Is pulse oximetry helpful for the early detection of critical congenital heart disease at high altitude?

Objective To assess the pulse oximetry as a method for screening critical congenital heart disease (CHD) in newborns. Study design This is an observational, transversal, descriptive simple study. The pre-ductal and postductal saturation were taken in term newborns that fulfilled the criteria of inclusion and exclusion in the Hospital Gineco-Obstetrico Isidro Ayora (HGOIA) in Quito. These measurements were performed between the 24 and 48 h after birth. Those newborns that saturated less than 90% on initial pulse ox & metry underwent 3 successive measurements at 1-h intervals. Those who saturate less than 90% after 3 measurements or have a difference higher than 3% in preductal saturation and postductal saturation (positive screening) underwent transthoracic echocardiography evaluate for CHD. Results Pulse oximetry from 963 newborns was evaluated. In Quito, at an altitude of 2820 meters above sea level (9252 feet), the mean preductal saturation was 92.76% (SD +/- 3) and the postductal saturation, 93.76% (SD +/- 4.7). Pulse oximetry in 53 patients (5.5%) was classified as a positive screening. No critical congenital heart diseases were found. Atrial septal defect (ASD) was the most common finding in a 46.94% (n = 23), followed by the association of patent ductus arteriosus (PDA) and ASD with a 12.24% (n = 6). Conclusion In this cohort of patients who underwent screening pulse oximetry, no critical congenital heart diseases (CHD) were observed. However, identifying those with oxygen saturation less than 90% after 3 successive measurements or a pre- and postductal oxygen difference of > 3% resulted in successful identification of ASD and PDA. It is necessary to implement new cutoff points in saturation values to identify critical cardiac anomalies in cities placed at a high altitude. The use of pulse oximetry should be recommended in all the newborns.