Gene modifiers of cystic fibrosis lung disease: A systematic review

BACKGROUND

Lung disease is the major source of morbidity and mortality in cystic fibrosis (CF), with large variability in severity between patients. Although accurate prediction of lung disease severity would be extremely useful, no robust methods exist. Twin and sibling studies have highlighted the importance of non-cystic fibrosis transmembrane conductance regulator (CFTR) genes in determining lung disease severity but how these impact on the severity in CF remains unclear.

METHODS

A systematic review was undertaken to answer the question "In patients with CF which non-CFTR genes modify the severity of lung disease?" The method for this systematic review was based upon the "Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)" statement, with a narrative synthesis of results planned.

RESULTS

A total of 1168 articles were screened for inclusion, with 275 articles undergoing detailed assessment for inclusion. One hundred and forty articles were included. Early studies focused on candidate genes, whereas more recent studies utilized genome-wide approaches and also examined epigenetic mechanisms, gene expression, and therapeutic response.

DISCUSSION

A large body of evidence regarding non-CFTR gene modifiers of lung disease severity has been generated, examining a wide array of genes. Limitations to existing studies include heterogeneity in outcome measures used, limited replication, and relative lack of clinical impact. Future work examining non-CFTR gene modifiers will have to overcome these limitations if gene modifiers are to have a meaningful role in the care of patients with CF.

Naïve regulatory T cells in infancy: Associations with perinatal factors and development of food allergy

BACKGROUND

In previous studies, deficits in regulatory T-cell (Treg) number and function at birth have been linked with subsequent allergic disease. However, longitudinal studies that account for relevant perinatal factors are required. The aim of this study was to investigate the relationship between perinatal factors, naïve Treg (nTreg) over the first postnatal year and development of food allergy.

METHODS

In a birth cohort (n = 1074), the proportion of nTreg in the CD4⁺ T-cell compartment was measured by flow cytometry at birth (n = 463), 6 (n = 600) and 12 (n = 675) months. IgE-mediated food allergy was determined by food challenge at 1 year. Associations between perinatal factors (gestation, labour, sex, birth size), nTreg at each time point and food allergy at 1 year were examined by linear regression.

RESULTS

A higher proportion of nTreg at birth, larger birth size and male sex was each associated with higher nTreg in infancy. Exposure to labour, as compared to delivery by prelabour Caesarean section, was associated with a transient decrease nTreg. Infants that developed food allergy had decreased nTreg at birth, and the labour-associated decrease in nTreg at birth was more evident among infants with subsequent food allergy. Mode of birth was not associated with risk of food allergy, and there was no evidence that nTreg at either 6 or 12 months were related to food allergy.

CONCLUSION

The proportion of nTreg at birth is a major determinant of the proportion present throughout infancy, highlighting the importance of prenatal immune development. Exposure to the inflammatory stimulus of labour appears to reveal differences in immune function among infants at risk of food allergy.

Utility of Endobronchial Ultrasound in Assessment of Intrathoracic Lesions in Paediatric Patients

INTRODUCTION

In adults, linear endobronchial ultrasound (EBUS) is the preferred modality to sample intrathoracic adenopathy and radial EBUS is a useful tool to biopsy peripheral pulmonary nodules. Utility in children is less well known.

OBJECTIVES

The objective of this study was to review the EBUS experience of two specialist centres to better define the current role of EBUS in paediatric practice.

METHODS

A retrospective record review of EBUS procedures undertaken in patients aged 0-17 years at the Royal Children's Hospital (Melbourne, Australia) and Thoraxklinik (Heidelberg, Germany) was performed. Data extracted included patient demographics, clinical presentation, bronchoscope (size and model), EBUS technique used, pathologic results, need for further invasive investigation, and complications.

RESULTS

Between 2008 and 2017, ten EBUS procedures were performed (6 linear EBUS and 4 radial EBUS). No complications were reported. Linear EBUS was performed on subjects who were between 4 and 15 years old, with a 100% diagnostic yield. Radial EBUS was non-diagnostic in three cases of non-malignant disease. In one case, it was used successfully for imaging alone.

CONCLUSION

Both linear and radial EBUS are safe and feasible in children. Diagnostic yield of linear EBUS was 100%. Radial EBUS did not demonstrate utility, likely reflecting the pathologies of underlying parenchymal masses in paediatric populations.

Lung function: population epidemiology and concordance in Australian children aged 11-12 years and their parents

OBJECTIVES

To describe the epidemiology of lung function in Australian children aged 11-12 years and their parents, and explore the degree of intergenerational concordance.

DESIGN

Cross-sectional study (the Child Health CheckPoint) nested in the Longitudinal Study of Australian Children (LSAC).

SETTING

Assessment centres in seven Australian cities and eight regional towns, February 2015 to March 2016. Families unable to attend a clinic appointment were offered a home visit during the same period.

PARTICIPANTS

1874 families (53% of all eligible) participated in the study. Lung function data were available for 1759 children aged 11-12 years and 1774 parents (1668 biological pairs).

OUTCOME MEASURES

Participants completed spirometry with measures including forced expiratory volume in 1 s (FEV₁), forced vital capacity (FVC) and mid expiratory flow (MEF), converted to z-scores using Global Lung Initiative equations. Parent-child concordance was assessed using Pearson's correlation coefficients and multivariable linear regression models. Survey weights and methods accounted for LSAC's complex sampling, stratification and clustering within postcodes.

RESULTS

All lung function measures followed approximately normal distributions. Mean (SD) for FEV₁, FVC and MEF z-scores in children were 0.33 (1.07), 0.83 (1.14) and -0.48 (1.09), respectively. Mean (SD) in parents were 0.28 (1.10), 0.85 (1.15) and -0.45 (1.10), respectively. Parent FEV₁, FVC and MEF were associated with child lung function with significant positive correlation coefficients (0.22, 95% CI 0.17 to 0.26; 0.24, 95% CI 0.20 to 0.29; and 0.24, 95% CI 0.20 to 0.29, respectively).

CONCLUSIONS

Mean lung volumes were larger but with smaller airway size than international standards for both parents and children in this population sample. Modest associations between parent and child lung function highlight the potential for better identification of 'at risk' populations. Therefore, these findings may aid the development of health policy that aims to prevent the onset or limit the progression of lung disease.

Telomere length: population epidemiology and concordance in Australian children aged 11-12 years and their parents

OBJECTIVES

To (1) describe the epidemiology of child and adult telomere length, and (2) investigate parent-child telomere length concordance.

DESIGN

Population-based cross-sectional study within the Longitudinal Study of Australian Children.

SETTING

Assessment centres in seven major Australian cities and eight selected regional towns; February 2015 to March 2016.

PARTICIPANTS

Of 1874 participating families, telomere data were available for analysis for 1206 children and 1343 parents, of whom 1143 were parent-child pairs. There were 589 boys and 617 girls; 175 fathers and 1168 mothers.

OUTCOME MEASURES

Relative telomere length (T/S ratio), calculated by comparing telomeric DNA (T) level with the single copy (S) beta-globin gene in venous blood-derived genomic DNA by quantitative real-time PCR.

RESULTS

Mean T/S ratio for all children, boys and girls was 1.09 (SD 0.56), 1.05 (SD 0.53) and 1.13 (SD 0.59), respectively. Mean T/S ratio for all parents, fathers and mothers was 0.81 (SD 0.37), 0.82 (SD 0.36) and 0.81 (SD 0.38), respectively. Parent-child T/S ratio concordance was moderate (correlation 0.24). In adjusted regression models, one unit higher parent T/S ratio was associated with 0.36 (estimated linear regression coefficient (β); 95% CI 0.28 to 0.45) higher child T/S ratio. Concordance was higher in the youngest parent-age tertile (β 0.49; 95% CI 0.34 to 0.64) compared with the middle (β 0.35; 95% CI 0.21 to 0.48) and oldest tertile (β 0.26; 95% CI 0.11 to 0.41; p-trend 0.04). Father-child concordance was 0.34 (95% CI 0.18 to 0.48), while mother-child was 0.22 (95% CI 0.17 to 0.28).

CONCLUSIONS

We provide telomere length population values for children aged 11-12 years and their mid-life parents. Relative telomere length was shorter in adults than children, as expected. There was modest evidence of parent-child concordance, which diminished with increasing parent age.

Telomere Length and Vascular Phenotypes in a Population-Based Cohort of Children and Midlife Adults

Background Telomere length has been inversely associated with cardiovascular disease in adulthood, but its relationship to preclinical cardiovascular phenotypes across the life course remains unclear. We investigated associations of telomere length with vascular structure and function in children and midlife adults. Methods and Results Population-based cross-sectional CheckPoint (Child Health CheckPoint) study of 11- to 12-year-old children and their parents, nested within the LSAC (Longitudinal Study of Australian Children). Telomere length (telomeric genomic DNA [T]/β-globin single-copy gene [S] [T/S ratio]) was measured by quantitative polymerase chain reaction from blood-derived genomic DNA. Vascular structure was assessed by carotid intima-media thickness, and vascular function was assessed by carotid-femoral pulse-wave velocity and carotid elasticity. Mean (SD) T/S ratio was 1.09 (0.55) in children (n=1206; 51% girls) and 0.81 (0.38) in adults (n=1343; 87% women). Linear regression models, adjusted for potential confounders, revealed no evidence of an association between T/S ratio and carotid intima-media thickness, carotid-femoral pulse-wave velocity, or carotid elasticity in children. In adults, longer telomeres were associated with greater carotid elasticity (0.14% per 10-mm Hg higher per unit of T/S ratio; 95% CI, 0.04%-0.2%; P=0.007), but not carotid intima-media thickness (-0.9 μm; 95% CI, -14 to 13 μm; P=0.9) or carotid-femoral pulse-wave velocity (-0.10 m/s; 95% CI, -0.3 to 0.07 m/s; P=0.2). In logistic regression analysis, telomere length did not predict poorer vascular measures at either age. Conclusions In midlife adults, but not children, there was some evidence that telomere length was associated with vascular elasticity but not thickness. Associations between telomere length and cardiovascular phenotypes may become more evident in later life, with advancing pathological changes.

Associations of Preeclampsia with Expiratory Airflows in School-Age Children Born Either at <28 Weeks or Weighing <1000 g

OBJECTIVES

To assess whether preeclampsia was associated with expiratory airflow at school-age in children born either extremely preterm (<28 weeks of gestation) or extremely low birthweight (ELBW; <1000 g birth weight).

STUDY DESIGN

Participants comprised 3 cohorts of children born extremely preterm/ELBW in the state of Victoria, Australia, in 1991-1992, 1997, or 2005. Expiratory airflows were measured at age 8 years, and results converted to z scores. Data were compared between those exposed to preeclampsia with those unexposed to preeclampsia; analyses were then adjusted for confounding perinatal variables. Analyses were repeated within subgroups of extremely preterm only and ELBW only.

RESULTS

Respiratory data were available for 544 of 717 (76%) survivors, of whom 95 (17%) had been exposed to preeclampsia. On univariable analysis, those exposed to preeclampsia had better z scores for flows for the forced expired volume in 1 second (zFEV₁) (mean difference 0.29, 95% CI 0.04-0.53; P = .022) and zFEV₁/forced vital capacity (mean difference 0.33, 95% CI 0.04-0.61; P = .025); the difference persisted for zFEV₁ after adjustment for confounding perinatal variables. Analyses confined to those born extremely preterm revealed little evidence for associations between preeclampsia and airflow. In analyses confined to those born ELBW, preeclampsia was associated with better zFEV₁, which persisted after adjustment (mean difference 0.33, 95% CI 0.04-0.63; P = .025).

CONCLUSIONS

Exposure to maternal preeclampsia was not associated with worse expiratory airflow in children born extremely preterm/ELBW; in fact, some airflows were better.

Aerosolized agents for airway clearance in cystic fibrosis

The outlook for people with cystic fibrosis (CF) has improved considerably as a result of conventional therapies including aerosolized agents for airway clearance. These will continue to play a significant role in maintaining well-being and improving survival, even as newer agents emerge that correct the underlying CF defect. In this review, we explore the evidence supporting the use of dornase alfa, hypertonic saline, and mannitol in improving mucus clearance in patients with CF from different age groups with differing disease severity. We also discuss the clinical use of these agents in the context of available international guidelines as well as practical considerations in the clinic, highlighting the importance of a multidisciplinary approach and shared decision-making. Unanswered questions regarding the optimal use of these agents are highlighted.

Pulmonary Mycobacterium abscessus complex in children with cystic fibrosis: A practical management guideline

The treatment of Mycobacterium abscessus complex (MABSC) pulmonary infections is an emerging challenge in patients with cystic fibrosis (CF). Multidrug therapy for prolonged durations is required and carries the significant burden of drug-related toxicity, cost and selective pressure for multiresistant bacteria. International guidelines acknowledge that clinical and in vitro data to support treatment regimens are limited, particularly in children. As part of a collaboration between the infectious diseases and respiratory units at our institution, we have developed a modified treatment guideline that aims to balance the aims of MABSC eradication and slowing disease progression with minimising drug toxicity and resistance. The outcomes of this treatment approach will be monitored and reported. In this manuscript, we discuss the available evidence for treatment choices and present our treatment guideline for paediatric patients with CF and MABSC infection.

The cumulative effect of inflammation and infection on structural lung disease in early cystic fibrosis

Introduction

Pulmonary inflammation and infection are important clinical and prognostic markers of lung disease in cystic fibrosis (CF). However, whether in young children they are transient findings or have cumulative, long-term impacts on respiratory health is largely unknown. We aimed to determine whether their repeated detection has a deleterious effect on structural lung disease.

Methods

All patients aged <6 years with annual computed tomography (CT) and bronchoalveolar lavage (BAL) were included. Structural lung disease on CT (%Disease) was determined using the PRAGMA-CF (Perth–Rotterdam Annotated Grid Morphometric Analysis for CF) method. The number of times free neutrophil elastase (NE) and infection were detected in BAL were counted, to determine cumulative BAL history. Linear mixed model analysis, accounting for repeat visits and adjusted for age, was used to determine associations.

Results

265 children (683 scans) were included for analysis, with BAL history comprising 1161 visits. %Disease was significantly associated with the number of prior NE (0.31, 95% CI 0.09–0.54; p=0.007) but not infection (0.23, 95% CI −0.01–0.47; p=0.060) detections. Reference equations were determined.

Conclusions

Pulmonary inflammation in surveillance BAL has a cumulative effect on structural lung disease extent, more so than infection. This provides a strong rationale for therapies aimed at reducing inflammation in young children.

Correcting standardized expiratory flows for prematurity in ex-preterm survivors-Is it necessary?

OBJECTIVE

To determine the effect of correcting for prematurity on standardized values for expiratory flow rates for participants from 5 years through to 70 years of age.

METHODS

In a theoretical model we assumed starting values for expiratory flows that were expected to give ranges within ±2 SD. Keeping expiratory flows, ethnicity and height constant, we then determined how z scores varied between 5 and 16.9 years, and, with two different fixed values for height and expiratory flows, between 16 and 70 years of ages, for both sexes. In a clinical example, we compared expiratory flows with age both corrected and uncorrected for prematurity between 144 survivors born extremely preterm and 141 term-born controls at both 8 and 18 years of age.

RESULTS

In the theoretical models, z scores mostly declined through childhood until the late teenage years, and then began to rise through later life. The maximum difference in z-scores between corrected and uncorrected scores for a participant born 4 months' preterm would occur in the early teenage years, and for the forced vital capacity would be approximately -0.09 SD wider. In the clinical example not correcting for prematurity resulted in a maximum gap between preterm and term cohorts 0.06 SD wider for the forced vital capacity at 8 years than if age was corrected for prematurity.

CONCLUSIONS

Correction for prematurity is not necessary in clinical practice, and is probably not required for research in studies of respiratory airflow through childhood or adulthood.

Cross-sectional associations between Ideal Cardiovascular Health scores and vascular phenotypes in 11- to 12-year-olds and their parents: The Longitudinal Study of Australian Children

BACKGROUND

Understanding early-life relationships between the Ideal Cardiovascular Health (ICVH) score and vascular phenotypes could inform likely effectiveness and timing of cardiovascular disease prevention strategies. We aimed to describe associations between ICVH scores and vascular phenotypes in 11- to 12-year-old children and their parents.

METHODS AND RESULTS

Cross-sectional ICVH scores (range 0-7, higher indicating better health), derived by summing dichotomized metrics for cholesterol, glucose, blood pressure (BP), body mass index (BMI), diet, physical activity and smoking, were constructed for 1235 adults (89% female, mean age 43 years) and 1028 children (48% female, 12 years). The median scores were 4 and 5 for adults and children respectively. Child ICVH scores were associated with parent scores (0.18 higher child score per additional point in parent's score, 95% CI 0.12 to 0.22, P < 0.001). Each additional point in the adult ICVH score was associated with slower carotid-femoral pulse wave velocity (PWV, -0.32 m/s, 95% CI -0.37 to -0.27), greater carotid elasticity (0.017%/mm Hg, 95% CI 0.014 to 0.020) and reduced carotid intima-media thickness (IMT, -7.3 μm, 95% CI -12.0 to -2.5). An additional point in the child score was associated with functional phenotypes (PWV -0.07 m/s, 95% CI -0.11 to -0.03; carotid elasticity 0.009%/mm Hg, 95% CI 0.004 to 0.015) but not structural phenotypes (IMT -1.8 μm, 95% CI -5.2 to 1.5).

CONCLUSION

Few Australian children and even fewer parents have ideal cardiovascular health. Lower ICVH scores were associated with adverse adult vascular phenotypes and adverse child vascular function. Family-based interventions optimizing ICVH metrics may delay onset and progression of subclinical atherosclerosis and later cardiovascular disease.

Large-Scale Production of Salt Fortified with Iodine and Iron

A new dry-mixing process for producing iodine- and iron-fortified salt on a large scale (20 30 metric tons per shift) was developed in salt factories at Valinokkam and Hyderabad, India. Common salt is mixed with 1% sodium hexametaphosphate, 0.5% ferrous sulphate heptahydrate, and 0.0055% potassium iodide or 0.007% potassium iodate in a ribbon blender. Dry mixing is superior to spray mixing and is associated with no operational problems. The fortified salt produced by this method retains the original colour of the unfortified salt, and the distribution of iodine and iron is uniform. The acceptability of the fortified salt is satisfactory, as various food preparations using the product are indistinguishable in colour, taste, and flavour from those containing unfortified salt

Development of a Simple Field Kit for Monitoring Iron in Fortified Salt

One practical way to control iron-deficiency anaemia is to fortify edible salt with iron. Effective implementation of a programme for producing and distributing iron-fortified salt requires regular monitoring of edible salt for iron, particularly at the retail sales and household levels. A simple, inexpensive (10 rupees) field kit was developed for this purpose. No glassware has to be carried, and reagents are supplied in the form of tablets. It is possible to detect iron fevers as low as 50 parts per million (ppm) and as high as 1,000 ppm. One kit can be used to test 200 salt samples.

The great leap backward: changes in the jumping performance of Australian children aged 11-12-years between 1985 and 2015

Previous data have indicated relative stability over time of paediatric jumping performance, but few data exist since the early 2000s. This study quantified the 30-year secular changes in jumping performance of Australian children aged 11-12-years using data from the Australian Schools Health and Fitness Survey (1985, n = 1967) and Growing Up in Australia's Child Health CheckPoint (2015, n = 1765). Both cohorts measured jumping performance (standing long jump distance), anthropometric and demographic data. Secular changes in jumping performance means and quantiles were examined using multivariable linear and quantile regression. Between 1985 and 2015, jumping performance declined by 16.4 cm or by 11.2% (standardised change 0.66 SD, 95%CI 0.60 to 0.73). Adjustment for body mass reduced the effect by 32%, although the decline remained (absolute change - 11.1 cm, 95%CI -12.5 to -9.7; percent change 7.7%, 95%CI 6.7 to 8.6; standardised change 0.51 SD, 95%CI 0.44 to 0.57). This decline was evident across all quantiles. The jumping performance of Australian children aged 11-12-years has declined between 1985 and 2015, with body mass changes accounting for only part of the decline. Efforts should continue to promote paediatric muscular fitness, reduce adiposity, and aim to reverse this decline in jumping performance.

Clinical utility of surveillance computed tomography scans in infants with cystic fibrosis

BACKGROUND

In cystic fibrosis (CF), irreversible lung disease arises in early life, and is often asymptomatic and unrecognised. Chest computed tomography (CT) scans have been used to detect asymptomatic lung disease in research; however, the clinical utility of chest CT is unknown. This study aimed to determine the effect of surveillance CT in early life on the clinical management of patients with CF.

WORKING HYPOTHESIS

Surveillance CT in early life changes the management of patients with CF.

METHODS

A medical record review of patients in the AREST-CF cohort who had chest CT at 1 and 3 years of age was performed. Information extracted included CT scan findings and the effect of CT results on clinical management.

RESULTS

The chest CT scans and records of 50 subjects with CF were reviewed. The majority of CT scans (n = 75; 75%) were abnormal. N = 31 (31%) of scans overall led to a direct change in management. The number of CT scans needed to be performed to lead to a treatment change was 3.2. The majority (n = 18, 58%) of changes in management were prompted by the finding of bronchiectasis.

CONCLUSION

To the authors knowledge, this is the first study to highlight that early life surveillance CT frequently results in changes in clinical management, and hence may have a role beyond research and in routine care. If this can be shown to contribute to improved outcomes (such as reduced rates of bronchiectasis), then, as radiation doses diminish, chest CT could have an important clinical role.

Bone health, activity and sedentariness at age 11-12 years: Cross-sectional Australian population-derived study

AIM

To examine cross-sectional associations of children's bone health (size, density, strength) with moderate-vigorous physical activity (MVPA) and sedentary behaviour by considering: (1) duration of activity, (2) fragmentation, and (3) duration/fragmentation combined.

METHODS

Design: Population-based cross-sectional study.

PARTICIPANTS

11-12 year-olds in the Longitudinal Study of Australian Children's Child Health CheckPoint. Exposures: MVPA and sedentary behaviour (7-day accelerometry), yielding (1) daily average durations (min/day) and (2) fragmentations (the parameter alpha, representing the relationship between activity bout frequency and bout length).

OUTCOMES

Tibial peripheral quantitative computed tomography (bone density, geometry, strength).

ANALYSIS

Multivariable regression models including activity durations and fragmentations separately and combined.

RESULTS

Of 1357 children attending the CheckPoint, 864 (64%) provided both bone and accelerometry data (mean age 11.4 years (standard deviation (SD) 0.5); 49% male). Mean daily MVPA and sedentary behaviour durations were 34.4 min/day (SD 28.3) and 667.9 min/day (SD 71.9) respectively for boys and girls combined. Each additional daily hour of MVPA was associated with small bone health benefits comprising greater periosteal and endosteal circumference (standardised effect sizes 0.25, 95% CI 0.10 to 0.40 and 0.21, 95% CI 0.03 to 0.39, respectively) and bone strength (0.26, 95% CI 0.14 to 0.38). Sedentary duration and fragmentation of either MVPA or sedentary behaviour showed little association with bone health.

CONCLUSIONS

In early adolescence, MVPA duration showed associations with better bone health that, while modest, could be of population-level importance. MVPA fragmentation and sedentary behaviour duration and fragmentation seemed less important.

Practical approach to the gastrointestinal manifestations of cystic fibrosis

Cystic fibrosis (CF) is the most common, life-shortening, genetic illness affecting children in Australia and New Zealand. The genetic abnormality results in abnormal anion transport across the apical membrane of epithelial cells in a number of organs, including the lungs, gastrointestinal tract, liver and genito-urinary tract. Thus, CF is a multi-system disorder that requires a multi-disciplinary approach. Respiratory disease is the predominant cause of both morbidity and mortality in patients with CF. However, there are significant and clinically relevant gastrointestinal, liver, pancreatic and nutritional manifestations that must be detected and managed in a timely and structured manner. The aim of this review is to provide evidence-based information and clinical algorithms to guide the nutritional and gastrointestinal management of patients with CF.

The clinical significance of oropharyngeal cultures in young children with cystic fibrosis

In children with cystic fibrosis (CF) the associations between oropharyngeal swabs (OPSs) for detection of Pseudomonas and lung disease have not been evaluated.OPS and bronchoalveolar lavage (BAL) samples were obtained annually in children with CF from 2005 to 2017. OPS test characteristics were calculated using BAL as "gold standard". Results were related to lung inflammation (BAL neutrophil elastase and interleukin-8), structural lung disease (chest computed tomography PRAGMA-CF (Perth-Rotterdam Annotated Grid Morphometric Analysis for CF) scores), respiratory exacerbations and future detection of Pseudomonas on BAL.From 181 patients, 690 paired OPS-BAL cultures were obtained. Prevalence of Pseudomonas in BAL was 7.4%. OPS sensitivity was 23.0% and specificity was 91.4%, reducing the post-test probability for a positive BAL following a negative OPS to 6.3%. Pseudomonas on OPS was not associated with lung inflammation or respiratory exacerbations, but was weakly associated with current PRAGMA-CF %Disease score (p=0.043). Pseudomonas on BAL was associated with positive neutrophil elastase (OR 4.17, 95% CI 2.04-8.53; p<0.001), increased interleukin-8 (p<0.001), increased all baseline PRAGMA computed tomography scores (p<0.001), progression of PRAGMA computed tomography scores (p<0.05) and increased risk of respiratory exacerbations (incidence rate ratio 2.11, 95% CI 1.15-3.87; p=0.017).In children with CF OPSs only marginally change the probability of detecting lower airway Pseudomonas and are not associated with lung disease indices nor exacerbations risk.

An approach to successful slide tracheoplasty in the low birth weight neonate with single lung

The advent of the slide tracheoplasty technique and a multi-disciplinary approach has improved outcomes of congenital tracheal stenosis. However, tracheal surgery in younger patients with pulmonary malformations, especially low birth-weight neonates, has been associated with increased mortality. Patients with very low birth-weight, pulmonary malformations and prematurity may be palliated prior to definitive tracheal surgery due to the poor prognosis. We report a successful and unique approach of delaying tracheal reconstruction to allow growth and development in the premature, very low birth-weight neonate (1046g) with left lung agenesis.