Oximetry screening (pulse oximetry), a rapid, non-invasive test that measures levels of oxygen in the blood of newborn babies is better at detecting cases of congenital heart defects than current screening techniques involving a mid-trimester ultrasound scan and a routine physical exam soon after birth, researchers reported in The Lancet. The authors added that pulse oximetry should be used routinely on all newborns.

With pulse oximetry, a sensor is placed on the baby's hand or foot. It is a quick and inexpensive test.

In developed nations, congenital heart defects are one of the main causes of death in young babies. Standard screening techniques do not detect a considerable number of life-threatening heart problems. Many babies with heart problems leave hospital undiagnosed, leaving them at high risk of complications, and death.

Although there have been studies on the benefits of oximetry screening for newborns, they were mostly small studies which could not make accurate conclusions, the authors explained.

In this large UK pulse oximetry study, Andre Ewer, from the University of Birmingham and Birmingham Women's Hospital, UK and team assessed the efficacy and accuracy of the test in identifying cases of critical congenital heart disease - disease that can cause death or requires invasive intervention within a month, or major congenital heart disease - requiring invasive intervention within a year.

20,000 apparently healthy newborns from six different maternity units across the country were screened with pulse oximetry before they left hospital. They were all followed up one year later.

They found that pulse oximetry had identified 75% of all critical cases and 49% of all major congenital heart defects.

The authors wrote:

"The detection rate of pulse oximetry, after excluding 35 cases of suspected congenital heart defects following antenatal ultrasound, was 58% for critical cases and 28% for all major cases."

When combining routine ultrasound and the physical examination at birth with pulse oximetry, the detection rate for critical congenital heart defects rose to 92% - not one baby died from undiagnosed heart disease.

Only 0.8% of the babies had a false positive result. However, six had significant heart defects and another 40 had other problems, including infections and respiratory disorders that required urgent medical treatment.

The researchers wrote:

"Pulse oximetry is a safe, non-invasive, feasible, and reasonably accurate test, which has sensitivity that is better than that of antenatal screening and clinical examination...It adds value to existing screening and is likely to be useful for identification of cases of critical congenital heart defects that would otherwise go undetected. The detection of other diseases . . . is an additional advantage."

They concluded:

"The results of this study enhance the strong evidence that indicates the potential benefits of predischarge pulse oximetry screening as a routine procedure."

In a Comment in the same journal, William Mahle from Emory University School of Medicine, Atlanta, USA and Robert Koppel from Cohen Children's Medical Center, New York, USA, wrote:

"The decision to introduce another screening assay for newborn babies is one that should be made after careful consideration. Health-care systems in the developed world are already heavily burdened. Yet the compelling data provided by Ewer and colleagues support inclusion of pulse oximetry into the care of the newborn baby."