Apparatus and methods for reducing foaming during saliva collection
A saliva collector comprises a reservoir, a bubble barrier, and a membrane, where the bubble barrier and membrane are arranged in tandem on a flow path from an inlet to an outlet on the reservoir. Air aspirated from a patient's oral cavity enters the reservoir through the inlet, passes through the bubble barrier to remove foam and bubbles, passes through the membrane to remove entrained liquid saliva, and passes out through the outlet.
1. A method for removing saliva from an air stream aspirated from a patient's oral cavity, said method comprising:
drawing, with a vacuum source, the air stream from an oral appliance held at least partially in the patient's oral cavity with a bite structure of the oral appliance held between upper and lower teeth of the patient, wherein drawing the air stream from the oral appliance maintains a clear breathing passage of the patient and reduces a likelihood of obstructive sleep apnea;
directing the air stream through a reservoir from an inlet, along a flow path, and to an outlet, wherein liquid saliva entrained in the air stream forms bubbles and foam; and
separating the bubbles and foam from the air stream to provide a pre-treated air stream by passing the air stream through a bubble barrier before passing the pre-treated airstream out through the outlet to the vacuum source, thereby minimizing entry of the saliva into the vacuum source and reducing a likelihood of fouling of the vacuum source,
wherein the bubble barrier comprises a mesh, and
wherein the mesh is cylindrical with the flow path passing radially inwardly and upwardly from the cylinder and further axially outwardly towards the outlet so that the foam and bubbles coalesce and return to a liquid state, separate, and fall to a bottom of the reservoir.
2. A method as in claim 1 , further comprising passing the pre-treated air stream through a membrane to separate the entrained liquid saliva, wherein the pre-treated air stream passes through the membrane after passing through the bubble barrier.
3. A method as in claim 2 , wherein the membrane has both hydrophobic and oleophobic properties with an air flow resistance less than 40 cmH 2 O at a flow rate of 120 ml/min.
4. A method as in claim 3 , wherein the membrane is composed of a material selected from the group consisting of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyethersulfone (PES), optionally coated to enhance oleophobicity to hydrophobic materials or to enhance hydrophobicity in hydrophilic materials.
5. A method as in claim 2 , further comprising disconnecting the reservoir from inlet and outlet conduits, draining collected saliva, cleaning the bubble barrier and membrane, and reconnecting the reservoir to the inlet and outlet conduits.
6. A method as in claim 1 , wherein directing the air stream comprises drawing a partial vacuum on the outlet of the reservoir.
7. A method as in claim 6 , wherein the oral appliance is connected to the inlet of the reservoir by tubing.
8. A method as in claim 1 , wherein the mesh is composed of a polymer.
9. A method as in claim 1 , wherein the barrier has openings with an area from 0.5 mm 2 to 2 mm 2 .
10. A method as in claim 1 , wherein the flow rate of the air stream is in the range from 20 ml/min to 1000 ml/min.
11. A method as in claim 1 , wherein the oral appliance held at least partially in the patient's oral cavity is configured to draw one or more of the soft palate or posterior portions of the tongue away from the pharynx to maintain the clear breathing passage.