[Ventilatory response to lung inflation after induced bronchospasm in healthy conscious subjects (author's transl)]

In 10 healthy conscious subjects we have studied the effect of a sustained bronchospasm induced by aerosol of carbachol on the pattern of breathing and the ventilatory response to lung inflation which reflects the Breuer Hering reflex. Bronchospasm was assessed by measuring airway resistance and functional residual capacity by plethysmography. After bronchospasm the ventilatory response to inflation was unchanged and the role played by afferents related to such a reflex in controlling pattern of breathing was preserved. Moreover the ration between the threshold volume of the reflex and tidal volume (VT) remained constant. These data suggest that this ration could represent a central set point for VT control. Variable changes in the ventilatory pattern were also observed and are discussed in relation to the previous data.