Apparatus and method for pneumatically driving an implantable medical device
A driver is disclosed for powering a pneumatically operated implantable device, such as an artificial heart with a left and a right ventricle. The driver includes a pair of compressors that each has a first and a second compression chamber. In a first mode of operation, both the first and the second compressor power the left and right ventricle of the artificial heart. In the event of a malfunction in the second compressor, the left and right ventricles of the artificial heart may be powered by the first compressor. Similarly, if a malfunction occurs in the first compressor, the artificial heart may be fully powered by the second compressor.
1. A pulsatile pneumatic driver configured to provide pneumatic power to an implantable artificial heart, the driver comprising:
a first compressor that includes a first pair of compression chambers, at least one of the first pair of compression chambers having a swept volume that is at least 160 cubic centimeters;
a second compressor that includes a second pair of compression chambers, at least one of the second pair of compression chambers having a swept volume that is at least 160 cubic centimeters;
a first air outlet and a second air outlet in selective communication with two or more compression chambers of the first and second pair of compression chambers; and
a valve that is movable between a normal operation position associated with a normal mode of operation of the driver, a first backup position associated with a first backup mode of operation of the driver and a second backup position associated with a second backup mode of operation of the driver;
wherein when in the normal mode of operation, the first air outlet is in fluid communication with one of the first pair of compression chambers and the second air outlet is in fluid communication with one of the second pair of compression chambers;
wherein when in the first backup mode of operation, the first air outlet is in fluid communication with one of the first pair of compression chambers and the second air outlet is in fluid communication with another of the first pair of compression chambers; and
wherein when in the second backup mode of operation, the first air outlet is in fluid communication with one of the second pair of compression chambers and the second air outlet is in fluid communication with another of the second pair of compression chambers.
2. The pulsatile pneumatic driver of claim 1 , further comprising:
a controller;
a first pressure sensor in fluid communication with the first air outlet and a second pressure sensor in fluid communication with the second air outlet;
a first pressure relief valve in fluid communication with the first air outlet and a second pressure relief valve in fluid communication with the second air outlet;
wherein the controller controls each of the first and second pressure relief valves to open at a pressure, as sensed by the first and second pressure sensors, respectively.
3. The pulsatile pneumatic driver of claim 1 , further comprising:
a controller;
a first pressure sensor in fluid communication with the first air outlet and a second pressure sensor in fluid communication with the second air outlet;
a first vacuum valve in fluid communication with the first air outlet and a second vacuum valve in fluid communication with the second air outlet, wherein the controller controls each of the first and second vacuum valves to maintain a user-defined vacuum level at the first and second air outlet, respectively, as a corresponding compression chamber is expanded.
4. The pulsatile pneumatic driver of claim 3 , wherein each of the first and second vacuum valves comprise a gate valve having a gate with a tear-drop shaped aperture.
5. The pulsatile pneumatic driver of claim 4 , further comprising:
a first check valve positioned between the first air outlet and the first vacuum valve, the first check valve configured to close fluid communication between the first air outlet and the first vacuum valve during compression of a corresponding compressor; and
a second check valve positioned between the second air outlet and the second vacuum valve, the second check valve configured to close fluid communication between the second air outlet and the second vacuum valve during compression of a corresponding compressor.
6. The pulsatile pneumatic driver of claim 1 , wherein each of the first pair of compression chambers and each of the second pair of compression chambers has a swept volume that is at least 195 cubic centimeters.
7. The pulsatile pneumatic driver of claim 1 , further comprising:
an implantable artificial heart having a right ventricle in fluid communication with the first air outlet and a left ventricle in fluid communication with the second air outlet.
8. The pulsatile pneumatic driver of claim 7 , wherein each of the left and right ventricles has a displacement of 70 cubic centimeters.
9. The pulsatile pneumatic driver of claim 7 , wherein at least one of the first pair of compressors and at least one of the second pair of compressors has a swept volume that is more than 2.5 times the displacement of each of the left and right ventricles of the implantable artificial heart.
10. The pulsatile pneumatic driver of claim 1 , wherein the first compressor includes a first cylinder and a first piston that moves through the cylinder, wherein one of the first pair of compression chambers lies on a first side of the first piston and another of the first pair of compression chambers lies on a second side of the first piston; and
wherein the second compressor includes a second cylinder and a second piston that moves through the second cylinder, wherein one of the second pair of compression chambers lies on a first side of the piston and another of the second pair of compression chambers lies on a second side of the second piston.
11. The pulsatile pneumatic driver of claim 10 , further comprising:
a first seal between the first cylinder and the first piston and a second seal between the second cylinder and the second piston, each of the first and second seals being free of liquid lubrication.
12. A pulsatile pneumatic driver configured to provide pneumatic power to an implantable artificial heart, the driver comprising:
a first compressor that includes a first pair of compression chambers;
a second compressor that includes a second pair of compression chambers;
a first air outlet and a second air outlet in selective communication with two or more compression chambers of the first and second pair of compression chambers;
a valve that is movable between a normal operation position associated with a normal mode of operation of the driver, a first backup position associated with a first backup mode of operation of the driver and a second backup position associated with a second backup mode of operation of the driver;
wherein when in the normal mode of operation, the first air outlet is in fluid communication with one of the first pair of compression chambers and the second air outlet is in fluid communication with one of the second pair of compression chambers;
wherein when in the first backup mode of operation, the first air outlet is in fluid communication with one of the first pair of compression chambers and the second air outlet is in fluid communication with another of the first pair of compression chambers; and
wherein when in the second backup mode of operation, the first air outlet is in fluid communication with one of the second pair of compression chambers and the second air outlet is in fluid communication with another of the second pair of compression chambers;
a controller that monitors operation of the driver and causes the valve to move from the normal operation position to one of the first and second backup positions upon detection of a fault;
wherein the fault comprises the first and second compressors operating more than 180 degrees out of phase with one another.
13. A pulsatile pneumatic driver configured to provide pneumatic power to an implantable artificial heart, the driver comprising:
a first compressor that includes a first pair of compression chambers;
a second compressor that includes a second pair of compression chambers;
a first air outlet and a second air outlet in selective communication with two or more compression chambers of the first and second pair of compression chambers;
a valve that is movable between a normal operation position associated with a normal mode of operation of the driver, a first backup position associated with a first backup mode of operation of the driver and a second backup position associated with a second backup mode of operation of the driver;
wherein when in the normal mode of operation, the first air outlet is in fluid communication with one of the first pair of compression chambers and the second air outlet is in fluid communication with one of the second pair of compression chambers;
wherein when in the first backup mode of operation, the first air outlet is in fluid communication with one of the first pair of compression chambers and the second air outlet is in fluid communication with another of the first pair of compression chambers; and
wherein when in the second backup mode of operation, the first air outlet is in fluid communication with one of the second pair of compression chambers and the second air outlet is in fluid communication with another of the second pair of compression chambers;
a controller that monitors operation of the driver and causes the valve to move from the normal operation position to one of the first and second backup positions upon detection of a fault;
wherein the controller monitors a first pair of redundant position sensors associated with the first compressor and a second pair of redundant position sensors associated with the second compressor to determine the fault.
14. A pulsatile pneumatic driver configured to provide pneumatic power to an implantable artificial heart, the driver comprising:
a first compressor that includes a first pair of compression chambers;
a second compressor that includes a second pair of compression chambers;
a first air outlet and a second air outlet in selective communication with two or more compression chambers of the first and second pair of compression chambers;
a valve that is movable between a normal operation position associated with a normal mode of operation of the driver, a first backup position associated with a first backup mode of operation of the driver and a second backup position associated with a second backup mode of operation of the driver;
wherein when in the normal mode of operation, the first air outlet is in fluid communication with one of the first pair of compression chambers and the second air outlet is in fluid communication with one of the second pair of compression chambers;
wherein when in the first backup mode of operation, the first air outlet is in fluid communication with one of the first pair of compression chambers and the second air outlet is in fluid communication with another of the first pair of compression chambers; and
wherein when in the second backup mode of operation, the first air outlet is in fluid communication with one of the second pair of compression chambers and the second air outlet is in fluid communication with another of the second pair of compression chambers;
a controller that monitors operation of the driver and causes the valve to move from the normal operation position to one of the first and second backup positions upon detection of a fault;
wherein the controller monitors pressure and flow rate associated with each of the first and second air outlets to identify the fault.