Objective measurement of cough during pulmonary exacerbations in adults with cystic fibrosis
- 1North West Lung Centre, South Manchester University Hospitals Trust, Manchester, UK
- 2Manchester Adult Cystic Fibrosis Centre, South Manchester University Hospitals Trust, Manchester, UK
- Correspondence to:
Dr J A Smith
North West Lung Research Centre, Wythenshawe Hospital, Southmoor Road, Wythenshawe, Manchester M23 9LT, UK;
- Received 17 August 2005
- Accepted 24 January 2006
- Published Online First 31 January 2006
Background: Little is known about cough frequency in adults with cystic fibrosis (CF). This study aimed to determine (1) daytime and overnight cough rates in patients with CF at the beginning and end of a course of antibiotics for treatment of an exacerbation; (2) the relationship between cough frequencies and standard clinical measures of disease; and (3) the relationship between objective cough rates and the subjective assessment of cough.
Methods: Nineteen adult patients admitted with a pulmonary exacerbation performed daytime and overnight sound recordings on admission; 13 had repeat recordings prior to discharge. Coughs were manually quantified in cough seconds (time spent coughing). Patients subjectively scored their cough using a visual analogue scale (VAS) and numerical score. Lung function, C-reactive protein (CRP) levels, and sputum weights were recorded.
Results: Cough rates fell substantially with treatment; median fall in cough rate was 51.3% (IQR 32.3–77.5) (p<0.001) for daytime and 72.2% (28.6–90.1) (p = 0.049) for overnight. Multivariate regression analyses showed that forced expiratory volume in 1 second and CRP levels predicted overnight cough rates on admission. On discharge, sputum volume predicted daytime cough rates. Only the change in overnight VAS correlated with the change in objective cough rates.
Conclusions: The cough rate significantly decreases with treatment of a pulmonary exacerbation in adults with CF. Lung function, sputum volume, and CRP influences the cough rate, with the effects differing from day to night and between admission and discharge. Subjective reporting of a nocturnal cough may indicate a pulmonary exacerbation of CF in adults.
Published Online First 31 January 2006
Funding: North West Lung Centre Research Fund.
Competing interests: none.