Evaluating bottoming-out of bariatric sized wheelchair cushions

Area of Science:

• Biomedical Engineering
• Rehabilitation Engineering
• Materials Science

Background:

• Wheelchair cushions are classified using HCPCS codes in the US.
• Skin Protection cushions are for users at risk of tissue damage.
• Bariatric cushions exceed 22 inches in width, but current testing is inadequate.

Purpose of the Study:

• To evaluate the performance of heavy-duty or bariatric wheelchair cushions.
• To use an anthropometrically appropriate buttock model and loading profile for testing.
• To determine if current testing methods are suitable for wider cushions.

Main Methods:

• A rigid buttock model simulating users of wider cushions (>55 cm) was developed.
• Six bariatric wheelchair cushions were tested using the model.
• Loads of 75 kg and 88 kg were applied, representing 50th and 80th percentile users.

Main Results:

• No cushions bottomed out at 88 kg, suggesting support for users up to 135 kg.
• Two of six cushions bottomed out or neared bottoming out at their maximum rated loads.
• Current testing protocols are insufficient for evaluating bariatric cushion performance.

Conclusions:

• A more valid approach is needed to classify Skin Protection bariatric cushions.
• Existing testing methods do not accurately reflect the performance of wider cushions.
• Further research is required to develop appropriate testing standards for bariatric users.