Carbon monoxide transfer factor
The carbon monoxide transfer factor ( English transfer factor of the lung for carbon monoxide , T LCO ) is a medical measure for the diffusion capacity of the lungs , i.e. H. for gas exchange between blood and air in the alveoli. It is part of the usual lung function measurements . For example, the current S3 guideline on lung cancer requires that the T LCO be determined prior to the surgical removal of a lung (it should be at least 60% of the norm).
To assess lung function, both ventilation ( spirometry ) and diffusion parameters must be determined in order to be able to record obstructive and restrictive disorders. Put simply, the T LCO remains normal in the case of pure ventilation disorders such as bronchial asthma , but decreases in the case of disorders of the alveolar membrane such as sarcoid , alveolitis or emphysema .
Since the oxygen concentration in the blood can only be determined with difficulty, CO is used for measurement as a readily soluble test gas that is not present in the blood. With the popular inhalation method, the patient inhales a test gas with 0.2% carbon monoxide as deeply as possible and then holds his breath for 10 seconds. The amount of CO dissolved in the blood during this time can be determined from the exhaled gas. The unit is mmol / min / kPa; in practice, however, the percentage deviation from the norm of healthy subjects is given. In the low concentration used, CO is not harmful to health.
Because carbon monoxide (CO) hemoglobin (Hb) binding is such an important factor in CO transfer, T LCO changes as a function of Hb concentration can be substantial. Online tools exist to perform this calculation.
The carbon monoxide transfer factor was first proposed as a functional parameter in 1957 by the Cambridge physiologist Francis John Worsley Roughton (1899–1972).
swell
- R. Kramme: Medical technology. Springer 2006, ISBN 3540341021 , pp. 120-122.
Individual evidence
- ↑ G. Goeckenjan et al .: Prevention, diagnosis, therapy and follow-up care of lung cancer . Interdisciplinary S3 guideline of the German Society for Pneumology and Respiratory Medicine and the German Cancer Society. 2010, p. e35 – e37 ( krebsgesellschaft.de [PDF]). Prevention, diagnosis, therapy and follow-up care for lung cancer ( memento of the original from November 15, 2011 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Setting the carbon monoxide transfer factor (TLCO) for the hemoglobin concentration
- ↑ DJ Lipscomb, K. Patel, JM Hughes: Interpretation of increases in the transfer coefficient for carbon monoxide (TLCO / VA or KCO). In: Thorax. 33, No. 6, 1978, pp. 728-733, PMID 746497 .
