Standardization of Sonographic Prognostication of Prenatally Diagnosed Congenital Diaphragmatic Hernia (CDH) Across the North American Fetal Therapy Network (NAFTNet)

Congenital diaphragmatic hernia (CDH) is a potentially lethal condition, with antenatal prognostication relying heavily on sonographic lung area determination. Although critical for prenatal counselling, inter-observer variability has been demonstrated in lung area measurement. To understand this variability, current practice patterns were evaluated through surveys, interviews and human factors analysis with usability testing and inter-rater agreement was determined for the three published lung area measurement methods (i.e.: antero-posterior, longest and trace) across the North American Fetal Therapy Network (NAFTNet). When comparing lung area methods, the trace method demonstrated the highest inter-rater agreement. Human factors analysis identified variability in sonographic image selection criteria and lung area measurement technique. This data informed the development of a standardized protocol for antenatal sonographic assessment of CDH, which underwent iterative redesigns through consecutive Plan-Do-Study-Act cycles among physicians and sonographers to meet the needs of users with various expertise and ultimately standardize prenatal CDH prognostication across NAFTNet.M.Sc