University of Southern California Mrs. T.H. Chan Division of Occupational Science and Occupational Therapy
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Pressure Reliefs

There are a number of habits that a person can do daily to make it much less likely that a pressure ulcer (which means the same thing as "pressure sore" or "bedsore") will develop. These pressure ulcer prevention practices or techniques are usually taught in hospitals or rehabilitation facilities to people who have recently had a spinal cord injury or experienced an illness that has caused limited mobility. But what people often find after they leave the hospital is that it can be hard to do the prevention practices exactly they way they were advised to do it, and they find their own way to carry out these techniques. As one of our study participants, Mitch, put it:

There are too many things that you had to be doing. I mean, okay, when you are in the hospital, when you first get injured, they give you all these instructions, you know. "You should relieve pressure every 15 minutes, and you should turn and do this, and you should exercise in range of motion." And, I mean, you can't do all that stuff! You do it in the hospital, but in real life, you can't do all that stuff. So, you do what you are able to do and what's comfortable and what's normal for you that fits into your daily life.

Another section in this guide lists a number of pressure ulcer prevention techniques; it is titled, "Prevention Techniques". This page is devoted to one of the most important of all ways to avoid getting a pressure ulcer, which is by doing pressure reliefs in two different ways: actively, and passively. But first, it might help to understand exactly what is happening in your body when you do any kind of pressure relief.

What does pressure do to your body? You may not realize it, but there is a lot of pressure just from the weight of your own body on your bony prominences, that is, areas where bones or joints "stick out" because there is very little tissue (that is, flesh) over them; these areas include the tailbone, hip bones, spine, heels, back of the head, backs of the ears, shoulders, elbows, and inside the knees where they rub together. As an example, the amount of pressure on your heels when lying down can be two or three times greater than when there is no pressure on them; the pressure on your bottom or tailbone when sitting can be 10 to 15 times higher than when there's no pressure! The problem with all this pressure is that it forces blood out of the area 1; since blood carries oxygen to all the body's cells, the area that is under pressure can experience ischemia, that is, tissue damage due to oxygen loss, and ischemia is the start of a pressure ulcer 2.

When a person's sense of feeling, or sensation, is working well, they quickly become aware when there is too much pressure on a part of their body, because there is a feeling of discomfort or feelings people sometimes describe as "pins and needles," or "my arm (or hand or leg or foot) fell asleep." Other examples are when sunglasses start to press too hard on the nose or ears and a person needs to move them, or when jewelry that fits tightly, such as clip earrings, a ring or an arm cuff, starts to pinch or "dig in" to the skin and a person needs to adjust the jewelry or take it off. That uncomfortable or tingling feeling causes a person to move around into another position, which releases the pressure and restores a good flow of blood. Unfortunately, after a spinal cord injury, sensation is limited or even missing from the parts of a person's body below the location of their injury. The result is that there is no feeling of discomfort, and so people do not know when there is too much pressure on an area of skin or a bony prominence. Without sensation, a person might not move their body, and the pressure will continue, causing more oxygen loss and ischemia.

How does pressure relief help? When you take weight off your bony prominences, you give the blood, and the oxygen that's in it, a chance to rush back into the area that was pressured and not getting enough oxygen; in fact, the body pours extra blood into an area that was cut off for an extra long period of time, helping the area heal 2.

Active pressure relief. Moving around, whether it is in a wheelchair or other type of seat or a bed, is active pressure relief. While making just a little movement might help relieve pressure, it's best to make sure that you move enough to take the pressure off of your bony prominences and allow the blood to pour back in. When lying in bed, studies show that changing positions at least once every two hours is the healthiest, best way to avoid pressure ulcers 1. When up in a wheelchair, and you are more involved with doing daily activities, it's much easier to move enough to relieve pressure more often than every two hours. The trick is to remember that it's time to move again! For example, one of our study participants, Frank, got an "Ironman" watch with an alarm in it that he sets to remind him every 15 minutes that it's time for a pressure relief; other people "listen to their body", that is, they pay attention to signals coming from inside their body that remind them that their body "wants" to move.

There are other ways to remind yourself it's time to move; think about your daily habits and find a way that fits your lifestyle. For example, do you use a computer? Do you watch favorite television programs? Do you attend classes, or go to work? These are all activities that are done on a schedule, so tying pressure reliefs to these activities can provide an automatic reminder that it's time to move.

How you do your active pressure relief is something you can decide, with advice from a health care provider like your doctor, physical therapist or occupational therapist. For example, people with strong triceps muscles in the upper arm (which usually means that the spinal cord injury is at C-8 or lower) can usually push against the arms of a wheelchair to move themselves into a new position. In the more than 35 years since her spinal cord injury, our study participant Alma, who has a spinal cord injury at C-1, has discovered that the best pressure relief system for her is to get out of her chair every 4 to 5 hours and lie down for a half-hour to 45 minutes. If she or her care attendant see any redness when they do a skin check, then Alma will take longer breaks and take them more often until the redness goes away. Alma's system may not work for everyone, but the point is that she listened to her body and discovered what is best for her. Choose the method that is easiest, safest and most effective for you to do.

Passive pressure relief. Devices that lessen the amount of pressure on your bony prominences for you provide passive pressure relief. Examples of this kind of equipment include supportive surfaces like wheelchair cushions; pads made of sheepskin, egg-crate foam or filled with air; air mattresses; or tilt-in-space wheelchairs 3. It is important that such equipment be customized for your needs by a specially trained health care provider, such as an occupational therapist or a physical therapist 3. For example, some people with limited trunk control might need to have the frame of their wheelchair "squeezed" to provide extra trunk support, and, if done properly, such adjustment of the wheelchair will not increase the possibility of getting a pressure ulcer 4. Even a cushion needs to be the right material and to be adjusted correctly for each individual's needs; as Frank said of getting the right kind of cushion, "See, everybody's body made different. Some people sit on different types of cushions, different types of weight, different types of build or whatever." He was speaking from experience: when his gel cushion broke, Frank got a pressure ulcer from sitting on the foam cushion he was using as a temporary replacement. (That's what inspired him to get the watch to remind him to do pressure reliefs.) Another study participant, Ken, got a new cushion that did not have a cut-out; by the end of the day, he had developed a pressure ulcer.

Whatever way you choose to do pressure reliefs, the important thing is that you do them, and do them often enough to prevent pressure ulcers. The key is working out a way to do pressure reliefs that it will become a healthy habit for you. Although it may seem at first that it will be hard to remember to do pressure reliefs, don't worry; it's easier than you think to make it a habit. As our study participant Mitch explained it,

[You have to] find ways that fit you and the way you live. Not every situation's gonna fit a person. You have to personalize every routine or class or whatever to fit that particular person.... I had personalized my own routine to a point where I don't even think about it now and I relieve pressure without even thinking about it. So that has already happened to me, but people who are newly hurt, they have to train themselves to do certain things. And that's where that comes in, where you personalize a particular routine. But once you already trained yourself to do a certain thing and it works, then it's pretty natural after that.

There are a number of articles on the Internet that give more helpful suggestions about pressure reliefs, as well as explaining how they can prevent pressure wounds. For example, Relieve Skin Pressure, which is illustrated with black-and-white drawings, was created for the PoinTIS information website at the University of Miami School of Medicine's Louis Calder Memorial Library. It carefully explains pressure relief suggestions for different parts of the body and for different situations, such as sitting or lying in bed. Another page with pictures and suggestions for pressure reliefs while sitting or lying in bed is Skin Care: Relieving Pressure on the Skin, on the website of the LIFE Center of the Rehabilitation Institute of Chicago; the same website also has Skin Care: Preventing Pressure Sores, a simple list of things to do, and not to do, to prevent pressure ulcers.

Good suggestions about pressure reliefs can also be found on websites with information about prevention techniques in general. WebMD, a website run by the publicly-traded company WebMD Corporation, displays ads along with health information. Pressure Sores (Pressure Ulcers; Bed Sores; Decubitus Ulcers) has basic information about pressure ulcers. It was written by Debra Wood, R.N., who has 20 years experience as a nurse; in this wonderful article, which is also used by a number of hospital websites across the country, Ms. Wood uses the word "repositioning" instead of saying "pressure reliefs."

If you are interested in information that is in the same style you might see in a hospital or rehabilitation facility, an excellent resource is Pressure Ulcers: What You Should Know, created by the Consortium for Spinal Cord Medicine, which is supported financially by the Paralyzed Veterans of America (PVA). This 45-page guide is easy to read and to use. You can download a free copy in PDF format. Úlceras por Decúbito: Lo Que Usted Debe Saber Una Guía para Personas con Lesiones Medulares ha sido producida en Español de parte del PVA por el Consorcio de Medicina de la Médula Espinal. Usted puede llamar a 1-888-860-7244.

You can also try this Spinal Cord Injury Manual. The manual was prepared for consumers by the Regional Spinal Cord Injury Center of the Delaware Valley, which is part of Thomas Jefferson University Hospital in Philadelphia, PA. Also, try this PDF on Prevention of Pressure Sores through Skin Care, from the Spinal Cord Injury Model System.

For those interested in more technical information about sensation, and how spinal cord injury limits sensation: The area of the body that sends its sensations to one particular part of the spine is called a dermatome; for example, the dermatome for T-11 roughly follows the waistline, just under the navel in the front and just above the tailbone in the back. This is similar to an area of the body that receives its impulses to move (also known as innervation) from one particular part of the spine, which is called a myotome; for example, the myotome for T-11 helps control muscles of the lower abdomen. Your physician or other health care professionals already have made you familiar with the areas of the body that are affected by your spinal cord injury. You can see a map of the body that shows Myotomes & Dermatomes on Apparelyzed, a website created by Simon, a man in England who received a spinal cord injury at C-5/C-6 in a car accident in 1992. Apparelyzed has two goals: first, it contains information about spinal cord injury and related conditions, and it also sells T-shirts with positive messages and other clothing designed by Simon; the profits from selling clothes help to pay for the expenses of maintaining the website. You can purchase a poster-sized version of the dermatome or myotome map from Apparelyzed.

1 Dharmarajan, T. S., & Ahmed, S. (2003). The growing problem of pressure ulcers. Postgraduate Medicine, 113, (5), 77-90.

2 Noble, M., Voegli, D., & Clough, G. F. (2003). A comparison of cutaneous vascular responses to transient pressure loading in smokers and nonsmokers. Journal of Rehabilitation Research and Development, 40, (3), 283-288.

3 Consortium for Spinal Cord Medicine. (2000). Pressure ulcer prevention and treatment following spinal cord injury: A clinical practice guideline for health-care professionals. Washington, DC: Paralyzed Veterans of America.

4 Maurer, C. L., & Sprigle, S. (2004). Effect of seat inclination on seated pressures of individuals with spinal cord injury. Physical Therapy, 84, (3), 255-261.