Exhaled carbon monoxide (eCO) has been widely implicated as a pulmonary biomarker in respiratory diseases. The aim of this study was to investigate whether the treatment of patients with severe acute exacerbation of chronic obstructive pulmonary disease (AECOPD) could be aided by monitoring the changes in eCO.
The levels of eCO along with routine clinical parameters were analyzed in 29 current smoker and 33 ex-smoker COPD patients, first at the time of hospital admission, and again at discharge following the standard treatment. Patients with AECOPD were also stratified according to sputum bacteria.
At exacerbation, the levels of eCO were increased in current smokers compared to ex-smokers (6.0 [2.0–9.5] versus 1.0 [1.0–2.0] ppm, p < 0.001). Similarly, eCO levels were higher in smokers after treatment (7.0 [2.0–12.5] versus 1.0 [1.0–2.0] ppm, p < 0.001). Treatment of AECOPD did not affect eCO concentrations. The levels of eCO were not statistically different between bacterial and non-bacterial AECOPD either. Investigating a subgroup of current smoker patients (n = 15), there was a significant correlation between the levels of eCO and blood carboxyhemoglobin concentrations both at exacerbation and discharge. No associations were found between eCO and lung function or blood gas parameters.
Our results suggest that monitoring eCO during the treatment of AECOPD is of limited clinical value.
Authors:A. Bikov, Zs Lazar, K. Schandl, B. Antus, G. Losonczy and Ildiko Horvath
Exercise-caused metabolic changes can be followed by monitoring exhaled volatiles; however it has not been previously reported if a spectrum of exhaled gases is modified after physical challenge. We have hypothesized that changes in volatile molecules assessed by an electronic nose may be the reason for the alkalization of the exhaled breath condensate (EBC) fluid following physical exercise.Ten healthy young subjects performed a 6-minute running test. Exhaled breath samples pre-exercise and post-exercise (0 min, 15 min, 30 min and 60 min) were collected for volatile pattern (“smellprint”) determination and pH measurements (at 5.33 kPa CO2), respectively. Exhaled breath smellprints were analyzed using principal component analysis and were related to EBC pH.Smellprints (p=0.04) and EBC pH (p=0.01) were altered during exercise challenge. Compared to pre-exercise values, smellprints and pH differed at 15 min, 30 min and 60 min following exercise (p<0.05), while no difference was found at 0 min post-exercise. In addition, a significant correlation was found between volatile pattern of exhaled breath and EBC pH (p=0.01, r=−0.34).Physical exercise changes the pattern of exhaled volatiles together with an increase in pH of breath. Changes in volatiles may be responsible for increase in EBC pH.