The measurement of exhaled carbon monoxide is influenced by airflow obstruction

Togores, B.; Bosch, M.; Agustí, A.G.N.

doi:10.1034/j.1399-3003.2000.15a32.x

Cited by 7 publications

(8 citation statements)

References 4 publications

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“…Various studies have tried to find an association between exhaled CO levels and the severity of asthma (8,12,22). In our study, the difference in exhaled CO levels between the patients of mild and moderate persistent asthma was not significant.…”

Section: Discussioncontrasting

confidence: 74%

“…Currently, exhaled CO is being evaluated as a noninvasive marker of airway inflammation in chronic obstructive pulmonary diseases, particularly, asthma (7)(8)(9)(10)(11)(12). Elevated levels of exhaled CO in patients of asthma with normal levels in patients treated with inhaled/oral corticosteroids have been reported in some of the studies (7,13,14).The predominant endogenous source of CO (∼85%) in the body is produced by the degradation of hemoglobin by the enzyme heme oxygenase (HO).…”

Section: Introductionmentioning

confidence: 98%

“…As CO analyzers are portable, simple to use and not very expensive, exhaled CO may be useful in non-invasive monitoring of asthma (8,9,18). Since, only a few studies, evaluating exhaled CO in asthma have been undertaken, its precise role in the management of bronchial asthma remains undefined.…”

Section: Introductionmentioning

confidence: 99%

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Exhaled Carbon Monoxide Levels: As a Marker of Clinical Severity and Control of Asthma

Grover

Kumar

2008

Journal of Asthma

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A study was conducted to evaluate the role of exhaled carbon monoxide (CO) levels in the management of patients with mild and moderate persistent bronchial asthma. Spirometry, exhaled CO measurements and symptom scoring was done before and after four weeks of treatment with inhaled corticosteroids. Exhaled CO levels were significantly elevated in patients of mild as well as moderate persistent asthma as compared to controls but the levels did not correlate with the disease severity. After four weeks of treatment, there was a decrease in exhaled CO levels in both the groups but the decrease was not found to be statistically significant. Therefore, clinically exhaled CO level is not a useful marker in bronchial asthma.

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Section: Discussioncontrasting

confidence: 74%

Section: Introductionmentioning

confidence: 98%

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Exhaled Carbon Monoxide Levels: As a Marker of Clinical Severity and Control of Asthma

Grover

Kumar

2008

Journal of Asthma

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“…This mechanism can be explained by the increased exercise-and post-exerciserelated ventilation (V Emax = 146 l min À1 ) as was also demonstrated by Hauck (1989). In contrast to the exercise effects, Togores et al (2000) showed a higher HbCO t 1/2 in patients with obstructive pulmonary disease, which was due to lower effective ventilation. Considering that a short bout of exercise (25 min) decreases t 1/2 by more than 40%, we may speculate that longer lasting exercise exerts much higher effects on HbCO degradation.…”

Section: Hbco Half-timementioning

confidence: 60%

The optimised CO-rebreathing method: a new tool to determine total haemoglobin mass routinely

2005

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A routine method to determine total haemoglobin mass (tHb) in clinical practice and sports medicine is non-existent. Radioactive tracers or other dilution procedures like the common CO-rebreathing method (Proc(com)) are impractical, the latter in particular because of the relatively long time of respiration. According to the multicompartment model of Bruce and Bruce (J Appl Physiol 95:1235-1247, 2003) the respiration time can be considerably reduced by inhaling a CO-bolus instead of the commonly used gas mixture. The aim of this study was to evaluate this theoretical concept in practice. The kinetics of the HbCO formation were compared in arterialised blood sampled from an hyperaemic earlobe after inhaling a CO-bolus (Proc(new)) for 2 min and a CO-O(2) mixture (Proc(com)) for approximately 10 min. The reliability of Proc(new) was checked in three consecutive tests, and phlebotomy was used to determine the validity. VO(2max) was determined with and without previous application of Proc(new) and the half-time of HbCO was registered also in arterialised blood after resting quietly and after the VO(2max) test. Proc(new) yielded virtual identical tHb values compared to Proc(com) when HbCO determined 5 min after starting CO-rebreathing was used for calculation. The typical error of Proc(new) was 1.7%, corresponding to a limit of agreement (95%) of 3.3%. The loss of 95 g (19) haemoglobin was detected with an accuracy of 9 g (12). After application of Proc(new) VO(2max) was reduced by 3.0% (3.7) (P=0.022) and half-time was lowered from 132 min (77) to 89 min (23) after the VO(2max) test. Inhaling a CO-bolus markedly simplifies the CO-rebreathing method without reducing validity and reliability and can be used for routine determination of tHb for various indications.

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“…The cause of the increased carboxyhaemoglobin levels in respiratory conditions, increased haem breakdown or increased uptake/reduced elimination of inhaled CO, remains to be clarified. However, the latter is indicated by several studies [9][10][11], and it is well known that exposure to ambient CO (passive smoking, car exhaust) is sufficient to increase exhaled CO [12][13].…”

Section: P Paredi Sa Kharitonov Pj Barnesmentioning

confidence: 99%

Exhaled carbon monoxide is not elevated in patients with asthma or cystic fibrosis

2002

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The measurement of exhaled carbon monoxide is influenced by airflow obstruction

Cited by 7 publications

References 4 publications

Exhaled Carbon Monoxide Levels: As a Marker of Clinical Severity and Control of Asthma

Exhaled Carbon Monoxide Levels: As a Marker of Clinical Severity and Control of Asthma

The optimised CO-rebreathing method: a new tool to determine total haemoglobin mass routinely

Exhaled carbon monoxide is not elevated in patients with asthma or cystic fibrosis

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