Congenital cardiovascular malformations (CCVMs) occur in five to 10 infants out of 1,000 live births and are associated with significant morbidity and mortality. Although a four-chamber view enables the detection of many malformations, the cost of routine fetal echocardiography makes it an impractical screening tool. Preliminary studies suggest that pulse oximetry may be an effective screening tool for hypoplastic left heart syndrome, coarctation, D transposition of the great arteries, pulmonary atresia with intact ventricular septum, tricuspid atresia, total anomalous pulmonary venous return, and tetralogy of Fallot in asymptomatic newborns. Suggested limitations of oximetry screening are aortic stenosis and coarctation with large ventricular septal defect. Koppel and colleagues determined the sensitivity, specificity, predictive value, and accuracy of pulse oximetry in detecting CCVMs in asymptomatic newborns.
A total of 11,281 asymptomatic newborns from the well-infant nurseries of two hospitals were included in the study. Exclusion criteria were any of the following abnormalities found on examination: cyanosis, tachypnea, grunting, flaring, retraction, murmur, active precordium, and diminished pulses.A single postductal oxygen saturation level was obtained at the time of metabolic screening in one hospital and on discharge in the other hospital. All newborns with 95 percent or less saturation underwent echocardiography.
Pulse oximetry detected three cases of CCVM (true positives), and two cases were diagnosed after discharge (false negatives). The false-negative cases were coarctation and hypoplastic left pulmonary artery with aortopulmonary collaterals, conditions that may not cause desaturation. Four echocardiograms were obtained, detecting three CCVMs and one case of delayed transition from fetal to neonatal circulation and self-limited pulmonary hypertension. Analysis showed a sensitivity of 60 percent, specificity of 99.95 percent, positive predictive value of 75 percent, negative predictive value of 99.98 percent, and accuracy of 99.97 percent. Of note, screening fetal echocardiography was more frequently used in one hospital (revealing nine CCVMs), which explains why rates of detection of CCVMs via pulse oximetry were lower in that hospital.
The authors conclude that in hospitals with lower rates of fetal echocardiography, pulse oximetry is a simple, reliable, and cost-effective screening test for CCVM in asymptomatic newborns.