Department of Pediatrics, Faculty of Medical Sciences, University of Campinas, Tessália Vieira de Camargo, 126, Cidade Universitária "Zeferino Vaz", Postal Code: 13083-887 Campinas, São Paulo, Brazil.
Department of Pediatrics, Faculty of Medical Sciences, University of Campinas, Tessália Vieira de Camargo, 126, Cidade Universitária "Zeferino Vaz", Postal Code: 13083-887 Campinas, São Paulo, Brazil; Department of Medical Genetics, Faculty of Medical Sciences, University of Campinas, Tessália Vieira de Camargo, 126, Cidade Universitária "Zeferino Vaz", Postal Code: 13083-887 Campinas, São Paulo, Brazil.
Pulmonology. 2019 Jan-Feb;25(1):21-31. doi: 10.1016/j.pulmoe.2018.04.006. Epub 2018 Jun 25.
Spirometry is the most frequently used test to evaluate the progression of lung damage in cystic fibrosis (CF). However, there has been low sensitivity in detecting early lung changes. In this context, our objective was to identify the correlation between parameters of volumetric capnography (VCap) and spirometric parameters during a submaximal treadmill exercise test.
A cross-sectional and controlled study which included 64 patients with CF (CFG) and 64 healthy control subjects (CG) was performed. The CFG was from a university hospital and the CG from local schools. All participants underwent spirometry and VCap before, during and after the submaximal treadmill exercise test. The main variable analyzed by VCap was the slope of phase 3 (slope 3), which indicates the [exhaled carbon dioxide] at the end of expiration, and expresses the heterogeneity of gas emptying in pulmonary periphery. The correlation analysis between spirometry and VCap was conducted using the Spearman correlation test, considering α=0.05.
The indices analyzed by VCap showed correlation with parameters of VCap. Slope 3 showed an inverse correlation with forced expiratory volume in the first second of forced vital capacity (FEV) in both groups and at all moments of the submaximal treadmill exercise test. Forced vital capacity (FVC) and FEV/FVC ratio showed an inverse correlation with slope 3 only for CFG. Values of slope 3 corrected by the spontaneous tidal volume (VT) and end-tidal carbon dioxide tension (PetCO) showed results similar to slope 3 analyzed separately.
Parameters of VCap such as slope 3, slope 3/VT and slope 3/PetCO correlated with sensitive variables of spirometry such as FEV, FVC and FEV/FVC ratio. For the evaluated variables, there was consistency in the correlation between the two tests, which may indicate the impact of CF on pulmonary physiology.
肺量测定法是评估囊性纤维化（CF）肺部损害进展最常用的检查方法。然而，其检测早期肺部变化的灵敏度较低。在这种情况下，我们的目的是确定最大程度亚极限踏车运动试验期间容积二氧化碳图（VCap）参数与肺量测定参数之间的相关性。
进行了一项横断面和对照研究，该研究纳入了 64 名 CF 患者（CFG）和 64 名健康对照者（CG）。CFG 来自一所大学医院，CG 来自当地学校。所有参与者在最大程度亚极限踏车运动试验之前、期间和之后都进行了肺量测定法和 VCap 检查。VCap 分析的主要变量是 3 相斜率（斜率 3），其表示呼气末的[呼出二氧化碳]，并表示肺外周气体排空的异质性。使用 Spearman 相关检验对肺量测定法和 VCap 之间的相关性进行分析，考虑到 α=0.05。
VCap 分析的指标与 VCap 参数相关。斜率 3 在两组和最大程度亚极限踏车运动试验的所有时刻均与用力肺活量的 1 秒内用力呼气量（FEV）呈负相关。用力肺活量（FVC）和 FEV/FVC 比值仅与 CFG 呈负相关。斜率 3 通过自发潮气容积（VT）和呼气末二氧化碳分压（PetCO）校正的值与单独分析的斜率 3 结果相似。
VCap 参数，如斜率 3、斜率 3/VT 和斜率 3/PetCO，与肺量测定法的敏感变量，如 FEV、FVC 和 FEV/FVC 比值相关。对于评估的变量，两种检查方法之间的相关性具有一致性，这可能表明 CF 对肺生理学的影响。
