[Oscillatory measurement of airway resistance with the custo vit in comparison with Oscillaire and whole body plethysmography].
The airway resistance was measured by forced oscillation technique with the pseudorandom noise method (Oscillaire, Jones) at multiple frequencies ranging from 6 to 26 Hz in steps of 2 Hz (Ros1). In addition, the oscillatory resistance was determined with the custo vit unit (Customed), the frequency of the pump generating the oscillation being selectable (Ros2), so that successive measurements were made at different frequencies. The custo vit is available in different technical versions. With the first version, a single frequency was used to measure the resonance frequency and to determine the associated resistance. By a different version, the impedance of various frequencies in the range between 6 and 16 Hz in steps of 2 Hz were determined for both methods. Finally, using 3 frequencies (8, 12 and 16 Hz) the total impedance was differentiated into resistance and reactance. In addition, the airway resistance was determined by bodyplethysmography. A clinical study was performed in a group of 21 healthy subjects and 34 patients with bronchial asthma and chronic obstructive lung disease. With both methods, the correlation of the resistance, determined by forced oscillation technique and Raw showed decreasing values with increasing frequency. In the case of the measurement of the airway resistance with the custo vit at resonance frequency, a poorer differentiation between normal subjects and patients with obstruction was obtained as compared with measurements made at a fixed frequency of 6 Hz. This is the result of a shift in the resonance frequency towards higher frequencies in the case of an obstruction, and the simultaneously occurring frequency-dependence of the resistance. A comparison of the impedance at different frequencies revealed comparable values with both methods, but in the case of the differentiation into resistance and reactance, it was seen that higher resonance frequencies were established with Ros1 as compared with Ros2 in the case of obstruction.
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D000403:Airway Resistance; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000175:diagnosis*; D008838:Microcomputers; D009991:Oscillometry / Q000295:instrumentation*; D010993:Plethysmography, Whole Body / Q000295:instrumentation*; D012123:Pulmonary Ventilation; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*
Die oszillatorische Messung des Atemwiderstands mit dem custo vit im Vergleich zum Oszillaire und zur Bodyplethysmographie.