When a juvenile court proceeding has been instituted before a county court sitting as a juvenile court, the original jurisdiction of the county court shall continue until the final disposition thereof and no appeal shall stay the enforcement of any order entered in the county court. After appeal has been filed, the appellate court, upon application and hearing, may stay any order, judgment, or decree on appeal if suitable arrangement is made for the care and custody of the juvenile. The county court shall continue to exercise supervision over the juvenile until a hearing is had in the appellate court and the appellate court enters an order making other disposition. If the appellate court adjudges the juvenile to be a juvenile meeting the criteria established in subdivision (1), (2), (3), or (4) of section 43-247, the appellate court shall affirm the disposition made by the county court unless it is shown by clear and convincing evidence that the disposition of the county court is not in the best interest of such juvenile. Upon determination of the appeal, the appellate court shall remand the case to the county court for further proceedings consistent with the determination of the appellate court.