Described herein are pumps that linearly reciprocate to assist with circulating blood within the body of a patient. Red blood cell damage may be avoided or minimized by such linear pump movement. The linearly reciprocating movement may also generate a pulsatile pumping cycle that mimics the natural pumping cycle of the heart. The pumps may be configured to reside at various body locations. For example, the pumps may be situated within the right ventricle, the left ventricle, the ascending aorta, the descending aorta, the thoracic aorta, or the abdominal aorta. In some instances, the pump may reside outside the patient.

A hemodialysis system configured to purge air from a blood circuit comprising: a dialyzer; a dialysis fluid circuit operable with the dialyzer via dialysis fluid inlet and outlet lines; the blood circuit operable with the dialyzer and including an arterial line, a venous line, a blood pump operable with the arterial line upstream of the dialyzer, and a physiologically acceptable fluid source in fluid communication with the arterial line upstream of the blood pump; and an air purging scheme wherein, with the dialysis fluid inlet and outlet lines connected to the dialyzer, air is purged using dialysis fluid or other physiologically acceptable fluid pumped by at least one of the fresh or used dialysis fluid pumps from the dialysis fluid circuit, through the dialyzer, into the blood circuit, in combination with dialysis fluid or other physiologically acceptable fluid from the source introduced directly into the blood circuit.

There is described an artificial heart comprising a pump, the pump comprising a housing (10) defining a substantially spherical cavity and comprising four vascular connectors (15.sub.in, 15.sub.out, 15.sub.in, 15.sub.out), namely two inlet connectors (15.sub.in, 15.sub.in) and two outlet connectors (15.sub.out, 15.sub.out) to connect the pump to the pulmonary and systemic circulation. A rotatable disc (11) is mounted within the housing (10) and secured to rotate about a fixed axis (12). Two oscillating palettes (16a, 16b) are mounted to rotate about a mobile axis (17) movable within a plane perpendicular to the fixed axis (12), wherein said palettes (16a, 16b) are connected together and are arranged on both sides of the rotatable disc (11), in a diametrically opposed fashion, to create two pumping units comprising each two variable sized chambers (20a, 20b, 20c, 20d) in fluid communication with one corresponding inlet and outlet connector respectively. The pump is provided with constrain means (21) configured to cause an oscillating movement of each oscillating palette (16a, 16b) relative to the rotatable disc (11), when the pump is operating, in order to produce simultaneously two suction strokes and two discharge strokes, so as to pump blood from the inlet connectors (15.sub.in, 15.sub.in) into one chamber (20a, 20c) of each pumping unit while expelling blood from the other chamber (20b, 20d) of each pumping unit through the outlet connectors (15.sub.out,15.sub.out). The pump further comprises a drive unit configured to operate the pump. According to the invention the drive unit is configured to produce a rotating magnetic field inside the pump housing (10).

Membranes are provided to be specially developed for use in chambers for artificial circulatory assistance which may be employed primarily in cardiovascular procedures, notably to produce arterial capacitance, to regulate blood pressure, to produce aortic counterpulsation and to pump blood. The membrane may have circular sections that may vary in size or not depending on the function to be performed and are interconnected so that the transition between one section and the other is smooth, regardless of the size of each section. Further, chambers and pumps may be used for cardiopulmonary bypass and a pumping system.

Membranes are provided to be specially developed for use in chambers for artificial circulatory assistance which may be employed primarily in cardiovascular procedures, notably to produce arterial capacitance, to regulate blood pressure, to produce aortic counterpulsation and to pump blood. The membrane may have circular sections that may vary in size or not depending on the function to be performed and are interconnected so that the transition between one section and the other is smooth, regardless of the size of each section. Further, chambers and pumps may be used for cardiopulmonary bypass and a pumping system.

A hemodialysis system includes a blood treatment machine, a blood pump housed by the blood treatment machine, a first dialysate pump housed by the blood treatment machine, a second dialysate pump housed by the blood treatment machine; and a fluid cassette including an upper portion and a lower portion. The fluid cassette further includes a blood pumping tube extending from the upper portion to the lower portion of the fluid cassette, a first dialysate pumping tube extending from the upper portion to the lower portion of the fluid cassette, and a second dialysate pumping tube extending from the upper portion to the lower portion of the fluid cassette.

A positive displacement pump that triggers with the beating of a mammalian heart, through the monitoring of an ECG signal is disclosed. A programmable delay from the detection of the forthcoming contraction of the heart enables the pump to syncopate the ejection of the fluid with the events occurring in the cardiovascular system. This delayed ejection could be used to overlay the ejected fluid from the pump with a pressure wave in the artery of systemic circulation through a catheter connection between the pump and a physiological model (e.g., cow, dog, human). The outcome of this use could be to raise the pulse pressure in the system to take advantage of physiological pathways that respond to this transient change in blood pressure. The novelty of this system stems from the adaptable control architecture designed to augment the pulsatile characteristics of the cardiovascular system. This inventive concept could be expanded to encompass the augmentation (dampen or enhance) of pulsatile characteristics in any oscillating flow system.

A pulsatile blood pump including a chamber having an upstream portion, a downstream portion, and a wall coupling the upstream portion to the downstream portion, the upstream portion defining an inlet sized to fit within a ventricle of a heart, the downstream portion defining an outlet, and the wall defining a bore; a piston disposed within the bore of the wall, the piston including a first side in continuous fluid communication with the ventricle of the heart when the inlet is within the ventricle of the heart and defining a travel path within the bore including an upstream direction toward the inlet and a downstream direction toward the outlet; and a valve coupled to the piston and defining a one-way fluid flow path within the chamber through the first side of the piston in the downstream direction.

A method for priming a hemodialysis treatment includes: providing a disposable cassette including at least a portion of a dialysate circuit and at least a portion of a blood circuit; placing a dialyzer in fluid communication with the dialysate circuit via a to-dialyzer dialysate line and a from-dialyzer dialysate line; placing the dialyzer in fluid communication with the blood circuit via an arterial blood line and a venous blood line; placing a source of dialysis fluid in fluid communication with the dialyzer; priming the dialysate circuit with dialysis fluid from the source while both the to-dialyzer dialysate line and the from-dialyzer dialysate line are connected at their dialyzer ends to the dialyzer; and priming the blood circuit with dialysis fluid from the source by actuating at least one valve provided by the disposable cassette.

A renal failure therapy machine includes a blood cleaning filter, a dialysis fluid circuit including a balance chamber, the balance chamber including a fresh dialysis fluid compartment configured to send fresh dialysis fluid to the blood cleaning filter and a used dialysis fluid compartment configured to receive used dialysis fluid from the blood cleaning filter, a fresh dialysis fluid line in fluid communication with the fresh dialysis fluid compartment of the balance chamber and the blood cleaning filter, and a flow restrictor in fluid communication with the blood cleaning filter, the flow restrictor configured to cause fresh dialysis fluid delivered from the fresh dialysis fluid compartment, through the fresh dialysis fluid line, to the blood cleaning filter to be pressurized so that a first amount of the fresh dialysis fluid performs convective clearance and a second amount of the fresh dialysis fluid performs diffusive clearance.