frequency sequence protocol after that the routine proceeds in a similar fashion to the vest fitting routine the person however breathes through the flow measuring device in a normal breathing pattern air flow from the patient is sampled either for a set time period for example two seconds or for a set number of breathes for example one or two breath cycles the first option is much easier since the detection of breath onset and end is often difficult particularly in view of the fluctuations added by compression device 104 the vest induced air flow signal is filtered from the patient generated air flow signal the result is then subtracted from the patient generated signal to obtain an induced air flow versus time the half cycles are integrated to obtain volume and the peaks are identified with both averaged over the selected interval and stored so that the frequencies having the greatest average induced air flow peaks and greatest average induced changes in lung volume can be identified the routine for identifying optimum operating frequencies for compression device 104 is illustrated in fig1 as depicted by box 134 it is necessary first to choose a frequency ordering protocol that is frequencies may be applied from smallest to largest or largest to smallest or randomly or by some other scheme once the protocol is established compression device 104 is operated as indicated by box 136 for this routine the person breathes normally as shown by box 138 in this regard curve 135 in fig1 substantially depicts a normal breathing cycle while curve 137 shows induced air flow superimposed thereon for the case of a properly fitting vest assuming the operating frequency.