[Exhaled breath condensate and its analysis--a new method in pulmonology].

In the middle of the nineties a new, non-invasive method for investigation of the lung aroused the interest of many researchers: the exhaled breath condensate. It shows the extent of the interest that in the last five years more than 80 original articles have been published in this theme. Many substances are found in the expired breath which are detectable in the liquid that we obtain by cooling (= condensing) the exhaled breath. The advantages of this method are that it is non-invasive, convenient, it could be performed with mechanically ventilated patients as well as with children. The most studied substance is the hydrogen-peroxide, which is the marker of oxidative stress, and its level in condensate is elevated in numerous inflammatory diseases. 8-isoprostane was also studied a lot, which is another marker of oxidative stress. Numerous substances could be even measured in condensate, so the decay-product of nitric-oxide (nitrite, nitrate, nitrotyrosine), further nitrosothiol, adenosine, ammonia, different ions, leukotrienes, cytokines; recently even other feature of condensate is examined, such as its pH. The different mediators could help us to know better the diseases, support the diagnosis, follow the treatment or the disease. In this study the authors attempt to present the most important knowledge till now.