Automatic ongoing adjustment of the cycling-off time of ventilator inflationphase during assisted ventilation in accordance with true respiratory rate ofa patient. Electrical signals are generated corresponding to the gas flowexchanged between patient and ventilator (flow) and/or to airway pressure(Paw) and the true respiratory rate of the patient (patient RR) is determinedon an ongoing basis from the flow and/or Paw. The current average cycleduration of patient respiratory efforts (current patient TTOT) is estimatedfrom patient RR. A current desirable duration of the inhalation phase(desirable TI) is calculated from the product of current patient TTOT aTI/TTOT ratio chosen to be in the physiological range, usually 0.25 to 0.50.The ventilator phase is caused to terminate in accordance with the desirableTI.
