Prediction of postnatal short-term outcomes in fetuses with isolated congenital left diaphragmatic hernia based on the lung to thorax transverse area ratio immediately before birth

Abstract

Purpose: In this study, we aimed to determine the clinical value of the lung to thorax transverse area ratio (LTR) as a predictive parameter of short-term postnatal outcomes in fetuses with isolated left-sided congenital diaphragmatic hernia (CDH). Subjects and Methods: Data from cases prenatally diagnosed with isolated left CDH between September 2005 and March 2012 were retrospectively collected from medical records. We divided the patients into two groups according to an LTR cutoff value of 0.08 immediately before birth. Differences in intact survival rate and duration of mechanical ventilation and supplemental oxygen were analyzed between the two groups using Fisher's exact test or the Mann-Whitney U test. The positive and negative predictive values of an LTR value < 0.08 in predicting a poor postnatal outcome were calculated. Poor outcome was defined as death or severe respiratory complications. The Spearman rank correlation was calculated to assess the correlation between LTR value and postnatal duration of ventilator support. Results and Discussion: Forty fetuses met the study criterion. The intact survival rate was significantly lower in patients with an LTR < 0.08 as compared with those with an LTR >= 0.08 (7/12 vs. 27/28). Additionally, the durations of mechanical ventilation and supplemental oxygen were significantly longer in the former group, and a negative correlation was noted between LTR values and duration of mechanical ventilatory support. When the LTR cutoff was < 0.08 for predicting a poor outcome, the positive predictive value and negative predictive value were 42% and 96%, respectively. Conclusion: The LTR was a useful predictive parameter of postnatal short-term outcomes in fetuses with isolated left CDH.