure that prevents blood supply and lymphatic drainage in the tissue, so the tissue dies. Inactivity, poor nutrition, and urinary or fecal incontinence are some of the risk factors in developing pressure sores. (For types of injury, see Table 1).
THE PROGRESSION
When you are evaluating a new decubitus, what you see is not what you get. The wound is conical shaped, and only about 30% can be seen. As time goes by, the wound will appear to progress, but in reality, you are finally seeing what was present all along. Decubiti can be classified into four stages (see Table 2). The most important contributing factor to the formation of pressure wounds in children is lack of adipose (fat) tissue. In children with cerebral palsy and other neuromuscular diagnoses, lack of adequate nutrition leads to inadequate amounts of fat. Furthermore, disuse atrophy and lack of volitional movement result in small muscles. Lack of fat and muscle cushion under boney prominences, such as the sacrum, leads to increased risk for pressure wounds.
Table 1. Types of injury
Sarah’s untreated pressure sore led to serious complications. The colonization of microorganisms caused severe local and systemic infection. Other complications can include osteomyelitis (bone infection).
Why did Sarah get this wound? She had a good cushion, but did not always remember to do her pressure reliefs. Nothing we can do will truly reduce the pressure on Sarah’s sacrum. We can only try to increase the distribution of the pressure. Think back to your physics class in college: pressure=force/area. The more area of support we can get in contact with the sacral area, the lower the peak pressures will be. By adjusting the volume of air, material, or fluid in the cushion, you can optimize this situation. The downside is that anything adjustable has more chance for over- or under-adjusting. In the past few years, all cushions have gotten more stable, more versatile, and better at positioning, aligning, and maintaining the pelvis.
SUCCESSFUL PREVENTION
Table 2. Four stages of decubiti
Pressure relief isn’t everything; there are many other factors that go into successful prevention. Most health care practitioners tend to focus on the cushion and the ratings of the different brands. Most cushions are promoted based on their properties when unloaded. It is very important to know what happens when Sarah is sitting in a wet diaper in nylon fabric pants in her wheelchair all day at school. She weighs well over 100 pounds, and her body temperature is at least 98°. Sarah needs a cushion that can support her weight, stay dry and clean, keep her pelvis neutrally aligned, and distribute pressure over a large area of body tissue.
There is no one magic cushion that is right for everyone. A more expensive cushion does not guarantee better protection. Each technology has its strengths and limitations. For many years, there was only one option for pressure relief: air. Then along came gel.
The gel companies were the first to address proper positioning and biomechanics as a preventive measure for pressure sores. The problem was that the gel cushions were not adjustable like the multichamber air options and, therefore, you were stuck with a preset volume for immersion. Gel cushions are, for the most part, out-of-the-box products. Gel cushion popularity is related to the ability to just take it out of the box and drop it into the wheelchair.
Did you know that gel flows? And eventually flows out from under the user and has to be repositioned? This means that once a week (or more often), you have to massage the gel, warm it up, and push it back into the hole and under where the sacrum will be positioned. If this is not done, the person is just sitting on the cover. Both air and gel are unstable surfaces. To compensate for this, many users end up sacral sitting. On the other hand, foam is stable, does not require a lot of maintenance, and may be the best choice for positioning and stability. Foam usually is also the least expensive option. (For more information on cushion types, see Table 3).
Table 3. Cushion comparison
RISK FACTORS
Poor nutrition and hydration and incontinence are risk factors and can present with a history of skin breakdown. In children with poor sensation, padding should be used on all surfaces that come in contact with their body and their position should be changed often. Consider using heel relief boots for sleep time. Risk is, of course, greater in children who have mobility problems and the inability to weight-shift. The use of medications, particularly sedatives, can add risk. Seizure and spasticity medications can also decrease children’s awareness of pressure or decrease their ability to shift their weight.
Sarah’s pressure sores formed because of constant pressure on her sacrum that shut down the blood vessels feeding that area of skin. Because she does not have feeling in her skin and joints, she does not shift her weight often enough. The resulting damage first appears on the skin surface as a red or dark patch. As the pressure sore progresses, the skin breaks down to form blisters, skin dies, and ultimately infection spreads to underlying tissues, bones, and joints. The surface damage is just the tip of the iceberg; the real damage lies beneath the skin. (See Table 4 for prevention tips)
The best approach to prevent pressure wounds in pediatric clients is to look at the combination of risk factors and need. If pressure relief is the most important objective, then you may need to compromise a bit on the positioning. If clients need positioning more than pressure relief, then a good contoured foam cushion will help them sit straighter and offer the level of pressure distribution they need.
For children with growing bodies and bones, sitting all day deforms hip joints and causes abnormal pressure distribution. A good cushion may spread the load, but the child still needs to get into another position as well as shift her weight. Weight shifts can be done manually by pushing up on the arms or, mechanically, by a power assist device on their power wheelchair. In a perfect world, the cushion would rock and weight shift the child. This would load and unload the skin and tissue, not just spread the load.
Ginny Paleg, PT, is an NDT-certified pediatric physical therapist in Washington, DC. She is a doctoral candidate and adjunct faculty member at the University of Maryland’s School of Physical Therapy in Baltimore. She can be reached at: vpale001@umaryland.edu.
