Breath-to-breath monitoring of inspiratory occlusion pressures in humans.

A pneumatically drive occlusion device has been designed to implement brief (ca. 130 ms) inspiratory airway occlusion and to monitor the associated inspiratory occlusion pressure (P100) on a breath-to-breath basis in humans. The device, which has a low resistance when patent, provides no discernible modulation of ventilation during steady and nonsteady states of moderate intensity cycle-ergometer exercise. With this technique, it is possible to undertake investigations of dynamic as well as steady-state P100 responses to stimuli such as extensive, inhaled CO2, and hypoxia.