Comparative study of the different factors influencing resistance of tubes to gas flow

With the help of a pneumotachograph and a pressure transducer the influences of tube diameter, tube length, tube shape, connectors of different shape and kinking are quantified. The influence of different gases on resistance is calculated. With the help of the shown data one can predict the influence of changes of the different factors. Rules for optimalisation are given and their clinical significance is discussed. Most significant factors are diameter and length of the tube, kinking over 50% and kinematic viscosity and density of the used gas mixture.