[Etiology and reproducibility of blood gas findings during stress testing in patients with obstructive respiratory tract diseases].

After the stabilization of the obstructive airways disease 14 patients performed 4 times exercise-tests of 6 minutes at a bicycle during one week. The basic values of the lung function showed with FEV1 of 66%, Rt of 5,74 hPa/l/s and IGV of 155% a strong disturbance of the mechanical features of the lung. At the mean during the exercise tests the PO2a remained with 69 Torr constant. PC2a increases at the same time for 3 Torr. After the exercise test a significant increase of PO2a of 11.4 Torr takes place. At the individual patients there was a great variability of the results between the different tests. Only three patients showed always a decrease of PO2a-values. The reason for this variability is the ventilation/perfusion inhomogeneity, which changes between the investigations. There are significant multilinear correlations between the FEV1%- as the IGV%-values and PO2a for the values at rest, during exercise as 5 min after the end of exercise. The exercise tests show at the PO(2a)-values the variability of the ventilation/perfusion inhomogeneity which dominates the bloodgas values. The important increase of the PO2a after the exercise test even at this patients can be of importance. The duration of this effect after multiple loads and the dependence of the workload should be investigated.