Pneumothoraces as a fatal complication of congenital diaphragmatic hernia in the era of gentle ventilation.

INTRODUCTION: Pneumothorax remains a life-threatening complication that occurs in congenital diaphragmatic hernia (CDH), even under respiratory management with gentle ventilation. The aim of this study was to evaluate the prevalence of pneumothoraces as a fatal complication during the management of CDH based on the results of a nationwide Japanese survey conducted in the era of gentle ventilation.

MATERIALS AND METHODS: A retrospective cohort study was performed as part of a nationwide Japanese survey of CDH. A total of 510 neonates with isolated CDH born between 2006 and 2010 were included in this study. The patients were divided into four groups according to operative findings related to the diaphragmatic defect size and operability, which represents the disease severity: defects less than 25%, defects more than 25% but less than 75%, defects more than 75%, and a patient group that was unable to undergo surgery. The prevalence of pneumothorax and the survival rate were compared with respect to each disease severity group. Each case was evaluated to determine whether the development of a pneumothorax was the primary cause of death.

RESULTS: Of the 510 neonates with isolated CDH, 69 patients developed a pneumothorax before and/or after surgical intervention. Of the 69 patients 38 patients died, and only 26 patients were discharged from the hospital without any major morbidity that requires home treatment ("intact discharge"). The prevalence of pneumothorax increased and the survival rate and intact discharge rate decreased as the severity of the disease worsened. The number of patients whose pneumothorax was presumed to be the primary cause of death also increased as the severity of the disease worsened. The survival rate of the patients with pneumothorax was significantly lower than that of the patients without pneumothorax among the groups with 25 to 75% defects and 75% or more defects.

CONCLUSIONS: Pneumothoraces was found to more likely occur in neonates with CDH associated with a large defect of the diaphragm. The survival rate and intact discharge rate decreased as the severity of the disease worsened, especially among the patients who developed pneumothorax accompanied by large diaphragmatic defects. No other risk factors related to pneumothorax occurrence were found, except for the severity of the disease itself, thus suggesting that pneumothorax was associated with a lethal outcome in neonates with CDH associated with a large defect of the diaphragm.