Nasal/oral cannula system and manufacturing
A nasal/oral cannula for collecting a flow of exhaled gases and its method of manufacture are disclosed. The cannula comprises an elongated tubular body having a first and a second end portion, a surface and an internal volume; a wall internally disposed within said tubular body, said wall defining a first subvolume of said internal volume in the lengthwise direction of the tubular body; and an inlet through said surface, for introducing exhaled gases into said first subvolume. The first end portion defines an exit port for exhaled gases from said subvolume, and said wall is arranged directly adjacent to said inlet.
1. A method of manufacturing a respiratory cannula system for collecting exhaled gases, the method comprising:
obtaining a mold, the mold comprising a first cavity for forming an elongated tubular body of a cannula and a second cavity for forming a first prong of the cannula;
positioning first and second insert pins at least partially inside said first cavity such that ends of the first and second insert pins are spaced from one another inside said first cavity by a gap, said gap for forming an inner wall within an interior of the elongated tubular body;
positioning a third insert pin at least partially inside said second cavity and said first cavity such that an end of the third insert pin contacts the first insert pin, thereby facilitating formation of an inlet hole through the elongated tubular body for collecting exhaled gases from the first prong, wherein the ends of the first and second insert pins are positioned within said first cavity such that said gap is arranged proximate said second cavity, thereby facilitating formation of said inner wall proximate said inlet hole; and
inserting material into said first and second cavities of the mold around the first insert pin, the second insert pin, and the third insert pin to form said elongated tubular body, said first prong, said inner wall, and said inlet hole of said cannula.
2. The method according to claim 1 , wherein the mold comprises a third cavity for forming a second prong of the cannula.
3. The method according to claim 2 , wherein said inlet hole is a first inlet hole through the elongated tubular body, and wherein the method further comprises positioning a fourth insert pin at least partially inside said third cavity and said first cavity such that an end of the fourth insert pin contacts the second insert pin, thereby facilitating formation of a second inlet hole through the elongated tubular body.
4. The method according to claim 3 , wherein the second inlet hole is spaced apart from and aligned with the first inlet hole along the elongated tubular body.
5. The method according to claim 3 , wherein said second inlet hole is configured to allow treating gases to flow to said second prong of the cannula.
6. The method according to claim 1 , further comprising:
obtaining a first nozzle; and
solvent bonding the formed cannula to the first nozzle.
7. The method according to claim 1 , wherein said mold further comprises a first body element and a second body element, and wherein the method further comprises separating the first and second body elements from one another after inserting said material into said first and second cavities.
8. The method according to claim 1 , wherein said second cavity comprises a conical shape.
9. The method according to claim 1 , wherein said material comprises PVC or polyurethane.
10. The method according claim 6 , wherein said solvent bonding the formed cannula to the first nozzle comprises:
dipping said formed cannula and said first nozzle in a solvent; and
mounting an end of the formed cannula to the first nozzle.
11. The method according to claim 6 , wherein said solvent comprises tetrahydrofuran or cyclohexanone, either used separately or in combination.