Liu Jia, Thomas Paul S
Faculty of Medicine, University of New South Wales, and Department of Respiratory Medicine, Prince of Wales Hospital, Randwick, Australia.
Respiration. 2007;74(2):142-5. doi: 10.1159/000094238. Epub 2006 Jun 26.
Exhaled breath condensate (EBC) is proving to be a technique which can sample markers of lung inflammation; however, many factors affect the collection process.
We hypothesised that lung volumes--tidal volume, minute volume and total lung capacity (TLC)--would dictate the volume of the EBC sample that could be collected.
First, the volume of EBC collected was measured while measuring the tidal volume and minute volume in normal, asthmatic and chronic obstructive pulmonary disease subjects. Second, the volume of EBC was compared between breathing at tidal volumes and breathing at vital capacity in normal subjects. TLC was measured by plethysmography.
The mean EBC volume was 5.55 +/- 0.50 microl/breath in normal subjects (n = 23), 3.56 +/- 0.33 microl/breath in chronic obstructive pulmonary disease patients (n = 25) and 5.77 +/- 0.50 microl/breath in asthmatic subjects (n = 17). EBC volume was significantly correlated with both tidal volume (Pearson's r = 0.775, p < 0.0005) and minute volume (Pearson's r = 0.425, p < 0.0005), but importantly, EBC volume was not significantly affected by age, gender or disease status. There was a significant difference in EBC volume when tidal breathing was compared with breathing at vital capacity (5.55 +/- 0.50 vs. 20.59 +/- 1.72 microl; p < 0.0001). No significant correlation was found between EBC volume and TLC (21 normal subjects).
These results suggest that tidal and minute volume can predict the amount of EBC that can be expected to be collected. No significant differences in the volume of EBC were seen between normal subjects and those with airway diseases.
呼气末冷凝液（EBC）已被证明是一种可对肺部炎症标志物进行采样的技术；然而，许多因素会影响采集过程。
我们推测肺容量——潮气量、分钟通气量和肺总量（TLC）——将决定可采集的EBC样本量。
首先，在测量正常、哮喘和慢性阻塞性肺疾病受试者的潮气量和分钟通气量时，测量所采集的EBC量。其次，比较正常受试者在潮气量呼吸和肺活量呼吸时的EBC量。通过体积描记法测量肺总量。
正常受试者（n = 23）的平均EBC量为5.55±0.50微升/呼吸，慢性阻塞性肺疾病患者（n = 25）为3.56±0.33微升/呼吸，哮喘受试者（n = 17）为5.77±0.50微升/呼吸。EBC量与潮气量（Pearson相关系数r = 0.775，p < 0.0005）和分钟通气量（Pearson相关系数r = 0.425，p < 0.0005）均显著相关，但重要的是，EBC量不受年龄、性别或疾病状态的显著影响。潮式呼吸与肺活量呼吸时的EBC量存在显著差异（5.55±0.50对20.59±1.72微升；p < 0.0001）。在21名正常受试者中，未发现EBC量与肺总量之间存在显著相关性。
这些结果表明，潮气量和分钟通气量可预测预期采集的EBC量。正常受试者与气道疾病患者的EBC量未见显著差异。
