Early Human Development 89S4 (2013) S8–S9 Pulse oximetry newborn screening for congenital heart defects. Is it really useful? Federico Schena *, Elena Ciarmoli, Alessandra Mayer, Alessia Cappelleri, Laura Bassi, Monica Fumagalli, Fabio Mosca Neonatal Intensive Care Unit, Department of Clinical Science and Comunity Health, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy Congenital heart diseases (CHDs) are the most common birth defects, occurring in 8–9/1,000 live births and they represent one of the leading cause of infant death in the developed countries. A timely diagnosis is beneficial as even most critical cases can be successfully repaired by cardiac surgery or interventional catheterization procedures or may undergo a satisfactory palliation. Conversely, a delayed diagnosis may expose patients to the detri- mental effects of prolonged hypoxia or hypoperfusion, worsen the preoperative condition and ultimately increase the risk of death or neurological sequelae [1]. With the advances in prenatal care many cases of CHDs are nowadays detected before birth. Nevertheless, the effectiveness of antenatal ultrasound screening is still not optimal and the detection rate of CHDs currently does not exceed 70% in the best case series. At the present time CHDs that grossly alter the size of the four cardiac chambers are easily recognized by fetal ultrasound while other severe defects such as aortic coarctation, transposition of the great arteries and anomalous pulmonary venous return are identified in less than half of the cases. Early clinical diagnosis of undetected CHDs may also be a difficult task for the neonatologist. A patent ductus arteriosus can mask an underlying structural defect in the first few days of life and therefore elude clinical examination so that CHDs may become evident with profound cyanosis, heart failure or cardiovascular collapse only after discharge from the newborn nursery. The rate of undetected CHD mainly depends on the time of hospital discharge: the sooner the babies are discharged the lower the detection rate. A recent study from a population registry in Tennessee reports an incidence of unrecognized critical CHD of 15 cases per 100,000 discharged newborns [2]. These patients represent the target for a potential neonatal screening program for CHDs Since most critical CHDs have a degree of hypoxaemia that would not necessarily produce visible cyanosis and therefore might not be clinically detectable, pulse oximetry has been proposed as a screening test for the detection of potentially life-threatening heart diseases in the newborns. Pulse oximetry is a rapid, accurate and low-cost method to measure arterial oxygen saturation and since it is completely painless and harmless, it is well accepted by parents. Several studies have been conducted in the last 10 years on the effectiveness of pulse oximetry as a screening tool for CHDs, some of them including a large population of neonates. * Corresponding author. 0378-3782/$ – see front matter © 2013 Elsevier Ireland Ltd. All rights reserved. The reported sensitivity and specificity of pulse oximetry differ among studies depending on the timing of the test and the oxygen saturation threshold. According to a recent metanalysis, based on the results of 11 published study, the overall sensitivity of pulse oximetry for detection of critical congenital heart defects is 76.5% while specificity is 99.9% [3]. The authors concluded that pulse oximetry meets the criteria to become an universal neonatal screening. In 2011 in the United States, the Secretary of Health and Human Services (HHS) with the endorsement of the American Accademy of Pediatrics recommended the universal implementation of pulse oximetry screening for critical CHDs and since then all birthing facilities countrywide are gearing up to put the exam into routine clinical practice [4]. However, a well-recognized limitation of this screening tool is the low sensitivity in detecting CHDs with obstruction to the systemic circulation (i.e. aortic coarctation, interrupted aortic arch, hypoplastic left heart syndrome) as oxygen saturation can remain within normal limits while the systemic perfusion may be insidiously compromised. It is therefore necessary that efforts to implement a more efficient screening test for CHDs are aimed to improve the recognition of this type of defect. Recently, some new generation pulse oximeters have been manufactured providing along with the oxygen saturation value, the peripheral perfusion index (PPI) a parameter that assesses the relative amount of arterial blood at the probe site. In 2007 De Wahl-Granelli and Östman-Smith established refer- ence values for PPI in healthy newborns in the first 5 days of life [5]. Median PPI measured at foot was 1.71 with interquartile range 1.20–2.50. They also measured PPI in a cohort of newborns with left heart obstruction and found that it was below the 5th percentile in 5 out of 9 patients; PPI was therefore proposed as a promising tool to improve the detection of congenital heart defects with low systemic perfusion but it has never been systematically assessed so far. On behalf of the Neonatal Cardiology Study Group of the Italian Society of Neonatology, we planned to perform a prospective multi- center, national study to assess the effectiveness of combined pulse oximetry and PPI as screening test for CHDs. The study will enroll 44,000 newborns. Arterial oxygen saturation and PPI are tested between 48 and 72 hours of life and measured from both preductal and postductal sites The test is considered positive when at least one of the following criteria is present: arterial oxygen saturation ≤95% at either upper or lower limb; a difference between upper and lower saturation >3%; PPI ≤0.9. When the test is positive, it