University of Arizona, Department of Emergency Medicine and College of Optical Sciences, 1609 North Warren Avenue, Room 116, Tucson, Arizona 85724-5057, USA.
J Biomed Opt. 2011 Oct;16(10):107004. doi: 10.1117/1.3638134.
Retinal oximetry offers potential for noninvasive assessment of central venous oxyhemoglobin saturation (SO(2)) via the retinal vessels but requires a calibrated accuracy of ±3% saturation in order to be clinically useful. Prior oximeter designs have been hampered by poor saturation calibration accuracy. We demonstrate that the blue-green oximetry (BGO) technique can provide accuracy within ±3% in swine when multiply scattered light from blood within a retinal vessel is isolated. A noninvasive on-axis scanning retinal oximeter (ROx-3) is constructed that generates a multiwavelength image in the range required for BGO. A field stop in the detection pathway is used in conjunction with an anticonfocal bisecting wire to remove specular vessel reflections and isolate multiply backscattered light from the blood column within a retinal vessel. This design is tested on an enucleated swine eye vessel and a retinal vein in a human volunteer with retinal SO(2) measurements of ∼1 and ∼65%, respectively. These saturations, calculated using the calibration line from earlier work, are internally consistent with a standard error of the mean of ±2% SO(2). The absolute measures are well within the expected saturation range for the site (-1 and 63%). This is the first demonstration of noninvasive on-axis BGO retinal oximetry.
视网膜血氧计通过视网膜血管提供了非侵入性评估中心静脉血氧饱和度 (SO(2)) 的潜力，但需要校准精度在±3%饱和度以内才能在临床上有用。先前的血氧计设计受到饱和度校准精度差的限制。我们证明，当从视网膜血管内的血液中分离出多重散射光时，蓝-绿光血氧计 (BGO) 技术可以在猪中提供±3%的精度。构建了一种非侵入式轴上扫描视网膜血氧计 (ROx-3)，它在 BGO 所需的范围内生成多波长图像。在检测路径中使用场停止与反共焦二分线一起使用，以去除镜面血管反射并从视网膜血管内的血液柱中分离多重后向散射光。该设计在一只去眼猪眼血管和一只人志愿者的视网膜静脉上进行了测试，视网膜 SO(2) 测量值分别约为 1%和 65%。这些饱和度使用早期工作中的校准线计算，与平均标准误差的±2% SO(2) 内部一致。绝对值在该部位的预期饱和度范围内(-1 和 63%)。这是首次证明非侵入式轴上 BGO 视网膜血氧计。
