Page modified at: 28/08/2011
Newborn Screening for Congenital Heart Disease using Pulse Oximetry
Pulse oximetry is a simple test which measures blood oxygen levels in newborns by means of a small skin sensor placed on the hands or feet. A major British study showed it can identify babies with congenital heart defects who would otherwise be missed by doctors.
Up to 3% of infant deaths are due to congenital heart defects and congenital heart defects are more common than Down Syndrome affecting about 1 in 125 pregnancies. Despite antenatal ultrasounds scans and newborn physical examination before discharge from hospital about 50% remain undiagnosed by the time they go home and many of these infants would under normal circumstances go on to develop serious complications or die. Identifying the problems early on allows doctors to correct or reduce them with surgery, where possible, or plan medication treatments.
A new study, the largest of its kind ever undertaken in the UK, tested the accuracy of pulse oximetry on more than 20,000 babies born at six maternity units across the West Midlands. In all cases the babies appeared to be healthy at birth.
The tests, conducted between February 2008 and January 2009, detected 53 cases of major congenital heart disease, 24 of which were critical. In 35 cases, congenital heart defects were already suspected after ultrasound examinations. But 18 cases identified by pulse oximetry had not been picked up by ultrasound. Overall the addition of the Pulse Oximetry test improved to detection rate to 92% and none died.
There were also 169 babies (0.8%) who had an abnormal oxygen test who did not have a congenital heart defect (false positive test) but many of these had other importnat health problems.
The findings were published in an online edition of The Lancet medical journal.
Lead investigator Dr Andrew Ewer, from the University of Birmingham, said: "This study has shown conclusively that this test is advantageous. We would like to see all babies being routinely tested. In this way the test will pick up additional babies who might otherwise have become very ill or even died."
The screening programme in Innermost Secrets is backed up by a Consultant Paediatric Cardiologist and all babies with abnormal tests would be referred to him for specialist examination and a possible cardiac scan (echocardiogram). Ideally babies should be checked within 24 hours or if not, as soon as possible after delivery.
What Does The Test Involve?
The test takes about 20 minutes and should not cause any discomfort or distress for the baby. It involves wrapping a special infra-red ligh sensor round the baby's foot and hand and measuring the oxygen levels for about 5-10 minutes for each. Normally the oxygen level or saturation is over 95% and the difference between hand and foot is less than 3%.
Even if the results of the test are abnormal, it does not mean the baby necessarily has a heart defect but is shouuld be checked over carefully to ensure he or she has a normal heart and is otherwise healthy.
It is estiamted that less than 8% of babies with a significant heart problem would be missed based on a normal antenaatl scan, pre discharge hopsital visit and a Pulse Oximetry check.