Postural orthostatic tachycardia syndrome (POTS) is a disabling condition characterized by orthostatic intolerance with tachycardia in the absence of drop-in blood pressure. A custom-built near-infrared spectroscopy device (NIRS) is applied to monitor the muscle oxygenation, noninvasively in patients undergoing incremental head-up tilt table (HUT). Subjects (6 POTS patients and 6 healthy controls) underwent 30 mins of 70fl on a HUT. The results showed a significant difference in deoxyhemoglobin (Hb), change-in-oxygenation (ΔO_xy) and blood volume (ΔBV) between patients and healthy controls. However, oxyhemoglobin (HbO₂) showed a significantly faster rate of change in the healthy controls during the first 10 mins of the tilt and during the recovery. This NIRS muscle oximetry tool provides quantitative measurements of blood oxygenation monitoring in diseases such as POTS.

循环血量(CBV)作为主要的血流动力学参数, 在心血管疾病的病情评估和手术监护中具有重要的临床应用价值。 将吲哚菁绿色素（ICG）作为示踪剂的脉搏色素谱法, 通过建立ICG稀释排泄的色素谱曲线, 实现CBV的在体无创测量。 在实际临床应用中, 由于受到血氧波动和环境背景光等干扰因素的影响, 脉搏色素谱法测量CBV的准确度低于预期值。 为解决这一问题, 研究了一种基于修正脉搏色素谱的循环血量检测方法。 具体操作是, 在患者的肘静脉处注入吲哚菁绿试剂, 利用光电传感器分别采集特征波长点的透射光谱信号和背景光电信号, 采用差分算法消除血氧波动和环境背景光的干扰影响, 建立准确的ICG色素谱曲线, 从而计算CBV等血流动力学参数。 与131I同位素“金标准法”相比较的试验结果表明, 该研究提出的基于修正脉搏色素谱的循环血量检测方法, 将CBV测量的平均相对误差从6.85%降低为4.53%, 显著提高了其测量准确度。

血流动力学参数检测一直是临床医学研究的热点。 针对临床上测量血流动力学参数的方法存在有创、 操作复杂、 不适合重复测量的问题, 研究了一种结合指示剂稀释理论与近红外光谱技术的指示剂光密度测量法, 实现了血流动力学参数的无创检测。 通过体外注射吲哚氰绿（ICG）色素指示剂, 建立其在血液循环系统中稀释代谢的动力学模型, 利用近红外发光探头在指端分时发送735, 805和940 nm三个波长的近红外光, 同时在手指对侧实时接收携带脉搏波信息的透射光信号, 将测得的信号上传至计算机进行分析处理得到随时间变化的ICG浓度并将其绘制成连续的色素浓度曲线, 根据该曲线确定色素平均传输时间MTT及初始色素含量Ct0等中间变量, 进一步推算出心排出量CO及循环血容量CBV两项血流动力学参数。 将该方法与临床上测量上述两种参数的“金标准”—热稀释法、 碘-131同位素标记法进行临床试验对比, 测得10组CO及CBV的试验对比数据, 经误差分析得到两项参数的相对误差最大值分别为8.88%和4.28%, 平均相对误差值均低于5%, 满足临床检测的精度要求, 为临床上血流动力学参数的测量提供了一种安全性强、 连续性好、 适应范围更为广泛的方法。

The measurement of circulating blood volume (CBV) is crucial in various medical conditions including surgery, iatrogenic problems, rapid fluid administration, transfusion of red blood cells, or trauma with extensive blood loss including battlefield injuries and other emergencies. Currently, available commercial techniques are invasive and time-consuming for trauma situations. Recently, we have proposed high-speed multi-wavelength photoacoustic/photothermal (PA/PT) flow cytometry for in vivo CBV assessment with multiple dyes as PA contrast agents (labels). As the first step, we have characterized the capability of this technique to monitor the clearance of three dyes (indocyanine green, methylene blue, and trypan blue) in an animal model. However, there are strong demands on improvements in PA/PT flow cytometry. As additional verification of our proof-of-concept of this technique, we performed optical photometric CBV measurements in vitro. Three label dyes—methylene blue, crystal violet and, partially, brilliant green—were selected for simultaneous photometric determination of the components of their two-dye mixtures in the circulating blood in vitro without any extra data (like hemoglobin absorption) known a priori. The tests of single dyes and their mixtures in a flow system simulating a blood transfusion system showed a negligible difference between the sensitivities of the determination of these dyes under batch and flow conditions. For individual dyes, the limits of detection of 3×10^–6 M ? 3×10^–6 M in blood were achieved, which provided their continuous determination at a level of 10^–5 M for the CBV assessment without a priori data on the matrix. The CBV assessment with errors no higher than 4% were obtained, and the possibility to apply the developed procedure for optical photometric (flow cytometry) with laser sources was shown.

Understanding muscle hemodynamics using near-infrared spectroscopy is increasingly evident in the recent spinal disorders-related literature. However, none of these human studies addressed the issue of physiological limits for the lumbar muscle within the same participants during various exercise modes. The purpose of this study is to evaluate physiological limits for the lumbar muscle during dynamic and static endurance tests. On three separate days, 22 healthy men and women performed three endurance protocols (static prone trunk extension, arm cranking, and pushing- pulling) until volitional exhaustion. For each protocol, minimum and maximum oxygenation and blood volume responses from the right lumbar erector spinae were obtained using a continuous dual wavelength near-infrared spectroscopy (Micro-Runman, NIM Inc., PA, USA). Statistical analysis showed that greatest reduction in oxygenation (minimum) were obtained during dynamic exercises: pushing-pulling (2.1 times) and arm cranking (2.03 times) versus static test （P < 0.05）. Physiological change (calculated as the difference between maximum during recovery and minimum at the point of volitional exhaustion) during static test was lower [(66-75% for oxygenation) and (34-46% for blood volume)] than dynamic exercises （P < 0.05）. Contrary to the theory that sufficient occlusion of blood flow to the lumbar muscle is possible with static trunk extension, it was concluded that a dynamic protocol until volitional exhaustion might be a good alternative in establishing near-infrared spectroscopy-derived physiological limits to the lumbar muscle. Further research is essential to identify an optimal calibration procedure for establishing true hypoxic values for the human lumbar muscle.

利用功能近红外光谱技术(functionality near infrared spectroscopy, fNIRs)探索帕金森病(parkinson′s disease, PD)大鼠模型的脑组织功能特性。 通过小动物磁共振(magnetic resonance imaging, MRI)和电子计算机断层扫描(computed tomography, CT)对PD大鼠模型进行影像学研究, 用fNIRs系统测试大鼠模型脑组织纹状体特征参数。 实验结果表明, PD大鼠脑部没有明显的形态结构变化； 优化散射系数(reduced scattering coefficient: μ′s)、 脑血容量(cerebral blood volume: CBV)在PD大鼠的纹状体部与对照组间存在显著的差别； fNIRs测量参数(μ′s、 CBV)与CT灌注(CTP)测定参数［CBF(cerebral blood flow), CBV］之间存在相关性。 这些结果表明fNIRs可以作为PD研究的重要参考手段。

糖尿病严重危害人类健康,无创血糖检测是医患双方的期望。 人体生理背景成分复杂、易变,各种组织信息混杂,导致直接测量人体的近红外光谱很难真实反映血液中血糖浓度变化信息。 提出血流容积差光谱相减法,即利用血流容积一直在变而人体组织背景和血液成分含量短时间不变的事实,通过相似背景扣除,有效消除人体组织背景干扰,获得反映血液成分信息的有效光谱信号。 为验证方法的有效性,自行研制相关实验系统,获得系统噪声好于20 μAU,并在波长1250 nm处取得信噪比为20000:1的有效光谱信号, 阐明现有条件下血流容积差光谱相减法在近红外无创血糖检验临床应用的可行性和优势。