Ventilator control system for mixing and delivery of gas
First Claim
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1. A ventilator system for the intermittent delivery of respiratory gas to a patient comprising:
- a rigid, fixed wall pressure containment vessel;
first and second inlet ports connected to said vessel, with each said inlet, port being in fluid communication with corresponding first and second separate sources of first and second respective component gases to be combined in a desired ratio to form said respiratory gas, said component gases having an initial known ratio, with said first and second inlet ports having associated corresponding first and second inlet valves for individually controlling the flow of each said component gas through said inlet ports to said vessel;
outlet means to connect said vessel in fluid communication with the patient;
sensor means to determine onset and completion of inhalation by the patient, to sense the pressure of said respiratory gas in the containment vessel following said completion of inhalation by of the patient, and to generate a differentiated pressure signal representing a rate of change of pressure in said containment vessel over a period of time;
inlet flow control means to sequentially control the flow of said first component gas into said containment vessel in response to said determination of completion of inhalation by the patient through said first inlet port while said second inlet port is closed, and to control the flow of said second component gas through said second inlet port while said first inlet port is closed, in a desired ratio responsive to the pressure of gas sensed in the containment vessel, including means for determining a desired pressure change value for each said component gas in said containment vessel corresponding to the number of moles of each said component gas required to fill said vessel with said desired ratio of said component gases to a desired fill pressure based upon a total pressure and said initial known ratio of component gases in said vessel, and means for determining an actual ratio of said component gases in said respiratory gas in said vessel based upon sensed changes in pressure of said component gases introduced into said containment vessel; and
outlet flow control means electrically connected to said sensor means to control the flow of said respiratory gas through the outlet means following said onset of inhalation in a predetermined manner responsive to said differentiated pressure signal based upon the rate of change in the pressure of gas sensed in the containment vessel.
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Abstract
The ventilator control system for delivery respiratory gas to a patient involves an apparatus which includes a pressure sensor for measuring the pressure within a gas containment vessel, the control of the flow of respiratory gas into the containment vessel responsive to pressure within the containment vessel, and the control of the outflow of respiratory gas responsive to changes in pressure in the containment vessel. Both the inflow of gas to a receiver tank and outflow of respiratory gas are responsive to modes of breathing being provided to a patient.
266 Citations
8 Claims
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1. A ventilator system for the intermittent delivery of respiratory gas to a patient comprising:
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a rigid, fixed wall pressure containment vessel; first and second inlet ports connected to said vessel, with each said inlet, port being in fluid communication with corresponding first and second separate sources of first and second respective component gases to be combined in a desired ratio to form said respiratory gas, said component gases having an initial known ratio, with said first and second inlet ports having associated corresponding first and second inlet valves for individually controlling the flow of each said component gas through said inlet ports to said vessel; outlet means to connect said vessel in fluid communication with the patient; sensor means to determine onset and completion of inhalation by the patient, to sense the pressure of said respiratory gas in the containment vessel following said completion of inhalation by of the patient, and to generate a differentiated pressure signal representing a rate of change of pressure in said containment vessel over a period of time; inlet flow control means to sequentially control the flow of said first component gas into said containment vessel in response to said determination of completion of inhalation by the patient through said first inlet port while said second inlet port is closed, and to control the flow of said second component gas through said second inlet port while said first inlet port is closed, in a desired ratio responsive to the pressure of gas sensed in the containment vessel, including means for determining a desired pressure change value for each said component gas in said containment vessel corresponding to the number of moles of each said component gas required to fill said vessel with said desired ratio of said component gases to a desired fill pressure based upon a total pressure and said initial known ratio of component gases in said vessel, and means for determining an actual ratio of said component gases in said respiratory gas in said vessel based upon sensed changes in pressure of said component gases introduced into said containment vessel; and outlet flow control means electrically connected to said sensor means to control the flow of said respiratory gas through the outlet means following said onset of inhalation in a predetermined manner responsive to said differentiated pressure signal based upon the rate of change in the pressure of gas sensed in the containment vessel. - View Dependent Claims (2, 3, 4)
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5. A method for intermittently delivering respiratory gas to a patient from a respirator by providing a rigid, fixed wall pressure containment vessel having first and second inlet ports, each of said inlet ports connecting the vessel in fluid communication with first and second separate sources of respective first and second component gases to be combined in said vessel in a desired ratio to form said respiratory gas, said respiratory gas in said vessel having an initial known ratio of said component gases;
- providing outlet means to connect the vessel in fluid communication with the patient;
providing sensor means to sense the pressure of said respiratory gas in the containment vessel; and
providing means to sequentially control the flow of said component gases through said inlet ports; and
output flow control means to control the flow of said respiratory gas through said outlet means, said method further comprising the steps of;determining onset and completion of inhalation by the patient; measuring the pressure of gas within said vessel following said completion of inhalation by the patient; determining pressure increase values for said first and second component gases in said vessel corresponding to the number of molecules of each said component gas required to fill said vessel with said desired ratio of said component gases to a desired fill pressure based upon the total pressure and said initial known ratio of component gases in said vessel; sequentially filling said vessel with said component gases to said corresponding pressure increase values while measuring pressure in said containment vessel in response to said determination of completion of inhalation by the patient, by introducing said first component gas into said vessel through said first inlet port while said second inlet port is closed, and said second component gas through said second inlet port while said first inlet is closed according to said pressure change values until said fill pressure of gas in said vessel is reached; measuring an actual pressure increase in said containment vessel for each said component gas introduced into said vessel; determining the ratio of said component gases in said containment vessel based upon said initial known ratio of component gases in said vessel, said total pressure and said actual pressure changes for each said component gas introduced into said vessel; withdrawing said gas from said vessel through said outlet means responsive to said determination of onset of inhalation; measuring an outflow rate of change in the pressure of gas in the vessel over time and generating a differentiated pressure signal representing the outflow rate of change of pressure in said vessel over said period of time; and controlling said withdrawing of gas from said vessel in a predetermined manner responsive to said outflow rate of change in the pressure of gas sensed in said containment vessel. - View Dependent Claims (6, 7, 8)
- providing outlet means to connect the vessel in fluid communication with the patient;
Specification