Neonatal Pulse Oximetry Screening for Congenital Heart Defects in Switzerland: Range of Pathology in Screening-Positive Individuals

Background: Timely recognition of critical congenital heart defects in neonates is eminent to decrease the associated morbidity and mortality. Clinical symptoms are often lacking within the first few days of life, and 30% of the patients with critical congenital heart defects leave the maternity unit without being diagnosed. Early detection c an be improved by measuring the transcutaneous oxygen saturation within the first hours of life. Recent studies on pulse oximetry (pox) screening report a specificity of 95.5 to 100% and a sensitivity of 62–97% for detecting critical congenital heart defects in neonates when postductal transcutaneous saturation is below 95%. Pox screening has been recommended in Switzerland since 2005 by the Swiss Societies of Neonatology and Paediatric Cardiology. The aim of this study was to assess the identification of critical c ongenital heart defects (CHD) through pox screening by describing patient c haracteristics in screening-positive individuals. Methods and results: From January 2009 to January 2011 all Swiss paediatric cardiologists were asked to voluntarily fill out a standardised questionnaire for each patient undergoing echocardiography on account of positive pox screening. Prenatally diagnosed CHD were excluded from this analysis. A total of 48 questionnaires were returned. 27 neonates (56%) had structural heart defects (true positive pox screening test results) including 24 neonates with critical heart defects. In 21 patients (44%), cardiac anatomy was normal (false positive pox-screening test results). In 10 out of the 21 patients, low saturation was explained by evidence of pulmonary hypertension on echocardiography, with right to left shunting through a patent foramen ovale or arterial duct. This analysis is limited by underreporting, meaning that the true number of patients detected with pox screening in Switzerland may be higher. In addition, some Swiss maternity units do not perform routine pox screening. Conclusion: The current practice of pox screening in Switzerland made it possible to identify 24 neonates with critical CHD within two years. T hese patients were diagnosed in time and referred for further treatment in a stable condition. The results of this study support the evidence for the further use of pox screening for CHD in Switzerland.