Carbon monoxide transfer coefficient (transfer factor/alveolar volume) in females versus males: Table 1

Self Cite

Progression of chronic obstructive pulmonary disease (COPD) has been studied predominantly by following change in forced expiratory volume in 1s (FEV1) which reflects both primary airway disease and associated alveolar disease. Carbon monoxide transfer (Tlco) (the product of the transfer coefficient Kco and alveolar volume Va) is the only simple, widely available test of alveolar function, but few studies have followed long-term changes in an individual. Seventeen middle-aged men with moderate chronic airflow obstruction (mean FEV1 56% of predicted values) were observed with yearly measurements of FEV1, Tlco and Kco over a mean of 18.9 yr. At the end of follow-up FEV1 had fallen to 29% of predicted values. Va, measured by single breath dilution, fell in each man. Kco at recruitment ranged from 41% to 110% predicted and remained >75% predicted in eight men at the end of follow-up supporting a phenotype of COPD with predominant airway disease and little emphysema. Fall in FEV1 was faster (2.03% predicted FEV1/yr) in seven men with low initial Kco<75% pred. than in men with initial Kco>75% pred. (1.14% predicted FEV1/yr, P=0.006). Repeated measurements of CO transfer in an individual should increase the present poor knowledge of the contribution of alveolar disease to the progression of chronic airflow obstruction.

Section: Normal Subjectssupporting

confidence: 73%

Evolution of changes in carbon monoxide transfer factor in men with chronic obstructive pulmonary disease

Osmanliev

Joyce

Watson

et al. 2005

Self Cite

“…The strong dependence of the K CO on V A has led to an ongoing debate whether or not the K CO is useful in restrictive lung diseases. 6,21 When restriction is similar to voluntary lowering of the inspiratory levels, the answers would be yes. In our opinion, the truth is more complicated, because in restrictive pulmonary disease vascular abnormalities can play an important role.…”

Section: Article In Pressmentioning

confidence: 99%

Diffusing capacity for nitric oxide: Reference values and dependence on alveolar volume

Lee

Zanen

Stigter

et al. 2007

Nitric oxide (NO) has a much stronger affinity for hemoglobin than carbon monoxide (CO); therefore, the DL(NO) (diffusing capacity for NO) is less influenced by changes in capillary blood volume than the DL(CO) (diffusing capacity for CO), and represents the true membrane diffusing capacity. We measured the combined single breath DL(NO)/DL(CO) in 124 healthy subjects, and generated reference equations for the DL(NO) and K(NO). In a subset of 21 subjects the measurements were performed on different inspiratory levels. The reference equation for DL(NO) in females is 53.47*H(height)0.077*A(age)-48.28(RSD5.22) and for males 59.84*H-0.25*A-44.20(RSD6.39). Reference equations for K(NO) in females is -2.03*H-0.025*A+11.52(RSD0.48) and for males -0.15*H-0.045*A+9.47(RSD0.65). The K(CO) (DL(CO)/V(A)) increases when V(A) (alveolar volume) decreases, probably due to an increase of blood volume per unit lung volume. The DL(NO) was much stronger related to the V(A), the K(NO) was almost independent of V(A). Because of the relative independence of the K(NO) on V(A), the K(NO) appears to be a much better index for the diffusion capacity per unit lung volume (transfer coefficient) than the K(CO).

“…Concerning the K CO , an ongoing debate exists whether the reference values are of much use. 31,32 The main problem lies in the fact that the regression equations for K CO simply do not exist: it is common practice to divide the reference value for DL CO by the reference value of the TLC. 9 These two reference values are obtained from different populations, which of course is not an ideal situation.…”

Section: Reference Valuesmentioning

confidence: 99%

Pattern of diffusion disturbance related to clinical diagnosis: The KCO has no diagnostic value next to the DLCO

Lee

Zanen

Bosch

et al. 2006