Pulse oximetry pinpoints heart defects antenatal U/S misses

Pulse oximetry screening for arterial oxygen saturation can detect critical congenital heart defects in newborns that antenatal ultrasonography overlooks, British researchers report in a study published online August 5 in The Lancet.

Of 20,055 asymptomatic newborns (more than 34 weeks’ gestation) screened by pulse oximetry before discharge from the hospital, 53 had major congenital heart disease (causing death or requiring invasive intervention by 12 months of age), and 24 of those infants had critical disease (causing death or requiring invasive intervention before 28 days), for a prevalence of 2.6 per 1,000 live births. Babies whose oxygen saturation fell below a predetermined level underwent echocardiography; all others were followed to 12 months of age. Pulse oximetry had a sensitivity of 75% for critical heart defects and 49.06% for all major defects. Excluding 35 patients with defects suspected after prenatal ultrasonography decreased the sensitivity to 58.33% for critical defects and 28.57% for all major defects, respectively.

“Pulse oximetry is a safe, noninvasive, feasible, and reasonably accurate test, which has a sensitivity that is better than that of antenatal screening and clinical examination,” the authors conclude. “It adds value to existing screening procedures and is likely to be useful for identification of cases of critical congenital heart defects that would otherwise go undetected.”

False-positive results occurred in 169 babies (0.8%), 6 of whom had significant but not major heart defects, and 40 of whom had other conditions requiring urgent medical intervention. “The detection of other diseases, such as significant congenital heart defects and respiratory and infective illnesses, is an additional advantage [of pulse oximetry],” the researchers note. They also observe that measuring both preductal and postductal oxygen saturation is more beneficial than postductal measurements alone and doesn’t take much longer to do.

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