Biomedical Engineering Program, University of North Dakota, Grand Forks, ND, USA.
Occupational Therapy Department, University of North Dakota, Grand Forks, ND, USA.
J Tissue Viability. 2022 Aug;31(3):491-500. doi: 10.1016/j.jtv.2022.04.004. Epub 2022 Apr 16.
Wheelchair users have a higher risk of developing pressure ulcers due to prolonged seated pressure. Pressure ulcers can be painful, may require surgical intervention, and even become life-threatening if infection occurs. To prevent pressure ulcers from forming the patient must either offload themselves or rely on a caregiver to move them allowing pressure redistribution over the seated area. In this work, we designed a dynamic air cushion to relieve pressure on loaded areas using sequences of inflation and deflation of the air cushion cells. The purpose of these sequences is to offload pressure from high-risk areas. To evaluate the effect of the alternating sequences on seated pressure and blood perfusion, we recorded interface pressure, skin blood flow, superficial tissue oxygen saturation, blood concentrations of oxygenated hemoglobin, and deoxygenated hemoglobin from twenty-one healthy volunteers who were asked to sit on the air cushion for static mode recording (3 min) and during the inflation/deflation sequences (up to 22 min). The alternating sequences consisted of ten combined inflation and deflation steps. Results showed that, after applying the alternating sequences, interface pressure reduced significantly (p=0.02) compared to the static mode. Moreover, the coefficient of variation of the seated pressure was higher (p<0.001) during the alternation sequence compared to the static mode. However, interface pressure under the right and left ischial tuberosities increased (p<0.001) during the alternation sequence compared to the static mode. In addition, during the alternating sequences, males had larger dispersion index values of both right and left ischial tuberosities pressure compared to females. Furthermore, the maximum value of oxygen saturation (p=0.04) and skin blood flow (p=0.001) increased during the pressure alternation sequences compared to the static mode. The study findings highlighted the positive effects of the designed dynamic air-cushion to relieve pressure on compressed areas and enhance blood perfusion similar to manual offloading approaches. The outcomes of this study are encouraging to evaluate the performance of the designed air cushion in studies involving wheelchair users.
轮椅使用者由于长时间坐姿，面临更高的压力性溃疡风险。压力性溃疡会带来疼痛，可能需要手术干预，甚至发生感染时还会危及生命。为了防止压力性溃疡的形成，患者要么自行减压，要么依靠护理人员帮助移动身体，以实现受压部位的压力再分布。在这项工作中，我们设计了一种动态空气垫，通过空气垫单元的充放气序列来减轻负载区域的压力。这些序列的目的是将压力从高风险区域转移走。为了评估交替序列对坐姿压力和血液灌注的影响，我们记录了 21 名健康志愿者的界面压力、皮肤血流、浅层组织氧饱和度、氧合血红蛋白和去氧血红蛋白的血液浓度，他们被要求坐在空气垫上进行静态模式记录（3 分钟）和充气/放气序列（最长 22 分钟）。交替序列由十个充气和放气步骤组成。结果表明，与静态模式相比，应用交替序列后，界面压力显著降低（p=0.02）。此外，与静态模式相比，交替序列中的坐姿压力变化系数更高（p<0.001）。然而，与静态模式相比，交替序列中右坐骨结节和左坐骨结节下的界面压力增加（p<0.001）。此外，在交替序列中，男性的右侧和左侧坐骨结节压力的离散指数值均大于女性。此外，与静态模式相比，在压力交替序列中，最大氧饱和度（p=0.04）和皮肤血流（p=0.001）增加。本研究结果强调了所设计的动态空气垫在缓解受压区域压力和增强血液灌注方面的积极效果，类似于手动减压方法。本研究的结果令人鼓舞，可用于评估设计的空气垫在涉及轮椅使用者的研究中的性能。
