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H Fukumasu

Publications and source records attributed to H Fukumasu.

48 records · Page 3Linked to original sources
PubMed1977

Implantation of the total artificial heart by lateral thoracotomy.

Progress in the techniques for surgical implantation of the artificial heart has progressed in parallel with the technology and design of the prosthesis. In the author's first experience with total artificial heart (TAH) implantation (1968) a trans-sternal split was used opening the sixth intercostal space on the right side across the sternum to the left space. This obviously was not the optimum approach but the complexity, design and size of the prosthesis required maximum exposure of the atria and great vessels. Subsequently the mid-sternal split incision was used. The Dacron fibril coated silicone rubber 8 cm Kwan-Gett ventricles implanted by the mid-sternal split sustained a calf for 14 days in 1972. A calf with the improved Jarvik 3 ventricles fabricated with the same material and implanted via mid-sternal split survived 19 days in early 1973. The surgical techniques for lateral (right) thoracotomy were adopted in this laboratory in 1973. These techniques were applicable only when the prosthesis fit better in the chest. This procedure has been adopted by other laboratories replacing the natural heart of the calf with a TAH. This report describes in detail the stepwise procedure for implantation of the total artificial heart by a lateral thoracotomy in the calf.

Animals↗
PubMed1976

Transapical left ventricular bypass (TALVB) without an auxiliary ventricle.

A simple transapical left ventricular bypass system employing a roller pump, transapical LV withdrawal catheter, and outflow filter for continuous blood filtration, has been developed and evaluated in unanesthetized sheep for periods beyond 2 wks. The system provides continuous partial LV bypass and is capable of totally maintaining the circulation in the presence of a vasodilator or when total bypass is desired. Blood damage is minimal and blood transfusions have not been required. The transapical withdrawal catheter has been left in the LV apex beyond 4 mos and demonstrates thrombus formation and myocardial histological changes which suggest this catheter should be removed after pumping or long-term anticoagulation provided.

Animals↗
PubMed1976

Saving the aortic and pulmonary artery valves with total heart replacement.

The natural aortic and pulmonary artery valves can be saved with excision of the ventricles and inflow valves. These valves remain functional and unaltered with implantation of an artificial heart, when pumped for 96 and 122 days. The capacity of the artificial heart to meet the physiological needs of the animal, during exercise and body growth, over 3 and 4 mos has been documented. All of the parameters monitored in 2 experiments for 3 mos (and continuing) and 4 mos clearly demonstrates the efficacy of meeting the cardiac needs with an artificial heart.

Animals↗
PubMedDate not supplied

Lack of CNS depression from large doses of trimethaphan in sheep.

It is not uncommon to observe prolonged CNS depression for several hours following controlled hypotension and halothane anesthesia for neurosurgery. The present study evaluates possible contribution of large doses of trimethaphan to CNS depression. Four adult sheep were placed on transapical left ventricular bypass (TALVB) withdrawing blood from the apex of the left ventricle through a roller pump, Pall Ultipor filter, and returning the blood to a carotid artery. In the awake and unanesthetized animals, 1 to 2 gm of trimethaphan were administered IV during each experiment while maintaining mean arterial pressure at 60 to 75 torr. Two sheep stood up and knelt down without obvious correlation with dose of trimethaphan administered at the time; two remained standing and continued eating during the trimethaphan infusion. Cardiovascular recovery from these large doses of trimethaphan was within 15 to 30 minutes after the conclusion of drug infusion. The data strongly suggest that large doses of trimethaphan have no significant CNS depression in the awake and unanesthetized sheep.

Animals↗
PubMedDate not supplied

The role of cardiac valves in artificial heart performance.

The criteria for the design, selection of materials, and fabrication of a total artificial heart have evolved over several years. As these criteria have become more sophisticated and exact, they have optimized the performance of all components within the system. A pump with sufficient volume and pressure output that fits in the available anatomic space was a primary objective. Concomitantly, a nonthrombogenic, durable material that was nondegradable in body fluids was being developed. The most easily managed energy source selected to date has been pulsed, compressed air programmed for gentle but effective systole and diastole. The evolution of good cardiac valves has been of major importance to the artificial heart effort. The historical development of the artificial heart has often centered around existing prosthetic valves which are currently an integral component of the complete system. A detailed analysis of the performance of the total artificial heart clearly identifies the role of the cardiac valve.

Animals↗