A high-frequency transvalvular blood pump (10) for temporary cardiac assist devices provides suction to decompress the ventricular cavity (18) during both systole and diastole. The intake end (30) of the pump (10) is connected to a cannula (12) which is inserted into the ventricular cavity (18) through the aortic valve (16), and which has an intake opening (22) at its distal end. The intake (30) and outflow (32) ends of the pump (10) are closed, respectively, by one-way valves (40, 42) which allow blood flow only in the direction of body perfusion. The pump (10) itself consists of a stiff barrel (26) whose interior volume can be alternately reduced and expanded by a flexible membrane (28) controlled by pneumatic or hydraulic pressure from extracorporeal structure through a percutaneously inserted lumen (24).

High-frequency transvalvular axisymmetric blood pump

An intra-arterial cardiac support system including multiple balloons for placement in the descending aorta with one balloon serving as a pumping balloon and one or more balloons serving as valve balloons, at least one of the valve balloons being positioned distal to the natural heart. The balloons are individually inflated and deflated to provide for sequential pumping action, with the sequence operating in timed relation to the sytstole and diastole of the natural heart.

Intra-arterial cardiac support system

Disclosed are devices and methods for the control of body fluid flow in the extracorporeal treatment of body fluid. Body fluid flow through on of a body fluid flow circuit (10, 50, 60, 100 or 250) is controlled by alternating applying vacuum pressure and positive pressure to the circuit through a pumping chamber (30, 51, 66, 102, or 200) coordinated with flow control valves (40, 42, 44, 62, 114, 116, 118, and 120) to effect a net downstream flow of body fluid through the circuit.

Devices and methods for body fluid flow control in extracorporeal fluid treatments

A non-invasive aortic blood flow sensor is disclosed. The sensor determines the blood flow in the aorta of a patient based on the pressure difference between the right and left subclavian arteries. The pressure of the subclavian arteries is non-invasively measured by determining the blood pressures in the arteries of the patient's right and left arms by means of tonometric blood pressure sensors. The signals from the tonometric sensors are first equalized to account for any pressure waveform distortion due to propagation of the pulse from the aorta to the sensor locations. Next, a correction is made for DC offset. The modified pressure signals are then compared, and the pressure difference determined. The blood flow is determined from the pressure difference by known pressure/flow relationships.

Non-invasive aortic blood flow sensor and method for non-invasively measuring aortic blood flow

A redundant, pneumatic driver for a blood pump in which a pair of pistons are contained in a common cylinder and their stroke rates and lengths are selectively controlled by a controller which non-invasively senses the circulatory system requirements of the patient in which the blood pump is implanted. The controller varies the stroke rates and lengths to meet such requirements and further is able to selectively switch driving functions from one piston to the other to provide a redundant driving capability.

Redundant piston pump for the operation of single or multiple chambered pneumatic blood pumps

The volume of blood pumped by an artificial ventricle or ventricular assist device is extracorporeally monitored as a function of the volume of fluid used to drive the ventricle. The ventricle is divided into two chambers by a flexible diaphragm. Fluid is alternately supplied to one chamber during systole and then removed from that chamber during diastole. In the preferred embodiment, during systole the rate of fluid flow is sensed by establishing a differential pressure between two points in the fluid's flow path. The differential pressure is converted to a proportional voltage which may be integrated to provide the desired volume over a given time interval, which corresponds to the cardiac output within ±5-10%.

Steven D. Nielson

Papers

Cardiac flow measurement system and method