Predicting neonatal outcome in isolated congenital diaphragmatic hernia using ultrasonographic pulmonary measurements

Objective: To study the potential of different methods of evaluating pulmonary measurements to predict neonatal outcome in cases with isolated congenital diaphragmatic hernia (CDH). Materials and Methods: Between January 2002 and December 2004, thirty-one fetuses with isolated CDH were prospectively evaluated. Fetal lung volumes were estimated by the rotational technique on three-dimensional ultrasonography (3D-US) and fetal weight by the Hadlock equation on two-dimensional ultrasound examinations, which allowed calculating the ultrasonographic fetal lung/body weight ratio (US-FLW), the observed/expected fetal lung volumes (o/e-FLV) and the lung-over-head ratio (LHR). These measurements were compared to each other and to neonatal outcome. Results: Good correlations were observed between the US-FLW ratio and the o/e-FLV (r=0.90, p<0.001) and the LHR (r=0.64, p<0.001). The US-FLW ratio was significantly lower in neonatal death cases (median: 0.009, range: 0.004-0.021) than in survivals (median: 0.011, range: 0.008-0.020, p=0.018), as well as the o/e-FLV (p=0.03) and the LHR (p=0.03). Accuracies of the US-FLW, the o/e-FLV and the LHR in predicting neonatal outcome were 64.52% (21/31), 80.65% (25/31) and 77.42% (24/31), respectively. Discussion: In isolated CDH, fetal size is directly related to neonatal outcome, which can be evaluated by different methods. However, the o/e-FLV seems to be the best parameter for this purpose.