Increased Carbon Monoxide in Exhaled Air of Asthmatic Patients

Abstract

Exhaled carbon monoxide (CO) concentrations were measured on a CO monitor by vital capacity maneuvers in asthmatic patients receiving or not receiving inhaled corticosteroids and in nonsmoking and smoking healthy control subjects. CO was detectable and measured reproducibly in the exhaled air of all subjects. The exhaled CO concentrations were higher in asthmatic patients not receiving inhaled corticosteroids (5.6+/-0.6 ppm, p < 0.001) and similar in asthmatic patients receiving inhaled corticosteroids (1.7+/-0.1 ppm) compared with those in nonsmoking healthy control subjects (1.5+/-0.1 ppm). Smoking healthy control subjects had the highest levels of exhaled CO concentration among the groups (21.6+/-2.8 ppm, p < 0.001). To examine whether inhaling corticosteroids reduce exhaled CO concentration in a given asthmatic patient, 12 patients with symptomatic asthma who were being treated by inhaled beta2-agonists alone underwent measurements of exhaled CO concentration before and 4 wk after the initiation of inhaled corticosteroid treatment. All patients had reductions in exhaled CO concentration (p < 0.001) and eosinophil cell counts in sputum (p < 0.01) that were accompanied by an improvement in airway obstruction. Changes in exhaled CO concentration were significantly related to those in the eosinophil cell counts in sputum (p < 0.001). The present study shows an elevation of exhaled CO in asthmatic patients that decreases with corticosteroid therapy. Increases in the exhaled CO levels therefore may reflect inflammation in the asthmatic lung.

Dose-dependent relationship between prenatal exposure to fine particulates and exhaled carbon monoxide in non-asthmatic children. A population-based birth cohort study

“…Uausuf et al [26] found eCO levels significantly higher (2.17±0.21) in children with persistent asthma compared to those with sporadic episodic asthma (1.39±0.18) and healthy children (1.01±0.12 ppm). As shown by Zayasu et al [27] asthmatic adults had eCO concentrations still higher (5.6±0.6 ppm) compared to nonsmoking healthy control subjects (1.5±0.1 ppm). However, non-asthmatic subjects with the symptoms of upper respiratory tract infections also presented eCO levels significantly elevated during the acute phase of the infection compared to recovery values (5.6±0.4 ppm vs. 1.0±0.1 ppm), which were similar result from oxidative stress experienced in the fetal period, and that HO activity in body tissues may be programmed in the fetal period by the exposure to fine particulate matter.…”

Does the Finding of Small Airway Obstruction in Pulmonary Function Tests Effect End-Expiratory Carbonmonoxide Level?

“…In two studies conducted by a Japanese group, the exhaled CO level was found to be higher in patients with asthma than in healthy individuals (2,3). In a meta-analysis that also referred to two studies conducted in Turkey (23,24), it was reported that the exhaled CO level was found to be higher in asthma patients who did not smoke than in those without asthma, and the CO level displayed a correlation with the severity of asthma (4).…”

“…CO is absorbed through smoking or can be produced endogenously in alveolar macrophages, endothelial cells, and other lung cells as a product of local inflammation and oxidative stress in individuals with airway diseases (1). In many studies, it was revealed that the end-expiratory CO (exhaled CO) level was higher in patients with severe asthma and lower in asthma patients receiving inhaled steroid therapy than in those not having therapy (2)(3)(4). Therefore, the exhaled CO level has recently begun to be used as an inflammatory biomarker in airway diseases such as asthma, chronic obstructive pulmonary disease (COPD), cystic fibrosis, and bronchiectasis (1,5).…”

Aerosol sampling using an electrostatic precipitator integrated with a microfluidic interface

“…Exhaled breath contains both gases, and aerosol droplets, however, the main focus of breath analysis thus far, has been on gas detection, which can contain: inorganic gases, i.e. NO [7] CO [8]; hydrocarbons, i.e. isoprene [9] ethane or pentane [10]; and volatile and non-volatile substances, such as isoprostane, cytokines, leukotrienes [11], proteins, nucleic acids, or polypeptides [12,13], bacteria or viruses.…”