Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona.
Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia.
Am J Physiol Regul Integr Comp Physiol. 2021 Mar 1;320(3):R268-R275. doi: 10.1152/ajpregu.00263.2020. Epub 2020 Dec 23.
The modified Campbell diagram provides one of the most comprehensive assessments of the work of breathing (Wb) during exercise, wherein the resistive and elastic work of inspiration and expiration are quantified. Importantly, a necessary step in constructing the modified Campbell diagram is to obtain a value for chest wall compliance (C). To date, it remains unknown whether estimating or directly measuring C impacts the Wb, as determined by the modified Campbell diagram. Therefore, the purpose of this study was to evaluate whether the components of the Wb differ when the modified Campbell diagram is constructed using an estimated versus measured value of C. Forty-two participants ( = 26 men, 16 women) performed graded exercise to volitional exhaustion on a cycle ergometer. C was measured directly at rest via quasistatic relaxation. Estimated values of C were taken from prior literature. The measured value of C was greater than that obtained via estimation (214 ± 52 mL/cmHO vs. 189 ± 18 mL/cmHO; < 0.05). At modest-to-high minute ventilations (i.e., 50-200 L/min), the inspiratory elastic Wb was greater and expiratory resistive Wb was lower, when modified Campbell diagrams were constructed using estimated compared with measured values of C ( = 0.001). These differences were however small and never exceeded ±5%. Thus, although our findings demonstrate that estimating C has a measurable impact on the determination of the Wb, its effect appears relatively small within a cohort of healthy adults during graded exercise.
改良坎贝尔图提供了一种对运动时呼吸功（Wb）最全面的评估方法，其中量化了吸气和呼气的阻力和弹性功。重要的是，构建改良坎贝尔图的必要步骤之一是获得胸壁顺应性（C）的值。迄今为止，尚不清楚估计或直接测量 C 是否会影响通过改良坎贝尔图确定的 Wb。因此，本研究的目的是评估当使用估计值和实测值 C 构建改良坎贝尔图时，Wb 的组成部分是否存在差异。42 名参与者（= 26 名男性，16 名女性）在自行车测功机上进行了分级运动直至力竭。在休息时通过准静态松弛直接测量 C。C 的估计值取自先前的文献。实测 C 值大于估计值（214 ± 52 mL/cmHO 与 189 ± 18 mL/cmHO；<0.05）。在适度到高分钟通气量（即 50-200 L/min）时，当使用估计值和实测值 C 构建改良坎贝尔图时，吸气弹性 Wb 更大，呼气阻力 Wb 更小（= 0.001）。然而，这些差异很小，从未超过±5%。因此，尽管我们的研究结果表明，估计 C 对 Wb 的确定有可测量的影响，但在健康成年人的分级运动中，其影响相对较小。
