Key principles of seating

Offloading

• Pressure relieving equipment does not remove all pressure or the need to reposition and do regular pressure relief.
• The pelvis is the most common site for developing a pressure injury.
• Reposition every 30 minutes for at least 60 seconds.
• There are a variety of techniques that can be used:

Maximise surface area contact

Pressure equals mass per unit area. Ischial tuberosities take most of the seated body weight (in neutral sitting) on a flat firm surface. The goal is to increase surface contact in sitting by distributing weight to the greater trochanters and onto the back of the thighs. This is best done with immersion.

Common issues affecting pressure distribution in sitting:

Cushion

• Incorrect set up can mean the air cushion may be over or underinflated: both can cause high pressure over the ischial bones.
• Inadequate gel or incorrect well width on the cushion can cause the person to “bottom out” through the gel.
• Incorrect dimensions such as too short depth or width can cause problems with thigh and/or greater trochanter and cause sliding forward in the chair.

Footplate height

• Neutral knee positioning is most ideal.

Seat rake/squeeze

• Too much seat rake/squeeze can increase ischial pressure.

Maintain or improve postural alignment

• Teach the person with SCI to check with a mirror, take a photograph or have someone else check the skin.
• Perform a postural assessment to determine issues and solutions.
• Start at the hips to provide a stable base of support (being mindful of cushion selection such as air or gel) and then assess above and below the hips.
• Comfort and functional independence are crucial in improving compliance and increased sitting tolerance.

Key considerations for postural alignment:

• The back support fits the person, not the chair.
• Lateral support should provide correct alignment without impacting functions such as propulsion or transfers.
• The correct height of the back support without impacting functions such as propulsion.
• Correct height and positioning of armrests.

Generic wheelchair and cushion considerations

• Check the wheelchair and cushion are well maintained.
• Educate the person on how to check and maintain correct cushion pressures. The cushion should be checked daily to see that it is correctly placed on the wheelchair and in working order.
• Wash cushion covers regularly as this will reduce bacterial growth on the cover.
• Metal sections on the wheelchair will heat up in hot environments and can cause burns.