Background The significance of pulmonary crackles, by their timing during inspiration, was described by Nath and Capel in 1974, with early crackles associated with bronchial obstruction and late crackles with restrictive defects. Crackles are also described as ‘fine’ or ‘coarse’. We aimed to evaluate the usefulness of crackle characteristics in the diagnosis of chronic obstructive pulmonary disease (COPD). Methods In a population-based study, lung sounds were recorded at six auscultation sites and classified in participants aged 40 years or older. Inspiratory crackles were classified as ‘early’ or ‘late and into the types’ ‘coarse’ and ‘fine’ by two observers. A diagnosis of COPD was based on respiratory symptoms and forced expiratory volume in 1 s/forced inspiratory vital capacity below lower limit of normal, based on Global Lung Function Initiative 2012 reference. Associations between crackle characteristics and COPD were analysed by logistic regression. Kappa statistics was applied for evaluating interobserver agreement. Results Of 3684 subjects included in the analysis, 52.9% were female, 50.1% were ≥65 years and 204 (5.5%) had COPD. Basal inspiratory crackles were heard in 306 participants by observer 1 and in 323 by observer 2. When heard bilaterally COPD could be predicted with ORs of 2.59 (95% CI 1.36 to 4.91) and 3.20 (95% CI 1.71 to 5.98), annotated by observer 1 and 2, respectively, adjusted for sex and age. If bilateral crackles were coarse the corresponding ORs were 2.65 (95% CI 1.28 to 5.49) and 3.67 (95% CI 1.58 to 8.52) and when heard early during inspiration the ORs were 6.88 (95% CI 2.59 to 18.29) and 7.63 (95%CI 3.73 to 15.62). The positive predictive value for COPD was 23% when early crackles were heard over one or both lungs. We observed higher kappa values when classifying timing than type. Conclusions ‘Early’ inspiratory crackles predicted COPD more strongly than ‘coarse’ inspiratory crackles. Identification of early crackles at the lung bases should imply a strong attention to the possibility of COPD.

中文翻译：

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重新审视吸气噼啪声——早期和晚期——通过噼啪声特征识别 COPD

背景 Nath 和 Capel 在 1974 年描述了肺部噼啪声的重要性，根据它们在吸气期间的时间，早期噼啪声与支气管阻塞有关，而晚期噼啪声与限制性缺损有关。裂纹也被描述为“精细”或“粗糙”。我们旨在评估裂纹特征在诊断慢性阻塞性肺疾病 (COPD) 中的有用性。方法 在一项基于人群的研究中，在 6 个听诊部位记录了肺音，并将其分类为 40 岁或 40 岁以上的参与者。两名观察者将吸气噼啪声分为“早”或“晚”，并分为“粗”和“细”两种类型。COPD 的诊断基于呼吸道症状和 1 秒用力呼气量/用力吸气肺活量低于正常下限，基于 2012 年全球肺功能倡议参考。通过逻辑回归分析裂纹特征与 COPD 之间的关联。Kappa 统计用于评估观察者间的一致性。结果 在纳入分析的 3684 名受试者中，52.9% 为女性，50.1% 为 65 岁以上，204 名 (5.5%) 患有 COPD。观察员 1 在 306 名参与者和观察员 2 的 323 名参与者中听到了基础吸气噼啪声。当双侧听到 COPD 时，可以预测 COPD 为 2.59（95% CI 1.36 至 4.91）和 3.20（95% CI 1.71 至 5.98），注释为观察者 1 和 2 分别根据性别和年龄进行了调整。如果双侧湿啰音粗糙，相应的 OR 为 2.65（95% CI 1.28 至 5.49）和 3.67（95% CI 1.58 至 8.52），并且在吸气早期听到时 OR 为 6.88（95% CI 2.59 至 18.29）和 7.63（99） %CI 3.73 至 15.62）。当一侧或双肺听到早期湿啰音时，COPD 的阳性预测值为 23%。我们在分类时间时观察到比类型更高的 kappa 值。结论 “早期”吸气爆音比“粗”吸气爆音更能预测 COPD。识别肺底部的早期湿啰音意味着高度关注 COPD 的可能性。