Lung function in adult survivors of very low birth weight, with and without bronchopulmonary dysplasia.

INTRODUCTION: The lung function outcome of cohorts of very low birth weight (VLBW; birth weight <1501 g) survivors born in the late 1970s or early 1980s into adulthood at an age when lung growth would be expected to have ceased is not well described. The aim of this study was to report lung function data in adulthood of VLBW survivors compared with normal birth weight controls (>2499 g), and in those who had bronchopulmonary dysplasia (BPD) compared with those without BPD. MATERIALS AND METHODS: Spirometry and lung volumes were measured according to standard guidelines when subjects were in their mid-20s; there were 47 survivors of birth weight <1000 g, 40 of birth weight 1000-1500 g, and 20 controls of birth weight >2499 g. Results were converted to z-scores. RESULTS: Both subgroups with birth weight <1501 g had significant reductions in airflow compared with controls, but not compared with each other. There were no significant differences between groups in variables reflecting air trapping. Within the VLBW cohort, those with BPD (n = 24) had reductions in airflow, including the z-score for the forced expired volume in 1 sec (FEV1 ), compared with those without BPD (n = 63). Within the VLBW cohort, there were positive relationships between FEV1 measurements earlier in childhood with those obtained at 25 years of age; these relationships were stronger in those who had BPD in the newborn period, and increased over time. CONCLUSIONS: VLBW survivors continue to have airways obstruction in their mid-20s compared with controls, particularly those who had BPD in the newborn period.

Outcomes of childhood asthma to the age of 50 years.

BACKGROUND: In 1964, The Melbourne Asthma Study was established to describe the spectrum and natural history of childhood asthma. OBJECTIVE: To describe the clinical and lung function outcome of childhood asthma to the age of 50 years. METHOD: Subjects were invited to complete an interviewer-administered questionnaire, skin prick testing, and measurement of lung function from the age of 7 years to the age of 50 years at 7-year intervals. RESULTS: Of 458 survivors (from the original 484 subjects at recruitment), 346 subjects (76%) participated, of whom, 197 completed lung function measurement. Asthma remission at the age of 50 years was 64% in those with wheezy bronchitis, 47% for those with persistent asthma, and 15% for those with severe asthma in childhood. Multivariable analysis identified severe asthma in childhood (odds ratio [OR] 11.9 [95% CI, 3.4-41.8]), female sex (OR 2.0 [95% CI, 1.1-3.6]), and childhood hay fever (OR 2.0 [95% CI, 1.0-4.0]) as risk factors for "current asthma" at age 50 years. There was no evidence of a difference in the rate of decline in FEV1 (mL/y, 95% CI) between the severe asthma group (15 mL/y [95% CI, 9-22 mL/y]) and all the other recruitment groups: control (16 mL/y [95% CI, 12-20 mL/y]), mild wheezy bronchitis (14 mL/y [95% CI, 8-19 mL/y]), wheezy bronchitis (16 mL/y [95% CI, 11-20 mL/y]), and persistent asthma (19 mL/y [95% CI, 13-24 mL/y]). CONCLUSION: The clinical and lung function outcome in adult life is strongly determined by asthma severity in childhood. The reduced lung function seen in adults is established in childhood and does not appear to decline more rapidly in adult years despite continuing symptoms.

Respiratory outcomes for the tiniest or most immature infants.

Extremely low birth weight (<1000 g birth weight) or extremely preterm (<28 weeks of gestation) infants are surviving in greater numbers as neonatal care advances. Many of these survivors, especially those who develop bronchopulmonary dysplasia, have more respiratory ill health in the first years after discharge home, reduced respiratory function and impaired exercise capacity throughout childhood and into adulthood compared with term-born controls. It is important to establish the long-term respiratory outcomes for the tiniest or most immature survivors as they grow older, since they may contribute disproportionately to rates of chronic obstructive pulmonary disease and respiratory ill-health in adulthood.

Geographical differences in first acquisition of Pseudomonas aeruginosa in cystic fibrosis.

RATIONALE: Risk of infection with Pseudomonas aeruginosa in cystic fibrosis (CF) may be associated with environmental factors. OBJECTIVES: To determine whether residential location is associated with risk of first acquisition of P. aeruginosa. METHODS: We performed bronchoalveolar lavage and upper airway cultures in children newly diagnosed with CF to identify infection with P. aeruginosa during infancy and early childhood. Children were assessed according to their residence in a regional or metropolitan area. Multilocus sequence typing was used to determine P. aeruginosa genotype. An environmental questionnaire was also administered. MEASUREMENTS AND MAIN RESULTS: A total of 105 of 120 (87.5%) infants diagnosed with CF were included in this study. Diagnosis in 65 infants (61.9%) followed newborn screening at mean age of 4.6 weeks. Sixty subjects (57.1%) were homozygous ΔF508, and 47 (44.8%) were female. Fifty-five (52.3%) infants were regional, of whom 26 (47.3%), compared with 9 of 50 (18.0%) metropolitan children, acquired infection with P. aeruginosa (odds ratio, 4.084; 95% confidence interval, 1.55-11.30). Age at acquisition was similar (regional: median, 2.31 yr; range, 0.27-5.96 yr; metropolitan: median, 3.10 yr, range, 0.89-3.70 yr). Strain typing identified P. aeruginosa genotypes often encountered in different ecological settings and little evidence of cross-infection. Ninety questionnaires (85.7%) were completed. Those who acquired P. aeruginosa were more likely to be living in a household that used water sprinkler systems (P = 0.032), but no differences were identified to explain increased risk of acquisition of P. aeruginosa in regional children. CONCLUSIONS: Geographical difference in residence of children with CF was associated with increased risk of first acquisition of P. aeruginosa, usually with strains associated with the environment rather than with cross-infection.

Respiratory function at age 8-9 after extremely low birthweight or preterm birth in Victoria in 1997.

To determine if respiratory function at 8 years of age in extremely low birth weight (ELBW; birth weight <1,000 g) or extremely preterm (EPT, <28 weeks' gestation) children born in 1997 remains worse than normal birth weight (NBW; birth weight, >2,499 g) and term (37-42 weeks) controls, particularly in those ELBW/EPT children who had bronchopulmonary dysplasia (BPD). This was a cohort study of 201 consecutive ELBW/EPT survivors born in the state of Victoria during 1997, and 199 contemporaneous randomly selected NBW/term controls. Respiratory function was measured at 8 years of age according to standard guidelines, and compared with previous cohorts born in 1991-1992. Respiratory function data were available for almost 75% of both cohorts. ELBW/EPT subjects had substantial reductions in airflow compared with controls (e.g., mean difference in forced expiratory volume in 1 sec [FEV1 ] -0.91 SD, 95% confidence interval [CI] -1.19 to -0.63 SD, and in maximum expiratory flow between 25% and 75% of vital capacity [FEF25-75% ] -0.96 SD, 95% CI -1.22 to -0.71). These differences were similar to those observed between ELBW/EPT and controls subjects born in 1991-1992. Within the ELBW/EPT cohort, children who had BPD in the newborn period had significant reductions in both the FEV1 (-0.76 SD) and FEF25-75% (-0.58 SD) compared with those who did not have BPD, which were not statistically significant from those in the 1991-92 cohort. ELBW/EPT children born in 1997 still have significantly abnormal lung function compared with NBW/term controls, but results were similar to an earlier era when survival rates were lower. Pediatr Pulmonol. 2013; 48:449-455. © 2012 Wiley Periodicals, Inc.

Lung function in preschool children with a history of wheezing measured by forced oscillation and plethysmographic specific airway resistance.

RATIONALE: Wheezing is common in preschool children, but objective evidence for airway obstruction and its reversibility are rarely available in clinical practice. We assessed whether abnormalities of lung function and bronchodilator response can be detected in preschool children using the forced oscillation technique and measurements of specific airway resistance. METHODS: Fifty-nine children with a history of wheeze and 24 healthy controls aged 3-6 years were recruited. Resistance and reactance at 6 and 8 Hz (Rrs6, Rrs8, Xrs6 and Xrs8, respectively) were measured using the forced oscillation technique and specific airway resistance was measured in a plethysmograph. z-Scores were calculated from published reference data. Tests were repeated 15 min after 400 mcg salbutamol. Bronchodilator response was expressed as the log-transformed ratio of postbronchodilator/prebronchodilator values. RESULTS: Technically acceptable measurements using the forced oscillation technique were obtained in n = 77 (93%) of children and in n = 56 (68%) using plethysmography. There was no significant difference in baseline lung function or bronchodilator response, assessed by either technique, between those with a history of wheeze and healthy controls. CONCLUSION: Measurement of lung function is feasible in preschool children, but neither of these techniques was able to identify diminished lung function or reversibility to bronchodilator in children with a history of wheeze.

Understanding of pulse oximetry among hospital staff.

AIM: To assess the level of understanding of pulse oximetry in a hospital setting and identify training needs. METHODS: Twenty nine nurses and 34 doctors anonymously completed a questionnaire survey previously used by researchers in Exeter, UK. Respondents were required to explain the basic principles of pulse oximetry and demonstrate an understanding of the physiological factors limiting its accuracy. They were asked to apply their knowledge in different clinical scenarios. RESULTS: A higher proportion of nurses than doctors demonstrated an awareness of the physiological limitations of pulse oximetry. The majority of respondents correctly identified normal ranges for adult patients. Twenty nine per cent of respondents did not know how a pulse oximeter worked. Respondents failed to recognise the clinical implications of low oxygen saturations in many of the hypothetical scenarios. Only 16% of respondents had received any formal training in the use of pulse oximetry, with 65% identifying a need for more training. CONCLUSIONS: Medical and nursing staff at Christchurch Hospital have a good understanding of pulse oximetry. A higher proportion of participants were aware of checking vital signs when the oximeter reading was unreliable, than in the original UK study cohort. A need was identified for further education in this core technique. Staff training may increase the clinical value of pulse oximetry.