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D LCO or T LCO (diffusing capacity or transfer factor of the lung for carbon monoxide (CO), [1]) is the extent to which oxygen passes from the air sacs of the lungs into the blood. Commonly, it refers to the test used to determine this parameter. It was introduced in 1909. [2]
The person then inhales a test gas mixture rapidly and completely, reaching the total lung capacity as nearly as possible. This test gas mixture contains a small amount of carbon monoxide (usually 0.3%) and a tracer gas that is freely distributed throughout the alveolar space but which doesn't cross the alveolar-capillary membrane.
People with COPD also exhibit a decrease in diffusing capacity of the lung for carbon monoxide due to decreased surface area in the alveoli, as well as damage to the capillary bed. [112] Testing the peak expiratory flow (the maximum speed of expiration), commonly used in asthma diagnosis, is not sufficient for the diagnosis of COPD. [111]
Diffusing capacity (or DLCO) is the carbon monoxide uptake from a single inspiration in a standard time (usually 10 seconds). During the test the person inhales a test gas mixture that consisting of regular air that includes an inert tracer gas and CO, less than one percent.
The rapidly diffusing gas is transported into the tissue faster than the slower diffusing gas is transported out of the tissue. [ 42 ] This can occur as divers switch from a nitrogen mixture to a helium mixture (diffusivity of helium is 2.65 times faster than nitrogen), [ 42 ] or when saturation divers breathing hydreliox switch to a heliox ...
TLC: Total lung capacity: the volume in the lungs at maximal inflation, the sum of VC and RV. TV: Tidal volume: that volume of air moved into or out of the lungs in 1 breath (TV indicates a subdivision of the lung; when tidal volume is precisely measured, as in gas exchange calculation, the symbol TV or V T is used.)
The electrochemical oxidation of the hydrogen, carbon monoxide or other organic intermediates by oxygen ions thus occurs on the anode side. [ 2 ] [ 3 ] More recently, proton-conducting SOFCs (PC-SOFC) are being developed which transport protons instead of oxygen ions through the electrolyte with the advantage of being able to be run at lower ...
The reaction HbO 2 + CO → HbCO + O 2 almost irreversibly displaces the oxygen molecules forming carboxyhemoglobin; the binding of the carbon monoxide to the iron centre of hemoglobin is much stronger than that of oxygen, and the binding site remains blocked for the remainder of the life cycle of that affected red blood cell. [9]