초록 ▼

For the purpose of carrying out an MMV-treatment (Mandatory Minute Volume) by means of a lung ventilator which includes a breathing-gas source from which a patient connected to the ventilator is able to breath spontaneously through an inspiratory line, and a ventilator unit which can be activated by

For the purpose of carrying out an MMV-treatment (Mandatory Minute Volume) by means of a lung ventilator which includes a breathing-gas source from which a patient connected to the ventilator is able to breath spontaneously through an inspiratory line, and a ventilator unit which can be activated by means of a control signal so as to deliver to the patient through the inspiratory line a mandatory breath of determinable tidal volume from the breathing-gas source, the flow of breathing gas through the inspiratory line is continuously sensed by means of a flow meter. In a control unit there is generated a signal which is representative of the continuous integral of the difference between a reference signal and the flow signal from the flow meter. The value of the integrated difference signal is compared with a given limit value. Each time the value of the integrated difference signal reaches the limit value, the ventilator unit is activated to deliver to the patient a mandatory breath of given tidal volume. Alternatively, the ventilator unit may be arranged to deliver to the patient mandatory breaths of a constant given frequency and of a tidal volume, whose magnitude is determined with each mandatory breath, by the difference prevailing between the value of the integrated difference signal and the limit value.

대표청구항 ▼

A device for controlling the operation of a lung ventilator including a breathing-gas source having means capable of delivering a volume of breathing gas per unit of time, which is at least equal to the maximum volume that may be required for the ventilation of the patient, an inspiratory line havin

A device for controlling the operation of a lung ventilator including a breathing-gas source having means capable of delivering a volume of breathing gas per unit of time, which is at least equal to the maximum volume that may be required for the ventilation of the patient, an inspiratory line having means for connecting the same to the airways of a patient and through which the patient can breathe spontaneously from said breathing-gas source, a ventilator unit connected to said breathing-gas source and activatably by an activation signal to deliver to the patient through said inspiratory line a mandatory breath of a predetermined tidal volume from said breathing-gas source, and an expiratory line having means for connecting the same to the airways of the patient and through which the patient can exhale, said device comprising a flow meter for sensing continuously the flow rate of breathing gas through said inspiratory line and generating a signal proportional to the momentary value of said flow rate, means for producing a reference signal substantially proportional to the minimum volume per unit of time, the so called minute volume, of breathing gas which the patient shall receive, said minimum volume per unit of time being less than the volume that the breathing gas source is capable of delivering, means for calculating continuously the total integral, during the entire inhalation and exhalation cycles of ventilation of the patient, of the difference between said reference signal and said flow rate signal and for producing a signal proportional to this integral, means for providing a first threshold signal having a value substantially proportional to said predetermined tidal volume of a mandatory breath, and means for comparing the value of said signal proportional to said integral and said first threshold signal and generating an activation signal for activating said ventilator unit to deliver a mandatory breath to the patient each time the value of said signal proportional to said integral reaches the value of said first threshold signal.