Common Questions

No. Pulse oximetry is most useful in detecting those forms of heart defects in which a baby can look entirely well a day after birth and become very ill within the next few days.

No. Most babies with CCHD will be diagnosed by prenatal ultrasound or by physical exam after birth. Pulse oximetry serves as one additional method of catching the 1 or 2% of babies with critical congenital heart disease that aren’t detected by prenatal ultrasound or newborn physical examination.

Screening after 24 hours of life and allowing a total of three chances to pass the screen will minimize the number of false positives.

If done at least 24 hours after birth, the chance of a serious heart defect ranges from 21% to 26%. Low oxygen saturation may also be due to other problems that might not yet have become apparent such as lung disease, bacterial infection, or other disease.

Oxygen saturations gradually increase in normal babies over the first several hours of life. If pulse oximetry screening is done too early, some babies will fail the screening even if their hearts are normal. However, by 24 hours, the vast majority of normal babies will have oxygen saturation greater than 95%. The average saturation for a 24-hour-old baby is 97%.

The first step is to examine the baby closely for other medical problems that could result in low oxygen saturation. If these are identified, the baby should receive the appropriate care for their particular problem. If there is no other cause for the low oxygen saturation, the baby should be evaluated for a critical congenital heart defect. That evaluation will usually involve an ultrasound test of the heart called an echocardiogram.

Other cardiac testing may be useful in certain circumstances. A chest x-ray may be helpful in looking for problems with the lungs. An electrocardiogram may be helpful if a heart rhythm disorder is suspected. Laboratory tests may help to determine the presence of infection or a metabolic disease. As helpful as these tests may be, however, they probably aren’t adequate to exclude the possibility of a critical congenital heart defect.

If a baby fails the pulse oximetry screening process and no other explanation for the low oxygen saturation is identified, an echocardiogram may be needed. In smaller communities and more rural hospitals, this may not be available. In this situation, the health care staff caring for the baby will often discuss the situation with a neonatologist or a pediatric cardiologist. The health care team caring for the baby may recommend that the baby go to another facility so that the echocardiogram can be performed. Depending on the circumstances, additional testing or observing the baby a little longer in the local hospital may be appropriate.