City University London, School of Engineering and Mathematical Sciences, Northampton Square, London, EC1V 0HB United Kingdom.
J Biomed Opt. 2010 Mar-Apr;15(2):027012. doi: 10.1117/1.3374355.
Splanchnic organs are particularly vulnerable to hypoperfusion. Currently, there is no technique that allows for the continuous estimation of splanchnic blood oxygen saturation (SpO(2)). As a preliminary to developing a suitable splanchnic SpO(2) sensor, a new reflectance fiber optic photoplethysmographic (PPG) sensor and processing system are developed. An experimental procedure to examine the effect of fiber source detector separation distance on acquired PPG signals is carried out before finalizing the sensor design. PPG signals are acquired from four volunteers for separation distances of 1 to 8 mm. The separation range of 3 to 6 mm provides the best quality PPG signals with large amplitudes and the highest signal-to-noise ratios (SNRs). Preliminary calculation of SpO(2) shows that distances of 3 and 4 mm provide the most realistic values. Therefore, it is suggested that the separation distance in the design of a fiber optic reflectance pulse oximeter be in the range of 3 to 4 mm. Preliminary PPG signals from various splanchnic organs and the periphery are obtained from six anaesthetized patients. The normalized amplitudes of the splanchnic PPGs are, on average, approximately the same as those obtained simultaneously from the periphery. These observations suggest that fiber optic pulse oximetry may be a valid monitoring technique for splanchnic organs.
内脏器官特别容易发生低灌注。目前，还没有一种技术可以连续估计内脏血氧饱和度（SpO₂）。在开发合适的内脏 SpO₂传感器之前，开发了一种新的反射式光纤光体积描记（PPG）传感器和处理系统。在确定传感器设计之前，进行了一项实验程序，以检查光纤源探测器分离距离对获得的 PPG 信号的影响。从四名志愿者处采集了分离距离为 1 至 8 毫米的 PPG 信号。分离范围为 3 至 6 毫米可提供具有最大幅度和最高信噪比（SNR）的最佳质量 PPG 信号。SpO₂的初步计算表明，3 毫米和 4 毫米的距离提供了最现实的值。因此，建议在光纤反射式脉搏血氧计的设计中，分离距离应在 3 至 4 毫米范围内。从六名麻醉患者获得了来自各种内脏器官和外周的初步 PPG 信号。内脏 PPG 的归一化幅度平均与同时从外周获得的幅度相同。这些观察结果表明，光纤脉搏血氧计可能是内脏器官的有效监测技术。
