The Effect of Dexmedetomidine on Oxygen During One Lung Ventilation in Pediatric Surgery.

"Infusion syringes are supplied with a concentration of 0.25 mcg / mL (dexmedetomidine or placebo) either 80 mcg / 20 mL, 200 mcg / 50 mL, or 400 mcg / 100 mL.~It begins with infusion of 4 ml within 10 minutes and then continues infusion, depending on the child's weight, at 1.6 ml / kg / h.~All injections will be prepared randomly by a doctor who did not participate in the study, and then placed in unmarked infusion pumps, given to an anesthesiologist (more than 10 years experience in pediatric anesthesia) without knowledge of the infusion content. The randomization process is carried out via sealed envelope technique.~The injections in both groups will be stopped before the skin is closed. Both patients and anesthesiologists blinded the study drug (dexmedetomidine or placebo) by infusion of solution (dexmedetomidine or placebo). Depending on the size in ml, to ensure that there is no bias and blindness to the medical team about what the drug is."

The same anesthesia, the same amount of Saline solution will be administered, instead of dexmedetomidine, with the same protocol