心臓ペーシング(電気刺激)は単に徐拍に対してだけではなく, 各種の頻拍に対しても用いられるようになり, それが単に治療に効果があるだけでなく, 頻拍のメカニズムを明らかにするという副産物を生んでいる.
re-entryメカニズムによる発作性上室性頻拍を, 1または2個の単一パルスあるいは高周波(100/secの頻数のパルスburstを50～250msec間)心房刺激や, A-V delay 30 msecの特殊な心房同期型ペースメー力による心室刺激で治療することが行われたが, 全例とまでいかなくても, 67～93%の場合に頻拍発作の停止をみることができ, 薬物抵抗性の頻拍症の治療の一つの大きな武器となることが期待される.
またこれらはWPW症候群のみならず, あるタイプの心室性頻拍に対しても有効である.
このようなペースメーカを植込み型とし, 臨床症例に植込んで経過を観察しているが, 植込み手術直後に頻拍発作をみた1, 2があっただけで, 頻拍抑制効果があることを認めている.
著者のこの講演に対し, 岩喬氏が討論を行ったので, あわせてここに掲載し, 読者諸氏の参考に供したい.

抄録全体を表示

Gas transfer performance of Landé-Edwards membrane oxygenator was evaluated using a testing and evaluation method which was developed in our laboratory and which was reproducible at different times and in different laboratories. Gas transfer characteristics and practical operation index were summarized as follows.
1. Both oxygen and carbon dioxide transfer rate were decreased as blood flow rate increased.
2. Both oxygen and carbon dioxide transfer rate were increased as oxygen blood flow ratio increased. The former was not increased markedly when oxygen blood flow ratio exceeded over 3.0. The latter was increased linearly until oxygen blood flow ratio increased up to 4.0.
3. As the practical operation index, optimum membrane index was 0.5L/min/M² and control index was between 2.5 and 3.5.

抄録全体を表示

Acute renal failure frequentry ocurres after prolonged extracorporeal circuration or low flow perfusion. Under moderate hypothermic cardiopulmonary bypass, renal blood flow and glomerular filtration rate are decareased, and all of the glomerular filtrate is reabsorbed in tublues. It is possible that the process of tubular necrosis is developed by the influence of the decrease of urinary flow through tubules. We think that maintenance of urinary flow protects the tubules from degeneration and necrosis, The reabsorption of glomerular filtrate in tubules is inhibited by profound hypothermia which inhibits the enzymic activities at renal tubules. When prolonged extracorporeal circnlation will be unavoidable, urinary flow must be maintained by profound hypothermia about 25°C on rectal temperature, purfusing blood volume of 50-60ml/min/kg of body weight, 2.0-2.21/min/m2 of body surface area.

抄録全体を表示

Since 1967, an artificial heart valve, named “Triflaps valve” has been tested. This valve prosthesis has three curved flaps and opens like a fan up to 70 degrees so that be able to maintain the central flow with a minimal turbulent.
In the experiment, this prosthesis was inserted into vena cava purposely to observe thromboformation on it. Five hours after the implantation of this prosthesis in vena cava, very thin thrombomembranous layer was spread over the surface of the flap, however that was implanted into descending aorta was not showed any thrombomembranous layer on the surface of the flap except around the joint.
Secondary, replacement in canine heart with this prosthesis was done to study hemodynamics experimentally. The valve prosthesis showed well competence.
Following repeated experiments, a female patient suffering from mitral stenoinsufficiency with chronic nephritis was replaced with this prosthetic valve for the first time.
This patient was unfortunately died of cardiopulmonary failure caused by uremia two days postoperatively. However, this “Triflaps valve” gave to us a big expectation of clinical use.

抄録全体を表示

A rechargeable cardiac pacemaker powered by a specially designed nickle cadmium power cell has been clinically used. The bipolar coaxial pacing catheter connects to the pulse generator with a twist-lock mechanism obviating the need for tools or ties. The small size of the pulse generator makes its implantation easier than conventional units. Recharging is performed by the patient at home for 94 minutes weekly.
Five units we have implanted are functioning and recharging according to specifications.

抄録全体を表示

Experimental studies and clinical applications of a new respirator (Electronically Controlled Respirator, E. C. R.) for new borns and infants were reported.
Using Ayre's T-tube methode, respiration was controlled by a solenoid valve, which was regulated by an electronic controller. Respiratory pattern showed slow elevation of intratracheal pressure during inspiration and rapid decrease of intratracheal pressure during expiration. Fine control of ventilating volume, time ratio of inspiration and expiration and FI O₂ were easily obtained. Assisted respiration and intermittent mandatory ventilation were also easily obtained using electromagnetic sensors applied on the chest or abdominal wall with minimal delay. Continuous monitoring of respiratory pattern and intratracheal pressure were obtained.
Clinical applications of E. C. R. was done since April 1970, mainely for the postoperative care of the patients with congenital heart disease who were less than twelve months of age and associated with severe resoiratory distress syndrome. Characters of E. C. R. stated above showed many advantages in respiratory care of severely ill newborns and infants and weaning from respirator was easier comparing to other respirators.

抄録全体を表示

This paper is a report of an utilization of artificial kidney for multi-purposes.
1. trial as a membrane oxygenetor:
Hollow Fiber Artificial Kidney (HFAK), and Disporsable Rhone-Poulene-Dialyser were used as a membrane oxygenator. Its efficiencies were tested by experimental studies. Clinical studies were also performed with series connection of three artificial kidney, one for extra-corporeal ultrafiltration method (SCUM), one for dialysis and one for exygenetor. Both experimental and clinical studies showed excellent results. Poor risk patient was successfully treated with utilization of artificial kidney for multipurposes. Extracorporeal circulation from vena cava to aorta, by use of membrane oxygenator with ECUM, is highly recommended for dialysis treatment of poor risk patient.
2. trial as a removal of cirrhotic ascitis by modified ultrafiltration using a HFAK: HFAK were used to control cirrhotic ascitis in 7 patients. HFAK was placed in vertical position and no dialysate was circulated. The inlet of the dialysis compartment was sealed by a rubber cap, and the outlet was connected to suction via a bottle. Four out of 7 patients were discharged from hospital with good clinical condition. Utilization of artificial kidney for multipurpose is highly recommended for treatment of cirrhotic ascitis patient.

抄録全体を表示

Copolymer of some α-amino acids show promise as a new class of materials suitable not only for the fabrication of implantable prostheses but also for the simulater of the collagenlike biomaterials constructed in the vein, pericardium, peritoneum and so on. The glutamic acid ester-leucine copolymer system is an example where the mechanical properties can be varied over a wide range. The relative thromboresistancy of the cast films prepared from the ratios of the benzyl or methyl ester of glutamic acids with leucine, listed below, was measured with a modified kinetic clotting protocal developed for this purpose. The result show that copolymers with high ratios of the γ-benzyl glutamate have a thromboresistancy superior to Silatic (MDX-4514 Dow Corning). As the ratio of the γ-benzyl glutamate decreased or replaced by γ-methyl glutamate, the thromboresistancy decreased and copolymers of D and E lie between that of glass and silastic.
A) Poly-γ-Benzyl-L-Glutamate.
B) Copoly (γ-Benzyl-L-Glu, L-Leu. 50: 50).
C) Coopoly (γ-Benzyl-L-Glu, L-Leu. 17: 83).
D) Copoly (γ-Methyl-L-Glu, L-Leu. 46: 54).
E) Copoly(γ-Benzyl-L-Glu, γ-Methyl-D-Glu. 19: 81).

抄録全体を表示