气体交换对单次呼吸氮试验第三相斜率的贡献。

Contribution of gas exchange to slope of phase III of the single-breath nitrogen test.

作者信息

Cormier Y, Bélanger J

出版信息

J Appl Physiol Respir Environ Exerc Physiol. 1981 Jun;50(6):1156-60. doi: 10.1152/jappl.1981.50.6.1156.

DOI:10.1152/jappl.1981.50.6.1156

Abstract

To study the influence of gas exchanges on the slope of phase III, single-breath nitrogen tests (SB-N2) and reversed tests (SB-R) were performed with 10 normal volunteers at expiratory flows of 100 ml.s-1, 500 ml.s-1,11.s-1, and 21.s-1. During the prolonged expiration required for the SB-N2 test, more O2 is consumed that CO2 eliminated. This factor could contribute to the rising slope of phase III. However, if one obtains a reversed slope of phase III (by having O2 as the residual gas and room air as the inspired gas), factors increasing N2 concentration with time of expiration should decrease the steepness of this reversed slope. Our data show that, at an expiratory flow of 100 ml.s-1, the slope of phase III was steeper in SB-N2 than in SB-R by 0.92 +/- 0.31% N2 1-1 (mean +/- SD, p less than 0.01). As the expiratory flow was increased to 500 ml.s-1, this difference decreased to 0.33 +/- 0.19% N2 1-1, and both slopes became similar in magnitude but opposite in direction at an expiratory flow of 1 1.s-1. These data suggest that active gas exchange has a significant influence on the slope of phase III of the SB-N2 test.

摘要

为研究气体交换对第三相斜率的影响，对10名正常志愿者进行了单次呼吸氮试验（SB-N2）和反向试验（SB-R），呼气流量分别为100 ml·s⁻¹、500 ml·s⁻¹、1 l·s⁻¹和2 l·s⁻¹。在SB-N2试验所需的长时间呼气过程中，消耗的O₂比呼出的CO₂更多。这一因素可能导致第三相斜率上升。然而，如果获得第三相的反向斜率（以O₂作为残气，室内空气作为吸入气体），随着呼气时间增加N₂浓度的因素应会降低该反向斜率的陡度。我们的数据表明，在呼气流量为100 ml·s⁻¹时，SB-N2中第三相的斜率比SB-R中陡0.92±0.31% N₂·l⁻¹（平均值±标准差，p＜0.01）。当呼气流量增加到500 ml·s⁻¹时，这种差异降至0.33±0.19% N₂·l⁻¹，并且在呼气流量为1 l·s⁻¹时，两个斜率大小相似但方向相反。这些数据表明，主动气体交换对SB-N2试验第三相的斜率有显著影响。