Subject and method: A randomized, placebo-controlled trial of over 70 patients undergoing umbilical surgery by caudal blockage and laryngeal mask anesthesia, divided into two groups: Group I using levobupivacaine 2mg / kg + fentanyl 1μg / kg, group II used bupivacaine 2mg / kg + fentanyl 1μg / kg for caudal blockage.