Re-evaluation of lung to thorax transverse area ratio immediately before birth in predicting postnatal short-term outcomes of fetuses with isolated left-sided congenital diaphragmatic hernia: A single center analysis

We aimed to investigate whether the lung-to-thorax transverse area ratio (LTR) immediately before birth is of diagnostic value for the prediction of postnatal short-term outcomes in cases of isolated left-sided congenital diaphragmatic hernia (CDH). We retrospectively reviewed the cases of fetal isolated left-sided CDH managed at our institution between April 2008 and July 2016. We divided the patients into two groups based on LTR immediately before birth, using a cut-off value of 0.08. We compared the proportions of subjects within the two groups who survived until discharge using Fisher's exact test. Further, using Spearman's rank correlation, we assessed whether LTR was correlated with length of stay, duration of mechanical ventilation, and supplemental oxygen. Twenty-nine subjects were included (five with LTR<0.08, and 24 with LTR≥0.08). The proportion of subjects surviving until discharge was 40% (2/5) for patients with LTR<0.08, as compared with 96% (23/24) for those with LTR≥0.08. LTR measured immediately before birth was negatively correlated with the postnatal length of stay (Spearman's rank correlation coefficient, rs=-0.486), and the duration of supplemental oxygen (rs=-0.537). Further, the duration of mechanical ventilation was longer in patients with a lower LTR value. LTR immediately before birth is useful for the prediction of postnatal short-term outcomes in fetuses with isolated left-sided CDH. In particular, patients with prenatal LTR value less than 0.08 are at increased risk of postnatal death.