초록 ▼

An improved system for making an accurate determination of the patient's compliance and airway resistance by ensuring that the flow to and/or from the patient at the end of a ventilator pause is, in fact, reduced to zero flow. The normal ventilator pause occurs at the end of an inspiratory cycle whe

An improved system for making an accurate determination of the patient's compliance and airway resistance by ensuring that the flow to and/or from the patient at the end of a ventilator pause is, in fact, reduced to zero flow. The normal ventilator pause occurs at the end of an inspiratory cycle where the ventilator terminates the breathing air delivery to the patient and then enters a pause period. Values are taken for the airway flow and pressure at the beginning of the pause period, that is at peak pressure, and a second set of readings is taken at the end of the pause period, called the plateau pressure. This second set of readings greatly simplifies solving the equations for patient resistance and compliance if the flow at that time is assumed to be zero. The present system monitors the flow at the end of the pause period and continually adjusts the circuit pressure in order to drive the flow at the end of the pause period to a zero flow value, thus improving the accuracy of the patient resistance and compliance calculation and achieving a more ideal pause pressure profile.

대표청구항 ▼

1. 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 t

1. 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.