Detection of the venous oxygen saturation in an oxygenation and perfusion model

The oxygenation, perfusion and metabolism of the brain-segmented in both hemispheres-can be estimated from the oxygenation and hemoglobin levels of the venous blood in the cerebral efferent vessels.Wepresent a phantom based model to simulate the anatomical target region which was connected to hemodynamic perfusion circuit to provide different oxygenation plateaus inside of the simulated target vessel. A developed triple-wavelength (770, 808 and 850 nm) multi-distance nearinfrared spectroscopy sensor (6 photodiodes (PD_1-6), linearly arranged, separated 6 mm each) was equipped to detect these different saturation levels. The saturation could be triggered to three consecutively passed plateaus (PL₁ = 55 ± 3%; PL₂ = 100 ± 0.3%; PL₃ = 55 ± 3%) for all 90 experiments (30 measurements per wavelength (3 d;10 d^-1)) while keeping the amount of total hemoglobin (tHb) and the other physiological blood parameters at constant levels (tHb = 11.8 ± 0.2 g dl^-1, blood temperature = 35.5 ± 0.5 °C, carbon dioxide partial pressure (pCO₂) = 44 ± 6 mmHg, Glucose = 99 ± 8mg dl^-1 and pH7.35 ± 0.04). The saturation plateaus inside of the target vessel could be detected reproducibly with the presented setup.