Response to acute hypercapnia in the parents of victims of sudden infant death syndrome.

The ventilatory response to acute hypercapnia was studied in 68 parents of victims of sudden infant death syndrome and 56 control subjects. Tidal volume, inspiratory time, and total respiratory cycle time were measured before and immediately after a vital capacity breath of 13% CO2 in oxygen. Instantaneous minute ventilation, mean inspiratory flow (tidal volume/inspiratory time), and respiratory timing (inspiratory time/total respiratory cycle time) were calculated. Both groups of subjects showed a marked increase in tidal volume (48.4% +/- 26.5%), instantaneous minute ventilation (56% +/- 35%), and tidal volume/inspiratory time (56.8% +/- 33.5%) after inhalation of the test gas, with little change in inspiratory time/total respiratory cycle time. There were no significant differences between the two groups for ventilation before or after inhalation of the test gas. The ventilatory response to acute hypercapnia is mediated by the peripheral chemoreceptors. These results suggest that an inherited abnormality of peripheral chemoreceptor function is unlikely to be a factor leading to sudden infant death syndrome.

Respiratory health and lung function in 8-year-old children of very low birth weight: a cohort study.

In comparison with a cohort of normal birth weight children, those of very low birth weight (less than 1501 g birth weight) had more wheezing illnesses and hospital readmissions for respiratory problems in the first 2 years of life; from 2 years to 8 years of age respiratory health was unrelated to birth weight. Lung function measurements at 8 years of age in very low birth weight children were similar to expected values; few children had severely abnormal lung function. On univariate analyses, forced vital capacity (FVC) and forced expired volume in 1 second (FEV1), but not flow rates, were lower in children who had survived bronchopulmonary dysplasia. However, the univariate analyses were misleading, because bronchopulmonary dysplasia occurred more frequently with lower birth weight, and lower birth weight in turn was strongly related to reduced FVC and FEV1. After adjusting for birth weight and other potential confounding variables, FVC and FEV1 were unrelated to bronchopulmonary dysplasia, and to neonatal ventilation. Flow rates were largely uninfluenced by perinatal events, but were reduced in children with asthma or recurrent bronchitis at 8 years of age. Passive smoking was unrelated to lung function at 8 years of age. However, the effects of passive or active smoking, or perinatal events, on respiratory function or health beyond 8 years of age in very low birth weight survivors remain to be determined.

Does nifedipine affect the diurnal variation of asthma in children?

Diurnal variations in airway caliber and in bronchial reactivity have been described. The mechanisms underlying these variations are not known. The hypothesis that these variations can be diminished by calcium channel blockers was tested by giving 22 asthmatic children 10 mg of nifedipine or identical placebo three times a day for 4 weeks in a double-blind, randomized, crossover-designed study. Treatment with nifedipine did not diminish the diurnal variations in airway caliber, judged from peak expiratory flow rates, or in bronchial reactivity, judged from bronchodilator responsiveness. Group mean amplitude of the diurnal variation in airway caliber was 10.5% on nifedipine and 10.6% on placebo. Group mean amplitude of the diurnal variation in bronchodilator responsiveness was 75.4% on nifedipine and 69.5% on placebo. There were no differences in mean peak expiratory flow rate between nifedipine and placebo periods. This study did not find any evidence to support the hypothesis that the diurnal variations in airway caliber and in bronchial reactivity can be diminished by calcium channel blockers.

Management of children hospitalized for laryngotracheobronchitis.

During a 12-month period, 527 consecutive admissions for laryngotracheobronchitis (LTB) were reviewed to determine the epidemiology of hospitalized LTB patients and to better define patients who may benefit from therapy other than close observation. Viral cultures were obtained in 442 patients and were positive in 70%. Disease severity at the time of admission was unrelated to patient age or sex. Duration of hospitalization, however, was inversely related to age (p less than 0.001). Laboratory investigations were rarely abnormal or of therapeutic value. Patients who on admission had stridor without sternal and chest wall retractions recovered rapidly and spontaneously; they were frequently discharged within 48 hours and never required artificial airways. Children who had sternal and chest wall retractions on admission experienced longer hospitalizations, frequently received medical intervention such as aqueous mist therapy or racemic epinephrine, and had a 6% risk of requiring artificial airway support. This group of children should be studied selectively for the benefits of specific medical therapies and diagnostic evaluations.

The role of piperacillin therapy in pulmonary exacerbations of cystic fibrosis: a controlled study.

Piperacillin was evaluated as an antipseudomonas antibiotic in a double-blind controlled trial involving 18 pulmonary exacerbations of cystic fibrosis. Standard antibiotic treatment (flucloxacillin plus tobramycin) was compared with standard treatment plus intravenous piperacillin administered according to two regimens. No added benefit from piperacillin was demonstrable on the basis of improvement in symptoms, physical signs, weight gain, pulmonary function tests, radiologic signs, or sputum Pseudomonas bacterial counts. Some patients experienced sensitivity reactions to piperacillin. In vitro, piperacillin was a potent antibiotic against all beta-lactamase-producing mucoid strains of Pseudomonas aeruginosa; however, in spite of the fact that adequate serum antibiotic concentrations were achieved, sputum bacterial counts did not correlate with either the clinical status or the use of piperacillin therapy.

Longitudinal study of lung mechanics in normal infants.

Lung mechanics and partial forced expiratory flows were measured serially in seven normal infants during the first year of life. Lung mechanics were measured by the end inspiratory occlusion technique and partial forced expiratory flows by the rapid chest compression method. Thoracic gas volume, compliance, and partial forced expiratory flows measured at functional residual capacity progressively increased with age and correlated with height cubed. Respiratory system resistance progressively fell whereas volume-corrected flows remained fairly constant over the study period. These findings provide longitudinal lung function data and support the concept of isotropic lung growth.

Inherent variability of pulmonary function tests in infants with bronchiolitis.

During the last decade, many new methods of assessing pulmonary function in infants have been introduced. However, considerable controversy has arisen when these different techniques are used to assess the efficacy of various inhaled medications. The currently employed measures of pulmonary function have been reported to have coefficients of variation of less than 10%. However, these figures refer to repeated measurements made in individual babies over a short period of time, with the infant in a constant position. They may not be applicable to studies on the effects of drugs when a significant time interval elapses between measurements, particularly if the infant is repositioned during this time. In the present study, we found that the variability of measurements of thoracic gas volume (TGV), passive respiratory mechanics, and forced expiration approximately doubled if the infant was taken out of the plethysmograph, or repositioned within the plethysmograph, between sets of measurements. The between-test coefficients of variation ranged from 4.8% to 18.9% for TGV, 7.8% to 23.5% for respiratory system resistance, from 5.0% to 24.1% for respiratory system compliance, and from 10.8% to 36.1% for maximal flow at functional residual capacity. These results demonstrate that the commonly employed infant pulmonary function tests have wide variability in infants with acute wheezing illnesses. Before studying the efficacy of therapeutic interventions in such infants, it is necessary to establish the individual variability of the tests in the infants under the conditions of the study. Failure to do so may result in erroneous conclusions and recommendations.

Childhood asthma and lung function in mid-adult life.

The longitudinal lung function data in 286 subjects from a 28 year follow-up of childhood asthma is reported. Airway obstruction in mid-adult life was present mainly in those with moderately severe asthma. Subjects who had been wheeze free for at least 3 years, even if asthma had been persistent in childhood, had normal lung function and no increased bronchial reactivity. Only two subjects, both with persistent asthma from childhood, failed to show an improvement in FEV1 of greater than 10% following inhalation of a beta-adrenergic agonist. Subjects with relatively mild asthma who had not taken inhaled steroids did not appear to be disadvantaged with respect to lung function.

Bronchoalveolar lavage or oropharyngeal cultures to identify lower respiratory pathogens in infants with cystic fibrosis.

As collections of lower respiratory tract specimens from young children with cystic fibrosis (CF) are difficult, we determined whether oropharyngeal cultures predicted lower airway pathogens. During 1992-1994, 75 of 90 (83%) infants with CF diagnosed by neonatal screening had 150 simultaneous bronchoalveolar lavage (BAL) and oropharyngeal specimens collected for quantitative bacterial culture at a mean age of 17 months (range, 1-52). Ten children undergoing bronchoscopy for stridor served as controls. Total and differential cell counts and interleukin-8 concentrations were measured in BAL fluid. A subset of bacterial pathogens were typed by pulsed field gel electrophoresis. A non-linear relationship with inflammatory markers supported a diagnosis of lower airway infection when > or = 10(5) colony-forming units/ml were detected. This criterion was met in 47 (31%) BAL cultures from 37 (49%) children. Staphylococcus aureus (19%), Pseudomonas aeruginosa (11%), and Hemophilus influenzae (8%) were the major lower airway pathogens. In oropharyngeal cultures, S. aureus (47%), Escherichia coli (23%), H. influenzae (15%), and P. aeruginosa (13%) predominated. The sensitivity, specificity, and positive and negative predictive values of oropharyngeal cultures for pathogens causing lower respiratory infections were 82%, 83%, 41%, and 97%, respectively. When there was agreement between paired oropharyngeal and BAL cultures, genetic fingerprinting showed some strains of the same organism were unrelated. We conclude that oropharyngeal cultures do not reliably predict the presence of bacterial pathogens in the lower airways of young CF children.

Severe viral respiratory infections in infants with cystic fibrosis.

Limited data in children with cystic fibrosis (CF) suggest that respiratory viral infections during infancy result in substantial morbidity. Eighty of 101 (79%) infants with CF diagnosed by neonatal screening during 1991-1996 were recruited into a prospective, multiple-birth cohort study. We aimed to perform an initial, then annual bronchoalveolar lavage (BAL) for bacterial and viral culture, cytology, IL-8, and elastolytic activity over the following 2 years. When possible, BAL was also performed during any hospitalization for a pulmonary exacerbation, and additional specimens for viral culture were collected by nasopharyngeal aspiration. Thirteen infants undergoing bronchoscopy for congenital stridor served as disease controls. During infancy, 31 children (39%) were hospitalized for respiratory disease and 20 (65%) cases had an etiologic agent identified. Respiratory viruses were detected in 16/31 (52%) cases, including four with simultaneous bacterial infection. Another four were infected with Staphylococcus aureus. Respiratory syncytial virus predominated and was found in seven infants. In the absence of bacteria, those with viral infections had acute onset of respiratory distress, were not treated with antibiotics, and had an uncomplicated hospital course. Compared to noninfected CF subjects and controls, infected infants had elevated BAL inflammatory indices (P < 0.01). Eleven of 31 (35%) hospitalized infants followed for 12-60 months acquired Pseudomonas aeruginosa, compared with only three of 49 (6%) subjects not hospitalized for respiratory symptoms during infancy (risk ratio 5.8, CI 1.9, 24). We conclude that respiratory viruses are important causes of hospitalization in CF infants. While viral infections were self-limited, they were accompanied by airway inflammatory changes, and admission to hospital was associated with early acquisition of Pseudomonas aeruginosa and persistent respiratory symptoms.

Changes in lung function between age 8 and 14 years in children with birth weight of less than 1,501 g.

We set out to determine whether lung function of children with a birth weight of <1,501 g changed relative to expectations between the ages of 8 and 14 years. We hypothesized that changes in lung function may differ between those of birth weight above and below 1,000 g. The subjects of this study were born in the Royal Women's Hospital, Melbourne. There were 86 consecutive survivors with birth weights <1,000 g born between January 1, 1977 and March 31, 1982, and 124 consecutive survivors with birth weights 1,000-1,500 g born between October 1, 1980 and March 31, 1982. Lung function was measured at both age 8 and 14 years, corrected for prematurity in 78% (67/86) of those with birth weight <1,000 g, and in 69% (86/124) of those with birth weight 1,000-1,500 g. Overall, lung function was similar to predicted values at both 8 and 14 years of age [e.g., (forced expired volume in 1 s, FEV1% predicted) at age 8 years mean 88.5% (SD 14.7) and at age 14 years, mean 94.9% (SD 13.8)]. There were significant changes, mostly improvements, in lung function between age 8-14 years relative to predicted values: FEV1 (% predicted) increased between 8-14 years of age by a mean of 6.4 (95% confidence interval, 4.4-8.3). The improvements in some lung function variables were significantly greater in those of birth weight <1,000 g compared with those of birth weight 1,000-1,500 g: improvement in FEV1 (% predicted) between age 8-14 years in infants with birth weight <1,000 g had a mean of 10.3 (SD 13.1), and in those with birthweight 1,000-1,500 g a mean of 3.3 (SD 10.1). We conclude that lung function improved significantly relative to predicted values in children of birth weight <1,501 g between age 8-14 years. The improvements were greatest in those of birth weight <1,000 g.

Multiple cavitating pulmonary nodules and clubbing in a 12-year-old girl.

We report on a 12-year-old girl with a prolonged history of cough and hemoptysis on three occasions. X-ray and computed tomography of the chest showed several cavitating lesions and mediastinal lymphadenopathy. Lung biopsy revealed nodular sclerosing Hodgkin's disease. Hodgkin's disease should be considered in the differential diagnosis of cavitating pulmonary lesions.

Prevalence of asthma in Melbourne schoolchildren: changes over 26 years.

OBJECTIVES: To determine the prevalence of asthma in the past 12 months in Melbourne schoolchildren aged 7, 12, and 15 years and to compare the prevalence of a history of asthma with that of 26 years ago. DESIGN: A questionnaire on respiratory symptoms was distributed to children for completion by parents and return to the school. Subjects were selected by a stratified cluster design. SETTING: Government and non-government schools in the greater Melbourne area, Australia. SUBJECTS: 10,981 children. Parents completed questionnaires for 3324 children aged 7, 2899 aged 12, and 2968 aged 15. The overall response rate was 90%. MAIN OUTCOME MEASURES: History of wheeze or asthma in the past 12 months and in lifetime. RESULTS: The prevalences of wheeze in the past 12 months were 23.1%, 21.7%, and 18.6% for 7, 12, and 15 year olds respectively. A history of wheeze was more common in boys than in girls at age 7 (443/1711 v 324/1614) and 12 (418/1767 v 322/1718) but not at age 15. Overall, 78% (1548) of those reporting wheeze also reported a history of asthma and 83% (1611) had used a bronchodilator. The prevalence of a history of asthma among 7 year olds was 46% compared with 19.1% in the 1964 survey, an increase of 141%. CONCLUSIONS: The current prevalence of asthma in Melbourne schoolchildren is high and has risen substantially over the past 26 years.

Agreement of aspiration tests using barium videofluoroscopy, salivagram, and milk scan in children with cerebral palsy.

To study the agreement between three tests for aspiration, barium videofluoroscopy, salivagram, and milk scan we studied 63 children with severe non-ambulant spastic quadriplegic cerebral palsy (CP) aged 14 months to 16 years (32 males, 31 females). The salivagram was most frequently positive (56%, 95% confidence interval 43 to 68%); the next most frequently positive was barium videofluoroscopy when aspiration was defined as the presence of either laryngeal penetration of material or frank aspiration (39%, 95% confidence interval 26 to 53%). The milk scan was rarely positive (6%, 95% confidence interval 2 to 16%). Agreement between the tests of aspiration was poor. The maximum agreement (kappa=0.20) was between aspiration as diagnosed with the salivagram and by barium videofluoroscopy. Positive tests for aspiration are frequent in children with severe CP. Frequency varies widely depending on the investigation used. There is poor agreement between tests used for the diagnosis of aspiration. This information is of importance in assessing the significance of test results.

Sarcoidosis in children.

Eight patients with sarcoidosis seen at the Royal Children's Hospital, Melbourne, during the past 10 years were reviewed. Five of the eight patients came from non-metropolitan areas. The major presenting symptoms were cough, fatigue and weight loss; peripheral lymphadenopathy and hepatomegaly were common. None of the patients had eye or central nervous system involvement. Seven patients had bilateral hilar adenopathy on chest radiograph and six had parenchymal lung changes. Angiotensin converting enzyme was measured in six patients and was elevated in all, while hypercalcaemia was present in three patients. Five patients had a tissue biopsy showing the characteristic non-caseating granulomas. Corticosteroid therapy was used for four patients and was given for hypercalcaemia in three patients and for severe restrictive lung disease in one patient.

Evaluation of directed coughing in cystic fibrosis.

Supervised directed coughing was compared to conventional physiotherapy (postural drainage, vibration and/or percussion and coughing) in 38 patients with cystic fibrosis aged 9-18 years admitted to hospital with an exacerbation of their pulmonary symptoms. Assessment included objective measures of pulmonary function and sputum characteristics. Both treatment groups showed significant improvement at the end of the 2-week period. When the patients were graded according to their pulmonary disease, those with mild-moderate disease demonstrated a significant improvement in both treatment groups whereas those with severe lung disease showed little improvement with either treatment. Directed coughing is as effective as conventional physiotherapy in the management of patients with cystic fibrosis admitted to hospital for treatment of an exacerbation of their pulmonary symptoms.

Nasotracheal intubation in acute laryngotracheobronchitis.

The case histories of 150 children admitted to hospital with acute laryngotracheobronchitis (LTB) are reviewed. Relief of severe upper airway obstruction was achieved by nasotracheal intubation in 27 children (18%). There was no mortality in this series. Nasotracheal intubation is therefore a safe and effective means of treating severe LTB. In addition, the importance of meticulous nursing care is stressed.