Therapeutic gas delivery device with pulsed and continuous flow control
Described are methods and devices for therapeutic or medical gas delivery that utilize at least one proportional control valve and at least one binary control valve. The proportional control valve may be in series with the binary control valve to provide a valve combination capable of pulsing therapeutic gas at different flow rates, depending on the setting of the proportional control valve. Alternatively, the proportional control valve and binary control valve may be in parallel flow paths.
1. A therapeutic gas delivery device comprising:
an inlet to connect to a source of therapeutic gas;
an outlet to connect to a device that introduces the therapeutic gas to a patient;
at least one binary control valve in fluid communication with the inlet and outlet that delivers a constant flow of the therapeutic gas;
at least one proportional control valve in fluid communication with the inlet and outlet that delivers a variable flow of the therapeutic gas, wherein the binary control valve and the proportional control valve are in parallel flow paths;
a control system that delivers the therapeutic gas through one or more of the binary control valve and the proportional control valve; and
wherein the control system is adapted to deliver the therapeutic gas to a patient in an amount proportional to a flow of breathing gas.
2. The therapeutic gas delivery device of claim 1 , wherein the control system delivers a continuous flow of therapeutic gas through the proportional control valve when a therapeutic gas demand is greater than or equal to 5% of a delivery range and delivers one or more pulses of therapeutic gas through the binary control valve when the therapeutic gas demand is less than or equal to 1% of the delivery range.
3. The therapeutic gas delivery device of claim 1 , wherein the binary control valve is a first binary control valve and the therapeutic gas delivery device further comprises a second binary control valve in parallel to the first binary control valve.
4. The therapeutic gas delivery device of claim 3 , wherein the first binary control valve and the second binary control valve deliver pulses of therapeutic gas at different flow rates.
5. The therapeutic gas delivery device of claim 4 , wherein the ratio of the flow rate of the first binary control valve to the flow rate of the second binary control valve is in the range from about 1:2 to about 1:10.
6. The therapeutic gas delivery device of claim 3 , wherein the control system delivers multiple pulses per breath through one or more of the first binary control valve and the second binary control valve.
7. The therapeutic gas delivery device of claim 1 , wherein the device that introduces the therapeutic gas to the patient is in fluid communication with a ventilator.
8. The therapeutic gas delivery device of claim 1 , wherein the device that introduces the therapeutic gas to the patient is a nasal cannula, endotracheal tube or a face mask.
9. The therapeutic gas delivery device of claim 1 , wherein the control system is adapted to provide a single pulse in a patient's breath through one or more of the binary control valve and the proportional control valve.
10. The therapeutic gas delivery device of claim 1 , wherein the source of therapeutic gas comprises nitric oxide or a nitric oxide-releasing agent.
11. A method of administering a therapeutic gas to a patient, the method comprising:
receiving a flow of therapeutic gas to a therapeutic gas delivery device having at least one binary control valve that delivers a constant flow of therapeutic gas and at least one proportional control valve that delivers a variable flow of the therapeutic gas, wherein the binary control valve and the proportional control valve are in parallel flow paths;
measuring a flow of breathing gas; and
delivering therapeutic gas to the patient during inspiration through one or more of the binary control valve and the proportional control valve in an amount proportional to the flow of breathing gas.
12. The method of claim 11 , wherein a continuous flow of therapeutic gas is delivered through the proportional control valve when a therapeutic gas demand is greater than or equal to 5% of a delivery range and one or more pulses of therapeutic gas is delivered through the binary control valve when the therapeutic gas demand is less than or equal to 1% of the delivery range.
13. The method of claim 11 , wherein the binary control valve is a first binary control valve and the therapeutic gas delivery device further comprises a second binary control valve in parallel to the first binary control valve.
14. The method of claim 13 , wherein the first binary control valve and the second binary control valve deliver pulses of therapeutic gas at different flow rates.
15. The method of claim 14 , wherein the ratio of the flow rate of the first binary control valve to the flow rate of the second binary control valve is in the range from about 1:2 to about 1:10.
16. The method of claim 13 , wherein the control system delivers multiple pulses per breath through one or more of the first binary control valve and the second binary control valve.