Hemodynamic changes in 8 patients after long-term cardiac pacing were discussed. The rate-output curve of these patients showed a tendency toward a flat tracing after long-term pacing. The pulse rate at maximal cardiac output decreased from 70 to 65 in two patients, and from 70 to 60 in one after long-term pacing. The stroke index of these patients decreased to an average of 42.7% after long-term pacing. These facts may indicate an increase of reserve cardiac performance. At the maximal output pulse rate, right atrial mean pressure never reached a higher value, and left ventricular work had a higher value both before and after long-term pacing.
A total hip prosthesis is required to satisfy three prerequisites: 1. Absence of reaction to bone and tissue, 2. Adequate connection with and fixation to the bone, 3. Supportability and durability similar to that of bone. In order to investigate each of these essential attributes of total hip prosthesis, authors conducted experimental studies. The latest type of total hip system in our clinic was manufactured after experimental studies which confirmed that the so-called three five-storied pagoda-shaped spikes attached to the artificial acetabulum were more effective than bone cement in achieving fixation between bone and prosthesis. Clinical results at two years after surgery were far more gratifying with this type than with any others. It has been about twenty years since total knee prostheses were used in our clinic and various types and materials have been used in the course of their development. Now we use the Jikei total knee prosthesis of so-called universal type with low-friction system as the latest type. In this system a block of HDP may replace the defect after resection of the tumor in the proximal end of tibia or distal end of femur. Follow-up study after surgery shows good results.
The circuit, the venous blood is drawn from the patients venous system into the membrane oxygenator by gravity dranage without recirculation, is quite simple. However, from the standpoint of oxygenation this method demonstrated a progressive deterioration of the performance.
It has become necessary to develop a new filtering type of artificial kidney for the development of an artificial kidney which is portable or capable of placing internally. As a result of study of a filtering membrane isolating plasma from blood, an expanded polytetrafluoroethylene (EPTFE) membrane treated with alcohol is found excellent for blood filtering membrane at present. The EPTFE membrane (thickness 11.5 micron, pore size 0.7 micron) used for the experiment is excellent in antithrombogenicity and in mechanical strength, and is also good for the use of blood filtration. Antithrombogenicity improves at the surface with negative electrical charge—the electret state. However, an EPTFE membrane treated with alcohol, in order to pass water, almost loses the above-mentioned effect.
Intracapillary clotting tendency is a disadvantage in capillary type artificial kidney, not only because of possible deterioration of dialysis performance, but also because of resultant augmentation of residual blood volume. In vitro examination of blood flow distribution performed in Cordis Dow HFAK Model 4 shows that blood flow rate is merely 1/4 to 1/5 less in a central portion of a capillary bundle than peripheral. Concurrently, there is a characteristic tendency that obstruction of capillaries due to clotting occurs more frequently in central capillaries than peripheral capillaries of HFAK clinically used. Considering that thrombus tends to develop in slow velocity on a foreign surface and blood will be more concentrated in central capillaries by ultrafiltration than peripheral capillaries, it is concluded that uneven distribution of blood flow is a acausative factor of “central clotting” of HFAK examined.
The pacemaker twiddler's syndrome, as reported by Bayliss and his associates, was described. Axial rotation of a Devices pulse generator in the subcutaneous pocket was noted 5 weeks after implantation in a 85 year old patient. Axial rotation was diagnosed due to the appearance of twitching of the underlying muscles and confirmed by the unpalpable anodal plate and lateral chest films. The factors to cause this complication were discussed. The coverage of pulse generator with tetoron mesh and fixation to the surrounding tissues in the pocket have prevented further rotation. The shape and design of the Devices pulse generator may be a causative factor to axial rotation in a rather capacious subcutaneous pocket.
Reducing dialysis time is important for the rehabilitation of chronic hemodialysis patients. Increased blood flow and membrane area would be required to shorten dialysis time without sacrificing efficiency or inducing side effects and complications. In recent fundamental experiment, it was confirmed that 3-hr dialysis with the 2.6m2 HFK used in a cuprophane membrane was as efficient as 5-hr dialysis with the 1.1m2 HFK. Our successful one year clinical experience with this system has prompted us to present this report here.
The lithium iodide power source is completely dry, produces no gas, has no significant self-discharge, shows no catastrophic failure, and loses power in a gradual fashion, thus giving months of foreknowledge of impending failure. The calculated in-vitro life of this system is greater than 10 years, while a conservative estimate of in-vivo life is 5 years. Seven lithium pacemakers were implanted in patients with Stokes-Adams syndrome. Only in the early period following the implant, pacing failure in one case and sensing failure in one case were noted in our seven patients. Our cases were followed up with the longest period of nine months with satisfactory functioning according to specifications.
This new type oxygenator has a oxygenating column which is L-letter shape has a vertical and horizontal tube. Venous blood enters the oxygenating column by gravity. Oxygenating column connects to the defoaming chamber which is center of oxygenator. The defoaming chamber has nylon mesh coated silicon and filter and gas exit tubes. Blood reservoir is S-letter shape and connects to the Defoaming chamber and arterial line. Heat exchanger of alminium is piping throughout the oxygenating column, the defoaming chamber and the blood reservoir. Heat exchange efficiency of new type oxygenator is much higher in degree compared with the Brown-Harrison, Travenol heat exchangers or Harvey's oxygenator or Temptrol one.