Development and evaluation of a self-regulating alternating pressure air cushion

Purpose: To investigate the effect of alternating air cells of a newly developed dynamic cushion on interface pressure and tissue oxygenation levels. Method: This cross-over experimental study included 19 healthy volunteers. The dynamic cushion used has an automatic self-regulating alternating pressure air-cell system with 35 small and four large air cells for maintaining posture while seated. This cushion also has 17 bottoming-out detectors that automatically inflate the air cells to release a high interface pressure. To assess the effect of this alternating system, participants sat on the new cushion with an alternating system or static system for 30 min and then performed push-ups. The interface pressure was monitored by pressure-sensitive and conductive ink film sensors and tissue oxygenation levels were monitored by near-infrared spectroscopy. A reactive hyperaemia indicator was calculated using tissue oxygenation levels as an outcome measure. Results: The peak interface pressure was not significantly different between the groups. The reactive hyperaemia indicator was significantly higher in the static group than in the alternating group. Conclusions: An alternating system has beneficial effects on blood oxygenation levels without increasing interface pressure. Therefore, our new cushion is promising for preventing pressure ulcers with patients with limited ability to perform push-ups.