Exhaled condensate - a medium obtained by a non-invasive method for the detection of inflammation mediators of the lung

Collection of exhaled condensate (freezing of expired air under conditions of spontaneous breathing) is a non-invasive method permitting the collectio n of material originating from the lung and the lower respiratory tract so that it can be used for diagnostic examinations. In order to be able to eva luate the diagnostic evidence of exhaled condensate samples in cases of res piratory disease of the calf, leukotriene B-4 (LTB4) in bovine exhaled cond ensate was determined. The influence of the breathing pattern and body temperature on the quantity of condensate to be collected was tested in a total of 49 exhaled condensa te samples. It became obvious that the exhaled condensate quantity obtained per time unit is dependent on the ventilation volume per time unit (minute volume). In exhaled condensate samples from 35 clinically healthy calves, LTB4 conce ntrations of less than 250 pg/mL exhaled condensate were detected. A total of 14 exhaled condensate samples from 7 calves was analyzed before and after experimental respiratory infection with Pasteurella multocida D. In parallel to the analysis of LTB4 in exhaled condensate, the lung functio n of the calves was examined by means of impulse oscilloresistometry. The i ncrease of LTB4 in the exhaled condensate post infection correlated signifi cantly (p less than or equal to 0.05) with decreases of respiratory reactan ce. The determination of LTB4 concentrations in exhaled condensate seems to be suitable, in principle, for the detection of inflammations in the respirato ry system of the calf. Further studies are needed for the evaluation of the diagnostic validity of the method.