Duranti Roberto, Filippelli Mario, Bianchi Roberto, Romagnoli Isabella, Pellegrino Riccardo, Brusasco Vito, Scano Giorgio
Dipartimento di Medicina Interna, Università di Firenze, Viale G.B. Morgagni 85, 50134 Florence, Italy.
Chest. 2002 Dec;122(6):2009-14. doi: 10.1378/chest.122.6.2009.
Inspiratory capacity (IC) has been proposed as a simple method to assess acute changes in functional residual capacity (FRC) with bronchodilation, assuming that total lung capacity (TLC) is unchanged. This assumption is based on studies using body plethysmography, which may not accurately measure TLC in severely obstructed subjects. The aim of this study is to validate the use of IC measured by optoelectronic plethysmography (OEP) [ICOEP], a noninvasive technique capable of computing changes in absolute lung volumes with great accuracy. MEWTHODS AND MEASUREMENTS: We studied 13 subjects with COPD in clinically stable condition at baseline and after 200 microg of inhaled albuterol. Changes in lung volumes were obtained from changes in chest wall volume (Vcw) measured by OEP and were compared with those measured by standard techniques.
Albuterol treatment caused a small but significant increase in FEV(1) and FVC, a significant decrease of Vcw at FRC (VcwFRC), but no changes of Vcw at TLC (VcwTLC) and breathing pattern variables. The reduction of VcwFRC was not correlated with either spirometric or breathing-pattern variables. IC measured with a pneumotachograph was highly correlated with and not significantly different from ICOEP (p < 0.001).
A single dose of inhaled albuterol does not significantly modify VcwTLC in subjects with COPD, thus validating the use of IC to measure changes of FRC in the assessment of reversibility of airway obstruction.
吸气容量（IC）已被提议作为一种简单方法，用于评估支气管扩张时功能残气量（FRC）的急性变化，前提是总肺容量（TLC）不变。这一假设基于使用体容积描记法的研究，但在严重阻塞性受试者中，该方法可能无法准确测量TLC。本研究的目的是验证通过光电容积描记法（OEP）[ICOEP]测量的IC的用途，这是一种能够高精度计算绝对肺容积变化的非侵入性技术。
我们研究了13例临床稳定的慢性阻塞性肺疾病（COPD）患者，在基线时以及吸入200微克沙丁胺醇后进行观察。肺容积变化通过OEP测量的胸壁容积（Vcw）变化获得，并与通过标准技术测量的结果进行比较。
沙丁胺醇治疗导致第一秒用力呼气容积（FEV₁）和用力肺活量（FVC）有小幅但显著的增加，功能残气量时的胸壁容积（VcwFRC）显著降低，但总肺容量时的胸壁容积（VcwTLC）和呼吸模式变量无变化。VcwFRC的降低与肺量计测量值或呼吸模式变量均无相关性。用呼吸流速仪测量的IC与ICOEP高度相关且无显著差异（p < 0.001）。
单剂量吸入沙丁胺醇不会显著改变COPD患者的VcwTLC，从而验证了在评估气道阻塞可逆性时使用IC来测量FRC变化的有效性。
