Evaluating the Effectiveness of Ketamine Plus Atropin as Anesthesia for Intrathecal Chemotherapy and Bone Marrow Procedure at Hue Central Hospital, Vietnam *Corresponding Author: Nguyen Thi Kim Hoa, Pediatric Center, Hue Central Hospital, 16 Le Loi Street, Hue city, Vietnam. Email: kimhoa.fmi@gmail.com