[Practical experiences with 2 oscillatory measuring procedures, Siregnost FD 5 and custo vit, in the assessment of chronic airway obstruction].

In patients with chronic obstructive airway disease, comparative examinations using body plethysmography were performed with a view to evaluating the effectiveness of two forced oscillation techniques, fixed-frequency and poly-frequency techniques in estimating disorders of respiration mechanics. At slight and moderate elevations in bronchial flow resistance, a better agreement was found between the custo vit resistance figure and body plethysmography. A differentiation of healthy subjects from patients with low-grade obstruction by means of the FD 5, requires the establishment of the phase angle (phi), too, while in the case of the custo vit unit, this is possible by demonstrating the frequency dependence of the impedance. Patients with more severe disease with secondary emphysematous changes, reveal a clear difference between the phase signal (psi) primarily measured on the FD 5, and the phase angle. Forced oscillation usefully supplements spirometery in the respiratory basic diagnostic work-up employed through-out treatment. Fixed-frequency techniques require the determination of the phase angle for assessment of peripheral obstructions; the advantage of the poly-frequency technique can be seen in the largely specific demonstration of the frequency dependency of the resistance.