What are appropriate values of relative krogh diffusion Constant of NO against CO and of theta-NO in alveolar septa?

Kazuhiro Yamaguchi; Takao Tsuji; Kazutetsu Aoshiba; Hiroyuki Nakamura; Shinji Abe

doi:10.1016/j.resp.2020.103415

What are appropriate values of relative krogh diffusion Constant of NO against CO and of theta-NO in alveolar septa?

Respir Physiol Neurobiol. 2020 May:276:103415. doi: 10.1016/j.resp.2020.103415. Epub 2020 Feb 14.

Authors

Kazuhiro Yamaguchi¹, Takao Tsuji², Kazutetsu Aoshiba³, Hiroyuki Nakamura⁴, Shinji Abe⁵

Affiliations

¹ Department of Respiratory Medicine, Tokyo Medical University, Tokyo 160-0023, Japan. Electronic address: yamaguc@sirius.ocn.ne.jp.
² Department of Respiratory Medicine, Tokyo Medical University, Tokyo 160-0023, Japan. Electronic address: taktsuji@tokyo-med.ac.jp.
³ Department of Respiratory Medicine, Tokyo Medical University Ibaraki Medical Center, Ibaraki 300-0395, Japan. Electronic address: kaoshiba@tokyo-med.ac.jp.
⁴ Department of Respiratory Medicine, Tokyo Medical University Ibaraki Medical Center, Ibaraki 300-0395, Japan. Electronic address: hiroyuki@tokyo-med.ac.jp.
⁵ Department of Respiratory Medicine, Tokyo Medical University, Tokyo 160-0023, Japan. Electronic address: sabe@tokyo-med.ac.jp.

PMID: 32068129
DOI: 10.1016/j.resp.2020.103415

Abstract

Objectives: To propose new physical constants for NO and CO (Krogh diffusion constant ratio (KD_NO/CO) and specific blood conductance for NO (θ_NO)) for calculating DMCO and Vc, according to Roughton-Forster's equation (Roughton and Forster, J. Appl. Physiol. 11: 290-302, 1957) from simultaneous DLNO and DLCO measurements.

Results and conclusions: (1) The Graham's law is unacceptable for determining KD_NO/CO because CO does not fulfil all the conditions of an "ideal" gas. We have re-estimated KD_NO/CO in a new way based on difference in molar volumes of two gases (molar volume theory). The KD_NO/CO thus decided is 2.34. (2) θ_NO measured with rapid-reaction, constant-flow method by Carlsen and Comroe (J. Gen. Physiol. 42: 83-107, 1958) may be underestimated by about 40 % due to unstirred water layer surrounding the erythrocyte. (3) Erythrocyte θ_O2 can be harvested from O₂ release kinetics in presence of high concentration of dithionite, which effectively removes the unstirred water layer-elicited effect. Multiplication of erythrocyte θ_O2 by erythrocyte KD_NO/O2 equals erythrocyte θ_NO, the value of which is 6.2 mL/min/mmHg/(mL⋅blood). According to the concepts of Kang et al. (RESPNB. 241: 62-71, 2017) and Borland et al. (RESPNB. 241: 58-61, 2017), in vitro θ_NO decided from rapid-mixing experiments may mirror bulk absorption of NO by erythrocytes. (4) In pulmonary capillaries, NO uptake takes place predominantly in the surface rim of the erythrocyte. This surface absorption of NO increases the θ_NO 10-fold versus bulk absorption of NO to about 60 mL/min/mmHg/(mL⋅blood).

Keywords: Bulk absorption of NO; Krogh diffusion constant; Molar volume theory; Specific gas conductance for NO; Specific gas conductance for O(2); Surface absorption of NO.

Publication types

Review

MeSH terms

Carbon Monoxide / metabolism
Diffusion*
Erythrocytes / metabolism*
Humans
Lung / metabolism*
Nitric Oxide / metabolism
Pulmonary Diffusing Capacity*
Respiratory Function Tests

Substances

Nitric Oxide
Carbon Monoxide