Special Interest Section
Screening for CCHD with Pulse Oximetry: Where Are We Now?
Regina Grazel, MSN RN BC APN-C
In 2009, five-day-old Cora Mae McCormick of Indiana died of an undiagnosed critical congenital heart defect (CCHD) that likely would have been detected with pulse oximetry (McCormick, n.d.). Cora is one of the thousands of infants in the United States, about 7,200 (or 2 per 1,000), that are born with critical congenital heart defects each year (US National Library of Medicine, 2017).
On September 21, 2011, the Secretary of Health and Human Services, Kathleen Sebelius, recommended that screening for CCHD be added to the recommended uniform screening panel (RUSP) (Mahle et al., 2012). Through advocacy efforts at many levels, states have enacted legislation and regulations to ensure infants are screened for CCHD. (Glidewell et al., 2015) These initiatives were led by professional associations including the American Academy of Pediatrics, the American Hospital Association, and NANN as well as parents, community organizations, and legislators.
New Jersey, Indiana, and Maryland initiated this newest newborn point-of-care screening in 2011, and in 2018, all 50 states have implemented statewide screening efforts. While screening practices, data collection, and reporting requirements vary across states (Glidewell et al., 2015), the benefits of CCHD screening using pulse oximetry as a public health measure have been widely substantiated. Analysis of death registry data revealed a 33% decline in infant deaths from CCHD in the eight states that had mandated screening for CCHD using pulse oximetry in 2013 compared to states that had not yet implemented mandates (Abouk et al., 2017). In addition to the benefit of lives saved, CCHD Screening was found to be cost effective, reaffirming the importance of this public health program (Grosse et al., 2017).
Congenital heart defects (CHDs) are the most common type of birth defect in the United States, affecting nearly 1% of births, and are the leading cause of infant death due to birth defects. About 25% of infants with CHD have a critical CHD requiring catheter intervention or surgery within the first year of life, usually shortly after birth (Centers for Disease Control and Prevention, 2018).
CCHD is not always detected prenatally or with physical examination, yet newborns with CCHD are at significant risk for disability and even death if their heart defects are not diagnosed and treated soon after birth. The addition of pulse oximetry screening to prenatal ultrasound and newborn examination improves detection of CCHD. Though pulse oximetry screening is unable to detect all cases of infants with CCHD, studies have shown that it can reliably detect disease in a significant number of infants who might otherwise be discharged from the hospital prior to diagnosis (de-Wahl Granelli et al., 2009; Hokanson, 2010; Riede et al., 2010).
Screening Conditions and Detection
Pulse oximetry makes it possible to discover hypoxemia well before cyanosis is detectable by the human eye (Hokanson, 2010). The screening has been shown to be an effective tool in the identification of CCHD and other conditions in the presence of hypoxemia. Pulse oximetry screening is most likely to detect the following seven forms of CCHD, as these defects usually result in hypoxemia (Oster et al., 2016):
- Hypoplastic left heart syndrome
- Pulmonary atresia (with intact septum)
- Tetralogy of Fallot
- Total anomalous pulmonary venous return
- Transposition of the great arteries
- Tricuspid atresia with intact septum
- Truncus arteriosus.
Other types of CCHD that may be detected via pulse oximetry screening, although not as consistently, include the following:
- Coarctation of the aorta
- Double-outlet right ventricle
- Ebstein anomaly
- Interrupted aortic arch
- Single ventricle.
Newborn pulse oximetry screening also aids in the early detection of other serious conditions that present with hypoxemia, including pulmonary hypertension, other types of congenital heart disease, pneumonia, and sepsis (Oster et al., 2016). The high prevalence of these treatable secondary conditions detected by pulse oximetry in the United States and other countries has led to increased global efforts to expand screening. The Birth Oximetry Routine for Newborns (BORN) Project is a screening initiative aimed at early identification of hidden health problems in all newborns, including those in low resource settings (Newborn foundation, n.d.).
Screening is now universal in the United States, yet there are many unanswered questions regarding optimal implementation. A stakeholder’s workgroup on newborn CCHD screening met in Washington, DC, at the American College of Cardiology’s Heart House in September to recognize the successes of screening in the United States and to identify next steps. The author had the privilege of representing NANN and the New Jersey Chapter, American Academy of Pediatrics (AAP), at the meeting.
The recommended screening algorithm endorsed by AAP (Kemper et al., 2011) has been widely adopted, although some states, such as New Jersey and Tennessee, have implemented alternative algorithms with success. No one algorithm has proven superior to another (McClain et al., 2017; Oster et al., 2016).
Data collection and reporting requirements for state screening programs are not uniform. The absence of mandates to report findings from CCHD screening across all states and the lack of a national database have hindered efforts to perform a comprehensive evaluation of this newborn screening program. Although the data elements collected and methods of collection vary, some states have reported their experiences with these results, helping to evaluate the effectiveness of different algorithms and inform future policies. The available data is under review, and recommendations regarding possible modifications are forthcoming. Some of the questions needing clarification include determination of optimal cut-off values, differential between pre and post ductal readings, timing of the screen, and number of repeat screens (McClain et al., 2017; Oster et al., 2016). A recent study by Diller et al. (2018) showed the feasibility of performing a single repeat screening attempt, instead of the currently recommended two repeat attempts, with minimal negative impact.
Due to normal physiologic changes in oxygen saturation at higher elevations, some hospitals in areas of high altitude have made several protocol modifications, including a slightly later time of screening to allow for transition and increased frequency and number of screening attempts to reduce the burden of false-positives. Further study of these approaches is needed to determine efficacy (Oster et al., 2016).
Screening with pulse oximetry should be incorporated into the routine care of out-of-hospital births. While the recommended minimum age for CCHD screening in the United States is 24 hours, screening at <24 hours of age can be performed but is associated with a higher false-positive rate. All birthing centers and providers of home births are encouraged to have policies regarding CCHD screening, evaluation, and referral of failed (positive) screens (McClain et al., 2017; Oster et al., 2016).
Neonatal Intensive Care Unit (NICU)
The recommended CCHD screening protocol was originally intended for newborns in the well-baby nursery, yet many states require screening of all infants irrespective of clinical status or setting, posing unique considerations for implementation in the NICU. Receipt of oxygen and echocardiography, range of gestational ages, routine use of pulse oximetry, and type and severity of disease conditions complicate a straightforward method to screening all NICU infants (McClain et al., 2017; Van Naarden Braun et al., 2017). Limited data are available regarding CCHD screening in the NICU, and the probability of a new CCHD diagnosis from screening in the NICU has yet to be determined (Manja et al., 2015).
The lack of clear guidelines and national recommendations for screening in all-level NICUs has led to wide variation in practice. Some units perform CCHD screening with pulse oximetry per the standard AAP protocol, whereas others have modified the protocol based on timing or use of supplemental oxygen. Some have excluded screening for sub-populations of NICU infants with certain characteristics (Oster et al., 2016; Suresh, 2013; Van Naarden Braun et al., 2017). Regardless of the practice, the intention of CCHD screening is early detection of critical defects before circulatory collapse and/or major complications; therefore, exclusion of all NICU infants from screening is not advised. Suresh (2013) postulates three approaches to screening and identifies NICU infants who have not undergone a fetal or post natal echocardiogram, and in whom physical signs of heart disease are absent or overlooked by clinicians, as those likely to benefit from screening. Manja et al. (2015) described a large single-center study and concluded that performing universal screening in the NICU is feasible but is associated with a higher false-positive rate compared with asymptomatic newborn infants, and no infant with CCHD was detected with screening during the study.
A larger evaluation involving 21 NICUs across five states (Van Naarden Braun et al., 2017) confirmed the feasibility of early screening (24–48 hours of admission or weaning from supplemental oxygen) for CCHD in the NICU. Their results showed a low burden of implementation as reported by nursing staff, low false-positive rates when the screen was performed without receipt of supplemental oxygen, and the majority of NICU infants represented a population that would benefit from screening at 24–48 hours—normal birthweight, not receiving oxygen, no prenatal diagnosis of a CHD or CCHD, and no echocardiography conducted before the screening. These NICU infants may benefit from screening for early detection of CCHD with minimal burden. The researchers acknowledged challenges when early screening was conducted on extremely preterm infants and those receiving supplemental oxygen. They caution that exclusion of subpopulations within the NICU introduces practice variation which may potentially lead to missed screens. One infant with a previously unsuspected CHD was detected, but no cases of CCHD were identified by screening in this study (Van Naarden Braun et al., 2017).
Provider and Family Education
Comprehensive provider and family education is necessary for successful implementation of a CCHD screening program. Providers should be aware of the benefits and limitations of screening and well versed in their state’s or hospital’s protocol for performing the screening, appropriate interpretation of the screening algorithm, and infant evaluation for failed screens. A passing screen does not rule out all heart disease. It is possible for an infant with CCHD to have normal pulse oximetry readings at the time of screening. Providers need to be vigilant, and parents should be instructed about potential signs and symptoms of CHD including feeding difficulties, poor weight gain, increased sleepiness, sweating about the head (especially during feeding), tachypnea, pallor, and cyanosis (Grazel, Anderson & Craft, 2017; McClain et al., 2017).
Despite the challenges and questions that remain, implementation of CCHD screening with pulse oximetry in the United States has been a tremendous success and is saving lives. At the stakeholder’s meeting in Washington, DC, Karin Ryan shared her story of how CCHD screening affected her family. Karin’s newborn, Greta, was a normal-appearing infant with a hidden critical heart defect that was detected with pulse oximetry screening. After a NICU admission and cardiac surgery, Greta is now a happy, healthy five year old (K. Ryan, personal communication, September 21, 2018). The Gordon family also attests to the value of CCHD screening that they attribute to saving their son Dylan’s life. With early detection of his cardiac defect through screening, Dylan Gordon was able to receive corrective surgery. As the first infant with a CCHD to be detected with the mandated screening in New Jersey, his parents strongly endorse the importance of this life-saving test. (Grazel, Anderson & Craft, 2017).
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