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Respir Investig. 2018 Mar;56(2):100-110. doi: 10.1016/j.resinv.2017.12.006. Epub 2018 Feb 2.

Simultaneous measurement of pulmonary diffusing capacity for carbon monoxide and nitric oxide.

Author information

1
Division of Comprehensive Sleep Medicine, Tokyo Women's Medical University, 8-1 Kawata-cho, Shinjuku-ku, Tokyo 162-8666, Japan. Electronic address: yamaguc@sirius.ocn.ne.jp.
2
Respiratory Medicine, Institute of Geriatrics Tokyo Women's Medical University, 2-15-1 Sibuya, Shibuya-ku, 150-0002 Tokyo, Japan. Electronic address: tsuji.takao@twmu.ac.jp.
3
Department of Respiratory Medicine, Tokyo Medical University Ibaraki Medical Center, 3-20-1 Chuou, Ami-machi, Inashiki-gun, 300-0395 Ibaraki, Japan. Electronic address: kaoshiba@tokyo-med.ac.jp.
4
Department of Respiratory Medicine, Tokyo Medical University Ibaraki Medical Center, 3-20-1 Chuou, Ami-machi, Inashiki-gun, 300-0395 Ibaraki, Japan. Electronic address: hiroyuki@tokyo-med.ac.jp.

Abstract

In Europe and America, the newly-developed, simultaneous measurement of diffusing capacity for CO (DLCO) and NO (DLNO) has replaced the classic DLCO measurement for detecting the pathophysiological abnormalities in the acinar regions. However, simultaneous measurement of DLCO and DLNO is currently not used by Japanese physicians. To encourage the use of DLNO in Japan, the authors reviewed aspects of simultaneously-estimated DLCO and DLNO from previously published manuscripts. The simultaneous DLCO-DLNO technique identifies the alveolocapillary membrane-related diffusing capacity (membrane component, DM) and the blood volume in pulmonary microcirculation (VC); VC is the principal factor constituting the blood component of diffusing capacity (DB,DB=θ·VC where θ is the specific gas conductance for CO or NO in the blood). As the association velocity of NO with hemoglobin (Hb) is fast and the affinity of NO with Hb is high in comparison with those of CO, θNO can be taken as an invariable simply determined by diffusion limitation inside the erythrocyte. This means that θNO is independent of the partial pressure of oxygen (PO2). However, θCO involves the limitations by diffusion and chemical reaction elicited by the erythrocyte, resulting in θCO to be a PO2-dependent variable. Furthermore, DLCO is determined primarily by DB (∼77%), while DLNO is determined equally by DM (∼55%) and DB (∼45%). This suggests that DLCO is more sensitive for detecting microvascular diseases, while DLNO can equally identify alveolocapillary membrane and microcirculatory abnormalities.

KEYWORDS:

Blood component; Blood volume; Diffusing capacity; Membrane component; Specific gas conductance

PMID:
29548647
DOI:
10.1016/j.resinv.2017.12.006
[Indexed for MEDLINE]

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