Zinc status and growth in infants and young children with cystic fibrosis

BACKGROUND

Zinc deficiency is associated with poor growth in children without cystic fibrosis (CF), but its impact on growth in children with CF is unknown.

OBJECTIVE

To determine the prevalence of low serum Zn (sZn) and its relationship with growth in the first 3 years of life in children with CF.

METHODS

We utilized data from infants with CF who were enrolled in a longitudinal study of nutrition and lung health and had sZn measured as part of clinical care. Cross-sectional correlations between sZn levels and growth z scores were assessed by Pearson's correlation coefficient. To identify factors associated with sZn status and its association to longitudinal growth patterns, multiple regression analysis with repeated measures were performed using generalized estimating equations.

RESULTS

A total of 106 sZn measurements from 53 infants were identified. Seventeen infants (32%) had intermittent Zn insufficiency, defined as at least one sZn <70 mcg/dl in their first 3 years of life. There were no significant cross-sectional associations between sZn and growth z scores. However, analysis of longitudinal growth patterns revealed that weight- and length-for-age z scores in children with intermittent Zn insufficiency were lower during early infancy and their weight-for-length z scores at age 3 years were also lower compared to those who were always Zn sufficient.

CONCLUSION

Low sZn occurs in one-third of children with CF in the first 3 years of life. Cross-sectional and longitudinal analyses revealed discrepant associations between sZn and growth. Therefore, prospective studies are needed to understand the role of Zn in growth in CF.

Outcomes of infants born during the first 9 years of CF newborn screening in the United States: A retrospective Cystic Fibrosis Foundation Patient Registry cohort study

INTRODUCTION

Newborn screening (NBS) for cystic fibrosis (CF) was implemented in all US states and DC by 2010. This hypothesis-generating study was designed to form the basis of additional analyses and to plan quality improvement initiatives. The aims were to describe the outcomes of infants with CF born during the first 9 years of universal NBS.

METHODS

We included participants in the CF Foundation Patient Registry born 2010-2018 with age of recorded CF diagnosis 0-365 days old. We compared the age of center-reported diagnosis, age at first CF event (defined as earliest sweat test, clinic visit, or hospitalization), demographics, and outcomes between three cohorts born between 2010-2012, 2013-2015, and 2016-2018.

RESULTS

In 6354 infants, the median age at first CF event decreased from the first to the third cohort. Weight-for-age (WFA) was < 10th percentile in about 40% of infants at the first CF Center visit. Median WFA z-score at 1-2 years was more than 0 but height-for-age (HFA) z-score was less than 0 through age 5-6 years. The second cohort had a higher HFA z-score than the first cohort at age 5-6 years. Pseudomonas aeruginosa infection was less common in later cohorts. About 1/3 of infants were hospitalized in the first year of life with no changes over time.

CONCLUSION

Over 9 years of CF NBS, median age at first CF event decreased. CF NBS had positive health impacts, but early life nutritional deficits and a high rate of infant hospitalizations persist.

Wheezing in preterm infants and children

Wheezing is a common outcome of preterm birth. This article will review the mechanisms, epidemiology, and treatment of wheezing in preterm children with and without a history of bronchopulmonary dysplasia.

Hyperinflation is associated with increased respiratory rate and is a more sensitive measure of cystic fibrosis lung disease during infancy compared to forced expiratory measures

BACKGROUND

The goal of this study was to identify clinical features associated with abnormal infant pulmonary function tests (iPFTs), specifically functional residual capacity (FRC), in infants with cystic fibrosis (CF) diagnosed via newborn screen (NBS). We hypothesized that poor nutritional status in the first 6-12 months would be associated with increased FRC at 12-24 months.

METHODS

This study utilized a combination of retrospectively and prospectively collected data from ongoing research studies and iPFTs performed for clinical indications. Demographic and clinical features were obtained from the electronic medical record. Forced expiratory flows and volumes were obtained using the raised volume rapid thoracoabdominal technique (RVRTC) and FRC was measured via plethysmography.

RESULTS

A total of 45 CF NBS infants had iPFTs performed between 12 and 24 months. Mean forced vital capacity, forced expiratory volume in 0.5 s, and forced expiratory flows were all within normal limits. In contrast, the mean FRC z-score was 2.18 (95% confidence interval [CI] = 1.48, 2.88) and the mean respiratory rate (RR) z-score was 1.42 (95% CI = 0.95, 1.89). There was no significant association between poor nutritional status and abnormal lung function. However, there was a significant association between higher RR and increased FRC, and a RR cutoff of 36 breaths/min resulted in 92% sensitivity to detect hyperinflation with 32% specificity.

CONCLUSION

These results suggest that FRC is a more sensitive measure of early CF lung disease than RVRTC measurements and that RR may be a simple, noninvasive clinical marker to identify CF NBS infants with hyperinflation.

Pediatric pulmonology year in review 2020: Physiology

Pulmonary physiology is a core element of pediatric pulmonology care and research. This article reviews some of the notable publications in physiology that were published in Pediatric Pulmonology in 2020.

Outcomes of repeat sweat testing in cystic fibrosis newborn screen positive infants

BACKGROUND

Infants with a positive cystic fibrosis (CF) newborn screen, only one identified CFTR mutation (NBS+/1 mut), and an initial intermediate sweat chloride (30-59 mmol/L) should have repeat sweat chloride testing (SCT). However, the outcome of repeat SCT and the relationship between initial sweat Cl and subsequent CF diagnosis have not been reported.

OBJECTIVE

The objective of this study was to analyze the outcomes of repeat SCT and subsequent CF diagnosis in NBS+/1 mut infants based on their initial sweat chloride concentration.

METHODS

We retrospectively identified all infants born in Indiana from 2007 to 2017 with NBS+/1 mut and initial SCT in the intermediate range. For each infant, we recorded the initial and repeat SCT results and/or a final CF diagnosis.

RESULTS

From 2007 through 2017 there were 2822 NBS+/1 mut infants of which 2613 (82%) had at least one SCT result. No infants with an initial SCT of 30-39 mmol/L were subsequently diagnosed with CF. Of the 31 infants with an initial SCT of 40-49 mmol/L, only 1 was subsequently diagnosed with CF. In contrast, 61% of those with SCTs of 50-59 mmol/L were later diagnosed with CF.

CONCLUSION

These results suggest that infants with a positive NBS for CF and one CFTR mutationwhose initial sweat chloride concentration is 50-59 mmol/L need to be monitored more closely forCF with strong consideration for earlier repeat SCTs and immediate genotyping.

Reduction of pulmonary exacerbations in young children with cystic fibrosis during the COVID-19 pandemic

To assess the impact of COVID-19 restrictions on cystic fibrosis (CF) pulmonary exacerbations (PEx) we performed a retrospective review of PEx events at our CF Center and compared the rate of PEx in 2019 versus 2020. Restrictions on social interaction due to the COVID-19 pandemic were associated with a lower number of PEx events at our pediatric CF Center, suggesting that these restrictions also reduced exposure to other respiratory viral infection in children with CF.

The remaining barriers to normalcy in CF: Advances in assessment of CF lung disease

Despite early diagnosis of cystic fibrosis (CF) through newborn screening, a substantial proportion of infants and young children with CF still demonstrate physiologic and structural evidence of lung disease progression, such as obstructive airway disease and bronchiectasis. The growing availability of highly effective CF transmembrane conductance regulatory modulator therapy to the vast majority of people with CF has led to the potential to alter the natural history of CF lung disease, but to assess the full impact of these therapies on CF lung disease and to help guide treatment, sensitive measures of early and mild disease are needed. Chest imaging using computed tomography or magnetic resonance imaging is one approach, but technologic barriers and/or concern about exposure to ionizing radiation may limit its use. However, advances in physiologic measurement techniques and exhaled breath analysis offer another option for assessment of CF lung disease.

Updated guidance on the management of children with cystic fibrosis transmembrane conductance regulator-related metabolic syndrome/cystic fibrosis screen positive, inconclusive diagnosis (CRMS/CFSPID)

Over the past two decades there has been considerable progress with the evaluation and management of infants with an inconclusive diagnosis following Newborn Screening (NBS) for cystic Fibrosis (CF). In addition, we have an increasing amount of evidence on which to base guidance on the management of these infants and, importantly, we have a consistent designation being used across the globe of CRMS/CFSPID. There is still work to be undertaken and research questions to answer, but these infants now receive more consistent and appropriate care pathways than previously. It is clear that the majority of these infants remain healthy, do not convert to a diagnosis of CF in childhood, and advice on management should reflect this. However, it is also clear that some will convert to a CF diagnosis and monitoring of these infants should facilitate their early recognition. Those infants that do not convert to a CF diagnosis have some potential of developing a CFTR-RD later in life. At present, it is not possible to quantify this risk, but families need to be provided with clear information of what to look out for. This paper contains a number of changes from previous guidance in light of developing evidence, but the major change is the recommendation of a detailed assessment of the child with CRMS/CFSPID in the sixth year of age, including respiratory function assessment and imaging. With these data, the CF team can discuss future care arrangements with the family and come to a shared decision on the best way forward, which may include discharge to primary care with appropriate information. Information is key for these families, and we recommend consideration of a further appointment when the individual is a young adult to directly communicate the implications of the CRMS/CFSPID designation.

[Surgical treatment of tricuspid valve disease due to permanent pacemaker lead]

Objective: To summarize the etiology and surgical treatment experience of tricuspid valve disease due to permanent pacemaker lead. Methods: The medical records of 22 patients who underwent tricuspid valve operation for tricuspid valve disease due to permanent cardiac pacemaker lead from January 2008 to December 2017 were retrospectively reviewed. There were 12 males and 10 females, with a mean age of (62.6±12.1) years old (45-82 years old). All patients underwent tricuspid valve surgery via open thoracotomy under general anesthesia, including 8 patients through median thoracotomy approach, 4 patients through right mini-thoracotomy approach, and 10 patients with endoscopy-assisted and totally endoscopic technique. Moreover, 8 patients underwent tricuspid valve replacement, and 14 patients received tricuspid valve repair. Results: During the operation, 10 cases of severe tricuspid regurgitation were detected due to valve and subvalvular structures dysfunction involved in the pacing electrode, 7 cases showed tricuspid annulus dilation, and pacing electrode-related infective endocarditis were involved in the tricuspid valve of 5 cases. Compared with conventional median thoracotomy surgery, the amount of postoperative drainage fluid and hospitalization time after minimally invasive surgery (including right mini-thoracotomy and endoscopic surgery) were significantly reduced [281(120, 489) ml vs 368(180, 560) ml, P=0.02; 9.2(4.8, 14.5) d vs 11.2(6.3, 16.9) d, P=0.03]. Postoperative echocardiographic data showed that the size of the right atrium and ventricle in these patients was significantly reduced compared with preoperative data, and their cardiac function were normal. There was no difference of pacing electrode parameters between pre-and postoperative period. All 22 patients were cured and discharged, with no valve-and pacemaker-related complications. Conclusions: Patients with tricuspid valve disease due to permanent cardiac pacemaker lead should actively undergo surgery including tricuspid replacement or repair according to different etiologies, which exhibit satisfactory outcomes. Minimally invasive endoscopic tricuspid surgery is a new technique for the treatment of isolated tricuspid valve disease, with less surgical trauma and faster recovery.

Quantity not sufficient rates and delays in sweat testing in US infants with cystic fibrosis

BACKGROUND

Diagnostic sweat testing is required for infants with positive newborn-screening (NBS) tests for cystic fibrosis (CF). Infants have "quantity not sufficient" (QNS) sweat volumes more often than older children. A comprehensive study of QNS sweat volumes in infants has not previously been reported.

METHODS

We surveyed US CF Centers to obtain QNS rates in all infants who had sweat testing at under 14 days and under 3 months of age. We then calculated QNS rates reported to the Cystic Fibrosis Foundation Patient Registry (CFFPR) 2010-2018 in 10-day increments from 1 to 60 days of life. We compared QNS sweat test rates in preterm (<37-weeks gestational age) vs term infants. We assessed age at sweat test and proportion of infants who did not have a sweat test reported by 60 days of age.

RESULTS

Thirty-nine of 144 (27%) of CF Centers reported a mean QNS rate of 10.5% (range, 0-100) in infants 14-days-old or younger. CFFPR data showed the highest QNS rates in the youngest infants and in those born before 37 weeks of gestation. The median age at sweat testing decreased over time, but more than 22% of infants did not have a sweat test reported by 60 days.

CONCLUSION

Higher QNS rates are seen in the youngest infants with CF, but more than 80% of infants younger than 2 weeks of age have adequate sweat volumes. Sweat testing should not be delayed in infants with a positive CF NBS test.

Pediatric pulmonology year in review 2019: Physiology

Pulmonary physiologic assessments are critical for the care and study of pediatric respiratory disease. In 2019, there were numerous contributions to this topic in Pediatric Pulmonology.

Early Neonatal Oxygen Exposure Predicts Pulmonary Morbidity and Functional Deficits at 1 Year

OBJECTIVE

To evaluate the predictive value of cumulative oxygen exposure thresholds over the first 2 postnatal weeks, linking them to bronchopulmonary dysplasia (BPD) and 1-year pulmonary morbidity and lung function in extremely low gestational age newborns.

STUDY DESIGN

Infants (N = 704) enrolled in the Prematurity and Respiratory Outcomes Program, a multicenter prospective cohort study, that survived to discharge were followed through their neonatal intensive care unit hospitalization to 1-year corrected age. Cumulative oxygen exposure (Oxygen_AUC14) thresholds were derived from univariate models of BPD, stratifying infants into high-, intermediate-, and low-oxygen exposure groups. These groups were then used in multivariate logistic regressions to prospectively predict post-prematurity respiratory disease (PRD), respiratory morbidity score (RMS) in the entire cohort, and pulmonary function z scores (N = 108 subset of infants) at 1-year corrected age.

RESULTS

Over the first 14 postnatal days, infants exposed to high oxygen averaged ≥33.1% oxygen, infants exposed to intermediate oxygen averaged 29.1%-33.1%, and infants exposed to low oxygen were below both cutoffs. In multivariate models, infants exposed to high oxygen showed increased PRD and RMS, whereas infants exposed to intermediate oxygen demonstrated increased moderate/severe RMS. Infants in the high/intermediate groups had decreased forced expiratory volume at 0.5 seconds/forced vital capacity ratio.

CONCLUSIONS

Oxygen_AUC14 establishes 3 thresholds of oxygen exposure that risk stratify infants early in their neonatal course, thereby predicting short-term (BPD) and 1-year (PRD, RMS) respiratory morbidity. Infants with greater Oxygen_AUC14 have altered pulmonary function tests at 1 year of age, indicating early evidence of obstructive lung disease and flow limitation, which may predispose extremely low gestational age newborns to increased long-term pulmonary morbidity.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01435187.

Pulmonary Outcomes Associated with Long-Term Azithromycin Therapy in Cystic Fibrosis

Rationale: Chronic azithromycin is commonly used in cystic fibrosis based on short controlled clinical trials showing reductions in pulmonary exacerbations and improved FEV₁. Long-term effects are unknown.

Objectives: Examine pulmonary outcomes among chronic azithromycin users compared with matched controls over years of use and consider combined azithromycin use in cohorts using chronic inhaled tobramycin or aztreonam.

Methods: This retrospective cohort study used the U.S. cystic fibrosis Foundation Patient Registry. Incident chronic azithromycin users were compared with matched controls by FEV₁% predicted rate of decline and rates of intravenous antibiotic use to treat pulmonary exacerbations. Propensity score methods were utilized to address confounding by indication. Predefined sensitivity analyses based on lung function, Pseudomonas aeruginosa (PA) status, and follow-up time intervals were conducted.

Measurements and Main Results: Across 3 years, FEV₁% predicted per-year decline was nearly 40% less in those with PA using azithromycin compared with matched controls (slopes, −1.53 versus −2.41% predicted per yr; difference: 0.88; 95% confidence interval [CI], 0.30–1.47). This rate of decline did not differ based on azithromycin use in those without PA. Among all cohorts, use of intravenous antibiotics was no different between azithromycin users and controls. Users of inhaled tobramycin and azithromycin had FEV₁% predicted per-year decline of −0.16 versus nonusers (95% CI, −0.44 to 0.13), whereas users of inhaled aztreonam lysine and azithromycin experienced a mean 0.49% predicted per year slower decline than matched controls (95% CI, −0.11 to 1.10).

Conclusions: Results from this study provide additional rationale for chronic azithromycin use in PA-positive patients to reduce lung function decline.

Urine gastrin-releasing peptide in the first week correlates with bronchopulmonary dysplasia and post-prematurity respiratory disease

RATIONALE

Bronchopulmonary dysplasia (BPD) is associated with post-prematurity respiratory disease (PRD) in survivors of extreme preterm birth. Identifying early biomarkers that correlate with later development of BPD and PRD may provide insights for intervention. In a preterm baboon model, elevated gastrin-releasing peptide (GRP) is associated with BPD, and GRP inhibition mitigates BPD occurrence.

OBJECTIVE

We performed a prospective cohort study to investigate whether urine GRP levels obtained in the first postnatal week were associated with BPD, PRD, and other urinary biomarkers of oxidative stress.

METHODS

Extremely low gestational age infants (23-28 completed weeks) were enrolled in a US multicenter observational study, The Prematurity and Respiratory Outcomes Program (http://clinicaltrials.gov/ct2/show/NCT01435187). We used multivariable logistic regression to examine the association between urine GRP in the first postnatal week and multiple respiratory outcomes: BPD, defined as supplemental oxygen use at 36 + 0 weeks postmenstrual age, and post-PRD, defined by positive quarterly surveys for increased medical utilization over the first year (PRD score).

RESULTS

A total of 109 of 257 (42%) infants had BPD, and 120 of 217 (55%) had PRD. On adjusted analysis, GRP level more than 80 was associated with BPD (adjusted odds ratio [aOR], 1.83; 95% confidence interval [CI], 1.03-3.25) and positive PRD score (aOR, 2.46; 95% CI, 1.35-4.48). Urine GRP levels correlated with duration of NICU ventilatory and oxygen support and with biomarkers of oxidative stress: allantoin and 8-hydroxydeoxyguanosine.

CONCLUSIONS

Urine GRP in the first postnatal week was associated with concurrent urine biomarkers of oxidative stress and with later diagnoses of BPD and PRD.

"Reactance inversion" at low frequencies in a child undergoing treatment of a cystic fibrosis exacerbation

INTRODUCTION

Impulse oscillometry (IOS) employs high frequency sinusoidal or impulse pressure and flow waveforms to interrogate the mechanical properties of the respiratory system. It has special applications to preschool and younger children who may have difficulty performing the repetitive forced expiratory maneuvers required for spirometry.

CASE PRESENTATION

We present a case illustrating improvements of respiratory system mechanics measured by IOS in a 6-year-old child with cystic fibrosis (CF) who demonstrated clinical and radiological improvement after a course of therapy with hospitalization and intravenous antibiotics, and initiation of a cystic fibrosis transmembrane regulator (CFTR) protein corrector/potentiator agent. We also report a new finding: observed lower than expected reactance at low compared to high frequencies ("reactance inversion").

CONCLUSION

Reactance inversion may reflect parallel pathway inhomogeneities in resistance and elastance or intrabreath airway inertance changes in young children with CF. Further study is needed in children with airway obstruction due to asthma, cystic fibrosis, and chronic lung disease of infancy to demonstrate the prevalence of this finding and whether it is specific to a measurement device.

Pediatric Pulmonology year in review 2018: Asthma, physiology/pulmonary function testing, and respiratory infections

Pediatric Pulmonology publishes original research, reviews, and case reports related to a wide range of children's respiratory disorders. In our "Year in Review" series, we summarize publications in our major topic areas from 2018, in the context of selected literature in these areas from other journals relevant to our discipline. This review covers selected articles on asthma, physiology/lung function testing, and respiratory infections.

Black Race Is Associated with a Lower Risk of Bronchopulmonary Dysplasia

OBJECTIVE

To use a large current prospective cohort of infants <29 weeks to compare bronchopulmonary dysplasia (BPD) rates in black and white infants.

STUDY DESIGN

The Prematurity and Respiratory Outcome Program (PROP) enrolled 835 infants born in 2011-2013 at <29 weeks of gestation; 728 black or white infants survived to 36 weeks postmenstrual age (PMA). Logistic regression was used to compare BPD outcomes (defined as supplemental oxygen requirement at 36 weeks PMA) between the races, adjusted for gestational age (GA), antenatal steroid use, intubation at birth, and surfactant use at birth.

RESULTS

Of 707 black or white infants with available BPD outcomes, BPD was lower in black infants (38% vs 45%), even though they were of significantly lower GA. At every GA, BPD was more common in white infants. The aOR for BPD was 0.60 (95% CI, 0.42-0.85; P = .004) for black infants compared with white infants after adjusting for GA. Despite the lower rate of BPD, black infants had a higher rate of first-year post-prematurity respiratory disease (black, 79%; white, 63%).

CONCLUSIONS

In this large cohort of recently born preterm infants at <29 weeks GA, compared with white infants, black infants had a lower risk of BPD but an increased risk of persistent respiratory morbidity.

Review of Cystic Fibrosis

Cystic fibrosis (CF) is an autosomal recessive disease characterized by pancreatic insufficiency and chronic endobronchial airway infection. This latter feature results in progressive bronchiectasis and ultimately respiratory failure, which is the leading cause of death in patients with CF. Other complications include sinusitis, diabetes mellitus, bowel obstruction, hepatobiliary disease, hyponatremic dehydration, and infertility. Diagnosis of CF is confirmed by demonstration of elevated sweat chloride. Most cases of CF are identified through newborn screening (NBS). There are also infants with positive NBS but inconclusive diagnostic testing; a small proportion of these infants may go on to develop CF. CF is a lifelong, life-limiting disease, but an organized care center network with multidisciplinary approach, quality improvement initiatives, and research has led to markedly increased survival and development of adult CF care programs. In the past few years, medications that directly target the underlying CF defect have been developed, which should result in even greater survival benefits. [Pediatr Ann. 2019;48(4):e154-e161.].

Persistent Wheeze in Infants: A Guide for General Pediatricians

Infants with persistent wheeze is a common diagnostic challenge for the general pediatrician because of the broad differential diagnoses. The initial diagnostic approach should include a comprehensive history, physical examination, and chest radiography. Additional testing may be warranted. Involvement of a pediatric pulmonary subspecialist may also be indicated. [Pediatr Ann. 2019;48(3):e110-e114.].

Tidal Breathing Measurements at Discharge and Clinical Outcomes in Extremely Low Gestational Age Neonates

RATIONALE

The relationship between respiratory function at hospital discharge and the severity of later respiratory disease in extremely low gestational age neonates is not well defined.

OBJECTIVES

To test the hypothesis that tidal breathing measurements near the time of hospital discharge differ between extremely premature infants with bronchopulmonary dysplasia (BPD) or respiratory disease in the first year of life and those without these conditions.

METHODS

Study subjects were part of the PROP (Prematurity and Respiratory Outcomes Program) study, a longitudinal cohort study of infants born at less than 29 gestational weeks followed from birth to 1 year of age. Respiratory inductance plethysmography was used for tidal breathing measurements before and after inhaled albuterol 1 week before anticipated hospital discharge. Infants were breathing spontaneously and were receiving less than or equal to 1 L/min nasal cannula flow at 21% to 100% fraction of inspired oxygen. A survey of respiratory morbidity was administered to caregivers at 3, 6, 9, and 12 months corrected age to assess for respiratory disease. We compared tidal breathing measurements in infants with and without BPD (oxygen requirement at 36 wk) and with and without respiratory disease in the first year of life. Measurements were also performed in a comparison cohort of term infants.

RESULTS

A total of 765 infants survived to 36 weeks postmenstrual age, with research-quality tidal breathing data in 452 out of 564 tested (80.1%). Among these 452 infants, the rate of postdischarge respiratory disease was 65.7%. Compared with a group of 18 term infants, PROP infants had abnormal tidal breathing patterns. However, there were no clinically significant differences in tidal breathing measurements in PROP infants who had BPD or who had respiratory disease in the first year of life compared with those without these diagnoses. Bronchodilator response was not significantly associated with respiratory disease in the first year of life.

CONCLUSIONS

Extremely premature infants receiving less than 1 L/min nasal cannula support at 21% to 100% fraction of inspired oxygen have tidal breathing measurements that differ from term infants, but these measurements do not differentiate those preterm infants who have BPD or will have respiratory disease in the first year of life from those who do not. Clinical trial registered with www.clinicaltrials.gov (NCT01435187).