Effectiveness of double‐layer air‐cell overlay on tangential force in healthy young women with their head in an elevated position

Aim:  A semi‐reclining position in a bed is not desirable from a pressure ulcer prevention viewpoint, even with the use of support surfaces, because such positioning often leads to bottoming out and body movement, which is a cause of shear. Thus, the authors have developed a new, double‐layer overlay to prevent the onset of pressure ulcers for patients who require a head‐elevation position of 45 degrees or higher. The effects on avoiding bottoming out during head elevation were reported. But the effects on tangential force (shear) were not verified because appropriate sensors were not available. The purpose of this study was to estimate the body movement on the double‐layer overlay by observing skin deformation in the gluteal region. Methods:  In order to observe the skin deformation in the gluteal region visually in a patient in the head elevation position, a transparent air‐cell overlay was created and compared with a single overlay for six healthy female subjects who were in the head elevation of 45 and 70 degrees. The subjects were all informed of the purpose of this study. Results:  The double‐layer overlay showed only significantly small displacement along the vertical axis at the head elevations of 45 and 70 degrees, and it was also effective with respect to the feelings felt by the subjects. Conclusion:  These results suggested that the double‐layer overlay seems effective for maintaining posture for those who need a head elevated position of 45 degrees or higher.