Sitting Pressures
- Sitting pressure is highest in the tissue directly under the hip bones: (from medial to lateral) the sacrum, ischial tuberosities, and the trochanters. This pressure constricts blood vessels and causes cell death, creating pressure ulcers.
Different postures and sitting modalities affect pressure distribution. Note the bone prominences in the pressure distribution.
- Factors that directly affect this distribution is whether the chair has arm supports or elevating leg supports; and whether the user is sitting up straight, slouching, or sitting back. Highest pressure is created when the user sits forward because no back support is used.
Air Cell Technology
Heat Dissipation and Air Flow
Moisture against the skin, usually do to sweating, can cause pressure ulcers by reducing skin strength, elasticity, and thickness. Therefore moisture control and temperature regulation is important for ulcer prevention.
- Higher density materials such as gels and foams can absorb more heat energy from the body, which can be beneficial for regulating temperature.
- Breathable materials allow air flow and accommodate evaporation.
- Waterproof covers are important for sterilization.
This works by pumping air through beads or fine sand materials, creating a fluid environment in which the patient can float. It creates a low pressure environment, uses a lot of energy, and requires a lot of space. This technology is not practical for a wheelchair application.
