RT Journal Article SR Electronic T1 Anti-inflammatory effects of inhaled carbon monoxide in patients with COPD: a pilot study JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 1131 OP 1137 DO 10.1183/09031936.00163206 VO 30 IS 6 A1 E. Bathoorn A1 D-J. Slebos A1 D. S. Postma A1 G. H. Koeter A1 A. J. M. van Oosterhout A1 M. van der Toorn A1 H. M. Boezen A1 H. A. M. Kerstjens YR 2007 UL http://erj.ersjournals.com/content/30/6/1131.abstract AB In vitro and in vivo studies have shown that carbon monoxide (CO) has both anti-inflammatory and anti-oxidant capacities. Since chronic obstructive pulmonary disease (COPD) is characterised by inflammation and oxidative stress, low-dose CO could be of therapeutic use. The aim of the present study was to investigate the feasibility and anti-inflammatory effects of 100–125 ppm CO inhalation in patients with stable COPD. In total, 20 ex-smoking COPD patients with post-bronchodilator forced expiratory volume in one second (FEV1) >1.20 L and FEV1/forced vital capacity <70% were enrolled in a randomised, placebo-controlled, crossover study. Effects on inflammation were measured in induced sputum and blood. CO inhalation was feasible and patients' vital signs were unaffected; 2 h·day−1 inhalation of low-dose CO on 4 consecutive days led to a maximal individual carboxyhaemoglobin level of 4.5%. Two exacerbations occurred in the CO period. CO inhalation led to trends in reduced sputum eosinophils (median reduction 0.25% point) and improved responsiveness to methacholine (median provocative concentration causing a 20% fall in FEV1 0.85 versus 0.63 mg·mL−1). Inhalation of 100–125 ppm carbon monoxide by patients with chronic obstructive pulmonary disease in a stable phase was feasible and led to trends in reduction of sputum eosinophils and improvement of responsiveness to methacholine. Further studies need to confirm the safety and efficacy in inflammatory lung diseases.