Critical congenital heart defects (CCHDs) represent a group of life-threatening heart malformations requiring intervention within the first days or weeks after birth. Although heart abnormalities represent the most common form of birth defects, prenatal ultrasound identifies less than half of all cases of CCHD. Unfortunately, these defects can also be missed during routine newborn examinations.
In a move to catch more of these defects, a new California law requires all birthing facilities to perform a painless, noninvasive pulse oximetry screening test to evaluate newborns’ blood-oxygen levels prior to discharge from the hospital.
“This test is important because some forms of CCHD cannot be detected by a routine physical exam in the first few days after birth,” explains UCLA neonatologist Jeffrey Smith, MD. “A baby with CCHD that is not detected in the hospital after birth can suddenly become critically ill at home and may die or suffer permanent injury before medical help can be obtained.”
Pulse oximetry, used in conjunction with a physical examination, is a simple procedure performed by placing a small probe on the baby’s right hand and either foot to measure how much oxygen is being carried in the blood. The measurement, known as the oxygen saturation, is expressed as a percentage of the maximum amount of oxygen that the blood can carry. A baby passes the screening test if the oxygen saturation level is 95 percent or greater in the right hand or a foot, and the readings differ by 3 percent or less. A reading below 95 percent may indicate the presence of heart or lung disease, infection or other problems. Misleading test results (false positives) are minimized if pulse oximetry is performed at least 24 hours after birth.
“Failing the test does not necessarily mean that a baby has CCHD, but it does mean that more testing is required,” says Mark Sklansky, MD, chief of pediatric cardiology and co-director of the Fetal Cardiology Program at Mattel Children’s Hospital UCLA. If other conditions that would explain the low oxygen level are not identified, then echocardiography (cardiac ultrasound) and further cardiac evaluation are the next steps. Research suggests that pulse oximetry screening in combination with a routine physical examination makes it possible to identify, before hospital discharge, more than 90 percent of newborns with CCHD.
“When the diagnosis of CCHDs is delayed, babies are at increased risk for irreversible damage to the brain, kidney, heart and other organs,” says Dr. Sklansky. “With early detection, we can intervene with critical medications, cardiac catheterization or open-heart surgery — all of which will not only save lives but also reduce preventable morbidity and optimize quality of life.”
Many hospitals, including UCLA, already provide pulse oximetry as a standard of care in their newborn nurseries. However, California hospitals are not required to perform the test in 100 percent of newborns until 2016. Drs. Sklansky and Smith recommend that parents request that the test be performed prior to hospital discharge if the hospital does not yet do so for all newborns.