Detection of the venous oxygen saturation in an oxygenation and perfusion model
K Rackebrandt, H Gehring – Biomedical Physics & Engineering Express, 2016
FEB 2016
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. We present 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 near-infrared spectroscopy sensor (6 photodiodes (PD1–6), 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 ± 8 mg dl−1 and pH 7.35 ± 0.04). The saturation plateaus inside of the target vessel could be detected reproducibly with the presented setup.
… heating unit (D8-G, Thermo Haake) to ensure a blood temperature of about 37 °C and a peristaltic pump (IKA-PA 20, Janke & Kunke) with a flow rate of 300 ml min −1 (figure 3). Additionally a reference measurement unit, consisting of a white light source (SL1, Stellarnet Inc.) and …
