Objective – To evaluate the use of pulse oximetry to screen for early detection of life threatening congenital heart disease.
Design – Prospective screening study with a new generation pulse oximeter before discharge from well baby nurseries in West Götaland. Cohort study comparing the detection rate of duct dependent circulation in West Götaland with that in other regions not using pulse oximetry screening. Deaths at home with undetected duct dependent circulation were included.
Setting – All 5 maternity units in West Götaland and the supraregional referral centre for neonatal cardiac surgery.
Participants – 39 821 screened babies born between 1 July 2004 and 31 March 2007. Total duct dependent circulation cohorts: West Götaland n=60, other referring regions n=100.
Main outcome measures – Sensitivity, specificity, positive and negative predictive values, and likelihood ratio for pulse oximetry screening and for neonatal physical examination alone.
Results – In West Götaland 29 babies in well baby nurseries had duct dependent circulation undetected before neonatal discharge examination. In 13 cases, pulse oximetry showed oxygen saturations 90%, and (in accordance with protocol) clinical staff were immediately told of the results. Of the remaining 16 cases, physical examination alone detected 10 (63%). Combining physical examination with pulse oximetry screening had a sensitivity of 24/29 (82.8% (95% CI 64.2% to 95.2%)) and detected 100% of the babies with duct dependent lung circulation. Five cases were missed (all with aortic arch obstruction). False positive rate with pulse oximetry was substantially lower than that with physical examination alone (69/39 821 (0.17%) v 729/38 413 (1.90%), PConclusion – Introducing pulse oximetry screening before discharge improved total detection rate of duct dependent circulation to 92%. Such screening seems cost neutral in the short term, but the probable prevention of neurological morbidity and reduced need for preoperative neonatal intensive care suggest that such screening will be cost effective long term.
False positive results with pulse oximetry
The “false” positive rate for oximetry screening was 69/39 821 (0.17%) (see fig). Table 3 shows that 45% (31/69) of the “false positive” babies detected by pulse oximetry had other significant heart malformation, lung problem, or infection. In terms of benefit derived by early detection of babies with pathology other than duct dependent heart disease, table 3 suggests that 12% required cardiac surgery, 29% required further follow-up, and that neonatal intensive care was required in 5 days for 26%.
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