Leung F W, Lo S K, Phan Q Q, Leung J W, Yanni G S, Jing J
Research and Medical Services, Sepulveda VAMC, California 91343, USA.
Gastrointest Endosc. 1995 Jan;41(1):18-24. doi: 10.1016/s0016-5107(95)70271-7.
Although the technique of endoscopic reflectance spectrophotometry has been applied in clinical studies, factors that modify the reproducibility of measurements have not been assessed systematically. To determine the limitations of the technique, measurements were made while endoscopic light intensity, systemic oxygen saturation, and orientation of the measuring probe were varied. The effects of hemorrhagic hypotension and exposure of the mucosa to 10% dextrose were also studied. When a large number (n = 480) of measurements in the human colon were considered, endoscopic light significantly decreased the index of oxygen saturation (ISO2) and increased the index of hemoglobin concentration (IHB). The decrease in ISO2, however, was small and unlikely to be of clinical importance despite being statistically significant. In one subject with chronic lung disease and baseline hypoxemia, administration of supplemental oxygen significantly increased oxygen saturation at the finger tip as measured by an oximeter and ISO2 of the buccal mucosa as measured by reflectance spectrophotometry. Varying the angle between the measuring probe and the gastric mucosa in rats from 90 degrees to 60 degrees did not affect ISO2 or IHB measurements. At 45 degrees, however, IHB but not ISO2 was significantly increased. Ischemia subsequent to induction of hemorrhagic hypotension and hyperemia induced by administration of 10% dextrose could be demonstrated reproducibly. We conclude that by lowering the intensity of endoscopic light and providing supplemental oxygen, errors in the measurement of IHB and ISO2, respectively, can be minimized. Minor deviations from the perpendicular orientation do not significantly affect ISO2 and IHB measurements. Attention to these details enhances the accuracy of endoscopic reflectance spectrophotometric recordings of ISO2 and IHB in clinical studies.
尽管内镜反射分光光度法技术已应用于临床研究，但尚未系统评估影响测量重复性的因素。为了确定该技术的局限性，在改变内镜光强度、全身氧饱和度和测量探头方向的同时进行了测量。还研究了出血性低血压和黏膜暴露于10%葡萄糖的影响。当考虑在人体结肠中进行大量（n = 480）测量时，内镜光显著降低了氧饱和度指数（ISO2）并增加了血红蛋白浓度指数（IHB）。然而，ISO2的降低幅度较小，尽管具有统计学意义，但不太可能具有临床重要性。在一名患有慢性肺病和基线低氧血症的受试者中，补充氧气后，通过血氧计测量的指尖氧饱和度以及通过反射分光光度法测量的颊黏膜ISO2均显著增加。将大鼠测量探头与胃黏膜之间的角度从90度改变到60度不会影响ISO2或IHB测量。然而，在45度时，IHB显著增加，而ISO2未受影响。出血性低血压诱导后的缺血和10%葡萄糖给药诱导的充血均可重复性地显示。我们得出结论，通过降低内镜光强度并提供补充氧气，可分别将IHB和ISO2测量中的误差降至最低。与垂直方向的微小偏差不会显著影响ISO2和IHB测量。在临床研究中关注这些细节可提高内镜反射分光光度法记录ISO2和IHB的准确性。
