Fluid pressure generating means
A fluid pressure generating means ( 10 ) for a heart assist device having blood pumping means. The pressure generating means ( 10 ) includes a housing ( 11 ), defining an interior volume ( 18 ), and having a substantially rigid first housing portion ( 12 ), a substantially rigid second housing portion ( 14 ), a flexible third housing portion ( 16 ) extending between the first ( 12 ) and second ( 14 ) housing portions and an inlet/outlet port ( 15 ) adapted for fluid communication with the blood pumping means. The pressure generating means ( 10 ) also includes a fluid filling the housing and a motor ( 20 ) disposed within the housing ( 11 ) and connected between the first ( 12 ) and second ( 14 ) housing portions. Actuation of the motor ( 20 ) moves the first ( 12 ) and second ( 14 ) housing portions relative to one another to generate fluid pressure changes at the inlet/outlet port ( 15 ). A related heart assist device and method for the treatment of congestive heart failure, myocardial ischemia and like conditions are also disclosed.
1. In a fluid pressure generating device for a heart assist device having a blood pumping means, the improvement comprising:
a housing defining an interior volume, and having a substantially rigid first housing portion, a substantially rigid second housing portion, a flexible third housing portion extending between the first and second housing portions and an inlet/outlet port connected to one of said housings and adapted to place the interior volume of the housing in fluid communication with the blood pumping means, wherein the third housing has an outer surface about its periphery, an inner surface facing into the interior of the housing and is joined along an edge to the first housing portion;
a liquid fluid for driving the blood pumping means filling the interior volume of the housing; and
a motor disposed within the interior volume of the housing and immersed within the fluid for driving the blood pumping means, the motor being connected between the first and second housing portions,
wherein actuation of the motor moves the first and second housing portions relative to one another to generate fluid pressure changes at the inlet/outlet port, wherein a positive pressure change causes inflation of the blood pumping means and a negative pressure change causes deflation of the blood pumping means.
2. The fluid pressure generating device as claimed in claim 1 , wherein the blood pumping means is adapted to displace blood from the aorta of a patient in counter-pulsation with the patient's heart.
3. The fluid pressure generating device as claimed in claim 2 , wherein the blood pumping means is adapted to displace blood from the ascending aorta of the patient.
4. The fluid pressure generating device as claimed in claim 1 , wherein the fluid pressure generating device is adapted to drive a conventional left ventricular assist device or an extra-ventricular co-pulsation heart compression device.
5. The fluid pressure generating device as claimed in claim 1 , wherein one of the first and second housing portions is moveable and the other of the first and second housing portions is fixed, the moveable housing portion being exposed to the outside of the heart assist device and adapted to interface with the lung of a patient.
6. The fluid pressure generating device as claimed in claim 1 , wherein one of the first and second housing portions is moveable and the other of the first and second housing portions is fixed, the moveable housing portion not being exposed to the outside of the heart assist device and the device including a flexible compliance chamber.
7. The fluid pressure generating device as claimed in claim 6 , wherein the compliance chamber is in contact with the lung of a patient.
8. The fluid pressure generating device as claimed in claim 1 , wherein the actuating means includes a nut coupled to one of the first and second housing portions and a threaded shaft coupled to the other of the first and second housing portions, the threaded shaft and the nut being threadedly engaged and the motor being adapted to rotate the nut relative to the threaded shaft.
9. The fluid pressure generating device as claimed in claim 8 , wherein the nut is connected to the moveable one of the first and second housing portions and the threaded shaft is connected to the fixed one of the first and second housing portions.
10. The fluid pressure generating device as claimed in claim 7 , wherein the threaded shaft is connected to the moveable one of the first and second housing portions and the nut is connected to the fixed one of the first and second housing portions.
11. The fluid pressure generating device as claimed in claim 1 , wherein the outflow of the fluid from the inlet/outlet port is axial to the housing.
12. The fluid pressure generating device as claimed in claim 1 , wherein the outflow of the fluid from the inlet/outlet port is radial to the housing.
13. The fluid pressure generating device as claimed in claim 1 , wherein the outflow of the fluid from the inlet/outlet port is tangential to the housing.
14. The fluid pressure generating device as claimed in claim 1 , wherein a surface of the device is curved to fit snugly with the chest wall or mediastinum of a patient.
15. The fluid pressure generating device as claimed in claim 1 , wherein the aortic compression means is in the form of a fluid operated cuff adapted to surround the patient's aorta.
16. The fluid pressure generating device as claimed in claim 1 , wherein the liquid is an oil or saline.
17. The fluid pressure generating device as claimed in claim 16 , wherein the oil is a silicone oil.
18. The fluid pressure generating device as claimed in claim 17 , wherein the oil has a viscosity between 10 and 100 centistokes.
19. The fluid pressure generating device as claimed in claim 18 , wherein the oil has a viscosity between 10 and 30 centistokes.