[1] Mentioned in Psalm 73:15 LXX ('rivers of (H)etham'). In the Hebrew Bible, this is Psalm 74:15: אַתָּה הוֹבַשְׁתָּ נַהֲרוֹת אֵיתָן ʾata hōḇašta naharōt ʾētan "you have dried up the permanent waters".
2The word אֵיתָן ʾētan denotes strength or permanence. It has nothing to do with blood. The Hebrew for blood is דָם dām. Perhaps the Suda is referring to הַדָּם hadām "the blood".