Background

Asthma control is not well reflected by spirometry, yet this is the most frequently used measure of lung function in asthma clinics. Oscillometry is an alternative technique suitable for those with severe asthma.

Objective

To investigate usefulness of oscillometry in subjects with severe asthma to determine which outcome variables best reflected asthma control.

Methods

Adults with severe asthma were recruited from a severe asthma clinic in Brazil. Oscillometry (conventional multifrequency measurements between 6 and 32 Hz; intrabreath tracking at 8 Hz) and spirometry were performed. Asthma control was determined by the asthma control test.

Results

A total of 60 adults were evaluated; mean age was 56.7 years. There was predominance of women (82%), and most patients (63%) reported onset of asthma symptoms in childhood or adolescence. There were no differences between controlled and uncontrolled asthma in spirometry. Uncontrolled asthma was associated with higher resistance (at 8 and 10 Hz) and more negative reactance (for 6, 8, and 10 Hz) (P < .05) on conventional oscillometry. Intrabreath oscillometry revealed significant differences between controlled and uncontrolled patients with asthma (P < .01 for changes in resistance and reactance between end expiration and end inspiration). The accuracy of the lung function tests in discriminating between controlled and uncontrolled asthma was higher for intrabreath variables (area under the curve = 0.65-0.72).

Conclusion

Oscillometry, particularly the intrabreath technique, better reflected asthma control than spirometry measures. Our findings suggest that oscillometry may be a useful technique to aid management of severe asthma, with a potential to reflect loss of disease control.

中文翻译：

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呼吸内示波法是评估成人重度哮喘疾病控制的敏感测试

背景

肺活量测定法不能很好地反映哮喘控制，但这是哮喘诊所最常用的肺功能测量方法。示波法是一种适用于重度哮喘患者的替代技术。

客观的

研究示波法在重度哮喘患者中的有用性，以确定哪些结果变量最能反映哮喘控制。

方法

患有严重哮喘的成年人是从巴西的一家严重哮喘诊所招募的。进行了示波法（6 到 32 赫兹之间的传统多频测量；8 赫兹的呼吸内跟踪）和肺活量测定法。哮喘控制由哮喘控制试验确定。

结果

共评估了 60 名成年人；平均年龄为 56.7 岁。女性占优势 (82%)，大多数患者 (63%) 报告在儿童期或青春期出现哮喘症状。肺活量测定中控制和未控制的哮喘之间没有差异。在常规示波法中，未控制的哮喘与更高的阻力（8 和 10 Hz）和更多的负电抗（6、8 和 10 Hz）相关（P < .05）。呼吸内示波法显示控制和未控制的哮喘患者之间存在显着差异（P< .01 表示呼气末和吸气末之间阻力和电抗的变化）。对于呼吸内变量（曲线下面积 = 0.65-0.72），肺功能测试在区分受控制和不受控制的哮喘方面的准确性更高。

结论

示波法，尤其是呼吸内技术，比肺活量测定法更能反映哮喘控制。我们的研究结果表明，示波法可能是一种有助于管理严重哮喘的有用技术，有可能反映疾病控制的丧失。