Effects on tissue oxygenation in the gluteal region with a smart pressure redistribution wheelchair cushion compared to a pressure relief manoeuvre.

Objective: The study examines the effects of the air-bladder offloading mode of a smart pressure redistribution wheelchair cushion on tissue oxygenation in the gluteal tissue of non-disabled participants. The hypothesis is that the cushion's offloading mode, which involves sequentially deflating its five air-bladders one at a time for a specific duration, would improve tissue oxygenation during sitting.

Methods: Two procedures were conducted. The first compared the cushion's offloads to a loaded control (LC) with the cushion on static mode, and the second compared the cushion's offloading mode to a standard manual offload performed by the participant. Three trials of each procedure were performed in randomized order. Tissue oxygenation was continuously monitored with three oxygenation parameters analysed: oxygen saturation (SO₂), oxygenated haemoglobin (OxyHb), and deoxygenated haemoglobin (DeoxyHb). Data recordings were segmented in each step of the offloading sequence for analysis. A paired t-test was performed for comparisons with significance considered at α = 0.05. Ten healthy adults participated in the study.

Impact: Results showed that as the air bladders deflated over time, the three evaluated parameters changed, affecting oxygenation even when other tissue areas were offloaded. The results indicated that the cushion's sacral offload had the greatest impact on improving tissue oxygenation among the five air-bladders in all ten subjects (p < 0.05). Furthermore, SO₂ during the cushion's offload in the sacral region was similar to a manual offload. The study results suggest that the cushion could benefit tissue oxygenation, especially for individuals unable to change positions independently. Further research is needed to determine its effectiveness for wheelchair users.