Ventless mask CPAP system

1. A CPAP system comprising:

a mask provided to a patient in use, the mask including a breathing chamber;

a flow generator in communication with the mask;

a positive pressure line to provide positive pressure air from the flow generator to the mask; and

a vacuum or return line provided to actively extract and/or remove gas exhausted by the patient,

wherein the vacuum or return line is configured and positioned to direct the gas exhausted by the patient to the flow generator without recirculation to the patient, and

the vacuum or return line is in communication with a vent outlet provided on the flow generator.

2. The CPAP system of claim 1 , wherein the mask includes a nozzle assembly including a pair of nozzles provided to respective nares of the patient in use.

3. The CPAP system of claim 2 , wherein at least one of the nozzles includes a dual wall construction including an inner wall and an outer wall defining a substantially annular passage therebetween in communication with the vacuum line.

4. The CPAP system of claim 2 , wherein the nozzle assembly includes a first end portion with an elbow in communication with the positive pressure line and a second end portion with an elbow in communication with the vacuum line.

5. The CPAP system of claim 2 , wherein the nozzle assembly includes a first end portion that is closed and a second end portion provided with an elbow, the nozzle assembly including a main body having a baffle therein to define a first chamber in communication with the positive pressure line and a second chamber in communication with the vacuum line.

6. The CPAP system of claim 5 , wherein the elbow includes at least a portion of each of the positive pressure line and the vacuum line.

7. The CPAP system of claim 5 , wherein the baffle is generally planar or a hollow cylinder.

8. The CPAP system of claim 1 , wherein the mask includes a port to communicate the chamber with the vacuum or return line.

9. The CPAP system of claim 1 , wherein the positive pressure line includes an air delivery tube, and the vacuum or return line includes a relatively smaller tube which is spirally wound around the perimeter of the air delivery tube.

10. The CPAP system of claim 1 , wherein the flow generator includes a blower and a vacuum pump.

11. The CPAP system of claim 10 , wherein the vacuum pump and the blower comprise separate components.

12. The CPAP system of claim 10 , wherein the vacuum pump is integral with the blower.

13. The CPAP system of claim 12 , wherein the integral vacuum pump and blower include a motor including first and second shaft ends and respective supply and vacuum impellers provided thereto.

14. The CPAP system of claim 1 , further comprising a noise reducing device or muffler within the flow generator provided between the vent outlet and the return or vacuum line.

15. A CPAP system of claim 1 , further comprising a control member or valve provided to the flow generator in communication with the vacuum or return line, wherein the control member or valve is controlled based on the sensing of at least one of pressure, flow and CO 2 .

16. The CPAP system of claim 15 , wherein the control member or valve is controlled at least in part based on a breathing pattern of the patient, wherein the control member or valve is closed during inhalation and open during exhalation.

17. The CPAP system of claim 1 , further comprising a blow-in valve provided to the positive pressure line.

18. The CPAP system of claim 1 , further comprising a bypass provided to the vacuum or return line, the bypass having access to a source of pressurized gas which is accelerated via a venturi, to thereby actively draw gas exhaled by the patient along the vacuum or return line.

19. The CPAP system of claim 1 , wherein the vacuum line is coupled to a vacuum pump operable at a constant rate.