A Pilot Study to Characterise Saliva and Sputum FTIR Spectral Profiles in Patients with COPD During Exacerbations and When Stable

Chronic Obstructive Pulmonary Disease (COPD) is a common and treatable condition that is characterised by predominately irreversible and progressive airflow limitation. COPD is a leading cause of morbidity and mortality worldwide and its prevalence is predicted to increase substantially in the coming decade1. In the United Kingdom (UK) alone, COPD affects an estimated 3 million people, with 1 million diagnosed and a further 2 million remaining undiagnosed2. Delays in an accurate diagnosis impacts on quality of life and healthcare resource utilisation. COPD is associated with a significant economic and social burden, with a single severe exacerbation requiring admission to hospital costing up to £1600, therefore having a major impact on NHS expenditure. COPD also has a personal burden, causing 24 million lost working days annually, costing the UK economy £3.8 billion3. Importance is placed on early detection of exacerbations of COPD as delays in starting treatment are associated with increased exacerbation severity, emergency healthcare use, a higher mortality and a more rapid decline in lung function. There is therefore a recognised need for widely accessible, easy-to-use tools to aid in the early detection of COPD exacerbations. Fourier Transform Infra-Red (FTIR) spectroscopy is an emerging field of medicine which has the potential to become established in the management of lung conditions. Previous studies4,5 have shown that sputum in patients with COPD analysed with infrared (IR) gave reproducible biological IR spectra with distinct signatures in 5 key regions, namely Amide A, two signatures in the Amide I region, Amide II and in glycoproteins. The additional information on the spectral profiles gathered in this study on saliva and sputum from patients with COPD, during both stable disease and exacerbations will help establish FTIR use in the management of these lung conditions. This study will provide essential information in the development process of a hand held FTIR spectroscope. Phase 1 will establish the infrared spectrum required for the analysis of saliva and sputum, which will inform the design of the daisy chain device (a pre-prototype device) used in phase 2. Phase 2 will test this infrared spectrum in the pre-prototype daisy chain device with further saliva and sputum samples, before this spectrum is incorporated into the eventual hand-held FTIR spectroscope.