Background: Measurements of lung function are routinely used in patients with cystic fibrosis (CF) to provide information that may be clinically relevant. Spirometry is the conventional lung function measurement used, however young children find spirometry difficult to perform and often cannot achieve the strict acceptability criteria for the test. The forced oscillation technique (FOT) is a lung function measurement that only requires tidal breathing and is easy for young children to perform. However, there is limited information about the utility of this technique in the clinical assessment of young children with CF who are unable to perform spirometry. Aims: The aim of this project was to evaluate the FOT for clinical assessment in 2 to 7 year old children with CF. Specifically this involved: 1. Technical assessment of the FOT in children with CF; 2. Comparisons of lung function using the FOT in children with CF and healthy children; 3. Evaluation of associations with factors known to be associated with lung disease including: i) inflammation ii) infection and iii) structural damage. Methods Lung function was measured in a cohort of 59 children between the ages of 2 and 7 years with CF at the time of quarterly clinic visits. Resistance and reactance at 6, 8 and 10Hz (Rrs6, Rrs8, Rrs10, Xrs6, Xrs8, Xrs10, respectively) were reported and expressed as Z scores. Children were classified as asymptomatic or symptomatic based on a respiratory questionnaire and physical examination at the time of testing. Bronchoalveolar lavage and high resolution computed tomography (HRCT) were performed annually under general anaesthesia annually. BAL fluid was assessed for the presence of micro-organisms and quantification of a range of inflammatory markers and HRCT used to determine the extent of structural abnormalities. Results: The between test repeatability (n=25) for lung function was within limits previously described in healthy children. No systematic bias was observed and repeatability was not affected by the presence of respiratory symptoms. Children with CF (n=57) had significantly increased Rrs6-10 (p<0.0001) and decreased Xrs6-10 (p<0.004) compared to healthy children. Rrs6 and Xrs6-10 were significantly worse in the presence of respiratory symptoms, and Rrs6-10 progressively worsened from an asymptomatic to a symptomatic clinic visit. Children with CF (n=48) had no greater bronchodilator response (BDR) compared to healthy children. BDR was not influenced by the presence of an infection or respiratory symptoms. No relationships between inflammatory markers and lung function (n=39) were identified when the presence of an infection was adjusted for. Children with a current infection (n=20) had increased Rrs6-10 (p<0.01) and decreased Xrs6-10 (p<0.04) compared to children who were uninfected (n=23). These relationships were most marked for children infected with Pseudomonas aeruginosa, with children having a reduced lung function between 0.95 and 1.47 of a Z score. No relationships with the presence or absence of mild structural abnormalities (bronchiectasis, bronchial wall thickening and air trapping) and lung function at the time of HRCT were identified (n=34). Conclusion: The FOT is a repeatable measurement of lung function in children with CF and reliable results can be obtained in children as young as 2 years old. Young children with CF exhibit altered respiratory function which was affected by the presence of factors known to be associated with lung disease. The FOT has the potential to provide useful information about changes in clinical status in young children with CF and may be used to direct management of patient lung disease.
| Identifer | oai:union.ndltd.org:ADTP/202494 |
| Date | January 2008 |
| Creators | Gangell, Catherine Louise |
| Publisher | University of Western Australia. School of Paediatrics and Child Health |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | Copyright Catherine Louise Gangell, http://www.itpo.uwa.edu.au/UWA-Computer-And-Software-Use-Regulations.html |
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