Level 2: Mid-level evidence
Diagnosis of congenital heart disease in newborns is sometimes delayed until after hospital discharge, increasing the risk of illness and death. A 2009 scientific statement from the American Academy of Pediatrics (AAP) and American Heart Association (AHA) stated that pulse oximetry screening after 24 hours of life, but before hospital discharge, may detect critical congenital heart disease, but that the utility of pulse oximetry in clinical practice had not yet been established.1
Several large cohort studies have shown pulse oximetry to be a highly specific screening tool for newborns. Two new articles now add to the discussion: one provides further evidence for the efficacy of pulse oximetry screening and the other describes an algorithm for a standardized approach to routine screening. 2,4
In a new cohort study, 20,055 newborn infants had pulse oximetry measurement in right upper and lower limbs.5 Results were classified as abnormal if the oxygen saturation was <95% in either limb or if the difference in oxygen saturation between limbs was >2% when both limbs were >95%. Infants with abnormal tests had a clinical exam, followed either by echocardiography or repeat pulse oximetry in 1-2 hours. All infants with normal pulse oximetry measurement were followed for 12 months for missed congenital heart defects.
Major congenital heart defects (defined as causing death or requiring invasive intervention within 12 months of age) were detected in 53 infants by echocardiography or clinical follow-up. Of these infants, 24 were found to have critical congenital heart disease. For major congenital defects, pulse oximetry was highly specific (99%) and had very high negative predictive value (99.86%). Sensitivity (49%) and positive predictive value (13.33%) were relatively low. The positive likelihood ratio was 49.9 and the negative likelihood ratio was 0.51.
These results suggest that infants with normal pulse oximetry are highly unlikely to have congenital defects and that infants with abnormal results would benefit from further testing. The diagnostic performance was similar for infants with critical congenital disease. In an analysis of 169 infants who had abnormal pulse oximetry screens and normal echocardiograms, noncardiac illnesses requiring urgent medical interventions were found in 23.7%.
In response to these newer data, routine use of pulse oximetry to screen for congenital heart disease is now recommended by AAP/AHA and as of September 2011, the Department of Health and Human Services (HHS) has recommended universal screening. A study group organized by the AAP, AHA, American College of Cardiology Foundation and HHS has recently published an algorithm for screening for critical congenital heart disease in well-baby and intermediate-care nurseries using pulse oximetry.
Under this algorithm (which differs slightly from the protocol described above), pulse oximetry is performed at 24 to 48 hours after birth on the right hand and either the right or left foot. The screen is abnormal if oxygen saturation is <90% in either location. The screen is normal if oxygen saturation is ≥95% in the hand or foot and there is ≤3% difference between hand and foot. Hourly rescreens are recommended in infants with saturations between 90% and 95% or if the difference is >3%. If after two repeat screens, criteria for negative screen have not been met, screening is considered positive.7
Alan Ehrlich, MD, is an assistant clinical professor in family medicine at the University of Massachusetts Medical School in Worcester, and the deputy editor for DynaMed, a database that provides evidence-based information on more than 3,200 clinical topics and is updated daily through systematic surveillance covering more than 500 journals.
3. BMJ. 2009;338:a3037
6. Pediatrics. 2011;128:740-752
All electronic documents accessed Nov. 18, 2011. This article was last updated Dec. 20, 2011.