Post-implementation review of pulse oximetry screening of well newborns in an Australian tertiary maternity hospital

Fifteen-minute consultation: How to spot serious heart disease in the newborn

Congenital heart disease (CHD) is common and important as it remains a leading cause of neonatal morbidity and appreciable mortality. Prenatal diagnosis, the presence of a murmur, cyanosis, tachypnoea and/or poor or differential peripheral pulses raise the suspicion of CHD aided by differential pre/postductal saturations. Yet even serious CHD may not be considered when such clues are absent. Nevertheless, there are clinical cues which may alert the clinician to the possibility of a significant CHD which may lead to an early and accurate diagnosis and appropriate intervention to achieve best results. This paper addresses these issues which become especially difficult if caring for infants away from facilities provided by tertiary centres. Tachypnoea on the first postnatal day is generally non-cardiac in origin. Exceptions include large arteriovenous fistulae and/or 'pump' (ventricular) failure. In addition, attention is drawn to two important confounding factors in the newborn, namely the patency of the ductus arteriosus and the initially high pulmonary vascular resistance, both of which alter and may mask the clinical findings of a serious cardiac abnormality. An appreciation of the physiological changes that occur in early infancy will aid the clinician's understanding of CHD as it affects the newborn.

Saturation screening for neonatal hypoxaemia within 6 h of life: Not all about congenital cardiac disease

AIMS

To assess the outcomes of an early oxygen saturation screening programme in apparently healthy newborns for the detection of cardiac and non-cardiac disease. To describe the aetiology and incidence of infants with oxygen saturations <95% in the first 6 h of life and describe the management to discharge. In addition, we sought to identify any risk factors for failed early saturations.

METHODS

This is a retrospective hospital cohort assessing outcomes of an early saturation screening programme performed in apparently healthy newborns. Infants with oxygen saturations less than 95% were identified and their clinical notes were hand-searched. Descriptive statistics were used to present demographics, proportion of infants who passed or failed screening, subsequent diagnoses and short-term outcome. Multivariate logistic regression was used to identify independent associations of clinical factors (birthweight, gestation, elective caesarean section and gender) with failed screening.

RESULTS

Between 2014 and 2019, 14 956 healthy newborns were assessed within the first 6 h, 94 (0.63%) failed the early saturation screen. The most common causes for saturation <95% were respiratory disease or delayed transition. There were 31 (33%) infants admitted to the NICU with an additional baby requiring emergency transfer to a cardiac centre. Infants were 28 times more likely to have saturations <95% if born by elective caesarean section (odds ratio 28, conflict of interest (18.54-42.82)).

CONCLUSION

In apparently healthy newborns, early assessment of oxygen saturation, combined with clinical assessment and subsequent intervention can identify important conditions and should be considered as standard care.

Early detection of significant congenital heart disease: The contribution of fetal cardiac ultrasound and newborn pulse oximetry screening

Fetal cardiac and newborn pulse oximetry screening has greatly facilitated the detection of cardiac abnormalities, which may be serious with potentially dire neonatal consequences. The prenatal diagnosis of a serious cardiac abnormality allows the attending obstetrician to organise the much safer in-utero transfer of the fetus for delivery at a tertiary centre, particularly if there is evidence of a duct-dependent lesion that may require the infusion of Prostaglandin E1 to maintain duct patency pending surgical intervention. Newborn pulse oximetry alerts the paediatrician that the baby may have a significant cardiac abnormality, which warrants further elucidation prior to discharge, rather than for the baby to represent unwell a few days later. Despite these advances, serious cardiac abnormalities may be missed on screening. Their detection then falls back onto the clinical acumen of the attending paediatrician/family physician to review the history, carefully elicit and evaluate the clinical signs further aided by whatever investigations that may be available at the birthing hospital, frequently less resourced than the tertiary centres. At the outset, a brief synopsis is provided of the clinical findings that may point to a cardiac abnormality. That is followed by a critical review of the accuracy of prenatal and newborn pulse oximetry screening with emphasis on the lesions that may be missed. Suggestions are made as to how to improve the diagnostic accuracy.

Updated Strategies for Pulse Oximetry Screening for Critical Congenital Heart Disease

Seven years after its addition to the US Recommended Uniform Screening Panel, newborn screening for critical congenital heart disease (CCHD) using pulse oximetry became mandatory in the United States. Although CCHD newborn screening reduces morbidity and mortality, there remain important opportunities to improve. An expert panel convened for a 1-day meeting in September 2018, including subject matter experts and representatives from stakeholder organizations. Presentations on CCHD outcomes, variations in approach to screening, and data and quality improvement helped identify improvement opportunities. The expert panel concluded that sufficient evidence exists to recommend modifying the current American Academy of Pediatrics algorithm by (1) requiring an oxygen saturation of at least 95% in both (formerly either) the upper and lower extremities to pass and (2) requiring only 1 repeat screen instead of 2 for cases that neither pass nor fail initially. The panel underscored the importance of improving public health reporting by further specifying the targets of screening and criteria for reporting outcomes (false-negative and false-positive cases). The panel also highlighted the need to ensure sufficient public health funding for CCHD newborn screening and opportunities for education and global implementation. Newborn screening for CCHD using pulse oximetry has led to significant improvements in child health outcomes. However, further important work is required to understand and improve the effectiveness and efficiency of screening.

Pulse oximetry screening in a midwifery-led maternity setting with high antenatal detection of congenital heart disease

Aim

To assess local and individual factors that should be considered in the design of a pulse oximetry screening strategy in New Zealand's midwifery‐led maternity setting.

Methods

An intervention study was conducted over 2 years. Three hospitals and four primary maternity units participated in the study. Post‐ductal saturation levels were measured on well infants with a gestation of ≥35 weeks. Infant activity and age (hours) at the time of the test were recorded.

Results

Screening was performed on 16 644 of 27 172 (61%) eligible infants. The age at which the screening algorithm was initiated varied significantly among centres. The probability of achieving a pass result (saturations ≥95%) in the context of no underlying pathology ranged from .94 for an unsettled infant screened <4 hours of age to .99 (P < .001) when the test was performed after 24 hours on a settled infant. Forty‐eight (0.3%) infants failed to reach saturation targets: 37 had significant pathology of which three had cardiac disease.

Conclusion

Screening practices were influenced by the setting in which it was undertaken. Infant activity and age at the time of testing can influence saturation levels. Screening is associated with the identification of significant non‐cardiac pathology.

Health professionals' views of newborn pulse oximetry screening in a midwifery-led maternity setting. "It's a good thing to do, but fund it!"

OBJECTIVE

To understand from health professionals who care for newborns their views on the introduction of pulse oximetry screening for the detection of hypoxaemia in a midwifery-led maternity setting. Although oximetry screening for newborns is internationally accepted, national screening is not yet introduced in New Zealand. In this context, we drew on maternity carers' reflections during a feasibility study of oximetry screening to provide perspectives on barriers and enablers to universal screening.

METHODS

Data were generated from nine focus groups during five months of 2018 in two north island regions of New Zealand. Participants' (n = 45) opinions about the use of oximetry screening in newborns were analysed thematically using an inductive approach.

FINDINGS

Overall, participants stated pulse oximetry screening was easy to do, non-invasive, and worthwhile. Midwives were reassured by screening that provided evidence of either a healthy baby or a need for urgent review. From participants' reports, we identified three themes: (1) oximetry screening for newborns is reassuring, practical and worthwhile; (2) midwifery services workload expectations and under-resourcing will hinder universal screening, and (3) location of the baby at the time of screening could impede universal access.

CONCLUSION AND IMPLICATIONS FOR PRACTICE

Midwives viewed implementing a national pulse oximetry screening programme as sensible but problematic unless resourced and funded appropriately. Policymakers should view the concerns of midwives about human and physical resources as significant and account for the need to resource this screening programme appropriately as a priority before implementation.

Consumer Satisfaction with Newborn Pulse Oximetry Screening in a Midwifery-Led Maternity Setting

Pulse oximetry screening to detect hypoxaemia in newborn infants was introduced at birthing facilities in New Zealand during a feasibility study determining barriers and enablers to universal screening in a midwifery-led maternity system focused on community values and partnership with, and participation by, consumers. During the 2-year study period, parents of infants who underwent pulse oximetry screening were invited to complete a written survey to investigate consumer satisfaction. Respondents ranked their satisfaction with the test and with information resources on a five-level Likert scale. Additional comments were added in a free text space. Participation was voluntary and anonymous. A total of 657 surveys were included for analysis. Consumers were satisfied with the screening procedure; 94% either agreed or strongly agreed that it is an important health check. Although the quality of information sources was deemed good, a third of participants indicated a wish to obtain more information. Some participants stated that retention of information was an issue, reporting that they were fatigued following the birth. Consumers are receptive to pulse oximetry screening. Sharing information (while considering the receptivity of parents) and engaging the parents of newborn infants are factors that are paramount to the success of newborn screening initiatives.

Pulse oximetry screening for critical congenital heart defects

BACKGROUND

Health outcomes are improved when newborn babies with critical congenital heart defects (CCHDs) are detected before acute cardiovascular collapse. The main screening tests used to identify these babies include prenatal ultrasonography and postnatal clinical examination; however, even though both of these methods are available, a significant proportion of babies are still missed. Routine pulse oximetry has been reported as an additional screening test that can potentially improve detection of CCHD.

OBJECTIVES

• To determine the diagnostic accuracy of pulse oximetry as a screening method for detection of CCHD in asymptomatic newborn infants• To assess potential sources of heterogeneity, including:○ characteristics of the population: inclusion or exclusion of antenatally detected congenital heart defects;○ timing of testing: < 24 hours versus ≥ 24 hours after birth;○ site of testing: right hand and foot (pre-ductal and post-ductal) versus foot only (post-ductal);○ oxygen saturation: functional versus fractional;○ study design: retrospective versus prospective design, consecutive versus non-consecutive series; and○ risk of bias for the "flow and timing" domain of QUADAS-2.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 2) in the Cochrane Library and the following databases: MEDLINE, Embase, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Health Services Research Projects in Progress (HSRProj), up to March 2017. We searched the reference lists of all included articles and relevant systematic reviews to identify additional studies not found through the electronic search. We applied no language restrictions.

SELECTION CRITERIA

We selected studies that met predefined criteria for design, population, tests, and outcomes. We included cross-sectional and cohort studies assessing the diagnostic accuracy of pulse oximetry screening for diagnosis of CCHD in term and late preterm asymptomatic newborn infants. We considered all protocols of pulse oximetry screening (eg, different saturation thresholds to define abnormality, post-ductal only or pre-ductal and post-ductal measurements, test timing less than or greater than 24 hours). Reference standards were diagnostic echocardiography (echocardiogram) and clinical follow-up, including postmortem findings, mortality, and congenital anomaly databases.

DATA COLLECTION AND ANALYSIS

We extracted accuracy data for the threshold used in primary studies. We explored between-study variability and correlation between indices visually through use of forest and receiver operating characteristic (ROC) plots. We assessed risk of bias in included studies using the QUADAS-2 tool. We used the bivariate model to calculate random-effects pooled sensitivity and specificity values. We investigated sources of heterogeneity using subgroup analyses and meta-regression.

MAIN RESULTS

Twenty-one studies met our inclusion criteria (N = 457,202 participants). Nineteen studies provided data for the primary analysis (oxygen saturation threshold < 95% or ≤ 95%; N = 436,758 participants). The overall sensitivity of pulse oximetry for detection of CCHD was 76.3% (95% confidence interval [CI] 69.5 to 82.0) (low certainty of the evidence). Specificity was 99.9% (95% CI 99.7 to 99.9), with a false-positive rate of 0.14% (95% CI 0.07 to 0.22) (high certainty of the evidence). Summary positive and negative likelihood ratios were 535.6 (95% CI 280.3 to 1023.4) and 0.24 (95% CI 0.18 to 0.31), respectively. These results showed that out of 10,000 apparently healthy late preterm or full-term newborn infants, six will have CCHD (median prevalence in our review). Screening by pulse oximetry will detect five of these infants as having CCHD and will miss one case. In addition, screening by pulse oximetry will falsely identify another 14 infants out of the 10,000 as having suspected CCHD when they do not have it.The false-positive rate for detection of CCHD was lower when newborn pulse oximetry was performed longer than 24 hours after birth than when it was performed within 24 hours (0.06%, 95% CI 0.03 to 0.13, vs 0.42%, 95% CI 0.20 to 0.89; P = 0.027).Forest and ROC plots showed greater variability in estimated sensitivity than specificity across studies. We explored heterogeneity by conducting subgroup analyses and meta-regression of inclusion or exclusion of antenatally detected congenital heart defects, timing of testing, and risk of bias for the "flow and timing" domain of QUADAS-2, and we did not find an explanation for the heterogeneity in sensitivity.

AUTHORS' CONCLUSIONS

Pulse oximetry is a highly specific and moderately sensitive test for detection of CCHD with very low false-positive rates. Current evidence supports the introduction of routine screening for CCHD in asymptomatic newborns before discharge from the well-baby nursery.

Barriers to the Implementation of Newborn Pulse Oximetry Screening: A Different Perspective

Pulse oximetry screening of the well newborn to assist in the diagnosis of critical congenital heart disease (CCHD) is increasingly being adopted. There are advantages to diagnosing CCHD prior to collapse, particularly if this occurs outside of the hospital setting. The current recommended approach links pulse oximetry screening with the assessment for CCHD. An alternative approach is to document the oxygen saturation as part of a routine set of vital signs in each newborn infant prior to discharge, delinking the measurement of oxygen saturation from assessment for CCHD. This approach, the way that many hospitals which contribute to the Australian New Zealand Neonatal Network (ANZNN) have introduced screening, has the potential benefits of decreasing parental anxiety and expectation, not requiring specific consent, changing the interpretation of false positives and therefore the timing of the test, and removing the pressure to perform an immediate echocardiogram if the test is positive. There are advantages of introducing a formal screening program, including the attainment of adequate funding and a universal approach, but the barriers noted above need to be dealt with and the process of acceptance by a national body as a screening test can take many years.

A comparison of the incidence of undiagnosed congenital heart disease in hospital born and home born children

OBJECTIVE

To evaluate the incidence of otherwise undiagnosed congenital heart disease (CHD) in a population of children born in a hospital with routine pulse oximetry (RPO) screening compared to children born at home.

METHODS

We reviewed 15 years of births at 2 hospitals for incidence of undiagnosed CHD with RPO. The Health Department reviewed the same data for out of hospital births.

RESULTS

A total of 50,545 hospital births were screened and 1,274 children were born outside the hospital. There were 28 hospital-born babies diagnosed with cyanotic CHD prior to nursery discharge. Only one of these babies would not have been diagnosed without RPO. Three children were missed and there were 3 false positives. Sensitivity and positive predictive value of RPO was 25%, specificity and negative predictive value of RPO exceed 99%. The incidence of CHD requiring RPO diagnosis was roughly one birth per 50,000. Two children born at home with undiagnosed CHD were missed. One of these children presented with neonatal demise.

CONCLUSION

RPO screening is still valuable in diagnosing CHD only diagnosable with RPO. However, the incidence of CHD requiring RPO to diagnose is similar to other congenital diseases which are not mandated national screening tests. In our limited experience a patient is roughly 25 times more likely to have undiagnosed CHD if they are born outside of a hospital.

Pulse Oximetry and Auscultation for Congenital Heart Disease Detection

OBJECTIVES

Pulse oximetry (POX) has been confirmed as a specific screening modality for critical congenital heart disease (CCHD), with moderate sensitivity. However, POX is not able to detect most serious and critical cardiac lesions (major congenital heart disease [CHD]) without hypoxemia. In this study, we investigated the accuracy and feasibility of the addition of cardiac auscultation to POX as a screening method for asymptomatic major CHD.

METHODS

A multicenter prospective observational screening study was conducted at 15 hospitals in Shanghai between July 1, 2012, and December 31, 2014. Newborns with either an abnormal POX or cardiac auscultation were defined as screen positive. All screen-positive newborns underwent further echocardiography. False-negative results were identified by clinical follow-up, parents' feedback, and telephone review. We assessed the accuracy of POX plus cardiac auscultation for the detection of major CHD.

RESULTS

CHD screening was completed in all 15 hospitals, with a screening rate of 94.0% to 99.8%. In total, 167 190 consecutive asymptomatic newborn infants were screened, of which 203 had major CHD (44 critical and 159 serious). The sensitivity of POX plus cardiac auscultation was 95.5% (95% confidence interval 84.9%-98.7%) for CCHD and 92.1% (95% confidence interval 87.7%-95.1%) for major CHD. The false-positive rate was 1.2% for detecting CCHD and 1.1% for detecting major CHD.

CONCLUSIONS

In our current study, we show that using POX plus cardiac auscultation significantly improved the detection rate of major CHD in the early neonatal stage, with high sensitivity and a reasonable false-positive rate. It provides strong evidence and a reliable method for neonatal CHD screening.

Perfusion Index and Pulse Oximetry Screening for Congenital Heart Defects

OBJECTIVE

To evaluate the efficacy of combined pulse oximetry (POX) and perfusion index (PI) neonatal screening for severe congenital heart defects (sCHD) and assess different impacts of screening in tertiary and nontertiary hospitals.

STUDY DESIGN

A multicenter, prospective study in 10 tertiary and 6 nontertiary maternity hospitals. A total of 42 169 asymptomatic newborns from among 50 244 neonates were screened; exclusion criteria were antenatal sCHD diagnosis, postnatal clinically suspected sCHD, and neonatal intensive care unit admission. Eligible infants underwent pre- and postductal POX and PI screening after routine discharge examination. Targeted sCHD were anatomically defined. Positivity was defined as postductal oxygen saturation (SpO₂) ≤95%, prepostductal SpO₂ gradient >3%, or PI <0.90. Confirmed positive cases underwent echocardiography for definitive diagnosis. Missed cases were identified by consulting clinical registries at 6 regional pediatric heart centers. Main outcomes were incidence of unexpected sCHD; proportion of undetected sCHD after discharge in tertiary and nontertiary hospitals; and specificity, sensitivity, positive predictive value, and negative predictive value of combined screening.

RESULTS

One hundred forty-two sCHD were detected prenatally. Prevalence of unexpected sCHD was 1 in 1115 live births, similar in tertiary and nontertiary hospitals. Screening identified 3 sCHD (low SpO₂, 2; coarctation for low PI, 1). Four cases were missed. In tertiary hospitals, 95% of unsuspected sCHDs were identified clinically, whereas only 28% in nontertiary units; in nontertiary units PI-POX screening increased the detection rate to 71%.

CONCLUSIONS

PI-POX predischarge screening provided benefits in nontertiary units, where clinical recognition rate was low. PI can help identify coarctation cases missed by POX but requires further evaluation in populations with higher rates of missed cases.

Critical congenital heart disease screening

Critical congenital heart disease (CCHD) is a heart lesion for which neonates require early surgical intervention to survive. Without intervention, the rates of mortality and survival with significant disability are extremely high. Early diagnosis can potentially improve health outcomes in newborns with CCHD. Until recent years, no routine screening protocol existed. In the last few years, pulse oximetry screening for CCHD in newborns has been added to the list of recommended uniform screening panels and advocated by several health-care authorities. A positive screening test result warrants an echocardiogram to evaluate for CCHD. Newborn screens do not usually require parental consent. However, most of the states mandates in the United States include a statement allowing exemption from the screen on the basis of parental religious or personal beliefs.

Timing of diagnosis affects mortality in critical congenital heart disease

OBJECTIVE

Screening for critical congenital heart disease (CHD) with prenatal ultrasound or postnatal pulse oximetry has the potential to improve outcome. To guide screening recommendations, this study aimed to identify the proportion and outcome of major CHD diagnosed before (early) or after (late) postnatal discharge prior to the introduction of postnatal oximetry screening.

DESIGN

A retrospective, population-based review of all major CHD in New Zealand from 2006 to 2010. The timing of diagnosis relative to discharge and to intervention in critical and non-critical cases with intention to treat was determined, as was the relationship of diagnostic timing to mortality at 1 year of age.

RESULTS

Late diagnosis occurred in 20% of critical and 51% of non-critical cases. Mortality occurred in 18% of critical vs 8% of non-critical cases. Mortality was lower with an early diagnosis of critical CHD (early diagnosis 16% vs late diagnosis 27%, p=0.04). Isolated critical CHD benefited most from early diagnosis (mortality, early diagnosis 12% vs late diagnosis 29%, p=0.002). Early diagnosis occurred in >90% critical complex CHD and hypoplastic left heart syndrome, 85% d-transposition of the great arteries (d-TGA) and 53% critical left ventricular outflow tract obstruction (LVOTO). Deaths in d-TGA and LVOTO primarily occurred prior to intervention and for d-TGA most often when birth was distant from the cardiac centre.

CONCLUSIONS

Excess mortality occurs following late diagnosis of critical CHD, and for d-TGA even with early diagnosis if intervention is not immediately available. Antenatal detection retains an important role in reducing mortality related to critical CHD.

Aspects of pulse oximetry screening for critical congenital heart defects: when, how and why?

Pulse oximetry (PO) screening for critical congenital heart defects (CCHD) has been studied extensively and is being increasingly implemented worldwide. This review provides an overview of all aspects of PO screening that need to be considered when introducing this methodology. PO screening for CCHD is effective, simple, quick, reliable, cost-effective and does not lead to extra burden for parents and caregivers. Test accuracy can be influenced by targets definition, gestational age, timing of screening and antenatal detection of CCHD. Early screening can lead to more false positive screenings, but has the potential to detect significant pathology earlier. There is no apparent difference in accuracy between screening with post-ductal measurements only, compared with screening using pre-ductal and post-ductal measurements. However, adding pre-ductal measurements identifies cases of CCHD which would have been missed by post-ductal screening. Screening at higher altitudes leads to more false positives. Important non-cardiac pathology is found in 35-74% of false positives in large studies. Screening is feasible in neonatal intensive care units and out-of-hospital births. Training caregivers, simplifying the algorithm and using computer-based interpretation tools can improve the quality of the screening. Caregivers need to consider all aspects of screening to enable them to choose an optimal protocol for implementation of CCHD screening in their specific setting.

Pulse Oximetry Screening for Critical Congenital Heart Disease after Home Birth and Early Discharge

OBJECTIVES

To assess the feasibility of pulse oximetry (PO) screening in settings with home births and very early discharge. We assessed this with an adapted protocol in The Netherlands.

STUDY DESIGN

PO screening was performed in the Leiden region in hospitals and by community midwives. Measurements were taken ≥ 1 hour after birth and on day 2 or 3 during the midwife visit. Primary outcome was the percentage of screened infants with parental consent. The time point of screening, oxygen saturation, false positive (FP) screenings, critical congenital heart defects (CCHDs), and other detected pathology were registered.

RESULTS

In a 1-year period, 3625 eligible infants were born. Parents of 491 infants were not approached for consent, and 44 refused the screening. PO screening was performed in 3059/3090 (99%) infants with obtained consent. Median (IQR) time points of the first and second screening were 1.8 (1.3-2.8) and 37 (27-47) hours after birth. In 394 infants with screening within 1 hour after birth, the median pre- and postductal oxygen saturations were 99% (98%-100%) and 99% (97%-100%). No CCHD was detected. The FP prevalence was 1.0% overall (0.6% in the first hours after birth). After referral, important noncritical cardiac and other noncardiac pathology was found in 62% of the FP screenings.

CONCLUSIONS

PO screening for CCHD is feasible after home births and very early discharge from hospital. Important neonatal pathology was detected at an early stage, potentially increasing the safety of home births and early discharge policy.