Pneumatically-operated gas demand apparatus

• US 6,237,594 B1
• Filed: 09/22/1999
• Issued: 05/29/2001
• Est. Priority Date: 09/22/1999
• Status: Expired due to Term

• Current Assignee: Salter Labs, LLC
• Original Assignee: Salter Labs
• Inventors: Davenport, James M.
• Primary Examiner(s): Dawson, Glenn K.
• Assistant Examiner(s): MITCHELL, TEENA KAY
• Application Number:
  US09/405,420
• Time in Patent Office: 615 Days
• Field of Search: 128/204.26, 128/204.23, 128/205.24, 128/200.14, 128/203.12, 128/207.18
• US Class Current: 128/204.26
• CPC Class Codes: A61M 11/06 of the injector type
• CPC Class Codes: A61M 15/0086 Inhalation chambers
• CPC Class Codes: A61M 16/0677 Gas-saving devices therefor
• CPC Class Codes: A61M 16/20 Valves specially adapted to medical respiratory devices
• CPC Class Codes: A61M 16/207 Membrane valves with pneumatic amplification stage, i.e. having master and slave membranes
• CPC Class Codes: A61M 16/209 Relief valves
• CPC Class Codes: A61M 2202/0007 introduced into the body
• CPC Class Codes: A61M 2202/0208 Oxygen
• CPC Class Codes: A61M 2202/03 Gases in liquid phase, e.g. cryogenic liquids

Abstract

A pneumatically-operated gas delivery device coupled in interruptible fluid communication between a recipient and at least one course of pressurized respiratory gas controls delivery of the respiratory gas to the recipient as the recipient inhales and exhales. The device includes a regulator mechanism, a supply valve and a sensing valve, wherein the supply valve delivers the respiratory gas to the recipient responsive to movement of the sensing valve. Gas flow to the supply valve is communicated from the gas source, the regulator mechanism and through a plurality of bolus chambers each of which chambers communicates a portion of the recipient'"'"'s demand gas flow rate from the regulator mechanism to the supply valve. The bolus chambers allow a high-flow pulse of respiratory gas to be delivered to the patient upon initiation of inhalation coupled with steady state flow for the remainder of inhalation. Distribution of the recipient'"'"'s gas flow rate among the several bolus chambers improves the dynamic performance of the device.

Claims

1. A pneumatically-operated gas demand apparatus coupled in interruptible fluid communication between a recipient and at least one source of a pressurized gas and adapted for controlling delivery of the pressurized gas to the recipient as the recipient inhales and exhales, comprising:

a supply valve and a sensing valve;

said supply valve being in communication with the at least one pressurized gas source, said sensing valve and the recipient, said supply valve being operable to move between a flow-supplying position and a flow-blocking position responsive to movement of said sensing valve;

said sensing valve being in communication with the at least one pressurized gas source, said supply valve and the recipient, said sensing valve being operable to move between a flow-stopping position whereby said supply valve assumes said flow-blocking position when the recipient exhales thereby preventing delivery of the gas to the recipient and a flow-causing position whereby said supply valve assumes said flow-supplying position when the recipient inhales thereby delivering the gas from the pressurized gas source to the recipient;

a regulator mechanism including at least one regulator disposed between and in interruptible fluid communication the pressurized gas source and said supply valve; and

a plurality of bolus chambers disposed between and in fluid communication with said at least one regulator and said supply valve, said plurality of bolus chambers comprising a bolus chamber adapted to accommodate a portion of pressurized gas flow delivered from said at least one regulator, and at least one additional bolus chamber adapted to accommodate at least one additional portion of pressurized gas flow delivered from said at least one regulator.

2. The apparatus of claim 1 wherein said bolus chamber and said at least one additional bolus chamber are connected in series.

3. The apparatus of claim 1 wherein said bolus chamber and said at least one additional bolus chamber are connected in parallel.

4. The apparatus of claim 1 further comprising:

a supply orifice element having a supply orifice formed therethrough, said supply orifice element being disposed and providing fluid communication between said at least one regulator and said bolus chamber; and

at least one additional supply orifice element having a supply orifice formed therethrough, said at least one additional supply orifice element being disposed and providing fluid communication between said at least one regulator and said at least one additional bolus chamber.

5. The apparatus of claim 1 wherein said portion of pressurized gas flow and said at least one additional portion of pressurized gas flow are unequal.

6. The apparatus of claim 1 wherein the ratio of maximum gas flow rate to minimum gas flow rate accommodated by said bolus chamber is about 3:

1.

7. The apparatus of claim 1 wherein the ratio of maximum gas flow rate to minimum gas flow rate accommodated by said at least one additional bolus chamber is about 3:

1.

8. The apparatus of claim 1 wherein the total gas flow rate accommodated by said bolus chamber and said at least one additional bolus chamber is about 0.5 to about 6 liters per minute.

9. The apparatus of claim 1 further comprising flow rate selector means for controlling flow of pressurized between the at least one pressurized gas source and said supply valve, said flow rate selector means including first flow control means for controlling pressurized gas flow from the at least one pressurized gas source and said at least one regulator and second flow control means for controlling pressurized gas flow from said plurality of bolus chambers to said supply valve.

10. In combination with a nebulizer for producing a medicament-containing aerosol and a source of pressurized gas, an intermittent gas delivery device disposed between and in intermittent fluid communication with the nebulizer and the source of pressurized gas, comprising:

a regulator mechanism in continuous fluid communication with and disposed downstream of the pressurized gas source;

a plurality of bolus chambers disposed downstream of and in fluid communication with said regulator mechanism, said plurality of bolus chambers comprising a bolus chamber adapted to accommodate a portion of pressurized gas flow delivered from said at least one regulator, and at least one additional bolus chamber adapted to accommodate at least one additional portion of pressurized gas flow delivered from said at least one regulator;

a plurality of supply orifices disposed and providing fluid communication between said regulator mechanism and said plurality of bolus chambers, each of said plurality of supply orifices providing fluid communication between said regulator mechanism and a respective one of said bolus chambers; and

a supply valve in downstream fluid communication with said plurality of supply orifices and operative to move between a flow-blocking position whereby the pressurized gas is prevented from flowing from the pressurized gas source to the nebulizer and a flow-supplying position whereby the pressurized gas flows from the pressurized gas source to the nebulizer such that a high flow pulse of pressurized gas first generates a fine-mist plume of the medicament-containing aerosol in the nebulizer and subsequently a steady state flow of pressurized gas continues to produce the fine-mist plume of the medicament-containing aerosol in the nebulizer until said supply valve moves to the flow-blocking position.

11. An intermittent gas delivery device according to claim 10 including a sense tube connected in fluid communication with said supply valve and having a sense tube inlet thereinto, said sense tube operative with a finger of the recipient to be placed over said sense tube inlet to cause said supply valve to be in the flow-blocking position and to be removed from said sense tube inlet to cause said supply valve to move to the flow-supplying position.