Pressure cushions and tilt-in-space wheelchairs to prevent pressure areas

Physiotherapists, occupational therapists and nurses can work with someone with cerebral palsy and their family to develop a comprehensive plan for preventing pressure areas.

Cerebral Palsy Alliance offers a service where our therapists can help a person decide on the best pressure prevention plan for them.

Therapy - Fees will apply for an assessment, recommendation of appropriate equipment and therapy. The cost will depend on the provider and the number of sessions a person needs. You should check with your provider to see if there will be additional costs to prepare pressure care prevention plans and funding applications, and for therapist’s travel to sessions.

Equipment – The price of a cushion or tilt-in-space wheelchair will vary considerably depending on the needs of the individual. You can ask your health care provider if you are eligible for funding to assist with the fees, cushion and wheelchair costs. Accessing this support will involve completing and submitting a funding application.

People with disability living in Australia may also be eligible for a health care rebate through Medicare or funding from the National Disability Insurance Scheme.

These specialised cushions are placed on the seat of a wheelchair to help reduce the pressure on the bony areas of the buttocks and tailbone. They are also used to support deformities of the hips and regulate heat and moisture. The cushions are made of one or more materials, most commonly foam, gel and air. There are many types available. Choosing the right cushion will depend on the person’s living environment, weight, mobility level, skin condition, posture in their wheelchair and the level of support they need.

Considerations: The cushions need to properly fit both the person and their wheelchair and other seating. All pressure cushions require a cover. The cushion cover will need to be carefully selected to ensure it fits properly and does not create forces that increase stress on the skin and the risk of developing pressure areas. They should be washable, especially for people who sweat, are incontinent, or eat and drink in their chairs. A second cushion cover is suggested to allow one to be washed while the other is in use. Placing towels, plastic sheets and other fabric over the cushion may reduce the benefits of the cushion and should be avoided.

With a tilt-in-space wheelchair, the entire seat and backrest tilt backwards within the wheelchair. The angle between the seat and backrest remains the same. As the angle of tilt increases, the pressure between the seat cushion and buttocks is reduced and redistributed to the backrest.

A person who uses a tilt-in-space wheelchair will stay in the upright position for most of the day, but move the seat and backrest into the tilted position for several short periods to reduce the pressure on their buttocks and help prevent pressure areas¹. By reducing pressure on the buttocks pressure areas can be prevented.

A tilted position is also often used to help hold an individual’s pelvis correctly in a wheelchair and to support the head and neck during everyday activities like eating, using eye-gaze control devices, communicating and school activities.

Considerations: Tilt-in-space seating can make a wheelchair larger, heavier and more expensive. Care must also be taken if someone is propelling their own tilt-in-space wheelchair in the tilted position as this can reduce the person’s vision and arm positioning, impacting on mobility and safety.

People with cerebral palsy are at greater risk of experiencing pressure areas if they are:

• Sitting or lying still for long periods
• Under- or over-weight
• Poorly nourished
• Incontinent
• Unable to feel pain or discomfort in the areas where pressure areas commonly develop²

Pressure areas are also more likely to develop when:

• Moisture is present
• Skin is dry or fragile
• Infection is present
• A person has trouble controlling their own temperature
• They have spine or hip deformities
• There is a change in health status or medication

Pressure areas are also known as pressure injuries, pressure sores, pressure ulcers and bedsores.

Two additional strategies are used to reduce pressure areas. They are not often used by people with cerebral palsy and are not included in this topic. One involves shifting weight in the wheelchair (called repositioning) and the other involves reclining the back rest of the wheelchair to redistribute pressures to different areas of skin.

Pressure cushions and wheelchairs will come with instructions and product information. It is very important to keep this information for future reference.

Before selecting equipment, a therapist will assess a person’s risk factors for developing pressure areas and create an appropriate prevention plan. This can involve mapping the risks and grading them on a scale based on the severity of existing pressure areas. The therapist will recommend regular monitoring of the person’s skin to help identify pressure areas early and ensure prevention wherever possible.

Assessing the severity

The damage pressure areas cause can range from mild to severe.

• Mild - appears as red skin
• Severe – appears as deep, open wounds which can be painful and restrict a person’s daily activities.

Careful assessment will also be required to ensure the correct pressure cushion and tilt-in-space wheelchair is trialled and selected.

A therapist will regularly review pressure cushions and wheelchairs to check they fit correctly, are comfortable and meet the needs of the individual with cerebral palsy.

We searched the medical and allied health literature to find research, published since 1995, evaluating the effects of pressure cushions and tilt-in-space wheelchairs.

The search aimed to find the best available evidence to answer two questions for children and adults with cerebral palsy.

1. What are the best cushions for preventing pressure areas?
   We included only articles involving longer term use of pressure cushions in day-to-day life.
   We did not include research measuring the pressure exerted on the buttocks and upper legs from short periods of sitting. This is because these research conditions do not take into consideration the other factors which may impact on pressure area development over time.
2. Does tilt-in-space reduce pressure areas on the buttocks, legs and lower back?

1 - Pressure cushions for preventing pressure areas

We didn’t find any research completed with people with cerebral palsy. We then drew on the best available evidence in other diagnostic groups. There was one good quality randomised controlled trial of 232 elderly people with limited mobility living in a nursing home³. The study compared a basic foam cushion with skin protection cushions (specifically designed to reduce pressures near bony areas). The overall incidence of pressure areas was lower than expected over the six-month study period, probably because all study participants had expert seating assessments and properly fitted wheelchairs, incontinence covers fitted to the cushions and a weekly skin review. There were, however, significantly fewer pressure areas in the group of participants who used the skin protection cushions.

We found two additional and related systematic reviews of studies which investigated pressure area prevention in a range of diagnoses^4,5. One review suggested that custom-fit air cushions, followed by gel cushions were more effective than water or foam cushions⁴. The other systematic review concluded that there was insufficient good quality research to draw conclusions about the most effective type of cushions⁵.

2 - Wheelchair tilt-in-space

We did not find any research which evaluated a reduction of pressure areas. We did locate many studies which measured short term pressures under the legs, buttocks and lower back when a seat was tilted in space at varying angles. The most informative evidence was from three systematic reviews of adults and/or children at risk of pressure areas^4,6,7 and three additional studies not included in these reviews^8,9,10. There were no studies with children or adults with cerebral palsy. Most studies included adults with spinal cord injury.

The findings from these studies are summarised below:

• As more angle of tilt-in-space is used, the pressures applied to the bony prominences in the buttocks when sitting are progressively reduced^4,8,9,10.
• Reducing pressures on the buttocks - Although researchers report it is difficult to identify a minimum amount of tilt-in-space to recommend^4,7, some authors suggest that 20° to 35° ^6,11 may be the minimum requirement for unloading pressures from the buttocks.
• Reducing pressures on the tailbone - Studies exploring the impact of tilt-in-space on pressures on the lower back suggest that at least 30° to 35° tilt is needed to minimise the displacement of pressure from the buttocks to the tailbone (sacrum and coccyx)^10,11.
• There are no guidelines about how often, or for how long, tilt-in-space should be applied over the course of the day to prevent pressure areas.
• Reclining the backrest in addition to tilt-in-space may further reduce the pressures exerted^11,12.

None of the research we located was carried out with people with cerebral palsy. We can, however, cautiously generalise the findings to children and adults with cerebral palsy as follows:

• Specialised cushions which are designed to protect skin and reduce pressure on the bony prominences are recommended for people with cerebral palsy at risk of pressure areas². Air and gel cushions are recommended over foam cushions^3,4.
• Pressure care should not be limited to use of a cushion. Tilt-in-space can be used, when appropriate, to provide short-term reduction of pressures on the bony prominences to reduce the risk of pressure areas. At least 30° to 35° degrees of tilt-in-space appears to be required to achieve pressure relief for the buttocks (ischial tuberosities) and tailbone (sacrum and coccyx)^10,11.
• Other components of prevention of pressure areas and discomfort are provision and maintenance of well-fitting wheelchairs and seating, with correctly adjusted armrests and leg rests, regular skin checks and care³, consideration of incontinence, and the appropriate use of cushion covers which minimise shearing effects.
• Other equipment such as commode chairs and splints need to be well fitting and checked regularly. Education is necessary to ensure carers transfer people with cerebral palsy carefully between equipment (e.g., bed to wheelchair) to minimise stress to skin.
• Maintaining a healthy weight and good nutrition are also important to reducing the risk of pressure areas.