Hughes J M B, Bates D V
Department of Respiratory Medicine, National Heart and Lung Institute, Imperial College, Hammersmith Hospital, 4 Cedars Road, London SW13 0HP, UK.
Respir Physiol Neurobiol. 2003 Nov 14;138(2-3):115-42. doi: 10.1016/j.resp.2003.08.004.
The single breath carbon monoxide diffusing capacity (DLCO sb), also called the transfer factor (TLCO), was introduced by Marie and August Krogh in two papers (Krogh and Krogh, Skand. Arch. Physiol. 23, 236-247, 1909; Krogh, J. Physiol., Lond. 49, 271-296, 1915). Physiologically, their measurements showed that sufficient oxygen (by extrapolation from CO) diffused passively from gas to blood without the need to postulate oxygen secretion, a popular theory at the time. Their DLCO sb technique was neglected until the advent of the infra-red CO meter in the 1950s. Ogilvie et al., J. Clin. Invest. 36, 1-17, 1957 published a standardized technique for a 'modified Krogh' single breath DLCO, which eventually became the method of choice in pulmonary function laboratories. The Roughton-Forster equation (J. Appl. Physiol. 1957, 11, 290-302) was an important step conceptually; it partitioned alveolar-capillary diffusion of oxygen (O2) and carbon monoxide (CO) into a membrane component (DM) and a red cell component (theta.Vc) where theta is the DLCO (or DL(O2)) per ml of blood (measured in vitro), and Vc is the pulmonary capillary volume. This equation was based on the kinetics of O2 and CO with haemoglobin (Hb) in solution and with whole blood Hartridge and Roughton, Nature, 1923, 111, 325-326; Proc. R. Soc. Lond. Ser. A, 1923, 104, 376-394; (Proc. R. Soc. Lond. Ser. B, 1923, 94, 336-367; Proc. R. Soc. Lond. Ser. A 1923, 104, 395-430; J. Physiol., Lond. 1927, 62, 232-242; Roughton, Proc. R. Soc. Lond. Ser. B 1932, 111, 1-36) and on the relationship between alveolar P(O2) and 1/DLCO. Subsequently, the relationship between DL(O2) (Lilienthal et al., Am. J. Physiol. 147, 199-216, 1946) and DL(CO) was defined. More recently, the measurement of the nitric oxide diffusing capacity (DLNO) has been introduced. For DL(O2) and DLNO the membrane component (as 1/DM) is an important part of the overall diffusion (transfer) resistance. For the DLCO, 1/theta.Vc probably plays the greater role as the rate limiting step. A crucial question, the effect of unstirred plasma layers on the 'true' value of thetaCO in vivo, has not been resolved, but this does not detract from the clinical role of the DLCO sb (TLCO) as an essential test of lung function.
单次呼吸一氧化碳弥散量（DLCO sb），也称为转运因子（TLCO），由玛丽和奥古斯特·克罗格在两篇论文中提出（克罗格和克罗格，《斯堪的纳维亚生理学杂志》23卷，236 - 247页，1909年；克罗格，《伦敦生理学杂志》49卷，271 - 296页，1915年）。从生理学角度来看，他们的测量结果表明，足够的氧气（通过从一氧化碳数据外推）从气体被动扩散到血液中，无需假定当时流行的氧气分泌理论。他们的DLCO sb技术一直被忽视，直到20世纪50年代红外一氧化碳测量仪出现。奥吉尔维等人（《临床研究杂志》36卷，1 - 17页，1957年）发表了一种“改良克罗格”单次呼吸DLCO的标准化技术，该技术最终成为肺功能实验室的首选方法。劳顿 - 福斯特方程（《应用生理学杂志》1957年，11卷，290 - 302页）在概念上是重要的一步；它将肺泡 - 毛细血管对氧气（O2）和一氧化碳（CO）的扩散分为膜成分（DM）和红细胞成分（θ.Vc），其中θ是每毫升血液的DLCO（或DL(O2)）（体外测量），Vc是肺毛细血管容积。该方程基于溶液中及全血中氧气和一氧化碳与血红蛋白（Hb）的动力学（哈特里奇和劳顿，《自然》，1923年，111卷，325 - 326页；《伦敦皇家学会学报》A辑，1923年，104卷，376 - 394页；（《伦敦皇家学会学报》B辑，1923年，94卷，336 - 367页；《伦敦皇家学会学报》A辑，1923年，104卷，395 - 430页；《伦敦生理学杂志》，1927年，62卷，232 - 242页；劳顿，《伦敦皇家学会学报》B辑，1932年，111卷，1 - 36页）以及肺泡P(O2)与1/DLCO之间的关系。随后，定义了DL(O2)（利林索尔等人，《美国生理学杂志》147卷，199 - 216页，1946年）与DL(CO)之间的关系。最近，一氧化氮弥散量（DLNO）的测量也被引入。对于DL(O2)和DLNO，膜成分（作为1/DM）是总扩散（转运）阻力的重要组成部分。对于DLCO，1/θ.Vc可能作为限速步骤起着更大的作用。一个关键问题，即未搅动血浆层对体内θCO“真实”值的影响尚未得到解决，但这并不影响DLCO sb（TLCO）作为肺功能重要检测指标的临床作用。
