The Department of Respiratory Medicine, Royal North Shore Hospital, Sydney, NSW, Australia.
Airway Physiology and Imaging Group and the Woolcock Emphysema Centre, The Woolcock Institute of Medical Research, Sydney, NSW, Australia.
Respirology. 2020 Jun;25(6):613-619. doi: 10.1111/resp.13688. Epub 2019 Sep 3.
Fixed airflow obstruction (FAO) in asthma occurs despite optimal inhaled treatment and no smoking history, and remains a significant problem, particularly with increasing age and duration of asthma. Increased lung compliance and loss of lung elastic recoil has been observed in older people with asthma, but their link to FAO has not been established. We determined the relationship between abnormal lung elasticity and airflow obstruction in asthma.
Non-smoking asthmatic subjects aged >40 years, treated with 2 months of high-dose inhaled corticosteroid/long-acting beta-agonist (ICS/LABA), had FAO measured by spirometry, and respiratory system resistance at 5 Hz (Rrs ) and respiratory system reactance at 5 Hz (Xrs ) measured by forced oscillation technique. Lung compliance (K) and elastic recoil (B/A) were calculated from pressure-volume curves measured by an oesophageal balloon. Linear correlations between K and B/A, and forced expiratory volume in 1 s/forced vital capacity (FEV /FVC), Rrs and Xrs were assessed.
Eighteen subjects (11 males; mean ± SD age: 64 ± 8 years, asthma duration: 39 ± 22 years) had moderate FAO measured by spirometry ((mean ± SD z-score) post-bronchodilator FEV : -2.2 ± 0.5, FVC: -0.7 ± 1.0, FEV /FVC: -2.6 ± 0.7) and by increased Rrs (median (IQR) z-score) 2.7 (1.9 to 3.2) and decreased Xrs : -4.1(-2.4 to -7.3). Lung compliance (K) was increased in 9 of 18 subjects and lung elastic recoil (B/A) reduced in 5 of 18 subjects. FEV /FVC correlated negatively with K (r = -0.60, P = 0.008) and Rrs correlated negatively with B/A (r = -0.52, P = 0.026), independent of age. Xrs did not correlate with lung elasticity indices.
Increased lung compliance and loss of elastic recoil relate to airflow obstruction in older non-smoking asthmatic subjects, independent of ageing. Thus, structural lung tissue changes may contribute to persistent, steroid-resistant airflow obstruction.
ACTRN126150000985583 at anzctr.org.au (UTN: U1111-1156-2795).
尽管接受了最佳吸入治疗且无吸烟史，哮喘仍会出现固定气流阻塞（FAO），这仍是一个严重的问题，尤其是随着年龄的增长和哮喘持续时间的延长。在患有哮喘的老年人中，已经观察到肺顺应性增加和肺弹性回缩力丧失，但它们与 FAO 的关系尚未确定。我们确定了哮喘患者异常肺弹性与气流阻塞之间的关系。
对年龄>40 岁、接受 2 个月高剂量吸入皮质激素/长效β激动剂（ICS/LABA）治疗的非吸烟哮喘患者进行肺功能检查，测量用力肺活量（FEV ）/用力肺活量（FVC），通过强迫振荡技术测量呼吸系统阻力在 5Hz（Rrs）和呼吸系统电抗在 5Hz（Xrs）。通过食管球囊测量压力-容积曲线计算肺顺应性（K）和弹性回缩力（B/A）。评估 K 和 B/A 与 1 秒用力呼气量/用力肺活量（FEV/FVC）之间的线性相关性，以及 Rrs 和 Xrs。
18 名受试者（男性 11 名；平均年龄±标准差：64±8 岁，哮喘持续时间：39±22 年）通过支气管扩张剂后用力肺活量（FEV）的 spirometry（（平均±标准差 z 分数）进行中度 FAO 测量：-2.2±0.5，FVC：-0.7±1.0，FEV/FVC：-2.6±0.7）和增加的 Rrs（中位数（IQR）z 分数）2.7（1.9 至 3.2）和降低的 Xrs：-4.1（-2.4 至-7.3）。18 名受试者中有 9 名的 FEV/FVC 与 K 呈负相关（r=-0.60，P=0.008），Rrs 与 B/A 呈负相关（r=-0.52，P=0.026），独立于年龄。Xrs 与肺弹性指数无相关性。
在老年非吸烟哮喘患者中，增加的肺顺应性和丧失的弹性回缩与气流阻塞有关，这与年龄无关。因此，结构性肺组织变化可能导致持续的、类固醇耐药的气流阻塞。
ACTRN126150000985583 在 anzctr.org.au（UTN：U1111-1156-2795）。
