Abstract
BACKGROUND--Carbon monoxide transfer factor (TLCO) varies inversely with the partial pressure of alveolar oxygen (PAO2). During exercise the PAO2 in the alveolar gas sample bag decreases so the TLCO increases more than would be expected from the effects of exercise alone. The effects of PAO2 on the estimation of TLCO during exercise have been investigated and studies have been performed to determine whether it is appropriate to standardise to a PAO2 of 16 kPa. METHODS--TLCO was estimated at rest and at a single level of exercise in six normal subjects using test gas mixtures of 0.3% carbon monoxide, 14% helium, and oxygen in three different percentages (17%, 21%, and 27%), remainder nitrogen. In three of the subjects an incremental exercise test with estimates of oxygen consumption (VO2) and cardiac frequency (fC) was also performed using a mixture containing 18% oxygen. RESULTS--TLCO decreased as levels of inspired oxygen increased. When standardised to a PAO2 of 16 kPa TLCO became independent of the inspired oxygen concentration. The significance of the curvilinear relations of TLCO and transfer coefficient to VO2 and fC improved. CONCLUSION--The single breath breath holding TLCO should be standardised to a PAO2 of 16 kPa when estimated during exercise.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- BLAKEMORE W. S., FORSTER R. E., MORTON J. W., OGILVIE C. M. A standardized breath holding technique for the clinical measurement of the diffusing capacity of the lung for carbon monoxide. J Clin Invest. 1957 Jan;36(1 Pt 1):1–17. doi: 10.1172/JCI103402. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cotes J. E., Dabbs J. M., Elwood P. C., Hall A. M., McDonald A., Saunders M. J. Iron-deficiency anaemia: its effect on transfer factor for the lung (diffusiong capacity) and ventilation and cardiac frequency during sub-maximal exercise. Clin Sci. 1972 Mar;42(3):325–335. doi: 10.1042/cs0420325. [DOI] [PubMed] [Google Scholar]
- FORSTER R. E., ROUGHTON F. J., CANDER L., BRISCOE W. A., KREUZER F. Apparent pulmonary diffusing capacity for CO at varying alveolar O2 tensions. J Appl Physiol. 1957 Sep;11(2):277–289. doi: 10.1152/jappl.1957.11.2.277. [DOI] [PubMed] [Google Scholar]
- Kanner R. E., Crapo R. O. The relationship between alveolar oxygen tension and the single-breath carbon monoxide diffusing capacity. Am Rev Respir Dis. 1986 Apr;133(4):676–678. doi: 10.1164/arrd.1986.133.4.676. [DOI] [PubMed] [Google Scholar]
- Kendrick A. H., Cullen J., Green H., Papouchado M., Laszlo G. Measurement of single-breath carbon monoxide transfer factor (diffusing capacity) during progressive exercise. Bull Eur Physiopathol Respir. 1986 Jul-Aug;22(4):365–370. [PubMed] [Google Scholar]
- McGRATH M. W., THOMSON M. L. The effect of age, body size and lung volume change on alveolar-capillary permeability and diffusing capacity in man. J Physiol. 1959 Jun 11;146(3):572–582. doi: 10.1113/jphysiol.1959.sp006212. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Morris A. H., Crapo R. O. Standardization of computation of single-breath transfer factor. Bull Eur Physiopathol Respir. 1985 Mar-Apr;21(2):183–189. [PubMed] [Google Scholar]
- Neville E., Kendrick A. H., Gibson G. J. A standardised method of estimating KCO on exercise. Thorax. 1984 Nov;39(11):823–827. doi: 10.1136/thx.39.11.823. [DOI] [PMC free article] [PubMed] [Google Scholar]
- ROUGHTON F. J., FORSTER R. E. Relative importance of diffusion and chemical reaction rates in determining rate of exchange of gases in the human lung, with special reference to true diffusing capacity of pulmonary membrane and volume of blood in the lung capillaries. J Appl Physiol. 1957 Sep;11(2):290–302. doi: 10.1152/jappl.1957.11.2.290. [DOI] [PubMed] [Google Scholar]
- Saltin B., Grimby G. Physiological analysis of middle-aged and old former athletes. Comparison with still active athletes of the same ages. Circulation. 1968 Dec;38(6):1104–1115. doi: 10.1161/01.cir.38.6.1104. [DOI] [PubMed] [Google Scholar]