J Korean Med Sci 2007; 22: 687-92 ISSN 1011-8934 Copyright The Korean Academy of Medical Sciences Survival Rate Changes in Neonates with Congenital Diaphragmatic Hernia and its Contributing Factors The purpose of this study was to demonstrate survival rate changes after the intro- duction of inhaled nitric oxide (iNO) therapy, and to identify the factors that influence these changes in neonates with a congenital diaphragmatic hernia (CDH) at a sin- gle center. A total of 48 neonates were divided into two groups based on the time of admission, i.e., into period I (P1; n=17; before the introduction of iNO therapy) and period II (P2; n=31; after the introduction of iNO therapy). Survival rates of the 48 neonates showed a tendency to increase from 53% during P1 to 77% during P2, but without a statistical significance, but a significant difference was found bet- ween survival rates during the two periods after adjusting for initial clinical charac- teristics, when the postoperative survival rate increased significantly from 69% for P1 to 100% for P2. The mean duration of preoperative respiratory management was significantly longer for P2 than for P1. Seven of 12 patients who received pre- operative iNO therapy due to persistent pulmonary hypertension or refractory pre- ductal hypoxemia in P2 survived after operation. We speculate that a management strategy based on iNO therapy and delayed operation, rather than differences bet- ween the initial clinical characteristics of the two study groups, might partially con- tribute to the observed improvements in postoperative and overall survival rates in neonates with CDH. Key Words : Congenital Diaphragmatic Hernia; Survival Rate; Inhaled Nitric Oxide Therapy Do-Hyun Kim#, June Dong Park#, Han-Suk Kim, So-Yeon Shim*, Ee-Kyung Kim, Beyong Il Kim, Jung-Hwan Choi, Gui Won Park Departments of Pediatrics and Surgery , Seoul National University College of Medicine, Seoul; Department of Pediatrics*, Gachon University of Medicine and Science, Incheon, Korea #The authors contributed equally. Received : 26 June 2006 Accepted : 11 January 2007 Address for correspondence Han-Suk Kim, M.D. Department of Pediatrics, Seoul National University College of Medicine, Seoul National University Children’s Hospital, 28 Yeongeon-dong, Jongno-gu, Seoul 110-744, Korea Tel : +82.2-2072-1696, Fax : +82.2-743-3455 E-mail : kimhans@snu.ac.kr INTRODUCTION Congenital diaphragmatic hernia (CDH) occurs in 1 per 2,000-5,000 live births and affects approximately 1,100 infants annually in the U.S.A. (1). CDH remains one of the most challenging and perplexing malformations in neonatal intensive care units (NICUs), and shows a high mortality rate due to pulmonary hypoplasia and/or intractable persis- tent pulmonary hypertension (PPH), despite aggressive peri- natal treatment. However, the relative rarity and clinical vari- ability of CDH makes it difficult to conduct well-designed clinical studies at a single institution and to establish the most suitable treatment. Despite advances in neonatal intensive care over the last 2 decades, the overall survival rate of neonates with CDH (64%) has changed only slightly in recent years, and to date, uniform standards for CDH management have not been established (2-4). Advanced therapies for CDH have included delayed oper- ation, extracorporeal membrane oxygenation (ECMO), high- frequency oscillatory ventilation (HFOV), surfactant, and inhaled nitric oxide (iNO) therapy. However, the effects of these modalities in terms of statistically significant survival 687 advantage in neonates with CDH have not been clearly deter- mined. In particular, the effect of iNO on the outcome in CDH remains controversial (5-7). In June 1998, iNO therapy was introduced as a new treat- ment modality in the NICU at Seoul National University Children’s Hospital. Following the introduction of this the- rapy, we found that the survival rate of neonates with CDH had changed, and thus, we conducted this retrospective study to determine whether iNO therapy had influenced the sur- vival rate, or whether the initial clinical characteristics of patients had co-incidentally become less severe. Thus, the purpose of this study was to determine survival rate changes after the introduction of iNO therapy, and to identify the factors that influence these changes in neonates with CDH at our institution. MATERIALS AND METHODS Study patients The medical records of 55 CDH patients, admitted to Seoul