Department of Physics/Electro-Optics Engineering, Jerusalem College of Technology, 21 Havaad Haleumi St., 91160 Jerusalem, Israel.
Department of Electro-Optical Engineering, Ben-Gurion University of the Negev. 1 Ben-Gurion Blvd, 8410501 Beer Sheva, Israel.
Sensors (Basel). 2018 Oct 15;18(10):3457. doi: 10.3390/s18103457.
Oxygen saturation in arterial blood (SaO₂) provides information about the performance of the respiratory system. Non-invasive measurement of SaO₂ by commercial pulse oximeters (SpO₂) make use of photoplethysmographic pulses in the red and infrared regions and utilizes the different spectra of light absorption by oxygenated and de-oxygenated hemoglobin. Because light scattering and optical path-lengths differ between the two wavelengths, commercial pulse oximeters require empirical calibration which is based on SaO₂ measurement in extracted arterial blood. They are still prone to error, because the path-lengths difference between the two wavelengths varies among different subjects. We have developed modified pulse oximetry, which makes use of two nearby infrared wavelengths that have relatively similar scattering constants and path-lengths and does not require an invasive calibration step. In measurements performed on adults during breath holding, the two-infrared pulse oximeter and a commercial pulse oximeter showed similar changes in SpO₂. The two pulse oximeters showed similar accuracy when compared to SaO₂ measurement in extracted arterial blood (the gold standard) performed in intensive care units on newborns and children with an arterial line. Errors in SpO₂ because of variability in path-lengths difference between the two wavelengths are expected to be smaller in the two-infrared pulse oximeter.
动脉血氧饱和度（SaO₂）提供了有关呼吸系统功能的信息。商业脉搏血氧仪（SpO₂）通过对红色和红外线区域的光体积描记脉搏进行非侵入性测量，利用氧合和去氧血红蛋白对不同光谱的光吸收。由于两种波长的光散射和光程长度不同，商业脉搏血氧仪需要基于从动脉血中提取的 SaO₂测量进行经验校准。它们仍然容易出现误差，因为两种波长之间的光程长度差异在不同个体之间有所不同。我们已经开发出了改良的脉搏血氧仪，它利用了两个附近的红外线波长，这两个波长具有相对相似的散射常数和光程长度，并且不需要侵入性的校准步骤。在对成人进行屏气测量期间，两种红外线脉搏血氧仪和商业脉搏血氧仪的 SpO₂变化相似。与在新生儿和儿童的动脉导管中在重症监护病房中进行的动脉血 SaO₂测量（金标准）相比，两种脉搏血氧仪的准确性相似。由于两种波长之间的光程长度差异的可变性导致的 SpO₂误差预计在两种红外线脉搏血氧仪中较小。
