Article Text

Download PDFPDF
Comparison of spontaneous and induced sputum for investigation of airway inflammation in chronic obstructive pulmonary disease
  1. A Bhowmik,
  2. T A R Seemungal,
  3. R J Sapsford,
  4. J L Devalia,
  5. J A Wedzicha
  1. Academic Department of Respiratory Medicine, St Bartholomew’s and Royal London School of Medicine and Dentistry, London Chest Hospital, London E2 9JX, UK
  1. Dr J A Wedzicha.

Abstract

BACKGROUND Although sputum induction is used as a technique to investigate lower airway inflammation in asthmatic subjects, advantages over spontaneous sputum in patients with chronic obstructive pulmonary disease (COPD) have not been investigated.

METHODS Samples of spontaneous sputum and sputum induced with 3% hypertonic saline for 14 minutes were collected from 27 patients with chronic obstructive pulmonary disease (COPD) who usually produced spontaneous sputum. Spirometric indices and oxygen saturation (Sao 2) were measured at seven minute intervals. The spontaneous, seven and 14 minute sputum samples were analysed for total and differential cell counts, cell viability, and interleukin 8 levels.

RESULTS Analysis of the sputum revealed that median cell viability was higher in the seven minute (62.8%; p = 0.004) and 14 minute (65%; p = 0.001) induced sputum samples than in spontaneous sputum (41.2%). There was no significant difference in total and differential cell counts or in interleukin 8 levels between spontaneous and induced sputum. During the sputum induction procedure the mean (SD) fall in forced expiratory volume in one second (FEV1) was 0.098 (0.111) l (p < 0.001) and in forced vital capacity (FVC) was 0.247 (0.233) l (p < 0.001). There was a small but significant fall in Sao 2 during sputum induction (p = 0.03).

CONCLUSIONS Induced sputum contains a higher proportion of viable cells than spontaneous sputum. There are no significant differences between the sputum samples obtained at seven minutes and at 14 minutes of hypertonic saline nebulisation. Sputum induction is safe and well tolerated in patients with COPD.

  • chronic obstructive pulmonary disease
  • induced sputum
  • airway inflammation

Statistics from Altmetric.com

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.