Evaluating bottoming-out of bariatric sized wheelchair cushions

In the United States, wheelchair cushions are classified using HCPCS codes. Cushions classified as Skin Protection cushions are provided for wheelchair users who are at risk of tissue damage. Cushions designed for bariatric users fall into a category of cushions with width of 22 inches or greater. Current coding procedures require tests that are designed for 41-43-cm-wide cushion so cannot evaluate wider cushions. The objective of this study was to evaluate the performance of heavy-duty or bariatric wheelchair cushions using an anthropometrically appropriate buttock model and loading profile. A rigid buttock model, designed to reflect the anthropometry of persons using cushions over 55 cm in width was loaded onto six bariatric-sized wheelchair cushions. Two applied loads, 75 and 88 kg, represented the 50th and 80th percentile of persons who would be expected to use a 55-cm-wide cushion. None of the cushions indicated a bottomed-out state at the 88 kg load, suggesting that they could adequately support users weighing 135 kg. However, when evaluating cushions at their maximum rated loads, two of the six cushions were approaching or had bottomed-out. This study indicates that a more valid approach to classify Skin Protection bariatric cushions is needed.