The effect of hematocrit on the efficacy of phototherapy for neonatal jaundice
The effect of hematocrit on the efficacy of phototherapy for neonatal jaundice
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DOI：
10.1038/pr.2013.67
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发表时间：
2013-07-01
影响因子：
3.6
通讯作者：
McDonagh, Antony F.
中科院分区：
文献类型：
--
作者：
Lamola, Angelo A.;Bhutani, Vinod K.;McDonagh, Antony F.
背景：光疗的治疗作用光谱范围为420 ~ 500 nm。然而，最近的一份关于荧光“绿松石”灯功效改善的报告显示，（类似于490 nm）与蓝光相比（类似于450 nm）强调了使用非常窄的波长范围来定义用于精确靶向光疗的最佳作用光谱的需要。我们用的是电流半导体-皮肤光学特性的经验模型，用于在可能被血红蛋白（Hb）混淆的各种波长下胆红素吸收的光的分数的稳健计算、黑色素和皮肤厚度。结果：所有计算的作用光谱都显示出一个位于472 ~ 480 nm的吸收峰（大部分在476 nm），与文献报道的胆红素460 nm吸收峰相比有明显的偏移。值得注意的是，作用光谱的相对振幅与红细胞压积（Hct）呈反比关系。结论：我们推测，在476 nm的窄范围的光将比蓝色（宽带）荧光灯有效60%。由于Hb是胆红素对光吸收的主要竞争者，因此计算还预测光疗的疗效取决于Hct。高Hct可降低治疗效率。
BACKGROUND: The therapeutic phototherapy action spectrum ranges from 420 to 500 nm. However, a recent report of improved efficacy of fluorescent "turquoise" light (similar to 490 nm) as compared with blue light (similar to 450 nm) underscores the need to define an optimal action spectrum for precision-targeted phototherapy using very narrow wavelength ranges.METHODS: We used a current semi-empirical model of the optical properties of skin for robust calculations of the fraction of light absorbed by bilirubin at various wavelengths that could be confounded by hemoglobin (Hb), melanin, and skin thickness. Applying assumptions regarding the wavelength dependence of bilirubin photochemistry, "action spectra" were assembled from the calculated values.RESULTS: All the calculated action spectra displayed a peak between 472 and 480 nm (most at 476 nm), which is a significant shift from the well-reported 460 nm absorption peak of bilirubin. Of note, the relative amplitudes of the action spectra showed an inverse relationship with hematocrit (Hct).CONCLUSION: We speculate that a narrow range of light at 476 nm would be 60% more effective than blue (broadband) fluorescent lamps. Because Hb serves as a major competitor of bilirubin for light absorption, the calculations also predict that the efficacy of phototherapy is dependent on the Hct. A high Hct could reduce therapeutic efficiency.