A device (100) for dispensing a therapeutic gas to a patient is disclosed. The device comprises a compressed gas cylinder (101) containing the therapeutic gas, first (103) and second (106) valves, first (104) and second (105) pressure regulators, and a measurement chamber (108) having a defined volume of therapeutic gas at a predetermined pressure set by the first pressure regulator. The compressed gas cylinder is coupled to the input of the first valve. The output of the first valve is coupled the input of the first pressure regulator. The output of the first pressure regulator is coupled to both the measurement chamber and the input of the second pressure regulator. The output of the second pressure regulator is coupled to the input of the second valve. The output of the second valve is coupled to the patient. A sequencing mechanism (107) is coupled to the first valve and the second valve. The sequencing mechanism alternately opens and closes the first and second valves to allow the measurement chamber to receive therapeutic gas from the compressed gas cylinder and then dispense the gas from the measurement chamber to the patient. When implemented in a hand-held dispenser, the hand-held dispenser may reliably deliver consistent doses of gas regardless of the unknown state and pressure of the therapeutic gas in the compressed gas cylinder.
