Multiple function blood coupler

Claim 1

A blood coupler for a heart-assist circulatory support system comprising power supply means for producing from a supply of hydraulic pumping fluid at a first temperature and a first pressure a supply of hydraulic fluid at a second higher temperature and a second higher pressure, a blood pump comprising a thin resilient expansible bladder sealed in a housing between openings adapted to be connected in a blood circulation system, said openings being provided with check valves to produce a pulsing unidirectional flow of blood through said bladder when hydraulic fluid is forced in and out of said housing outside of said bladder, and fluid exchange means connected between said housing and said power supply by a supply line containing pumping fluid at said first temperature and pressure and a return line containing pumping fluid at said second temperature and pressure, said fluid exchange means comprising an inlet chamber, an outlet chamber, a communicating passage between said inlet chamber and said outlet chamber, and thermally conductive piston means movable in said communicating passage to vary the volume of said inlet chamber with respect to the volume of said outlet chamber, means connecting said outlet chamber to said housing to exchange hydraulic fluid with said pump, means responsive to a drop in pressure in said bladder for connecting said supply line to said inlet chamber to admit a slug of fluid to said inlet chamber, thereby moving said piston means to drive fluid into said pump to compress said bladder while cooling the fluid in the inlet chamber and heating the fluid in the outlet chamber, while cooling the fluid in the housing and heating blood in the bladder, and means responsive to the volume of said outlet chamber for connecting said inlet chamber to said return line and disconnecting said supply line when said outlet chamber reaches a predetermined minimum volume.