BACKGROUND: Much remains unknown about the consequences of very low birth weight (VLBW) and bronchopulmonary dysplasia (BPD) on adult lungs. We hypothesized that VLBW adults would have impaired lung function compared with controls, and those with a history of BPD would have worse lung function than those without. METHODS: At age 26 to 30 years, 226 VLBW survivors of the New Zealand VLBW cohort and 100 term controls born in 1986 underwent lung function tests including spirometry, plethysmographic lung volumes, diffusing capacity of the lung for carbon monoxide, and single-breath nitrogen washout (SBN 2). RESULTS: An obstructive spirometry pattern was identified in 35% VLBW subjects versus 14% controls, with the majority showing mild obstruction. Compared with controls, VLBW survivors demonstrated significantly lower forced expiratory volume in 1 second (FEV 1), FEV 1 /forced vital capacity (FVC) ratio (FEV 1 /FVC), forced expiratory flow at 25% to 75% of FVC and higher residual volume (RV), RV/total lung capacity (TLC) ratio (RV/TLC), decreased diffusing capacity of the lung for carbon monoxide, and increased phase III slope for SBN 2. The differences persisted after adjustment for sex and smoking status. Within the VLBW group, subjects with BPD showed significant reduction in FEV 1 , FEV 1 /FVC, and forced expiratory flow at 25% to 75% of FVC, and increase in RV, RV/TLC, and phase III slope for SBN 2 , versus subjects without. The differences remained after adjustment for confounders. CONCLUSIONS: Adult VLBW survivors showed a higher incidence of airflow obstruction, gas trapping, reduced gas exchange, and increased ventilatory inhomogeneity versus controls. The findings suggest pulmonary effects due to VLBW persist into adulthood, and BPD is a further insult on small airway function.

BackgroundVery low birth weight (less than 1500 g) is associated with increased morbidity and costs of health care in childhood. Emerging evidence suggests these infants face a range of health and social problems as young adults. We studied all New Zealand very low birth weight infants born in 1986 (when 58 % were exposed to antenatal corticosteroids) in infancy, with later follow-up at 7 to 8 years and 23 to 24 years. We now aim to assess the cohort at 26–28 years compared with controls.Methods/designThe case sample will comprise a minimum of 250 members of the 1986 New Zealand national very low birth weight cohort (77 % of survivors). Outcomes will be compared with a control group of 100 young adults born at term in 1986. Following written informed consent, participants will travel to Christchurch for 2 days of assessments undertaken by experienced staff. Medical assessments include growth measures, vision, respiratory function, blood pressure and echocardiogram, renal function, dental examination and blood tests. Cognitive and neuropsychological functioning will be assessed with standard tests, and mental health and social functioning by participant interview. A telephone interview will be conducted with a parent or significant other person nominated by the respondent to gain a further perspective on the young person’s health and functioning. All those born at less than 28 weeks’ gestation, plus a random subset of the cohort to a total of 150 cases and 50 controls, will be offered cranial magnetic-resonance imaging. Statistical analysis will examine comparison with controls and long-term trajectories for the very low birth weight cohort.DiscussionThe research will provide crucial New Zealand data on the young adult outcomes for very low birth weight infants and address gaps in the international literature, particularly regarding cardiovascular, respiratory, visual and neurocognitive outcomes. These data will inform future neonatal care, provide evidence-based guidelines for care of preterm graduates transitioning to adult care, and help shape health education and social policies for this high risk group.Trial registrationAustralian New Zealand Clinical Trials Registry ACTRN12612000995875. Registered 1 October 2012Electronic supplementary materialThe online version of this article (doi:10.1186/s12887-015-0413-9) contains supplementary material, which is available to authorized users.

Baseline arterial oxygen levels and K(CO) are key measures in predicting the hypoxemic response to acute altitude exposure in patients with COPD. The impairment in gas exchange associated with COPD is a significant mechanism causing altitude-related hypoxemia in this group.

Background and objective: Oxygen is used in many clinical scenarios, however the variable performance of nasal cannulae makes determining the precise fraction of inspired oxygen (FiO2) difficult.We developed a novel method for measurement of the tracheal FiO2 using a catheter placed via bronchoscopy. We investigate the effects of oxygen delivery, respiratory rate, mouth position and estimated minute ventilation (VE) on the FiO2 delivered by nasal cannulae. Methods: The catheter was placed in 20 subjects. Tracheal gas concentrations were analysed during six 5-min treatments controlling for oxygen delivery rate, respiratory rate and mouth position. Ventilation was monitored with respiratory inductive plethysmography (RIP). The FiO2 delivered by nasal cannulae was compared between treatments, and we investigated the relationships among the FiO2, alveolar partial pressure of oxygen (PAO2) and VE. Conclusions: Continuous measurement of the FiO2 using a transtracheal catheter provides detailed insight into inspiratory changes of the FiO2 delivered by nasal cannulae. Our study confirms that respiratory rate, VE and mouth position significantly influence the inspired oxygen concentration. These parameters should be accounted for when prescribing oxygen.

In 2008, as part of the changes to develop integrated health care services in the Canterbury region of New Zealand, the local health board in collaboration with general practitioners, respiratory specialists and scientists introduced a programme for general practices to provide laboratory-quality spirometry in the community. The service adhered to the 2005 ATS/ERS international spirometry standards. The spirometry service was provided by trained practice nurses and community respiratory nurses, and was monitored and quality assured by certified respiratory scientists in the Respiratory Physiology Laboratory, Christchurch Hospital and CISO (Canterbury Initiative Services Organisation). These two organisations were responsible for organising training seminars and refresher courses on spirometry technique and interpretation of results. A total of 10 practices have now become approved spirometry providers, with the number of tests carried out in the primary care setting increasing gradually. Consistently high-quality spirometry tests have been obtained and are now presented on a centrally available results database for all hospital and community clinicians to review. Although the service has proved to be more convenient for patients, the tests have not been delivered as quickly as those carried out by the Respiratory Physiology Laboratory. However, the time scales for testing achieved by the community service is considered suitable for investigation of chronic disease. The success of the service has been dependent on several key factors including hospital and clinical support and a centralised quality assurance programme, a comprehensive training schedule and online clinical guidance and close integration between primary and secondary care clinicians.