Inflammation and Infection Research Centre, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia.
J Breath Res. 2012 Sep;6(3):036002. doi: 10.1088/1752-7155/6/3/036002. Epub 2012 Jun 28.
Exhaled breath condensate (EBC) collection is an innovative method of non-invasively sampling the lung, and can detect a variety of volatile and non-volatile biomarkers, but the disadvantage is the small volume of sample collected. It was hypothesized that a collection system at a lower temperature would increase the volume collected, but may alter the relative concentration of the biomarkers of interest. EBC was collected in a cross-over study using a custom-made collection system, cooled using either wet (4 °C) or dry ice (-20 °C) in randomized order in normal non-smoking volunteers. The volume of the EBC collected per unit time was determined as were conductivity, the concentrations and total amount of protein, hydrogen peroxide, and nitrite/nitrate concentrations. Dry ice was associated with a 79% greater volume of EBC than the wet ice (1387 ± 612 µL; 773 ± 448 µL respectively, p < 0.0001). Conductivity was influenced by the temperature of collection (18.78 ± 6.71 µS cm(-1) for wet ice and 15.32 ± 6.28 µS cm(-1) for dry ice, p = 0.02) as was hydrogen peroxide (1.34 ± 0.88 µg mL(-1) for wet ice and 0.68 ± 0.32 µg mL(-1) for dry ice, p = 0.009) while the concentrations and total values for protein and nitrate/nitrite were not significantly different (p > 0.05). This pilot study suggests that lower collection temperatures facilitate the collection of a larger sample volume. This larger volume is not simply more dilute, with increased water content, nor is there a simple correction factor that can be applied to the EBC biomarkers to correct for the different methods.
呼出气冷凝物（EBC）采集是一种非侵入性采样肺部的创新方法，可以检测多种挥发性和非挥发性生物标志物，但缺点是采集的样本量小。有人假设，在较低温度下采集系统会增加采集的样本量，但可能会改变感兴趣的生物标志物的相对浓度。在一项使用定制采集系统的交叉研究中，在正常不吸烟志愿者中，以随机顺序使用湿冰（4°C）或干冰（-20°C）冷却，收集 EBC。测定单位时间内 EBC 的采集量、电导率、蛋白质、过氧化氢、亚硝酸盐/硝酸盐浓度的浓度和总量。干冰收集的 EBC 量比湿冰多 79%（分别为 1387 ± 612µL；773 ± 448µL，p<0.0001）。收集温度影响电导率（湿冰为 18.78 ± 6.71µS cm(-1)，干冰为 15.32 ± 6.28µS cm(-1)，p=0.02），过氧化氢也是如此（湿冰为 1.34 ± 0.88µg mL(-1)，干冰为 0.68 ± 0.32µg mL(-1)，p=0.009），而蛋白质和硝酸盐/亚硝酸盐的浓度和总量没有显著差异（p>0.05）。这项初步研究表明，较低的采集温度有助于采集更大的样本量。这个更大的体积不是简单地更稀释，水含量增加，也没有一个简单的校正因子可以应用于 EBC 生物标志物来纠正不同的方法。
