Impact of pulse oximetry screening to detect congenital heart defects: 5 years’ experience in a UK regional neonatal unit

Pulse oximetry screening (POS) has been shown to be an effective, non-invasive investigation that can detect up to 50–70% of previously undiagnosed congenital heart defects (CHDs). The aims of this study were to assess the accuracy of POS in detection of CHDs and its impact on clinical practice. All eligible newborn infants born between 1 Jan 2015 and 31 Dec 2019 in a busy regional neonatal unit were included in this prospective observational study. A positive POS was classified as two separate measurements of oxygen saturation < 95%, or a difference of > 2% between pre- and post-ductal circulations. Overall, 23,614 infants had documented POS results. One hundred eighty nine (0.8%) infants had a true positive result: 6 had critical CHDs, 9 serious or significant CHDs, and a further 156/189 (83%) infants had significant non-cardiac conditions. Forty-three infants who had a normal POS were later diagnosed with the following categories of CHDs post-hospital discharge: 1 critical, 15 serious, 20 significant and 7 non-significant CHDs. POS sensitivity for detection of critical CHD was 85.7%, whereas sensitivity was only 33% for detection of major CHDs (critical and serious) needing surgery during infancy; specificity was 99.3%.Conclusion: Pulse oximetry screening showed moderate to high sensitivity in detection of undiagnosed critical CHDs; however, it failed to detect two-third of major CHDs. Our study further emphasises the significance of adopting routine POS to detect critical CHDs in the clinical practice. However, it also highlights the need to develop new, innovative methods, such as perfusion index, to detect other major CHDs missed by current screening tools. What is Known:• Pulse oximetry screening is cost effective, acceptable, easy to perform and has moderate sensitivity and high specificity in detection of critical congenital heart defects.• Pulse oximetry screening has been implemented many countries including USA for detection of critical congenital heart defects, but it is not currently recommended by the UK National Screening Committee. What is New:• To our knowledge, this is the first study describing postnatal detection and presentation of all the infants with congenital heart defects over a period of 5 years, including those not detected on the pulse oximetry screening, on the clinical practice. • It emphasises that further research required to detect critical congenital heart defects and other major CHDs which can be missed on the screening tools currently employed in clinical practice.

Prevalence of the five newborn screening tests

Neonatal screening is essential for child health and has the following purposes: (1) pulse oximetry screening to evaluate congenital heart diseases; (2) red reflex examination to investigate eye diseases; (3) newborn hearing screening test to evaluate congenital hearing diseases; (4) tongue test to evaluate the lingual frenulum and identify communication and feeding problems; (5) the Guthrie test to screen for metabolic diseases. This study investigated the prevalence of the five neonatal screening tests and its associated institutional and socio-cultural factors using a cross-sectional study with 415 mother and baby binomials from public maternity hospitals in Natal, RN, Brazil in 2019. Pearson’s chi-squared, Mann-Whitney and Poisson regression tests were used, with a significance of p ≤ 0.05 and a 95% confidence interval. The sample loss was 71 mothers (17%). The prevalence in the first week and at the end of 28 days was 93% and 99.5% (pulse oximetry screening), 60% and 97.6% (red reflex examination), 71.9% and 93.6% (Guthrie test), 35.5% and 68.2% (hearing screening test), and 19% and 48.9% (tongue test). Only 152 newborns (36.6%) underwent all five tests. The performance of the tests was associated in the final model (p ≤ 0.05) with the residence of the mothers in the state capital (PR = 1.36; 95% CI = 1.18–1.56) and the provision of guidance for mothers about the five tests in maternity hospitals (PR = 1.30; 95% CI = 1.08–1.67). None of the tests met full coverage, and regional inequities were identified indicating the need to restructure the institutions, training and qualification procedures to improve of the work processes and longitudinal care.

Newborn pulse oximetry screening for critical congenital heart defects

We looked at existing recommendations and supporting evidence addressing the effectiveness of pulse oximetry effective for detecting critical congenital heart defects (CCHDs) in newborns. We also looked at the impact of timing of oximetry and the site of testing in the accuracy of screening, and at the potential harms and limitations of pulse oximetry screening,We conducted a literature search up to the 13th of August 2019 by using key terms and manual search in selected sources. We summarized the recommendations and the strength of the recommendation when and as reported by the authors. We summarized the main findings of systematic reviews with the certainty of the evidence as reported.Current evidence supports consistent accuracy for detection of CCHDs in newborns by pulse oximetry screening in addition to antenatal ultrasonography and clinical examination. Overall, early diagnosis of CCHD with pulse oximetry is judged to be beneficial and cost-effective, and potential harms associated with false-positive tests are not serious, while missing CCHDs and other serious diseases detected by hypoxaemia in absence of pulse oximetry screening can lead to serious consequences. The site of testing (post-ductal versus pre- and post-ductal) had no significant effect on sensitivity nor specificity for detection of CCHDs.

Evaluation of Newborn Screening Test for Critical Congenital Heart Disease (Cchd) in a Private Medical Center in Mexico and its Implications for being at 2550 Meters above Sea Level

Pulse oximetry screening test (POT) has been shown to be useful for in early detection of critical congenital heart disease (CCHD). The precise oxygen saturation expected at altitudes above 1500 meters above sea level is unknown, and its usefulness in children born above this height is also unknown. The target is to describe the results obtained from the POT in 100 apparently healthy newborns in a private hospital at 2550 meters above sea level where most of them were evaluated by one or more fetal-stage ultrasounds for the detection of CCHD among other things. Sex, resuscitation and weeks of gestation did not alter the results. 95 patients had “normal” prenatal ultrasound, of which 32% tested positive POT, and CCHD was also ruled out after clinical follow-up. It was concluded that all the patients with a positive test were healthy. We suggest possibility of modifying the POT parameters in order to avoid false positives is also discussed.

Impact of Pulse Oximetry Screening to Detect Congenital Heart Defects: 5 Years’ Experience in a Regional Neonatal Unit in the UK

Pulse oximetry screening (POS) has been shown to be an effective and non-invasive investigation that can detect up to 50-70% of previously undiagnosed congenital heart defects (CHDs). The aims of this study were to assess the accuracy of POS in detection of CHDs and its impact on the clinical practice. All the eligible newborn infants born between Jan 2015 and Dec 2019 in busy regional neonatal unit were included in the prospective observational study. Of the 25185 eligible infants, 189 (0.8%) infants had a true positive results: 6 had critical CHDs, 9 serious or significant CHDs, and a further 156/189 infants had significant non-cardiac conditions. 43 infants who had a normal POS were later (post-hospital discharge) diagnosed with following category of CHDs: 1 critical, 15 serious, 20 significant and 7 non-significant CHDs. POS sensitivity for detection of critical CHD was 85.7% and its specificity was 99.3%. However, its sensitivity for detection of all the major CHDs needing surgery during infancy was 33%.ConclusionPulse oximetry screening showed moderate and high sensitivity in detection of undiagnosed critical CHDs, however it failed to detect two-third of the major CHDs. Our study further emphasises the significance of adopting routine POS to detect critical CHDs in the clinical practice. However, it also highlights the need to develop new, innovative methods to detect other major CHDs missed by pulse oximetry screening and other current screening tools.