BiOSENCY, Cesson-Sévigné, France.
University of Strasbourg and CNRS, Strasbourg Cedex, France.
J Biomed Opt. 2020 Oct;25(10). doi: 10.1117/1.JBO.25.10.105001.
The arterial carbon dioxide (CO2) partial pressure PaCO2 is a clinically relevant variable. However, its measurement requires arterial blood sampling or bulky and expensive transcutaneous PtcCO2 meters. While the spectrophotometric determination of hemoglobin species-such as oxy-hemoglobin (O2Hb) and deoxy-hemoglobin (HHb)-allowed for the development of pulse oximetry, the measurement of CO2 blood content with minimal discomfort has not been addressed yet.
Characterizing human carbamino-hemoglobin (CO2Hb) absorption spectrum, which is missing from the literature. Providing the theoretical background that will allow for transcutaneous, noninvasive PaCO2 measurements.
A tonometry-based approach was used to obtain gas-equilibrated, lysed, diluted human blood. Equilibration was performed with both CO2, dinitrogen (N2), and ambient air. Spectrophotometric measurements were carried out on the 235- to 1000-nm range. A theoretical background was also derived from that of pulse oximetry.
The absorption spectra of both CO2Hb and HHb were extremely close and comparable with that of state-of-the-art HHb. The above-mentioned theoretical background led to an estimated relative error above 30% on the measured amount of CO2Hb in a subject's blood. Auxiliary measurements revealed that the use of ethylene diamine tetraacetic acid did not interfere with spectrophotometric measurements, whereas sodium metabisulfite did.
CO2Hb absorption spectrum was measured for the first time. Such spectrum being close to that of HHb, the use of a theoretical background based on pulse oximetry theory for noninvasive PaCO2 measurement seems extremely challenging.
动脉血二氧化碳（CO2）分压 PaCO2 是一个具有临床相关性的变量。然而，其测量需要进行动脉采血，或使用笨重昂贵的经皮 PtcCO2 监测仪。虽然血红蛋白各型（如氧合血红蛋白[O2Hb]和去氧血红蛋白[HHb]）的分光光度测定允许发展脉搏血氧饱和度测定，但尚未解决最小不适感下 CO2 血含量的测量问题。
描述目前文献中缺失的人类碳氧血红蛋白（CO2Hb）吸收光谱，为经皮、无创 PaCO2 测量提供理论背景。
采用基于张力测定的方法从人血中获取气体平衡、裂解、稀释的样本。平衡气体为 CO2、氮气（N2）和环境空气。在 235-1000nm 范围内进行分光光度测量。此外，还从脉搏血氧饱和度测定的理论背景中推导出理论背景。
CO2Hb 和 HHb 的吸收光谱非常接近，且与现有 HHb 光谱相当。上述理论背景导致对受试者血液中 CO2Hb 测量量的估计相对误差超过 30%。辅助测量显示，乙二胺四乙酸的使用不干扰分光光度测量，而亚硫酸氢钠则会干扰。
首次测量了 CO2Hb 吸收光谱。由于其光谱与 HHb 非常接近，因此基于脉搏血氧饱和度测定理论的无创 PaCO2 测量的理论背景似乎极具挑战性。
