Relationship between mattress internal air pressure and interface pressure distribution in the lateral position

Previous research shows that maximum interface pressure increases when the patient is lying in the lateral position. However, it was unclear whether it was better to increase or decrease the internal air pressure to reduce the maximum interface pressure in the lateral position; thus, this study investigated this issue. In this study, we investigated the change in pressure redistribution because of the difference in internal air pressure between the supine and lateral positions on an active air mattress for pressure ulcer prevention management. Each participant's five internal air pressure values served as the independent variables. The interface pressure on the active air mattress was measured for 20 minutes. The sacral left iliac crest and left greater trochanteric interface pressures were measured using a portable pressure-measuring device. When seven of the 10 participants switched from the supine position to the left lateral position, there was a decrease in the maximum interface pressure as the internal air pressure increased. The maximum interface pressure in the greater trochanter in the lateral position was twice that in the sacral region in the supine position. These results show that increasing the internal air pressure in the lateral position might help reduce the maximum interface pressure.