This post was authored by John Gordon Harold, MD, MACC, immediate past president of the ACC.

On a yearly basis critical congenital heart conditions affect three out of every 1,000 live births, accounting for nearly 30 percent of all infant fatalities in the U.S. As physicians we have come a long way in our ability to treat these conditions in a timely manner, often using prenatal sonograms to identify structural heart disease. However, the sensitivity of congenital heart disease (CHD) is highly fickle, with operator expertise, fetal position, gestational age, and defect type causing prenatal sonography to entirely miss many newborns with CHD, let alone critical conditions that need immediate intervention.

Serving as a crucial diagnostic addendum is the use of pulse oximetry screening. Incorporated into newborn assessments, this noninvasive test measures the percentage of hemoglobin in the blood that is saturated with oxygen and its pulse rate. As many physiologists understand oxygen breathed in through the lungs attaches to the red blood cell protein hemoglobin. This newly oxygenated blood then circulates to the body’s various tissues. The arterial hemoglobin saturated with oxygen is known to be right red, while venous hemoglobin with less oxygen is a darker hue. Using these principles of spectrophotometry, pulse oximetry leverages the light absorption characteristics of hemoglobin and the pulsatile nature of arterial blood flow to determine the saturation of oxygen in the blood, calculating the differences in the oxygen-rich versus oxygen-poor blood hemoglobin through an oximetry probe placed on the foot.

The structural defects of critical congenital heart disease are often associated with abnormally low levels of oxygen in the blood, otherwise known as hypoxemia. Using pulse oximetry screening to find these diminished measurements is incredibly important. Time is of the essence when it comes to critical congenital heart disease. The risk of morbidity and mortality increases substantially when there is a delay in diagnosis and referral to a tertiary center with the expertise in treating these unique patients.

Thankfully, as of 2011, the recommendations set forth by the Health and Human Services Advisory Committee on Heritable Disorders in Newborns and Children has added newborn screening for critical congenital heart disease to the Recommended Uniform Screening Panel for States. Pulse oximetry screening is also being adopted by individual hospitals, with more states now requiring the test outright. The American Academy of Pediatrics, the ACC, the American Heart Association, and the March of Dimes all recommend that the screening be done no earlier than 24 hours after birth and prior to the newborn being discharged from the hospital.

It is estimated that over 80 percent of births are now being screened in the U.S. Currently, only six states have incomplete implementation and eight states have no legislation or regulatory mandate. In Europe, a few countries have a national recommendation similar to the U.S., including Ireland. Man y have pilot projects, but the Nordic countries lead the way with implementation. Australia, Asia, South America and Africa are all active either studying implementation or have active pilots running.

Though pulse oximetry screening does not detect all critical congenital heart diseases, it is undoubtedly a progressive means of improving the care and outcomes for neonates with the condition.

This is just one of the many important topics in the field of cardiology that will be discussed during congressional meetings on Capitol Hill tomorrow during the ACC’s Legislative Conference. Stay tuned for additional coverage from the Conference on the Blog!

Read more about this topic in my recently published Circulation editorial, or in my New York Times Letter to the Editor published last fall.

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