Biomedical Optics Research Laboratory (BORL), Department of Neonatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
Adv Exp Med Biol. 2018;1072:381-385. doi: 10.1007/978-3-319-91287-5_61.
Liquid blood phantoms are a tool to calibrate, test and compare near-infrared spectroscopy (NIRS) oximeters. They comprise a mixture of saline, blood and Intralipid, which is subsequently oxygenated and deoxygenated to assess the entire range of tissue oxygen saturation (StO) from 0% to 100%. The aim was to investigate two different deoxygenation methods: yeast versus nitrogen (N) bubbling. The phantom was oxygenated with pure O in both experiments, but deoxygenated by bubbling N in the first and by addition of yeast and glucose in the second experiment. A frequency domain NIRS instrument (OxiplexTS) was used as reference and to monitor changes in the reduced scattering coefficient (μ') of the phantom. Both deoxygenation methods yielded comparable StO values. The deoxygenation was slower by a factor 2.8 and μ' decreased faster when bubbling N. The constant bubbling of N mechanically stresses the Intralipid emulsion and causes a decrease in μ', probably due to aggregation of lipid droplets. Deoxygenation by N requires a more complex, air tight phantom. The gas flow cools the liquid and temperature needs to be monitored more closely. Consequently, we recommend using yeast for phantom deoxygenation.
液态血仿体是一种用于校准、测试和比较近红外光谱（NIRS）血氧计的工具。它由生理盐水、血液和 Intralipid 混合而成，随后进行充氧和脱氧处理，以评估组织氧饱和度（StO）从 0%到 100%的整个范围。目的是研究两种不同的脱氧方法：酵母与氮气（N）鼓泡法。在两项实验中，血仿体均使用纯 O 进行充氧，但在第一项实验中通过鼓泡 N 进行脱氧，而在第二项实验中通过添加酵母和葡萄糖进行脱氧。使用频域 NIRS 仪器（OxiplexTS）作为参考，并监测血仿体的散射系数（μ'）的变化。两种脱氧方法都产生了可比的 StO 值。通过 N 鼓泡脱氧的速度慢了 2.8 倍，μ'的下降速度也更快。N 的持续鼓泡会对 Intralipid 乳剂造成机械压力，导致μ'下降，可能是由于脂质滴的聚集。使用 N 进行脱氧需要一个更复杂的、密封的血仿体。气流会使液体冷却，因此需要更密切地监测温度。因此，我们建议使用酵母进行血仿体脱氧。
