Seton Ragnar, Thornell Greger, Persson Anders
Ångström Space Technology Centre, Div. of Microsystems Technology, Dept. of Materials Science and Engineering, Uppsala University The Ångström Laboratory Lägerhyddsvägen 1, 752 37 Uppsala, Sweden Postal: Box 534 Uppsala 751 21 Sweden
RSC Adv. 2020 Oct 5;10(60):36386-36395. doi: 10.1039/d0ra03877f. eCollection 2020 Oct 1.
Premature neonates are too small for repeated blood sampling, but still require precise monitoring of blood gas levels. The standard method therefore involves transcutaneous blood gas monitoring (TBM), analyzing gas that permeates the skin. The method involves skin heating and requires frequent relocation of a rigid sensor that is adhesively mounted to the skin, which makes the monitoring intermittent and can cause tissue damage. To mitigate this, this paper introduces a TBM concept that replaces the sensor with a small, non-adhesive, flexible, polydimethylsiloxane patch, routing the gases through skin-facing microchannels laid out in various configurations, to an external optical emission spectroscopy system (OES). As the OES depends on a constant flow of gas, we have investigated the effects external loads, both vertical and with a transverse component, have on the aerodynamic resistance of the patches. The experiments show that patches with 200 μm wide channels can withstand uniformly distributed forces up to 25 N with a change in aerodynamic resistance of about 0.01 mbar per sccm per newton. In subsequent measurements, the proof of concept (POC) TBM system showed a strong and fast blood gas signal that was unaffected by all likely loads in the intended application. Moreover, the rise time of the signal is shown to be inversely proportional to the aerodynamic resistance, and the signal strength to be proportional to the skin area exposed to the microchannels. With these results, the POC TBM system is a viable first step towards truly continuous blood gas monitoring of prematurely born children.
早产新生儿体型过小，无法进行反复采血，但仍需要精确监测血气水平。因此，标准方法是采用经皮血气监测（TBM），即分析透过皮肤的气体。该方法需要对皮肤进行加热，且需频繁重新放置通过粘贴固定在皮肤上的刚性传感器，这使得监测具有间歇性，还可能导致组织损伤。为缓解这一问题，本文介绍了一种TBM概念，用一个小型、无粘性、柔性的聚二甲基硅氧烷贴片取代传感器，将气体通过以各种配置布置的面向皮肤的微通道输送到外部光学发射光谱系统（OES）。由于OES依赖于恒定的气体流量，我们研究了垂直和带有横向分量的外部负载对贴片空气动力学阻力的影响。实验表明，具有200μm宽通道的贴片能够承受高达25N的均匀分布力，每牛顿每标准立方厘米每秒的空气动力学阻力变化约为0.01毫巴。在后续测量中，概念验证（POC）TBM系统显示出强烈且快速的血气信号，该信号不受预期应用中所有可能负载的影响。此外，信号的上升时间与空气动力学阻力成反比，信号强度与暴露于微通道的皮肤面积成正比。基于这些结果，POC TBM系统是朝着真正连续监测早产儿童血气迈出的可行的第一步。
