A quick, non-invasive test that measures blood oxygen levels in newborns detects more cases of life-threatening congenital heart defects than current standard approaches and should be adopted into the routine assessment of all newborns before discharge from hospital, according to an Article published Online First in The Lancet.
Congenital heart defects are one of the leading causes of deaths in infants in the developed world. Current screening techniques involving a mid-trimester ultrasound scan and a routine physical examination shortly after birth fail to detect many life threatening heart abnormalities. As a result, a substantial number of babies leave hospital undiagnosed which can lead to higher rates of complications and even death. Previous research has reported the potential of pulse oximetry screening* for identifying significant or life-threatening congenital heart defects in newborn babies, but most earlier studies were small and underpowered to estimate accuracy.
In the largest UK pulse oximetry test accuracy study to date, Andrew Ewer from University of Birmingham and Birmingham Women's Hospital, Birmingham, UK and colleagues prospectively assessed the ability of the test to detect critical congenital heart disease (causing death or requiring invasive intervention before 28 days) or major congenital heart disease (causing death or requiring invasive intervention before 12 months of age).
Between February 2008 and January 2009, over 20 000 apparently healthy newborn babies from six maternity units across the UK were screened with pulse oximetry before discharge from hospital and followed up to 12 months of age.
The authors found that pulse oximetry detected 75% of critical cases and 49% of all major congenital heart defects. 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 pulse oximetry was combined with routine ultrasound and newborn physical examination, it improved the detection of critical congenital heart defects to 92%, and no babies died from undiagnosed heart disease.
Pulse oximetry had a false positive rate of 0.8% (169 babies). However, six of these babies had significant heart defects, and a further 40 babies had additional problems (respiratory disorders and infections) that required urgent medical intervention.
The authors say: "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 conclude: "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 say: "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."
Dr Andrew Ewer, Birmingham Women's Hospital, Birmingham, UK. T) +44 (0) 121 472 1377 Ext 4403 or +44 (0)7968 449897 (mobile) E) a.k.ewer@bham.ac.uk
Dr William Mahle, Emory University School of Medicine, Atlanta, USA. T) +1 404 694 682 E) MahleW@kidsheart.com
Notes to Editors: *Pulse oximetry is quick, inexpensive test that measures oxygen levels in the blood using a sensor placed on a hand or foot. Clinically undetectable hypoxaemia is present in most life threatening cases, so low oxygen levels can indicate a heart problem
Journal
The Lancet