Patent ID: 8326421

Claim:
A ventricular assist device comprising: an intra-aortic balloon pump sized and shaped to dangle inside a patient's aorta, the pump having a wall made at least in part from a moisture-resistant material; a skin interface; an internal drive line connecting the balloon pump to the skin interface; an external driver comprising a rigid bellows, a prime mover actuating the bellows, and valves arranged to permit multiple pumping modes, the prime mover being operably connected to a power source; an arterial interface, sized and shaped to pass the internal drive line through an arterial wall; an external drive line connecting the skin interface to the external driver; a controller; and an air pressure sensor configured to detect the pumping air pressure inside the fluid system as a function of time, the air pressure sensor being so connected to the controller as to allow transmission of a signal representative of the pumping air pressure to the controller; wherein: the balloon pump, the internal drive line, the skin interface, the external drive line, and the driver form a fluid system for containing pumping air to act as a pumping medium; and the controller is programmed to: operate the valves and the prime mover such that the pumping air is not pressurized more than a predetermined amount above a sensed blood pressure, wherein operating the prime mover includes controlling the amount of power provided to the prime mover from the power source; cause the valves to adopt a closed pumping mode in which no air is added to or vented from the fluid system; cause the external driver to pump through multiple consecutive inflation-deflation cycles during the closed mode; cause the valves to adopt an open mode in which contraction of the bellows by the prime mover causes air in the fluid system to be vented from the fluid system and expansion of the bellows by the prime mover causes ambient air to be drawn into the fluid system, thereby charging the fluid system with new pumping air to act as the pumping medium; detect leaks by: receiving the signal from the air pressure sensor; comparing the pressure of the pumping air to a predetermined normal operating range by a predetermined set of operating criteria; and triggering an error state if the pressure is outside the normal operating range; and control inflation of the balloon pump by: based on the signal from the air pressure sensor, determining the time taken to inflate the balloon pump once; comparing the time required to inflate the balloon pump to a target time stored in the controller; if the time required to inflate the balloon is not within a predetermined range of the target time, calculating the power input to the external driver necessary to cause the time required to inflate the balloon to match the target time; and adjusting the amount of power subsequently provided to the driver based on the calculation.