Figure 3From: Non-invasive monitoring of tissue oxygenation during laparoscopic donor nephrectomy Linear relationship of calculated mean normalized ROI (region of interest) values and measured venous sO 2 as the FiO 2 is decreased from 100% to 8% in four different kidneys. R2 = 0.9722 (â—‹), 0.9854 (â–¡), 0.9624 (â–³) and 0.9801 (â—‡).Back to article page