Patent ID: 7364682

Claim:
A method of forming a cannula comprising the steps of: assembling a cannula mandrel assembly comprising separable engageable parts including a main body mandrel, at least one nasal prong mandrel, and a mouthpiece mandrel including a fluid passage prong having a first end to connect with the main body mandrel and a retainer prong spaced apart from and extending along the fluid passage prong and having a first end terminating adjacent the main body mandrel; heating the cannula mandrel assembly to a desired temperature; providing an uncured cannula forming polymeric material in flowable state; applying at least one coating of the polymeric material to the cannula mandrel assembly to provide a desired material thickness coating on the cannula mandrel assembly and forming the cannula; at least partially curing the coating of the polymeric material on the cannula mandrel assembly; and disassembling the cannula mandrel assembly by withdrawing the at least one prong mandrel, the mouthpiece mandrel including the fluid passage prong and the retainer prong and the main body mandrel from the formed cannula, and introducing a shape retaining material into a retainer passage formed by the retainer prong.