ETH Zurich, Institute for Biomechanics, 8093 Zurich, Switzerland.
University Hospital Zurich, Division of Plastic Surgery and Hand Surgery, 8091 Zurich, Switzerland.
Biomed Res Int. 2019 Mar 6;2019:4027976. doi: 10.1155/2019/4027976. eCollection 2019.
Pressure ulcers (PUs) result from localised injury to the skin and underlying tissue and usually occur over a bony prominence as a result of pressure, often in combination with shear forces. Both pressure magnitude and duration are thought to be key risk factors in the occurrence of PUs, thus exposing wheelchair-bound subjects to high risk of PU development. As a result, wheelchairs that incorporate tilt-in-space and recline functions are routinely prescribed to redistribute pressure away from their ischial tuberosities. The goal of this study was to analyse the role of full-body tilt and recline angles in governing sitting interface pressure and blood circulation parameters in elderly subjects and thereby investigate the efficacy of tilt-in-space wheelchairs for aiding pressure relief activity. Sitting interface pressure and ischial blood flow parameters were examined in 20 healthy elderly subjects while seated in a tilt-in-space and recline wheelchair. Five different angles of seat tilt (5°, 15°, 25°, 35°, and 45°) were assessed in combination with three different angles of backrest recline (5°, 15°, and 30°). The results of the study show that when compared to the upright reference posture, every position (except 15°T/5°R) resulted in a significant decrease in sitting interface pressure. Ischial blood flow also showed significant increases at four different positions (45°T/15°R, 15°T/30°R, 35°T/30°R, and 45°T/30°R) but only at larger tilt-in-space and recline angles. The results therefore suggest that small tilt-in-space and recline angles are indeed able to reduce sitting interface pressures, whereas changes in ischial blood flow only occur at larger angles. In the literature, cell deformation is thought to be dominant over tissue ischemia in the development of tissue necrosis and PUs. Therefore, together with our findings it can be concluded that frequently undertaking small adjustments in tilt-in-space and recline angle might be important for preventing cell deformation and any associated cell necrosis. Larger angles of tilt-in-space and recline seem to support blood flow returning to the tissues, which is likely to play a positive role in healing damaged tissue.
压力性溃疡（Pressure ulcers，PU）是由于皮肤和皮下组织的局部损伤引起的，通常发生在骨隆突处，是由于压力引起的，通常与剪切力有关。压力的大小和持续时间都被认为是发生压力性溃疡的关键风险因素，因此使轮椅使用者面临着发生压力性溃疡的高风险。因此，通常会为轮椅使用者开具具有倾躺功能的轮椅，以将压力从坐骨结节处重新分布。本研究的目的是分析全身倾斜和后倾角度在控制老年受试者坐姿界面压力和血液循环参数方面的作用，从而研究倾躺式轮椅在缓解压力方面的效果。本研究对 20 名健康老年人进行了坐姿界面压力和坐骨血流参数检测，他们坐在倾躺式和后倾式轮椅上。评估了 5 种不同的座椅倾斜角度（5°、15°、25°、35°和 45°），并结合 3 种不同的椅背后倾角度（5°、15°和 30°）。研究结果表明，与直立参考姿势相比，除 15°T/5°R 外，每种姿势都会导致坐姿界面压力显著降低。坐骨血流在 4 个不同位置（45°T/15°R、15°T/30°R、35°T/30°R 和 45°T/30°R）也显示出显著增加，但仅在更大的倾躺空间和后倾角度下。因此，研究结果表明，小角度的倾躺空间和后倾确实能够降低坐姿界面压力，而坐骨血流的变化仅发生在较大的角度。在文献中，细胞变形被认为是组织缺血导致组织坏死和压力性溃疡的主要原因。因此，结合我们的研究结果可以得出结论，经常在倾躺空间和后倾角度上进行小的调整对于防止细胞变形和任何相关的细胞坏死可能非常重要。更大的倾躺空间和后倾角度似乎有助于血液回流到组织中，这可能对受损组织的愈合起到积极作用。
