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Chronic obstructive pulmonary disease
Bronchoscopic validation of the significance of sputum purulence in severe exacerbations of chronic obstructive pulmonary disease
  1. Néstor Soler1,
  2. Carlos Agustí1,
  3. Joaquim Angrill1,
  4. Jorge Puig De la Bellacasa2,
  5. Antoni Torres1
  1. 1Servei de Pneumologia, Institut Clínic del Tòrax, Hospital Clínic, IDIBAPS Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain
  2. 2Servei de Microbiologia, Hospital Clínic, IDIBAPS Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain
  1. Correspondence to:
    Dr A Torres
    Servei de Pneumologia, Institut Clínic del Tòrax, Hospital Clínic, IDIBAPS Universitat de Barcelona, Villarroel 170, 08036 Barcelona, Spain; atorres{at}ub.edu

Abstract

Background: Antibiotics are commonly prescribed in exacerbations of chronic obstructive pulmonary disease (COPD). However, the role of bacteria in these exacerbations is controversial.

Objective: To identify clinical predictors of bacterial infection as a cause of exacerbation, considering the protected specimen brush (PSB) as the gold standard.

Methods: Clinical data, sputum and PSB samples were collected from 40 patients with COPD requiring hospitalisation due to severe exacerbations who had not received previous antibiotic treatment.

Results: Quantitative cultures of PSB samples (n = 40) yielded 23 potential pathogenic microorganisms (PPMs) at concentrations of ⩾102 colony-forming units/ml in 18 (45%) patients. Sputum samples were obtained from all 40 patients. Culture of good-quality sputum samples (n = 18) yielded 16 PPMs corresponding to 14 (35%) patients. The concordance between the PSB and sputum rate was high (κ = 0.85, p<0.002). The self-reporting patient observation of sputum purulence (odds ratio (OR) 27.20 (95% confidence interval (CI) 4.60 to 60.69), p = 0.001), the percentage predicted forced expiratory volume in 1 s (FEV1%) <50 (OR 2.27 (95% CI 1.55 to 3.21), p = 0.014), >4 exacerbations in the past year (OR 6.9 (95% CI 0.08 to 1.08), p = 0.028) and previous hospitalisations due to COPD (OR 4.13 (95% CI 1.02 to 16.07), p = 0.041) were associated with the presence of PPMs in the distal airways. The operative characteristics for predicting distal airway infection when patients presented with purulent exacerbation were as follows: sensitivity 89.5%, specificity 76.2%, positive predicted value 77.3% and negative predicted value 88.9%.

Conclusions: The self-reporting presence of purulence in the sputum, as well as common previous exacerbations and hospitalisations due to COPD in patients with severe airflow obstruction (FEV1% <50) predict the presence of bacterial infection in the distal airways. The use of these clinical variables may help in selecting candidates to receive antibiotic treatment.

  • CFU, colony-forming units
  • COPD, chronic obstructive pulmonary disease
  • FEV1%, percentage predicted forced expiratory volume in 1 s
  • FVC, forced vital capacity as a percentage of predicted
  • MIC, minimum inhibitory concentration
  • PaCO2, arterial CO2 pressure
  • PaO2, arterial oxygen pressure
  • PPM, potential pathogenic microorganism
  • PSB, protected specimen brush

https://doi.org/10.1136/thx.2005.056374

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    Footnotes

    • Published Online First 23 August 2006

    • Funding: This study was supported by Marató TV3 (04050530 and 04040210), grant FISS (PI041136 and PI030113), Red Gira (V-2003-REDG063-0), Red Respira (V-2003-REDC11B-0) and CIBER, CB 06/06/0028.

    • Competing interets: None declared.