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RationaleThe respiratory outcomes for adult survivors of preterm birth in the postsurfactant era are wide-ranging with prognostic factors, especially those encountered after the neonatal period, poorly understood.ObjectivesTo obtain comprehensive ‘peak’ lung health data from survivors of very preterm birth and identify neonatal and life-course risk factors for poorer respiratory outcomes in adulthood.Methods127 participants born ≤32 weeks gestation (64%, n=81 with bronchopulmonary dysplasia (BPD), initially recruited according to a 2 with-BPD:1 without-BPD strategy), and 41 term-born controls completed a lung health assessment at 16–23 years, including lung function, imaging and symptom review. Risk factors assessed against poor lung health included neonatal treatments, respiratory hospitalisation in childhood, atopy and tobacco smoke exposure.Measurements and main resultsYoung adults born prematurely had greater airflow obstruction, gas trapping and ventilation inhomogeneity, in addition to abnormalities in gas transfer and respiratory mechanics, compared with term. Beyond lung function, we observed greater structural abnormalities, respiratory symptoms and inhaled medication use. A previous respiratory admission was associated with airway obstruction; mean forced expiratory volume in 1 s/forced vital capacity z-score was −0.561 lower after neonatal confounders were accounted for (95% CI −0.998 to –0.125; p=0.012). Similarly, respiratory symptom burden was increased in the preterm group with a respiratory admission, as was peribronchial thickening (6% vs 23%, p=0.010) and bronchodilator responsiveness (17% vs 35%, p=0.025). Atopy, maternal asthma and tobacco smoke exposure did not influence lung function or structure at 16–23 years in our preterm cohort.ConclusionsEven after accounting for the neonatal course, a respiratory admission during childhood remained significantly associated with reduced peak lung function in the preterm-born cohort, with the largest difference seen in those with BPD. A respiratory admission during childhood should, therefore, be considered a risk factor for long-term respiratory morbidity in those born preterm, especially for individuals with BPD.

Background: Right shift of the peripheral oxyhaemoglobin saturation (SpO2) versus inspired oxygen pressure (PIO2) curve is a sensitive marker of pulmonary gas exchange. Objectives: The aim of this study was to assess the impact of prematurity and bronchopulmonary dysplasia (BPD) on gas exchange and right-to-left shunt in the neonatal period, and its evolution over the first year of life. Method: We assessed shift and shunt in extremely preterm (EP) and very preterm (VP) infants at 36 and 44 weeks’ postmenstrual age (PMA), and at 1-year corrected postnatal age (cPNA). PIO2 was decreased stepwise to achieve SpO2 between 85 and 98%. Shift and shunt were calculated from paired SpO2/PIO2 measurements using customized software. Results were examined cross-sectionally at each time point, and longitudinally using generalized linear regression. Term infants were assessed at 44 wk PMA as a comparative reference. Results: Longitudinal modelling showed continuous decline in shift in EP and VP infants during the first year of life. There was no difference in shift compared to term infants at 44 wk PMA (p = 0.094). EP infants with BPD had higher shift than infants without BPD at 36 wk PMA (p < 0.001) and 44 wk PMA (p = 0.005) but not at 1-year cPNA. Conclusions: In the absence of lung disease, prematurity per se did not result in reduced gas exchange at 1-year cPNA. We report ongoing, significant improvements in pulmonary gas exchange in all preterm infants during the first year of life, despite evidence of early deficits in gas exchange in EP infants with BPD.

Children born preterm have impaired lung function and altered lung structure. However, there are conflicting reports on how preterm birth impacts aerobic exercise capacity in childhood. We aimed to investigate how neonatal history and a diagnosis of bronchopulmonary dysplasia (BPD) impact the relationship between function and structure of the lung, and aerobic capacity in school-aged children born very preterm. Preterm children (≤ 32 w completed gestation) aged 9–12 years with (n = 38) and without (n = 35) BPD, and term-born controls (n = 31), underwent spirometry, lung volume measurements, gas transfer capacity, a high-resolution computer tomography (CT) scan of the chest, and an incremental treadmill exercise test. Children born preterm with BPD had an elevated breathing frequency to tidal volume ratio compared to term controls (76% vs 63%, p = 0.002). The majority (88%) of preterm children had structural changes on CT scan. There were no differences in peak VO2 (47.1 vs 47.7 mL/kg/min, p = 0.407) or oxygen uptake efficiency slope when corrected for body weight (67.6 vs 67.3, p = 0.5) between preterm children with BPD and term controls. There were no differences in any other exercise outcomes. The severity of structural lung disease was not associated with exercise outcomes in this preterm population. Children born preterm have impaired lung function, and a high prevalence of structural lung abnormalities. However, abnormal lung function and structure do not appear to impact on the aerobic exercise capacity of preterm children at school age.

Preterm birth rates are increasing and now account for >11% of global births. Simultaneously, advances in neonatal care have led to increased survival of lower gestation neonates. A complication of preterm birth, and the biggest determinant of survival, is lung and airway immaturity. After preterm birth, the immature respiratory system is exposed to pro-inflammatory stimuli like injury from resuscitation and oxygen toxicity. The airway epithelium, the physical barrier between insults and the airways, is particularly vulnerable to injury. If epithelial barrier integrity cannot be restored rapidly following damage (i.e. via aberrant repair), the respiratory system is left unprotected, increasing the risk of infection, inflammation and tissue damage. Altered epithelial repair may play an important role in the ongoing respiratory health problems experienced by preterm survivors, including severe respiratory infections throughout early life, or low and declining lung function [1–3]. Deficits are further exacerbated in those with bronchopulmonary dysplasia (BPD). The mechanisms contributing to ongoing respiratory problems are currently unknown, although probably begin in early life. Until now, understanding the role of the preterm epithelial barrier has been limited by a lack of appropriate cellular models. Our study aimed to assess the reparative capacity of the airway epithelium in survivors of preterm birth and its association with early life outcomes, with the hypothesis that preterm airway epithelial cells have an abnormal repair mechanism., Nasal epithelial cells from very preterm infants have a functional defect in their ability to repair beyond the first year of life, and failed repair may be associated with antenatal steroid exposure https://bit.ly/39OFJs7

Birth prior to term interrupts the normal development of the respiratory system and consequently results in poor respiratory outcomes that persist throughout childhood. The mechanisms underpinning these poor respiratory outcomes are not well understood, but intrinsic abnormalities within the airway epithelium may be a contributing factor. Current evidence suggests that the airway epithelium is both structurally and functionally abnormal after preterm birth, with reports of epithelial thickening and goblet cell hyperplasia in addition to increased inflammation and apoptosis in the neonatal intensive care unit. However, studies focusing on the airway epithelium are limited and many questions remain unanswered; including whether abnormalities are a direct result of interrupted development, a consequence of exposure to inflammatory stimuli in the perinatal period or a combination of the two. In addition, the difficulty of accessing airway tissue has resulted in the majority of evidence being collected in the pre-surfactant era which may not reflect contemporary preterm birth. This review examines the consequences of preterm birth on the airway epithelium and explores the clinical relevance of currently available models whilst highlighting the need to develop a clinically relevant in vitro model to help further our understanding of the airway epithelium in preterm birth.

Children born preterm have impaired lung function and altered lung structure. However, there are conflicting reports on how preterm birth impacts aerobic exercise capacity in childhood. We aimed to investigate how neonatal history and a diagnosis of bronchopulmonary dysplasia (BPD) impact the relationship between function and structure of the lung, and aerobic capacity in school-aged children born very preterm.Preterm children (≤ 32 w completed gestation) aged 9-12 years with (n = 38) and without (n = 35) BPD, and term-born controls (n = 31), underwent spirometry, lung volume measurements, gas transfer capacity, a high-resolution computer tomography (CT) scan of the chest, and an incremental treadmill exercise test.Children born preterm with BPD had an elevated breathing frequency to tidal volume ratio compared to term controls (76% vs 63%, p = 0.002). The majority (88%) of preterm children had structural changes on CT scan. There were no differences in peak V̇OChildren born preterm have impaired lung function, and a high prevalence of structural lung abnormalities. However, abnormal lung function and structure do not appear to impact on the aerobic exercise capacity of preterm children at school age.

Oscillometry (also known as the forced oscillation technique) measures the mechanical properties of the respiratory system (upper and intrathoracic airways, lung tissue and chest wall) during quiet tidal breathing, by the application of an oscillating pressure signal (input or forcing signal), most commonly at the mouth. With increased clinical and research use, it is critical that all technical details of the hardware design, signal processing and analyses, and testing protocols are transparent and clearly reported to allow standardisation, comparison and replication of clinical and research studies. Because of this need, an update of the 2003 European Respiratory Society (ERS) technical standards document was produced by an ERS task force of experts who are active in clinical oscillometry research.The aim of the task force was to provide technical recommendations regarding oscillometry measurement including hardware, software, testing protocols and quality control.The main changes in this update, compared with the 2003 ERS task force document are 1) new quality control procedures which reflect use of “within-breath” analysis, and methods of handling artefacts; 2) recommendation to disclose signal processing, quality control, artefact handling and breathing protocols (e.g.number and duration of acquisitions) in reports and publications to allow comparability and replication between devices and laboratories; 3) a summary review of new data to support threshold values for bronchodilator and bronchial challenge tests; and 4) updated list of predicted impedance values in adults and children.

Preterm birth accounts for approximately 11% of births globally, with rates increasing across many countries. Concurrent advances in neonatal care have led to increased survival of infants of lower gestational age (GA). However, infants born

Rationale Survivors of preterm birth are at risk of chronic and lifelong pulmonary disease. Follow-up data describing lung structure and function are scarce in children born preterm during the surfactant era. Objectives To obtain comprehensive data on lung structure and function in mid-childhood from survivors of preterm birth. We aimed to explore relationships between lung structure, lung function and respiratory morbidity as well as early life contributors to poorer childhood respiratory outcomes. Methods Lung function was tested at 9–11 years in children born at term (controls) and at ≤32 weeks gestation. Tests included spirometry, oscillatory mechanics, multiple breath nitrogen washout and diffusing capacity of the lung for carbon monoxide. Preterm children had CT of the chest and completed a respiratory symptoms questionnaire. Main results 58 controls and 163 preterm children (99 with bronchopulmonary dysplasia) participated. Preterm children exhibited pulmonary obstruction and hyperinflation as well as abnormal peripheral lung mechanics compared with term controls. FEV 1 was improved by 0.10 z-scores for every additional week of gestation (95% CI 0.028 to 0.182; p=0.008) and by 0.34 z-scores per z-score increase in birth weight (0.124 to 0.548; p=0.002). Structural lung changes were present in 92% of preterm children, with total CT score decreased by 0.64 (−0.99 to −0.29; p Conclusions Abnormal lung structure in mid-childhood resulting from preterm birth in the contemporary era has important functional consequences.

Introduction: Babies born preterm have altered control of breathing and a blunted hypoxic ventilatory response (HVR) in early postnatal life. We aimed to assess the HVR at 12-15 months corrected postnatal age (PNA) and determine any lasting effects of neonatal exposures on the HVR. Methods: The HVR was evaluated in infants born Results: Preterm infants (N=39; 16 with BPD) were studied at a mean (SD) age of 14.4 (1.0) months corrected PNA. A small HVR was observed as increased VT (mean difference hypoxic minute 1 from baseline =0.84 mL/kg) and consequently increased VT/Ttot (4.31 mL/s), VT/Ti (9.19 mL/s) and VE (25.98 mL/min/kg); all p Conclusion: Some infants born very preterm fail to have a ventilatory response to hypoxia beyond the first year of life.

Introduction: Airway epithelial cells (AECs) line the airway to create a protective barrier between the lung and the external environment. Very preterm birth ( Methods: Nasal brushings were used to collect AECs from infants born very preterm (n=35, 24-31.7wks gestation, 1.07-1.22yrs corrected at sampling). Control samples were provided by children born at term (n=6, >37wks gestation, 2.4-6.5yrs at sampling). Cultured AECs were scratch wounded and repair tracked for 72 hours (IncuCyte ZOOM®, Essen Bioscience). Wound closure was then assessed for correlations with neonatal factors including gestation, birthweight, duration of respiratory support, and steroid exposure. Results: Term AECs achieved complete repair within 60 hours. Repair in successfully cultured preterm AECs (n=22) was significantly altered and fell into three categories; delayed but complete repair (>80% n=5), significant but incomplete closure (50-80% n=6) and incomplete closure (20-50% n=10). Neonatal factors did not predict altered wound repair, though infants born to mothers completing a course of antenatal steroids (n=13) exhibited significantly worse repair (p=0.017, 47.30% vs 74.02%). Conclusion: Data confirm that preterm infants have an intrinsic functional defect in their airway reparative capacity. Exposure to antenatal steroids may further alter repair and raises questions about the long-term impact of antenatal steroid use.

To evaluate the role of upper airway dysfunction, indicated by altered vocal quality (dysphonia), on the respiratory symptoms of children surviving very preterm birth.Children born32 weeks of gestation participated in 2 separate assessments during midchildhood. The first visit assessed voice quality by a subjective evaluation using the Consensus Auditory-Perceptual Evaluation of Voice and a computerized analysis of the properties of the voice via the Acoustic Voice Quality Index. The second assessment recorded parentally reported respiratory symptoms and measures of lung function, including spirometry, lung volumes, oscillatory mechanics, and a cardiopulmonary exercise test.Preterm children (n = 35; median gestation 24.3 weeks) underwent paired voice and lung assessments at approximately 11 years of age. Preterm children with dysphonia (n = 25) reported significantly more respiratory symptoms than those with normal voices (n = 10) including wheeze (92% vs 40%; P = .001) and asthma diagnosed by a physician (60% vs 10%; P = .007). Lung function outcomes were generally not different between the dysphonic group and the group with normal voice (P .05), except for the oscillatory mechanics measures, which were all at least 0.5 z score lower in the dysphonic group (XrsThe upper airway may play a role in the respiratory symptoms experienced by some very preterm children and should be considered by clinicians, especially when symptoms are in the presence of normal lung function and are refractory to treatment.

Bronchopulmonary dysplasia (BPD), also known as Chronic Lung Disease (CLD), is a chronic respiratory condition of prematurity with potential life-long consequences for respiratory well-being. BPD was first described by Northway in 1967, when the mean gestation of preterm infants with BPD was 34 weeks’ postmenstrual age (PMA). Survival of preterm infants at lower gestational ages has increased steadily since 1967 associated with marked improvements in respiratory management of respiratory distress syndrome. Currently, BPD develops in approximately 45 % of all infants born extremely preterm (Stoll et al., 2015). These smaller and more immature babies are born during the late canalicular or early saccular period of lung development. Not surprisingly, the pathophysiology of BPD also evolved since classical BPD was described. As the nature and our understanding of BPD evolved, so too the definitions and classification of BPD changed over time. These differing and ever-changing definitions hamper clinical benchmarking as they are interpreted and applied inconsistently, and define BPD and its severity by non-standardised treatments rather than independent evaluations of structure or function. A standardised, unambiguous definition and classification of BPD is essential for evaluation and improvement in clinical practice, both within an individual unit, as well as across and between neonatal networks. The determination and implementation of diagnostic criteria and severity classification that is standardised, globally applicable, and that has prognostic utility for clinical outcomes and guidance of ongoing respiratory management remain of utmost importance. This review describes the evolution of BPD definitions, evaluates the benefits and limitations of each approach, and discusses alternative approaches that may improve the functional assessment of BPD severity.

A refined software algorithm was recently proposed for the analysis of infant multiple breath washout (MBW) measurements. The proposed algorithm uses the change in end-inspiratory molar mass between the wash-in and wash-out curves (EIMM-step) to define the required step response correction of the MM signal and is assumed to provide an accurate evaluation of complete washout of the tracer gas, in comparison to the current software algorithm which applies the change in end-expiratory molar mass (EEMM)-step. We aimed to evaluate the use of the EIMM-step method in a broad range of infants. We performed retrospective analyses comparing the EIMM- and EEMM-step change methods in MBW data collected from infants with cystic fibrosis (CF), infants born preterm, and healthy infants using an ultrasonic flowmeter. We found that the EIMM-step correction significantly increased LCI and functional residual capacity (FRC) in infants with CF, preterm infants, and healthy infants compared with the EEMM-step method. In addition, more than half the measurements that were technically acceptable and repeatable using the EEMM-step correction in healthy infants were excluded after using the EIMM-step correction. We found a large difference between the EIMM- and EEMM-steps in healthy infants indicating incomplete washout, suggesting the need for a longer washout time with using the EIMM-step analysis method. The data indicates that the EIMM-step analysis method may have the potential to generate false abnormal LCI values in individuals without lung disease. Revised normative data may be required if this method is universally adopted. Pediatr Pulmonol. 2017;52:10-13. © 2016 Wiley Periodicals, Inc.

User verification of device accuracy using test loads should encompass the expected range of Zrs to be tested; this letter clarifies the definition of Zrs ranges of the population being tested. Manufacturers should report accuracy of both Rrs and Xrs.https://bit.ly/2ZrnOCD

Evidence regarding the prevalence of expiratory flow limitation (EFL) during exercise and the ventilatory response to exercise in children born preterm is limited. This study aimed to determine the prevalence of EFL as well as contributing factors to EFL and the ventilatory response to exercise in preterm children with and without bronchopulmonary dysplasia (BPD). Preterm children (≤32 weeks gestational age) aged 9–12 years with (n=64) and without (n=42) BPD and term controls (n=43), performed an incremental treadmill exercise test with exercise tidal flow–volume loops. More preterm children with BPD (53%) had EFL compared with preterm children without BPD (26%) or term controls (28%) (p, Children born preterm have an increased prevalence of expiratory limitation during exercise associated with reduced lung function and lower gestational age http://ow.ly/jLsk30leOVI

RATIONALE Increasing evidence suggests the forced oscillation technique (FOT) has the capacity to provide non-invasive monitoring and diagnosis of respiratory disease in young children. However, which FOT outcomes provide the most pertinent clinical information is currently unknown. The aim of this study was to determine which FOT outcomes were most sensitive for differentiating between health and specific childhood respiratory disease. METHODS Respiratory impedance was measured using a commercial device (i2M, Chess Medical, Belgium) in children aged between 3 and 7 years, who had been diagnosed with either cystic fibrosis (N = 84), asthma (N = 99) or were born very preterm (N = 114). Z-scores were calculated for respiratory system resistance (Rrs) and reactance (Xrs) at 6, 8, and 10 Hz, the resonance frequency (Fres), frequency dependence (Fdep4-24 ), and area under the reactance curve (AX). Pairwise comparisons of the area under the receiver operating characteristic (ROC) curve were used to determine the most relevant FOT variables. RESULTS AND CONCLUSIONS The FOT outcomes best able to discern between health and disease were Fres (P

Children born preterm, less than 37 weeks’ gestation, are at increased risk of viral respiratory infections and associated complications both during their initial birth hospitalisation and in their first years following discharge. This increased burden of viral respiratory infections is likely to have long term implications for lung health and function in individuals born preterm, particularly those with bronchopulmonary dysplasia. Several hypotheses have been put forward to explain the association between early life viral respiratory infection and development of suboptimal lung health and function later in life following preterm birth. Although preterm infants with diminished lung function, particularly small airways, might be particularly susceptible to asthma and wheezing disorders following viral infection, there is evidence that respiratory viruses can activate number of inflammatory and airway re-modelling pathways. Therefore, the aim of this review is to highlight the perinatal and early life risk factors that may contribute to increased susceptibility to viral respiratory infections among preterm infants during early life and to understand how respiratory viral infection may influence the development of abnormal lung health and function later in life.

Summary Background Data on longitudinal respiratory follow-up after preterm birth in the surfactant era are scarce and of increasing importance, with concerns that preterm survivors are destined for early onset chronic obstructive airway disease. We aimed to comprehensively assess lung function longitudinally from early childhood to mid-childhood in very preterm children (≤32 weeks gestation), and to explore factors negatively impacting on lung function trajectories. Methods Preterm children (with and without bronchopulmonary dysplasia) and healthy term children as controls were studied. All preterm participants were born at 32 weeks' gestation or earlier at King Edward Memorial Hospital, Perth, WA, Australia, between 1997 and 2003. Bronchopulmonary dysplasia was defined as at least 28 days of supplemental oxygen requirement as assessed at 36 weeks' post-menstrual age. Spirometry, oscillatory mechanics, gas exchange, lung volumes, and respiratory symptoms were assessed at three visits, two in early childhood (4–8 years) and one in mid-childhood (9–12 years). CT of the chest was done in preterm children in mid-childhood. Respiratory symptoms were documented via questionnaire at each visit. Data were analysed longitudinally using linear mixed models. Findings 200 very preterm children (126 with bronchopulmonary dysplasia and 74 without bronchopulmonary dysplasia) and 67 healthy term control children attended 458 visits between age 4 and 12 years. Chest CT was done on 133 preterm children at a mean age of 10·9 (SD 0·6) years. Preterm children, with and without bronchopulmonary dysplasia, had declines in spirometry z-scores over time compared with controls: forced expiratory volume in 1 s (FEV 1 ), forced expiratory flow at 25–75% of the pulmonary volume, and FEV 1 /forced vital capacity all declined by at least 0·1 z-score per year in children with bronchopulmonary dysplasia (all p 1 z-score decline of −0·61 (95% CI −1·03 to–0·19; p=0·005) more than those without. Similarly, children exposed to tobacco smoke, those with earlier gestation, or those requiring more neonatal supplemental oxygen declined at a faster rate. Interpretation Lung function trajectories are impaired in survivors of very preterm birth. Survivors with bronchopulmonary dysplasia, ongoing respiratory symptoms, or CT changes reflecting inflammation have the poorest trajectories and might be at increased risk of lung disease in later life. Close targeted pulmonary follow-up of these individuals is necessary. Funding National Health and Medical Research Council grants APP634519, APP1073301 (to SJS), APP1077691 (to JJP), and APP1025550 (to GLH), Princess Margret Hospital Foundation, and Raine Medical Foundation.

To the Editor,We read with interest a recent report in the present journal, in which flocked nasal swab was compared with nasopharyngeal aspirate with regard to sensitivity for detection of respira...

SummaryBackground Multiple breath washout (MBW) testing with SF6 gas mixture is routinely used to assess ventilation distribution in infants. It is currently unknown whether SF6 changes tidal breathing parameters during MBW in infants. We investigated if SF6 does change tidal breathing parameters in infants and whether a separate tidal breathing trace prior to MBW testing is necessary. Methods Tidal breathing during MBW was compared to standard tidal breathing in room air in healthy infants (n = 38), preterm infants (n = 41), and infants with cystic fibrosis (n = 41). Outcomes included inspiratory and expiratory times (TI and TE), time to peak tidal inspiratory and expiratory flow (tPTIF and tPTEF), tidal volume (VT), respiratory rate (f), and minute ventilation (VE). Results Breath times were all significantly increased for both healthy (TE: −0.0790 [−0.10566, −0.05217]; mean difference [95% confidence intervals]) and CF (−0.109 [−0.15235, −0.06607]) infants during the MBW wash-in (P

One of the most significant complications of preterm birth is bronchopulmonary dysplasia (BPD). The pathophysiology of BPD has changed in recent years as advances in neonatal care have led to increased survival of smaller, more preterm, infants who display alterations to alveolar and pulmonary microvascular development. It is becoming clear that infants with 'new' BPD experience lung disease that persists into later childhood, however, the oldest of these children are just now entering young adulthood and therefore the longer term pulmonary implications remain unknown. The role of lung function testing in the identification and subsequent management of patients with lung disease resulting from a neonatal classification of BPD is reviewed based on the underlying pathophysiology of the disease.

Introduction: Longitudinal, population-based studies are essential to assess the burden of respiratory viruses, particularly in children at high risk of respiratory disease. Parental sample collection is feasible, but extended postage times may affect sample quality. Aims and objectives: To assess the effect of environmental exposure on detecting respiratory viruses and pathogenic bacteria in nasal specimens collected from preterm infants. We hypothesised that prolonged environmental exposure would not affect viral detection, but that pathogenic bacterial frequency would be higher. Method: Two consecutive nasal swabs were collected from each infant close to the time of discharge from their birth hospitalisation. One swab was stored immediately at -80°C, and the other was randomised into four groups. Each group was exposed to ambient, non-air conditioned room temperature for 3, 5, 7 or 14 days to simulate the postage environment. Local relative humidity and ambient temperature were obtained daily from the Bureau of Meteorology. Specimens were assessed for the detection of 12 viral and 7 bacterial nucleic acids using PCR. Results: Mean daily temperature and relative humidity were 21.3oC and 80.7%, respectively. Of the 760 molecular assays completed from 20 infants, one tested positive for a respiratory virus (parainfluenza type I). The frequency of detecting pathogenic bacteria was 65% for Staphylococcus aureus and 5% for Streptococcus Pneumoniae . Environmental exposure for up to 14 days did not affect the frequency of detecting respiratory viruses or pathogenic bacteria. Conclusion: This study supports the use of postage of nasal specimens for assessment of respiratory viruses and bacteria in the community.

Bronchopulmonary dysplasia (BPD) is characterised by inflammation in the developing airways and lung parenchyma. The ability of low-frequency forced oscillation technique (LFOT) to measure the impact of BPD on peripheral lung growth and function is unknown. We aimed to measure airway and pulmonary tissue mechanics in very preterm infants with/without BPD. We hypothesised that BPD alters the pulmonary mechanical properties compared to infants without BPD. LFOT (1-12 Hz) was applied to unsedated preterm infants during a short apnoea (4-7 s) provoked via the Hering-Breuer reflex (1-4 rapid manual inflations). Peak inflation pressure was 20cmH2O. Outcome variables were determined by fitting the constant phase model to the data, and analysed using t-test and multiple linear regression. 70 of 85 infants had acceptable tests: [median (range) GA 286w (234-316)] at a median (range) 355w (340-374) postmenstrual age. 25 infants had BPD (mild n=10, moderate n=7, severe n=8) according to the NICHD criteria. Newtonian resistance (R) (mean difference (SD): 3.88 (1.71); p 0.026) was significantly lower in infants with BPD than infants without BPD. Presence of BPD did not impact tissue damping, elastance, or hysteresivity. Length independently predicted all outcome variables. Duration of nCPAP was independently associated with R. In our cohort of infants, length rather than presence of BPD was the primary determinant of parenchymal mechanics: our findings may be explained by similar tissue mechanics in infants with/without BPD due to mild BPD, or that the effect size of BPD on LFOT outcome variables is low. Funding: NHMRC (1047689,1057514,1077691), MHRIF, Hungarian Scientific Research Grant #105403

Introduction: Delayed early oxygen uptake (VO2) recovery reflects disease severity in chronic lung or heart disease, linked to delayed recovery of muscle energy stores. No previous studies have investigated this in children born very preterm where altered lung structure may impair recovery Hypothesis: Children born preterm have a delayed early VO2 recovery associated with worse neonatal lung disease. Methods: Children born very preterm ( Results: 61 preterm children (27 with bronchopulmonary dysplasia) and 28 controls were assessed. There were no differences in peak VO2 of preterm compared with term children (46.4±, 6.8 vs 47.7 ±5. mL.min−1.kg−1), nor between VO2 recovery at 1 min (85 ±, 0.1 vs 86 ±, 0.1%), 2min (22.8 ± 0.07 vs 24.5 ± 0.06%) or 5min (16.5 ±0.04 vs 18.8 ± 0.07%). Time to 50% peak VO2 was similar between preterm and term children (51.0± 11.9 vs 51.8 ± 12.8s). There were no associations between VO2 recovery and GA or O2 use in the neonatal period. Conclusion: Children born preterm have normal early oxygen uptake recovery following a maximal exercise test. This is consistent with the well preserved aerobic capacity observed in this group.

Background The burden of childhood respiratory illness is large in low and middle income countries (LMICs). Infant lung function (ILF) testing may provide useful information about lung growth and susceptibility to respiratory disease. However, ILF has not been widely available in LMICs settings where the greatest burden of childhood respiratory disease occurs. Aim To implement and evaluate a pilot study of ILF testing in a semi-rural setting in South Africa. Method Infant lung function testing was established at a community hospital in South Africa. All measures were done in unsedated infants during sleep. Measurements, made with the infant quietly breathing through a face mask and bacterial filter, included tidal breathing (TBFVL), exhaled nitric oxide (eNO), and sulphur hexafluoride multiple breath washout (MBW) measures using an ultrasonic flow meter and chemoluminescent NO analyzer. Results Twenty infants, mean age of 7.7 (SD 2.9) weeks were tested; 8 (40%) were Black African and 12 (60%) were mixed race. Five (25%) infants were preterm. There were 19 (95%) successful TBFVL and NO tests and 18 (90%) successful MBW tests. The mean tidal volume was 30.5 ml (SD 5.9), respiratory rate 50.2 breaths per minute (SD 8.7), and eNO 10.4 ppb (SD 7.3). The mean MBW measures were: functional residual capacity 71 ml (SD 13) and the lung clearance index 7.6 (SD 0.5). The intra-subject coefficient of variations (CV) of lung function measures were similar to published normative data for Caucasian European infants. Conclusion In this study we demonstrate that unsedated infant lung function measures of tidal breathing, MBW, and eNO are feasible in a semi-rural African setting with rates comparable to those reported from high income countries. Pediatr Pulmonol. 2015; 50:49–54. © 2013 The Authors. Pediatric Pulmonology published by Wiley Periodicals, Inc.

To the Editor : The mannitol challenge is an indirect challenge that increases airway surface liquid osmolality resulting in bronchoconstriction [1, 2]. Mannitol challenge tests are used clinically to diagnose asthma and, in particular, exercise-induced broncoconstriction (EIB) in adults and children above 6 years of age [3]. To date, mannitol has not been used as a challenge agent in children under 6 years of age and the feasibility and safety of its use in this age group is unknown. The assessment of bronchial responsiveness in young children is difficult and limited by the cooperation of the child. The standardisation of lung function tests suitable for use in young children, such as the interrupter technique or the forced oscillation technique (FOT), provide an opportunity to assist in the assessment of bronchial responsiveness in young children and a variety of challenge tests using FOT have been reported in young children [4]. The aim of this preliminary study was to assess the feasibility and safety of the mannitol challenge test in young children using the FOT as the objective outcome measure. 20 children aged 3–7 years were recruited; 10 of these children were healthy and 10 children had a history of parentally reported exercise-induced symptoms (EIS) in the past year. The mannitol challenge test (Aridol; Pharmaxis, Frenchs Forest, Australia) was performed as previously published [2], with the exceptions that the respiratory resistance at 8 Hz ( R rs8) from the FOT was used as the primary outcome and the definition of a positive response was altered, as detailed below. Prior to …

Background We assessed the effect of posture on ventilation distribution and the impact on associations with structural lung disease. Methods Multiple breath washout (MBW) was performed in seated and supine postures in 25 healthy children and 21 children with CF. Children with CF also underwent a chest CT scan. Functional residual capacity (FRC), lung clearance index (LCI) and moment ratios were calculated from the MBW test. CT scans were evaluated for CF-related structural lung disease. Results FRC was lower in the supine than in the seated posture, whereas LCI was higher in the supine than in the seated posture. In children with CF, associations between LCI and the extent of structural lung disease were stronger when performed in the supine posture. Conclusions Body posture influences lung volumes and ventilation distribution in both healthy children and children with CF. MBW testing in the supine posture strengthened associations with structural lung damage.

Background and Aim: Pulmonary inflammation and oxidative stress contribute to the pathogenesis of bronchopulmonary dysplasia (BPD) following preterm birth. We aimed to measure inflammation and oxidative stress non-invasively, using exhaled breath condensate (EBC), in neonates with and without BPD. We also aimed to determine if markers of inflammation and oxidative stress were present later in infancy and relate biomarker levels to disease severity. Methods: EBC was collected from very preterm infants (GA Results: EBC collection is feasible in preterm infants at 36w PMA (N=5) and 12-15 months (N=20) at a volume that allows metabolomic profiling (215.0 ± 121.2 μL). Markers of inflammation and oxidative stress were detected above 3.9 pg.mL -1 and 0.8 pg.mL -1 respectively (ELISA) in all infants, regardless of BPD classification. Surprisingly, biomarker levels were higher in infants without BPD (48.8 ± 28.0 pg.mL -1 ) than in infants with BPD (17.8 ± 14.1 pg.mL -1 ; p Conclusion: EBC is a non-invasive technique capable of determining the lung metabolome in preterm infants. Preterm infants exhibit on-going inflammation and oxidative stress at 12-15 months corrected age, regardless of BPD classification.