An article published online first in The Lancet reveals that a quick, non-invasive test measuring blood oxygen levels in newborns can detect a larger number of cases of life-threatening congenital heart defects than current standard approaches and should be included into the routine assessment of all newborns prior to their discharge from hospital.

One of the highest causes of infant deaths in the developed world is congenital heart defects. Mid-trimester ultrasound scans and routine physical examinations shortly after birth, fail to identify many life threatening heart abnormalities with current screening techniques. Resulting in considerable number of babies going undiagnosed after leaving the hospital, which can lead to increased rates of complications or even death. Previous studies, although most earlier investigations were small and underpowered to estimate accuracy, reported the potential of pulse oximetry screening for identifying significant or life-threatening congenital heart defects in newborns.

In the UK’s largest pulse oximetry test accuracy study to date, Andrew Ewer and colleagues from the University of Birmingham and Birmingham Women’s Hospital, UK, prospectively evaluated the ability of the test to identify critical congenital heart disease (causing death or requiring intrusive intervention before 28 days) or major congenital heart disease (causing death or requiring intrusive intervention before 12 months of age).

Between February 2008 and January 2009, across six maternity units around the UK, over 20,000 apparently healthy newborn babies were screened with pulse oximetry before discharge from hospital and followed up to 12 months of age.

The researchers discovered that pulse oximetry detected 75% of critical cases and 49% of all major congenital heart defects. After not including 35 cases of suspected congenital heart defects following antenatal ultrasound, the detection rate of pulse oximetry was 58% for critical cases and 28% for all major cases.

The detection of critical congenital heart defects improved to 92%, and no babies died from undiagnosed heart disease, when pulse oximetry was combined with routine ultrasound and newborn physical examination.

In 169 babies, pulse oximetry had a false positive rate of 0.8%. Six of these babies however, had significant heart defects, and an additional 40 babies had further problems (respiratory disorders and infections) that required urgent medical intervention.

The authors explained:

“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.

(conclusion) 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, 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.”

Amy Thompson, Senior Cardiac Nurse at the British Heart Foundation, said:

“We know that congenital heart disease affects around one in every 145 births and, although great progress has been made in the treatment and care of congenital heart disease, early and rapid detection is key for greater survival.

Not all babies who are born with a heart defect will show any signs or symptoms, so problems can go unnoticed. This is a promising piece of research which shows how a quick and simple test could help to detect more heart defects and make a real difference.”

Written by Grace Rattue