Lung clearance index and early detection of Cystic Fibrosis lung disease

http://www.ncbi.nlm.nih.gov/pubmed/22323305

Am J Respir Crit Care Med. 2012 Feb 9. [Epub ahead of print]
Early Cystic Fibrosis Lung Disease Detected by Bronchoalveolar Lavage and Lung Clearance Index.
Belessis Y, Dixon B, Hawkins G, Pereira J, Peat J, Macdonald R, Field P, Numa A, Morton J, Lui K, Jaffe A.
Source
Department of Respiratory Medicine, Sydney Children's Hospital, Randwick, Sydney, New South Wales, Australia.

Abstract
RATIONALE:
Unrecognised airway infection and inflammation in young children with cystic fibrosis (CF) may lead to irreversible lung disease therefore early detection and treatment is highly desirable.

OBJECTIVES:
To determine whether the lung clearance index (LCI) is a sensitive and repeatable non-invasive measure of airway infection and inflammation in newborn-screened children with CF.
METHODS:
Forty-seven well children with CF (mean age, 1.55 years) and 25 healthy children (mean age, 1.26 years) underwent multiple-breath washout testing. LCI within and between-test variability was assessed. Children with CF also had surveillance bronchoalveolar lavage (BAL) performed.

MEASUREMENTS AND
MAIN RESULTS:
Mean (SD) LCI in healthy children was 6.45 (0.49). LCI was higher in children with CF, 7.21 (0.81), P < 0.001. The upper limit of normal for LCI was 7.41. Fifteen (32%) children with CF had an elevated LCI. LCI measurements were repeatable and reproducible. Airway infection was present in 17 (36%) children with CF including 7 (15%) with Pseudomonas aeruginosa. Polymicrobial growth was associated with worse inflammation. LCI was higher in children with Pseudomonas, 7.92 (1.16), than in children without Pseudomonas, 7.02 (0.56), P = 0.038. LCI correlated with BAL interleukin-8, R2 =0.20, P =0.004 and neutrophil count R2 =0.21, P =0.001. A LCI below the upper limit of normality had a high negative predictive value (93%) in excluding Pseudomonas.

CONCLUSIONS:
LCI is elevated early in CF especially in the presence of Pseudomonas and airway inflammation. LCI is a feasible, repeatable and sensitive non-invasive marker of lung disease in young children with CF.