Cardiopulmonary response to exercise in adults born very preterm.

This study aims to compare cardiopulmonary response to aerobic exercise between young adults born very preterm, including a subgroup with bronchopulmonary dysplasia (BPD), and term controls.Seventy-one adults (18-29 years) born <30 weeks' gestational age (24 with BPD) and 73 term controls were recruited. Assessment included cardiopulmonary exercise testing with impedance cardiography. We compared group differences in peak O2 consumption (peak VO2) and in ventilatory and cardiovascular responses to exercise using linear regression analyses.Preterm participants had reduced peak VO2 (mean difference -2.7; 95% CI -5.3, -0.1 mL·kg-1 lean body mass·min-1) versus controls. Those with BPD achieved lower peak work-rate compared to term controls (-21; 95% CI -38, -5 watts). There was no difference across groups in breathing reserve, ventilatory efficiency, peak heart rate and cardiac output. VO2 to work-rate relationship (ΔVO2/ΔWR) was reduced in preterm versus term. Peak systolic blood pressure and circulatory power (systolic blood pressure*VO2) were also lower in BPD versus term controls. In the preterm group, longer NICU stay and lower peak cardiac output were associated with lower peak VO2Results suggest limitations with peripheral O2 uptake in the muscle with reduced ΔVO2/ΔWR and peak circulatory power, but normal cardiac output. Investigations into skeletal muscle perfusion and O2 use during exercise are warranted to better understand mechanisms of exercise limitation.

An Official American Thoracic Society Workshop Report: Translational Research in Rare Respiratory Diseases.

Rare respiratory diseases (RRDs) are a heterogeneous group of disorders that collectively represent a significant health care burden. In recent years, strong advocacy and policy initiatives have led to advances in the implementation of research and clinical care for rare diseases. The development of specialized centers and research networks has facilitated support for affected individuals as well as emerging programs in basic, translational, and clinical research. In selected RRDs, subsequent gains in knowledge have informed the development of targeted therapies and effective diagnostic tests, but many gaps persist. There was therefore a desire to identify the elements contributing to an effective translational research program in RRDs. To this end, a workshop was convened in October 2015 with a focus on the implementation of effective transnational research networks and collaborations aimed at developing novel diagnostic and therapeutic tools. Key elements included an emphasis on molecular pathogenesis, the continuing engagement of patient advocacy groups and policy makers, the effective use of preclinical models in the translational research pipeline, and the detailed phenotyping of patient cohorts. During the course of the workshop, current logistical and knowledge gaps were identified, and new solutions or opportunities were highlighted.

Clinical outcomes associated with Staphylococcus aureus and Pseudomonas aeruginosa airway infections in adult cystic fibrosis patients.

BACKGROUND: Staphylococcus aureus (SA) is the most prevalent organism infecting the respiratory tract of CF children, and remains the second most prevalent organism in CF adults. During early childhood, SA infections are associated with pulmonary inflammation and decline in FEV1, but their clinical significance in adult CF patients is poorly characterized. METHODS: We conducted a retrospective cross-sectional study to determine the association between airway microbiology and clinical outcomes (FEV1, rate of pulmonary exacerbations, CRP levels and clinical scores). RESULTS: In a cohort of 84 adult CF patients, 24 % were infected with SA only, 60 % were infected with PA, and 16 % had neither PA nor SA. CF patients with SA experienced fewer pulmonary exacerbations and lower CRP levels than those with PA. CONCLUSION: In adult CF patients, SA infections alone, in the absence of PA, are a marker of milder disease.

Lymphangioleiomyomatosis and Tuberous Sclerosis Complex in Quebec: Prevalence and Health-care Utilization.

BACKGROUND: Lymphangioleiomyomatosis (LAM) is a manifestation of tuberous sclerosis complex (TSC) that causes destruction of the lung and chronic respiratory failure. Population-based estimates of demographics, clinical outcomes, and health-care utilization are lacking for TSC and LAM. METHODS: Data on demographics, clinical outcomes, and health-care utilization in the Quebec ministerial provincial health-care database were analyzed for their association with TSC and LAM. RESULTS: A total of 1,004 subjects with TSC were identified using International Classification of Diseases, Ninth and 10th Revisions, codes for a prevalence of one in 7,872 people. There were 38 subjects with LAM, nine of whom also had TSC. Mean ages as well as the mean age at death were lower in the LAM and TSC group than in the control group. Mortality rates were higher in subjects with LAM than in those with TSC or in control subjects. Subjects with LAM experienced more medical visits and hospitalizations than did those with TSC and control subjects; these were associated with higher health-care costs. Frequently prescribed drugs in TSC or LAM included anticonvulsants, antidepressants, and sedatives; the use of mammalian target of rapamycin inhibitors was uncommon. CONCLUSIONS: The prevalence of TSC in Quebec, Canada, is similar to estimates from previously published surveys. LAM is likely underreported, perhaps due to suboptimal case identification or referral. Health-care utilization and mortality for LAM are high, suggesting that timely diagnosis and therapy could be beneficial. Mental health disorders may be an unrecognized clinical feature of LAM. These results provide a population-based background for policymakers and researchers to better address the needs of patients with TSC and LAM.

Healthcare utilization and health-related quality of life of adult survivors of preterm birth complicated by bronchopulmonary dysplasia.

AIM: This study aims to characterize the impact of preterm birth, respiratory distress syndrome and bronchopulmonary dysplasia on quality of life and healthcare utilization in adulthood. METHODS: A mail survey on quality of life and respiratory health was sent to a list of potential subjects identified using the databases of the Régie de l'asssurance maladie du Québec. Four groups of adults born between 1987 and 1993 were compared: (i) preterm with bronchopulmonary dysplasia, (ii) preterm with respiratory distress syndrome, (iii) preterm without respiratory complications and (iv) term controls. As a complement, data from the governmental healthcare administrative databases were extracted for responders. RESULTS: Although the groups differed in their use of healthcare services and prescription drugs, no clinically significant difference was observed for Saint George's Respiratory Questionnaire (SGRQ), SF-36v2 and Medical Research Council (MRC) Dyspnea Scale scores. However, compared to term subjects, bronchopulmonary dysplasia subjects were less likely to access higher education and more likely to be either invalid or unemployed. CONCLUSION: Compared to term subjects, subjects with a history of prematurity and respiratory distress syndrome or bronchopulmonary dysplasia had similar health-related quality of life and respiratory symptoms despite greater use of healthcare services and prescription drugs.

Bronchopulmonary dysplasia - trends over three decades.

OBJECTIVES: To describe the characteristics of bronchopulmonary dysplasia (BPD) and respiratory distress syndrome subjects, along with the trends in severity and mortality associated with BPD over the past three decades. METHODS: Retrospective study of BPD and respiratory distress syndrome subjects born between 1980 and 2008, and admitted to Montreal Children's Hospital (Montreal, Quebec). Data were abstracted from hospital records. RESULTS: Gestational age and birth weight were correlated with the occurrence of BPD with each additional week of gestation and 100 g in birth weight being associated with an OR of developing BPD of 0.77 and 0.89, respectively. BPD severity was associated with male sex, Apgar score and the occurrence of neonatal pneumonia. Significant trends were observed for lower mortality despite lower gestational age and birth weight, greater maternal age and multiple gestations. CONCLUSION: Mortality from BPD has improved over the past three decades despite significant trends toward more pronounced prematurity and lower birth weights.

OBJECTIF: Décrire les caractéristiques des sujets atteints de la dysplasie bronchopulmonaire (DBP) et du syndrome de détresse respiratoire, de même que les tendances quant à la gravité de la DBP et à la mortalité s'y rapportant depuis 30 ans. MÉTHODOLOGIE: Les chercheurs ont mené une étude rétrospective des sujets atteints de la DBP et du syndrome de détresse respiratoire nés entre 1980 et 2008 et hospitalisés à L'Hôpital de Montréal pour enfants, au Québec. Ils ont tiré les données des dossiers hospitaliers. RÉSULTATS: Les chercheurs ont corrélé l'âge gestationnel et le poids de naissance avec l'occurrence de DBP, chaque nouvelle semaine de grossesse et nouvelle tranche de 100 g de poids de naissance s'associant à un RRR de DBP de 0,77 et de 0,89, respectivement. La gravité de la DBP s'associait au sexe masculin, à l'indice d'Apgar et à l'occurrence d'une pneumonie néonatale. Les chercheurs ont observé des tendances importantes de diminution de la mortalité malgré un âge gestationnel et un poids de naissance moins élevés, l'âge plus avancé des mères et des gestations multiples. CONCLUSION: La mortalité liée à la DBP a diminué depuis 30 ans, malgré des tendances importantes vers une prématurité plus prononcée et un plus petit poids à la naissance.

Long-term impact of bronchopulmonary dysplasia on pulmonary function.

BACKGROUND: Bronchopulmonary dysplasia (BPD) and the longterm respiratory consequences of prematurity are unfamiliar to adult respirologists and remain under-recognized entities to adult caregivers. In Canada, the incidence of preterm births and its main chronic respiratory complication, BPD, have increased over the past 25 years. OBJECTIVE: To describe the posthospitalization morbidity, medication use, health care use and pulmonary function tests of a large cohort of individuals with preterm birth complicated by BPD. METHODS: A retrospective review of the hospital records of 322 preterm infants with BPD was conducted. Outcome variables were compared across levels of disease severity. Differences between groups were tested with one-way ANOVA for continuous variables and the Mantel-Haenszel chi-squared test for ordinal variables. RESULTS: Outcomes after the initial hospitalization that were associated with the initial severity of BPD were as follows: hospital readmissions in the first two years of life, the presence of developmental delay, forced expiratory volume in 1 s and forced vital capacity on pulmonary function tests in patients between eight and 15 years of age. CONCLUSION: Initial BPD severity was an important predictor of pulmonary function abnormality and health care use during childhood.

Occurrence and severity of bronchopulmonary dysplasia and respiratory distress syndrome after a preterm birth.

BACKGROUND: Despite notable advances in neonatal care, bronchopulmonary dysplasia (BPD) remains an important complication of preterm birth, frequently resulting in prolonged hospital stay and long-term morbidity. METHODS: A historical cohort study of all preterm infants (gestational age younger than 37 weeks) admitted to the Montreal Children's Hospital (Montreal, Quebec) between January 1, 1980, and December 31, 1992, was conducted. Information collected included demographic data, maternal and perinatal history, and main neonatal outcomes. Independent risk factors associated with BPD were identified by univariate analysis using one-way ANOVA, t tests or Mantel-Haenszel χ(2) testing. Severity of disease was studied using an ordinal multinomial logistic regression model. RESULTS: In total, 1192 preterm infants were admitted, of whom 551 developed respiratory distress syndrome and 322 developed BPD. For each additional week of prematurity, the risk of developing BPD increased by 54% (adjusted OR 1.54/week [95% CI 1.45 to 1.64]). For each point subtracted on the 1 min Apgar score, the risk of developing BPD was increased by 16% (OR 1.16 [95% CI 1.1 to 1.3]). BPD was also associated with the presence of patent ductus arteriosus (OR 3.5 [95% CI 2.1 to 6.0]), pneumothorax in the first 48 h (OR 9.4 [95% CI 3.6 to 24.8]) or neonatal pneumonia/sepsis in the neonatal period (OR 1.9 [95% CI 1.1 to 3.2]). Severity of BPD was associated with gestational age, 1 min Apgar score, very low birth weight and the presence of neonatal pneumonia/sepsis. CONCLUSION: Factors associated with BPD following a preterm birth were the degree of prematurity, birth weight, Apgar score at 1 min, and the presence of patent ductus arteriosus, pneumothorax or neonatal pneumonia/sepsis.

Harvesting airway surface liquid: a comparison of two techniques.

The quantity and composition of airway surface liquid (ASL) are essential to host defense. To date, attempts to harvest ASL and measure its composition have yielded conflicting results. We investigated the physical principles underlying two techniques that were proposed for harvesting ASL: filter paper pledgets and polyethylene catheters. We compared the force and pressure generation and the kinematics of capillarity-induced fluid uptake with both techniques. Both have significant limitations for harvesting ASL, generating physiologically significant pressures (filter paper, 60.4 Pa; polyethylene, 14.3 Pa) that could potentially compromise epithelial integrity. Furthermore, filter paper generates a force 85-fold higher than the polyethylene catheter, which is associated with a very high rate of uptake of liquid and a large total amount of liquid relative to ASL thickness. While the PE catheter harvests liquid more gently, it is only effective when ASL surface tension is below 31 mN/m. These limitations likely account for some of the variability in reported ASL composition, and highlight the need for improved methods for harvesting ASL.