Patent ID: 6371113
Filing Date: 2002-04-16
Classification: A61M

Abstract:
A ventilator system for a patient circuit providing breathing gas to a patient connected to the patient circuit during an inhalation phase of a breath and receiving exhaled gases from a patient in an exhalation phase of a breath, said ventilator system providing an indication of the pressure in the patient's lungs, said ventilator system comprising:a ventilator; a drive conduit fluidly connecting said ventilator to the patient circuit for allowing said ventilator to increase the pressure in the patient circuit to deliver a quantity of breathing gas through the patient circuit to the patient in the inhalation phase and to reduce the pressure in the patient circuit to allow breathing gas to be exhaled by the patient during the exhalation phase, said ventilator further providing a pause period following the inhalation phase; a flow sensor in the patient circuit for sensing the presence of a gas flow to or from a patient in the patient circuit during the pause period, said sensor providing a signal indicative of the sensing carried out by the sensor; exhalation pressure control means for altering the pressure in the patient circuit during the exhalation phase; processor means for controlling said pressure control means within the pause period to provide a controlled reduction of pressure in the patient circuit during the pause period of a given breath, said processor means receiving the signal from said flow sensor and operating said exhalation pressure control means in a subsequent breath of the patient, in the event gas flow is sensed in the given breath, to alter the controlled pressure reduction in the subsequent breath in a manner tending to reduce the flow of gas to or from the patient to zero by the end of the pause period; and means for obtaining a pressure measurement indicative of that in the patient circuit, a pressure measurement taken when gas flow in the patient circuit is zero comprising an indication of the pressure in a patient's lungs.