Abstract: An apparatus for perfusing the heart of a patient with oxygenated blood detects the blood pressure at the point of supply, usually the aortic root or a coronary blood vessel, and transmits this pressure to a pressure switch which controls a solenoid valve for recycling blood driven by a roller pump to the oxygenator, or, selectively, through a surge tank and to the point of supply within the patient's vascular system. The surge tank has an air cushion therein for holding essentially constant the pressure at which the blood is supplied to the patient, and, thus, for holding constant the pressure at the point of supply.The system is fail-safe since the pressure switch can be connected to the solenoid so that blood is pumped to the surge tank and thence to the patient in the event of the failure of an electrical connection to the solenoid valve.

Abstract: A bag for the separation of components in blood by gravitational settlement or centrifugation, has an upper chamber and a lower chamber connected by a slender neck, there being access conduits to each of said chambers and said neck. The bag is so dimensioned that for blood having a normal hematocrit the interfaces between packed red cells and the buffy coat and between the buffy coat and the plasma will lie within the neck. The neck can then be clamped off or otherwise sealed to separate the phases sharply and to permit virtually 100% recovery of the plasma and the packed red cells. In a second embodiment, the buffy coat can be isolated and seals within the system opened to permit intermixing of the plasma and the packed red blood cells under completely sterile conditions. A special support makes it possible for the blood bag to be subjected without distortion to centrifugation.

Abstract: An apparatus provides for continuous filtration of a mother liquor and continuous removal of solids from the filter element so that the apparatus need not be shut down for cleaning or replacement of the filter element. The solids are separated from the mother liquor as a concentrated suspension and the apparatus can be replicated in stages using successively finer filters so that a filtrate free of particles above any specified particle size can be obtained.