Congenital heart diseases are among the most common congenital anomalies and occur with an incidence of approximately 8ınd12 / 1,000 live births worldwide. This figure does not cover minor lesions such as bicuspid aortic valves and small atrial or ventricular septal defects. Most of these defects do not need treatment or treatment is needed after infancy. Other defects are severe and usually require early treatment in the neonatal period. Critical congenital heart disease is defined as structural heart defects that are associated with hypoxia in the neonatal period and have significant morbidity and mortality potential in early life. Critical congenital heart disease is estimated to be ~3 in 1000 live births. It is estimated that 50% of congenital heart diseases are detected by prenatal ultrasound. Even if a standard neonatal examination is performed, 13 to 55% of patients with critical congenital heart disease can be discharged from the hospital without being diagnosed.

Screening of infants with non-invasive oxygen saturation measurement has been proposed as an adjunct to early detection of critical congenital heart disease.

The American Academy of Pediatrics, the American Cardiology Foundation and the American Heart Association have targeted 7 specific lesions for the pulse oximetry screening protocol: truncus arteriosus, transposition of the great arteries, tricuspid atresia, tetralogy of Fallot, total pulmonary venous return anomaly, hypoplastic left heart syndrome and pulmonary atresia.

The reference values of peripheral perfusion (PPI) index has been established for normal newborns between 1 and 120 h of age.

Lower PPI values than 0.70 may indicate illness. Including cut-off values for PPI in pulse-oximetry screening for duct dependent congenital heart disease is a promising tool for improving the detection of critical congenital heart disease with duct-dependent systemic circulation.

We aimed to investigate screening critical congenital heart disease and also to establish normal values of oxygen saturation and perfusion index at high altitude.

Inclusion Criteria:

• The newborns delivered in Ataturk University Hospital and ≥34 weeks of gestational age were eligible for the study.

Exclusion Criteria:

• Outborn and premature babies (<34 weeks) were not included. Babies with a prenatal diagnosis of congenital heart disease were excluded.

Newborns with ≥34 weeks of gestational age