Patent ID: 7357786

Claim:
A passively still-air insulated and electrically actively warmed disposable outlet patient flow line system for in-line blood/fluid warmers comprising: A.) a flexible tube flow line made of polyvinyl chloride or other resinous material has a central blood-carrying tube about 0.12 inch inside diameter and a wall thickness of about 0.04 inch, and is supported inside a larger tube which is co-extruded with said central tube and has an outside diameter of about 0.37 inch and a wall thickness of about 0.04 inch, said central and outer tubes being interconnected by co-extruded webs about 0.04 inch thick which appear in cross section as a planar diametrical web across the entire cross section with the exception of said central tube's lumen, wherein an annular space between said central and outer tubes is filled with heat insulative still air, B.) said flexible tube flow line having an inlet end adapted to connect to the warm blood outlet of an in-line blood warmer apparatus and an outlet end adapted to a patient intravenous site, C.) a flexible elongated electrical resistance heater segment located within each half of said annular air space, D.) said flexible elongated electrical resistance heater segments extending in length from about one half to nine tenths the length of said flexible tube flow line, and extending all the way to said outlet end of said flexible tube flow line, E.) said flexible elongated electrical resistance heater segments being electrically and mechanically joined together at said outlet end of said flexible tube flow line forming a series electrical resistance heater, F.) the two proximal ends of said flexible elongated electrical resistance heater segments being electrically and mechanically adapted to be removably connected to a temperature controller located in said blood warmer apparatus, G.) said flexible elongated electrical resistance heater segments being maintained at a controlled temperature of about 42C, whereby convective heat loss to cooler ambient air is replaced and blood is maintained at normothermic temperature near 42C while passing slowly at very low flow rates through said patient flow line system to the patient's i.v. site.