吸烟者的结构功能小气道测试何时才能真正反映小气道?

IF 3.3 3区 医学 Q1 PHYSIOLOGY
Journal of applied physiology Pub Date : 2024-08-01 Epub Date: 2024-07-15 DOI:10.1152/japplphysiol.00209.2024
Sylvia Verbanck, Shane Hanon, Jef Vandemeulebroucke, Eef Vanderhelst, Manuel Paiva
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引用次数: 0

摘要

引言:如果多次呼吸冲洗(MBW)得出的尖叶通气异质性(Sacin)真正代表了外周单元,那么第一次 MBW 呼气的 N2 第三阶段应该是曲线形的。这是由于气体扩散和对流的叠加效应导致了在整个呼气过程中相邻肺单位之间 N2 浓度的平衡。我们对 CT 证实患有功能性小气道疾病的吸烟者进行了研究。方法:计算整个第三阶段 40ms 间隔内的瞬时 N2slopes,并以第三阶段平均 N2 浓度归一化。N2 相-III(凹)曲线性被量化为瞬时 N2 斜率在 1 秒间隔内超过相 II 峰值的下降速率;对于不受扩散影响的线性 N2 相-III,该速率为 0L-1/s。实验曲线和现有模型模拟 N2 曲线的 N2phase-III 曲线均来自正常外周肺模型和末端支气管缺失模型(50% 或 30% 结核病左侧)。结果:在 46 名有外周肺破坏 CT 证据的吸烟者(66 (+8) 岁;49 (+26) 包年)中,比较了 (fSAD+fEmphys)>20% (-0.26+0.14(SD) L-1/s;n=24) 和 (fSAD+fEmphys)+0.12(SD)L-1/s;n=22) 的瞬时 N2 斜率降幅(P=0.014)。实验值在末端支气管逐渐缩小的现实外周肺模型预测范围内:模型模拟得到的 N2 瞬时斜率下降值为-0.09L-1/s(正常肺;100%TB 左侧)、-0.17L-1/s(正常肺 50%TB左侧)和-0.29L-1/s(30%TB左侧)。讨论:在有基于 CT 的小气道功能性改变证据的吸烟者中,可以证明 Sacin 确实代表了最边缘的气腔。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
Structure-function in smokers: when a small airways test really reflects the small airways.

If multiple-breath washout (MBW)-derived acinar ventilation heterogeneity (Sacin) really represents peripheral units, the N2 phase-III of the first MBW exhalation should be curvilinear. This is essentially due to the superposed effect of gas diffusion and convection resulting in an equilibration of N2 concentrations between neighboring lung units throughout exhalation. We investigated this in smokers with computed tomography (CT)-proven functional small airway disease. Instantaneous N2-slopes were computed over 40-ms intervals throughout phase-III and normalized by mean phase-III N2 concentration. N2 phase-III (concave) curvilinearity was quantified as the rate at which the instantaneous N2-slope decreases past the phase-II peak over a 1-s interval; for a linear N2 phase-III unaffected by diffusion, this rate would amount to 0 L-1/s. N2 phase-III curvilinearity was obtained on the experimental curves and on existing model simulations of N2 curves from a normal peripheral lung model and one with missing terminal bronchioles (either 50% or 30% TB left). In 46 smokers [66 (±8) yr; 49 (±26) pack·yr] with CT-based evidence of peripheral lung destruction, instantaneous N2-slope decrease was compared between those with (fSAD+fEmphys) > 20% [-0.26 ± 0.14 (SD) L-1/s; n = 24] and those with (fSAD+fEmphys) < 20% [-0.16 ± 0.12 (SD) L-1/s; n = 22] (P = 0.014). Experimental values fell in the range predicted by a realistic peripheral lung model with progressive reduction of terminal bronchioles: values of instantaneous N2-slope decrease obtained from model simulations were -0.09 L-1/s (normal lung; 100% TB left), -0.17 L-1/s (normal lung 50% TB left), and -0.29 L-1/s (30% TB left). In smokers with CT-based evidence of functional small airway alterations, it is possible to demonstrate that Sacin really does represent the most peripheral airspaces.NEW & NOTEWORTHY In smokers with computed tomography-based evidence of functional small airway alterations by parametric response mapping, it is possible to demonstrate that the multiple-breath washout-derived Sacin, an index of acinar ventilation heterogeneity, actually does represent the most peripheral airspaces. This is done by verifying on experimental N2 washout curves of the first breath, N2 phase-III concavity predicted by the diffusion-convection interdependence model.

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来源期刊
CiteScore
6.00
自引率
9.10%
发文量
296
审稿时长
2-4 weeks
期刊介绍: The Journal of Applied Physiology publishes the highest quality original research and reviews that examine novel adaptive and integrative physiological mechanisms in humans and animals that advance the field. The journal encourages the submission of manuscripts that examine the acute and adaptive responses of various organs, tissues, cells and/or molecular pathways to environmental, physiological and/or pathophysiological stressors. As an applied physiology journal, topics of interest are not limited to a particular organ system. The journal, therefore, considers a wide array of integrative and translational research topics examining the mechanisms involved in disease processes and mitigation strategies, as well as the promotion of health and well-being throughout the lifespan. Priority is given to manuscripts that provide mechanistic insight deemed to exert an impact on the field.
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