| 摘要 |
A system and method of controlling the termination of the inhalation phase in a pressure support ventilation system is disclosed, in which an expiratory trigger sensitivity, or ratio of inspiratory flow rate to peak inspiratory flow rate at which the inspiration phase is terminated, is varied in proportion to variations in a calculated respiratory time constant. The system includes sensors for monitoring pressure and flow of gas during each breath, and, based on the sensor outputs, calculates the respiratory time constant for one breath or a series of breaths. The expiratory trigger sensitivity is automatically increased with increasing patient respiratory time constant, providing a closed loop control of expiratory trigger sensitivity. The expiratory trigger sensitivity may also be varied in response to changes in supra-plateau pressure.
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