Researchers propose tweak to pulse oximetry testing for CHD
Modifying the American Academy of Pediatrics’ (AAP) critical congenital heart disease (CCHD) screening algorithm to include one repeat pulse oximetry test instead of two could identify more infants with other serious diseases that require attention, according to a study published online April 24 in Pediatrics.
Pulse oximetry—which measures oxygen concentrations in the blood—has been recommended by several professional societies for early detection of CCHD in infants. Congenital heart disease affects approximately 40,000 infants in the U.S. each year, with about 25 percent of those cases deemed “critical” and requiring surgery or catheterization within a year, wrote senior author Matthew E. Oster, MD, MPH, and colleagues.
The AAP recommends pulse oximetry be tested in a newborn’s right hand and right foot, with above 95 percent concentration representing a passing grade and below 90 percent representing a failing grade. In between those values—or a greater than 3 percent difference between hand and foot readings—calls for a repeat test. The subsequent tests can yield a passing or a failing result, but if the test comes back indeterminate three times it is deemed a fail.
Oster et al. found that only one repeat test may be a better solution because it can identify more non-CCHD conditions that still require intervention. Some babies in this category might pass the test if given a third opportunity, but two tests are all that’s needed to rule-in or rule-out nearly all CCHD cases.
In this collaborative study with Children’s Healthcare of Atlanta (CHOA) and nearby Northside Hospital, screening results were collected for 77,148 newborns over a four-year period. Importantly, about 80 percent of the cases of CCHD were detected prenatally and those infants were excluded from the analysis.
For those who completed pulse oximetry screening, the current AAP algorithm demonstrated a 99.96 percent specificity, a 14.3 percent sensitivity and a false-positive rate of 0.043 percent—about 1 in every 2,500 live births.
The specificity and sensitivity would have remained the same with only one repeat test and the false-positive rate would have increased marginally to 0.054 percent—one in every 2,000 live births. Nine additional newborns were found to have indeterminate results under the two-test algorithm.
While none of them were discharged with CCHD or a significant non-CCHD diagnosis, 10 of the babies (31 percent) from the original cohort with the same, false-positive test results were discovered to have serious issues that needed to be addressed. Pulmonary hypertension accounted for half of these cases.
“We found that CCHD screening by using pulse oximetry has limited ability to detect additional cases of CCHD in a tertiary birth center with a high prenatal detection rate,” wrote Oster, the director of the Cardiac Outcomes Research Program at CHOA, and coauthors. “However, we demonstrate that screening can detect other important non-CCHD diseases in newborns, and we would propose that modifying the algorithm to have only one repeat screen instead of two may identify additional newborns with significant hypoxemic disease, both cardiac and noncardiac, with a minimal impact on the CCHD screening false-positive rate.”
The researchers pointed out their hospital has a level III nursery; hospitals at levels I or II may have lower prenatal CCHD detection rates and therefore higher pulse oximetry detection rates. Their results showed only one infant with CCHD was appropriately identified by the test, so the non-CCHD complications were the most important to consider.
“Although the primary purpose of CCHD pulse oximetry screening has been to target and identify infants with CCHD, using pulse oximetry screening can additionally target newborns with other significant diseases, leading to earlier evaluation, diagnosis, and potentially lifesaving intervention,” they wrote. “Simplifying the algorithm may also improve compliance and interpretation of screening.”
Daniel joined TriMed’s Chicago editorial team in 2017 as a Cardiovascular Business writer. He previously worked as a writer for daily newspapers in North Dakota and Indiana.