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Structural lung disease and neutrophil-dominated airway inflammation is present from 3 months of age in children diagnosed with cystic fibrosis after newborn screening. We hypothesised that azithromycin, given three times weekly to infants with cystic fibrosis from diagnosis until age 36 months, would reduce the extent of structural lung disease as captured on chest CT scans.

In the Saline Hypertonic in Preschoolers (SHIP) study, inhaled 7% hypertonic saline improved the lung clearance index in children aged 3–6 years with cystic fibrosis, but it remained unclear whether improvement is also seen in structural lung disease. We aimed to assess the effect of inhaled hypertonic saline on chest CT imaging in children aged 3–6 years with cystic fibrosis.

Objectives: Azithromycin is used to modulate exuberant inflammatory response in patients with cystic fibrosis (CF). The purpose of this study was to determine the association between long-term use of azithromycin in CF patients and change over time in macrolide susceptibility of Staphylococcus aureus and Haemophilus spp.Methods: The study was performed at the Erasmus MC–Sophia Children's Hospital. CF patients' sputum cultures were obtained at routine visits and at pulmonary exacerbations. All cultures between January 1999 and March 2004 were included. Antibiotic susceptibility of S. aureus and Haemophilus spp. was tested routinely. Susceptibility was compared with isolates from sputum of non-CF patients. Logistic regression was used to analyse the association between azithromycin use and resistance, adjusting for age, Pseudomonas carriage and time-trends.Results: In March 2004 one-third of CF patients were on azithromycin maintenance treatment. S. aureus (715 isolates) and/or Haemophilus (537 isolates) were cultured in 141 of the 155 patients on one or more occasions. The study period was divided into octiles. Erythromycin resistance in S. aureus increased from 6.9 to 53.8% and clarithromycin resistance in Haemophilus spp. from 3.7 to 37.5%. Resistance but also isolation rates were strongly related to azithromycin use. Resistance of 3217 S. aureus control isolates remained stable and resistance of 3257 Haemophilus controls increased, although at a slower rate than CF isolates.Conclusions: Over a 4 year period, azithromycin maintenance therapy in our CF population was associated with an increase in macrolide resistance in S. aureus and Haemophilus spp.

Jet nebulizers are frequently used for asthma treatment in children. Aim of study To evaluate technical maintenance, cleaning procedures, bacterial contamination and performance of nebulizers used by out patients. Methods We selected 39 families where an asthmatic child was on maintenance treatment with a nebulizer. User aspects of nebulizer therapy were evaluated with a questionnaire. Bacterial samples were taken from the liquid container of the nebulizer, the NaCl 0.9% solutions used as diluent, and from the aerosol. We measured the operating pressure generated by the compressor with a manometer. Particle-size of the aerosol was measured by laser diffraction. Results None of the nebulizers were periodically maintained. The cleaning procedure was insufficient in 38% of the users. One or more strains of pathogenic micro-organisms were cultured from 18/39 reservoirs, 16/39 NaCl 0.9% solutions, and 5/10 aerosols. Operating pressure was lower than specified by the manufacturer in 50% of the nebulizers. There was a straight negative linear correlation between age of the nebuliser and the respirable output. Conclusion Periodically technical maintenance of nebulizers and evaluation of user aspects is needed. Only single dose vials of NaCl 0.9% should be used to dilute aerosol medication.

In order to measure small volumes displaced (1-700 µl) by contracting airways without changing the load (pressure) we developed a new device: the microplethysmograph (MP).Methods: The cannulated airway (A) is connected with the measurement cone (M) of a MP. The pressure difference between cone M and the identical reference cone (R) is measured using a differential pressure transducer (D) (LCVR 0-2 cm H2O, Celesco, USA). The fluid volume in both cones can be increased to increase its full scale sensitivity from 700 to only 10 µl. The height (H) of the MPG can be varied to set the pressure (P) in the airway.Measurement: As the airway contracts, fluid will move into cone M inducing a pressure rise. This pressure rise is compensated by lowering the MPG to keep conditions isobaric. The pressure difference between cone M and R is measured by transducer D.Conclusion: We developed a highly sensitive and stable microplethysmograph for measurement of extremely small volume changes in isobaric conditions. We think that this system is applicable to pediatric research in many fields.