We hypothesized that in children, the current anesthesia care (combined light general anesthesia and caudal analgesia) may decrease incidence of intra and or postoperative de-saturation( SaO2 < %95), the need of oxygen during child's transport to the PACU and during his stay in the recovery room, compared with children who receive intravenous narcotics for intra and postoperative pain relief.