[Dependence of airway resistance and intrathoracic gas volume on airflow and respiratory frequency in health adults].

With a routine body plethysmograph with computerized calculation of airway resistance (Rt) and intrathoracic gas volume (IGV) on 11 healthy volunteers the correlations between Rt, IGV, breathing frequency (15-120) and flow (1.4-4.2 l/s) were examined. Rt increases significantly with increasing flow. In the range of clinical examinations with increasing frequency in the range between 15 and 30/min the flow increases only for a small amount. The increase of airway resistance in this range is very small. At an increase of the flow from 1 to 2 l/s an increase of Rt of 20% can be expected. An increase of the flow for 300% (1.25-5.0 l/s) is followed by an increase of Rt for 60%. IGV values are not influenced by these different frequencies and flows.