GB885674A - Improvements in or relating to mechanical hearts - Google Patents

Abstract

885,674. Artificial hearts. INTERSCIENCE RESEARCH CORPORATION. July 20, 1959, No. 24855/59. Class 81 (2). [Also in Group XXVIII] An artificial heart for permanent installation in the chest cavity of a human or animal, comprises a casing, a pump within the casing, valved tubes extending through the casing for connection to natural blood vessels and driving mechanism in the easing to actuate the pump, a power supply cable and the tubes being sealed to the casing at their point of entry. As shown, Figs 1 and 2, a box 3 fastened to the thigh contains batteries, a current converter such as a vibrator and a manual speed control 8, and a cable 5 connects the batteries with an electric motor, preferably an induction motor 7, a bushing 12 of nylon or the like sealing the cable to the casing 2. The control 8 may be so set that the motor 7 cannot be turned off. The motor is mounted on a platform 13 to the bottom of which is secured, e.g. by vulcanization, one side of a diaphragm 21 of plastic material such as polyethylene. The opposite side of the diaphragm is secured to a movable platform 20 whilst a second diaphragm 29 has one side secured to the underside of the platform 20 and the opposite side to the bottom of the casing 2. The chambers 22, 34 formed by the diaphragms are alternately enlarged and decreased by the raising and lowering of the platform 20 by means of rods 19 attached to bars 18 each of which carries a flattened loop 17 in which engages a crank 16 on each end of the motor shaft 15. Tubes 25 and 26 for connection to the superior and inferior vena cava and the pulmonary artery respectively are integral with the diaphragm 21 and comprise valves at thickened points 27, 28. Tubes 30, 31 with similar valves 32, 33 connect the chamber 29 with the aorta and the pulmonary vein respectively. Mechanism for actuating valves 27 and 32 comprises a cam wheel 35 fixed to the shaft 15 and having a cam follower 37 which through links 38, 40 reciprocates an actuating bar 42 and through rods 43 (one only shown) a second actuating bar 45. Mechanism on the opposite side of the casing is similar but out of phase with that above described so that valves 27 and 32 are open whilst valves 28, 33 are closed and vice versa. Rotation of the shaft 15 through 10 degrees lowers the platform 20 compressing the diaphragm 29 and opens the valves 27 and 32 which remain open during rotation through the next 170 degrees; rotation through a further 10 degrees raises the platform 20, compressing the diaphragm 21, closes the valves 27 and 32 and opens the valves 28, 33 which remain open during rotation through the final 170 degrees. In another embodiment, Fig. 5, in which blood can flow simultaneously to and from both the lungs and the body, the heart comprises chambers 60, 66, 71, 77 compressed and expanded by the action of rods 19a on platforms 52, 54, and valves 57, 63, 69, 74 actuated by bars 78, 80, 81, 82 to remain open whilst valves 59, 65, connecting chambers 60 with 77 and 66 with 71 respectively, actuated by bars 85, 87, remain closed and vice versa. The driving mechanism for the rods 19a and valve-actuating bars is similar to that of the first embodiment. In operation, during the first phase, the valves 59, 65 are closed and the chambers 66, 67 compressed, causing blood to be expelled through tubes 62, 73 to the aorta and pulmonary artery respectively whilst blood is returned from the pulmonary vein through a tube 68 to the chamber 71 and from the superior and inferior vena cava to the chamber 60. In the second phase the valves 57, 63, 69, 74 are closed, the valves 59, 65 are opened and the chambers 60 and 71 compressed, blood being forced therefrom through tubes 76 and 70 respectively into chambers 77 and 66. In both embodiments, the interior of the casing is fitted with lubricating fluid such as light oil in pressure equilibrium with the body fluid of the human or animal.