RESPIRATORY FACE MASK AND BREATHING CIRCUIT ASSEMBLY

1 . A respiratory face mask and breathing circuit assembly, comprising:

a disposable respiratory face mask and breathing circuit assembly;

a breathing circuit disposed in fluid communication between said disposable respiratory face mask, a gas delivery device, and a vacuum source;

said breathing circuit protecting an enclosed environment from exposure to exhalation gas received from said disposable respiratory face mask.

2 . The assembly of claim 1 , further comprising:

said assembly adapted to be used with commercially available nitrous oxide gas handling equipment used in dentistry; and

said assembly avoiding contamination of a surrounding environment with built-up waste N 2 0 gas;

whereby sedation is practiced safely and effectively in a hospital or other clinical environment.

3 . The assembly of claim 1 , further comprising:

said breathing circuit including a main tubular limb, a branched coupling, and a scavenging limb;

said main tubular limb having opposed first and second ends;

said main tubular limb defining a gas supply lumen of first diameter and an exhalation lumen of second diameter disposed co-axially with respect to said first diameter lumen along substantially the entire length thereof.

4 . The assembly of claim 3 , further comprising:

said first end of said main tubular limb in fluid communication with a gas coupling member for removable attachment to said face mask;

said branched coupling being attached to said second opposed second end of said main tubular limb and defining a main tubular limb connection port, a gas supply connection port and a scavenging limb connection port.

5 . The assembly of claim 4 , further comprising:

said branched coupling including a first gas flow passage extending between said main limb connection port and said fresh gas supply port for supplying fresh gas to said main limb gas supply lumen and a second gas flow passage extending between said main limb connection port and said scavenging limb connection port for receiving exhaled breath from said face mask through said gas coupling member and said main limb exhalation lumen.

6 . The assembly of claim 5 , further comprising:

said scavenging limb further including a one-way valve, a flexible exhalation bag, and a scavenging tube;

said flexible exhalation bag having an entry opening and an exit opening;

said one-way valve being disposed in said scavenging limb between said branched coupling scavenging limb connection port and said entry opening of said flexible exhalation bag such that said entry opening is connected to said branched coupling scavenging limb connection port through said one-way valve, permitting unidirectional flow of exhaled gas from said face mask through said branched coupling scavenging limb connection port into and through said entry opening; and

said scavenging tube connected to said exit opening for conveying to said vacuum source exhaled air received in said flexible exhalation bag from said branched coupling scavenging limb connection port through said one-way valve;

said waste gas being evacuated from the environment surrounding said patient when said breathing circuit apparatus is disposed in fluid communication between said face mask, said gas delivery device and said vacuum source and a patient breathes through said mask and said main limb of said breathing circuit;

said breathing circuit apparatus being disposable after a single-use to avoid cross-contamination from one patient to another.

7 . The assembly of claim 6 , further comprising:

said flexible exhalation bag having a first end and an opposed second end, said first entry opening being located in said first end and said second exit opening being located in said second opposed end;

said first entry opening in said first end being connected to said one-way valve, permitting unidirectional flow of exhaled gas from said face mask through said branched coupling scavenging limb connection port into and through said first entry opening of said flexible exhalation bag; and

said second exit opening in said opposed second end of said flexible exhalation bag being connected to said scavenging tube.

8 . The assembly of claim 7 , further comprising:

a vacuum modulating valve for modulating the vacuum produced by said vacuum source to prevent collapse of said flexible exhalation bag;

said vacuum modulating valve disposed in said scavenging tube portion of said scavenging limb.

9 . The apparatus of claim 8 , further comprising:

said vacuum modulating valve for modulating the vacuum produced by said vacuum source including an outer tube having a first diameter and an inner tube having a second diameter, said first diameter being greater than said second diameter;

at least one opening formed in said vacuum modulating valve enabling ambient air to enter said outer tube and to flow through said inner tube; and

said inner tube adapted to be connected to said vacuum source.

10 . The apparatus of claim 9 , further comprising:

said disposable face mask being adapted to cover at least the nose and mouth of a patient.

11 . The apparatus of claim 10 , further comprising:

said gas being selected from a group of gases including nitrous oxide, oxygen, or mixtures of nitrous oxide and oxygen.

12 . The apparatus of claim 9 , further comprising:

said disposable face mask adapted to engage said underside of the patient's chin; and said disposable face mask including a sealing cushion adapted to engage said underside of said patient's chin.