Tzen Yi-Ting, Brienza David M, Karg Patricia E
Department of Health Care Sciences, UT Southwestern Medical Center, USA; Department of Physical Medicine and Rehabilitation, UT Southwestern Medical Center, USA; Department of Orthopedic Surgery, UT Southwestern Medical Center, USA.
Department of Rehabilitation Science and Technology, University of Pittsburgh, USA.
J Tissue Viability. 2019 Nov;28(4):173-178. doi: 10.1016/j.jtv.2019.09.006. Epub 2019 Sep 26.
The purpose of this study was to investigate the effectiveness of local cooling in reducing reactive hyperemia after ischemia at the ischial tuberosities for people with spinal cord injury (SCI) during normal seating. The degree of the reactive hyperemic response is indicative of the extent of cellular stress caused by the ischemia. We hypothesized that reactive hyperemic skin blood flow (SBF) responses will be lower when local cooling is implemented by the wheelchair seat cushion. This study used a repeated measures design, and each subject underwent two conditions: normal seating with temperature control 'on' (cooling) and 'off' (non-cooling) for 30 min. Twenty-three participants with traumatic SCI were recruited. SBF and skin temperature were collected before, during and after seating. SBF signals were processed with short-time Fourier analyses to examine the underlying vascular control mechanisms, including the following (corresponding frequency bands): metabolic (0.0095-0.02 Hz), neurogenic (0.02-0.05 Hz), and myogenic (0.05-0.15 Hz) spectral densities. Our results showed that with cooling, skin temperature decreased (range -0.4 ~ -3.1 °C, p = 0.002), and reactive hyperemia parameters (normalized peak SBF and perfusion area) were reduced (p = 0.02, p = 0.033, respectively). In addition, changes in normalized peak SBF (non-cooling - cooling) was moderately correlated with changes in normalized metabolic and neurogenic spectral densities. Our findings suggested that local cooling has a positive effect on reducing the cellular stress caused by ischemia during normal seating. Metabolic and neurogenic SBF control mechanisms may play a minor role. Further exploration of the effect of temperature control on pressure injury prevention is warranted.
本研究的目的是调查局部降温对脊髓损伤（SCI）患者在正常坐姿下坐骨结节缺血后反应性充血的减轻效果。反应性充血反应的程度表明了缺血引起的细胞应激程度。我们假设，当通过轮椅座垫进行局部降温时，反应性充血皮肤血流量（SBF）反应会降低。本研究采用重复测量设计，每位受试者经历两种条件：温度控制“开”（降温）和“关”（不降温）的正常坐姿各30分钟。招募了23名创伤性SCI患者。在就座前、就座期间和就座后收集SBF和皮肤温度。对SBF信号进行短时傅里叶分析，以检查潜在的血管控制机制，包括以下方面（相应频段）：代谢（0.0095 - 0.02Hz）、神经源性（0.02 - 0.05Hz）和肌源性（0.05 - 0.15Hz）频谱密度。我们的结果表明，降温时皮肤温度降低（范围为 -0.4~ -3.1°C，p = 0.002），反应性充血参数（归一化峰值SBF和灌注面积）降低（分别为p = 0.02，p = 0.033）。此外，归一化峰值SBF（不降温 - 降温）的变化与归一化代谢和神经源性频谱密度的变化呈中度相关。我们的研究结果表明，局部降温对减轻正常坐姿下缺血引起的细胞应激有积极作用。代谢和神经源性SBF控制机制可能起次要作用。有必要进一步探索温度控制对预防压力性损伤的影响。
