Newborn Screening Test Could Increase Early Detection of Heart Disease

Routine screening of blood oxygen levels before discharge from hospital improves the detection of life threatening congenital heart disease in newborns and may save lives, according to a new study.

Researchers at Queen Silvia Children's Hospital (Gothenburg, Sweden) screened 39,821 babies born between July 2004 and March 2007 in all five maternity units in West Gotaland (Sweden), and at the Swedish supraregional referral center for neonatal cardiac surgery. The babies were screened with a pulse oximeter before routine physical examination to assess the diagnostic accuracy of pulse oximetry for detection of duct dependent heart disease, compared to neonatal physical examination alone.

The researchers found that in apparently well babies ready for discharge a combination of clinical examination and pulse oximetry screening had a detection rate of 82.8% for duct-dependent heart disease. The detection rate of physical examination alone was 62.5%. Pulse oximetry also had a substantially lower false positive rate (0.17%) compared to physical examination alone (1.90%). However, some babies had been detected before discharge examination, meaning that the introduction of pulse oximetry screening in the West Gotaland region improved the total detection of duct dependent heart disease to 92%. This was significantly higher than the 72% detection rate in other regions not using the screening technique. Babies discharged from hospital without diagnosis had higher mortality than those diagnosed in hospital (18% versus 0.9%). In addition, no babies died in West Gotaland from undiagnosed heart disease, but there were five deaths in the other regions. Interestingly, the researchers also found that improved detection was achieved by a maximum of just five minutes of extra nursing time per baby. The study was published in the January 8, 2009, issue of the British Medical Journal (BMJ).

"Such screening seems cost neutral in the short term, but the probable prevention of neurological morbidity and reduced need for preoperative neonatal intensive care suggest that such screening will be cost effective long term," concluded lead author Professor Ingegerd Östman-Smith, M.D., Ph.D., and colleagues of the department of pediatric cardiology.

Pulse oximetry is a quick and non-invasive method for measuring the concentration of oxygen in the blood of newborns, using a sensor placed on a hand or on a foot for a few minutes before the baby leaves hospital. Babies with low measures could have a life threatening heart abnormality, since a fetal blood vessel called the ductus arteriosus--which bypasses the baby's nonfunctioning lungs when in the uterus and normally closes off soon after birth--remains partly open. The current screening technique of a routine clinical examination shortly after birth fails to identify many of these babies because duct-dependent heart disease often lacks heart murmurs; 30% of such infants leave the hospital without their condition being diagnosed, which leads to higher rates of complications such as circulatory collapse with organ damage and sometimes death.

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Queen Silvia Children's Hospital