The Hebrew and Greek that is often translated as “As the LORD lives, (I swear)” in English is translated in Dan as “I swear before the true living God” to “not to imply that God could die, contrasting with the dead false gods.”
Like many languages (but unlike Greek or Hebrew or English), Spanish uses a formal vs. informal 2nd person pronoun (a familiar vs. a respectful “you”). Spanish Bibles all use only the informal 2nd person pronoun (tú), with the exception of Dios Habla Hoy (DHH) (third edition: 1996) which also uses the formal pronoun (usted). In the referenced verses, the formal form is used.
Sources and for more information: P. Ellingworth in The Bible Translator 2002, p. 143ff. and R. Ross in The Bible Translator 1993, p. 217ff.