Method of fabricating a heater coil for a catheter used to monitor cardiac output
First Claim
1. A method for making a heater for a catheter that is employed to monitor cardiac output, comprising the steps of:
- (a) providing a catheter having at least one lumen adapted to accept a heater lead;
(b) coating a wire with a thermoplastic material to form a coated lead;
(c) winding the coated lead around the catheter to form a heater coil, said heater coil having gaps between adjacent coils of the coated lead; and
(d) elevating the temperature of the heater coil above a melting temperature of the thermoplastic material, causing said material to flow into and fill the gaps between adjacent coils of the coated lead and bonding the heater coil to the catheter.
4 Assignments
0 Petitions
Accused Products
Abstract
A heater (12) for a catheter (10) used in monitoring constant cardiac output is fabricated using a bifilar wire (21) coated with polyvinyl chloride (PVC) like the material used for the catheter. The bifilar wire is coated with the PVC using a conventional extrusion technique, producing a coated lead (24, 32). This coated lead is wrapped around the exterior surface of the catheter, forming a helical coil. Heat is applied to the coated lead to melt the PVC coating, causing it to bond the lead to the catheter. The melted PVC also flows into gaps (23) or notches between adjacent coils of the lead, producing a relatively smooth outer surface for the heater coil when the PVC coating cools. The bifilar wire can alternatively be wrapped in-line with PVC tape (29) or film and the PVC material heated to flow around the wire, bonding it to the catheter'"'"'s outer surface.
29 Citations
26 Claims
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1. A method for making a heater for a catheter that is employed to monitor cardiac output, comprising the steps of:
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(a) providing a catheter having at least one lumen adapted to accept a heater lead; (b) coating a wire with a thermoplastic material to form a coated lead; (c) winding the coated lead around the catheter to form a heater coil, said heater coil having gaps between adjacent coils of the coated lead; and (d) elevating the temperature of the heater coil above a melting temperature of the thermoplastic material, causing said material to flow into and fill the gaps between adjacent coils of the coated lead and bonding the heater coil to the catheter. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for attaching a heater to a catheter comprising the steps of:
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(a) winding an insulated heater wire around an exterior surface of the catheter; (b) applying a plastic material over the insulated heater wire; (c) subjecting the plastic material to an elevated temperature so that the plastic material experiences a change in state and secures the insulated heater wire to the exterior surface of the catheter; and (d) cooling the plastic material to an ambient temperature. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16)
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17. A method for producing a coiled conductor having a substantially smooth surface, on an exterior of a catheter, said method comprising the steps of:
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(a) extruded a thermoplastic coating on a wire, said thermoplastic coating being selected in part for its characteristic melting temperature, said wire having an electrically insulating layer that is substantially covered by the thermoplastic coating; (b) coiling the wire covered by the thermoplastic coating around the catheter, forming a plurality of adjacent coils; and (c) heating the thermoplastic coating on the wire that is coiled above its characteristic melting temperature, causing the thermoplastic coating to melt and flow, forming a substantially smooth outer surface over the adjacent coils and adhering the wire to the catheter. - View Dependent Claims (18, 19, 20, 21)
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22. A method for securing a heater on an exterior of a catheter, said method comprising the steps of:
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(a) coiling an insulated wire around an outer surface of the catheter, forming a plurality of adjacent coils; (b) covering the coils of the insulated wire with a plastic material; and (c) heating the plastic material to an elevated temperature so as to cause the plastic material to change state and form around the outer surface of the coils, said plastic material thereby securing the insulated wire to the outer surface of the catheter. - View Dependent Claims (23, 24, 25, 26)
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Specification