We have introduced a personal computer and developed software in order to improve safety of high-speed atherectomy and perform effective treatment with it. The system is configured so that it can detect the rotation signal from the record output terminal of RC 500 Rotablator Console (Boston Scientific Corporation, a treatment device), and display charts on a screen of a personal computer. Principal function is to notify a doctor in attendance with two different audible alarms if the rotational speed drops by 5,000 rpm or more and 10,000 rpm or more from the maximum rotational speed respectively. In addition to that, ablation time, maximum rotational speed, maximum rotational drop speed, maximum rotational speed reduced by the ablating rotational speed in progress (integral) are displayed for each ablation. By the clinical application of this software, it became easier to understand the position and the hardness of the arterial sclerosis in the coronary artery and the software has contributed to the increase of safety in ablation technique and effective treatment.

View full abstract

The medical service systems at disasters have been thoroughly reexamined since the Hanshin Awaji Earthquake Disaster. The number of helicopters boarded by physicians has been increased and used for transportation of patients requiring urgent medical treatments. Since a helicopter usually flies at the altitude of 1,000-2,000 m above the sea level, respirators installed on it are required to have correcting function for the altitude. In the present study, the correcting function for the altitude was tested on 12 types of respirators provided by 11 makers in an artificial chamber. The tidal volume and respiratory frequency in each respirator were adjusted to 500ml and 15/min at 610m, respectively. The tidal volume was measured at 610m, 2,000m, and 3,000m to cover the altitudes where transportation by helicopters is frequently performed in Japan. The altitudes were attained at the three speeds; 150m/min, 300m/min, and 450m/min. Alveolar carbon dioxide (P_ACO_2) and oxygen pressures (P_AO_2) were estimated from the alveolar ventilation equation and the alveolar gas equation assuming the dead space; 150ml, VO_2; 250ml, and VCO_2; 200ml. The results were as follows. 1) Ten of 12 respirators were equipped with correcting function for altitude; the tidal volume increased with increasing altitude. In three respirators with the highest correcting function, tidal volume increased from the baseline of 500±53ml to 617±52ml at 2,000m, and 685±52ml at 3,000m on averages for three respirators. 2) The reduction in P_AO_2 with increasing altitude was attenuated in respirators with correction compared with that in those with no correction. In three respirators with the highest correcting function, P_AO_2 was 98±3mmHg at 610m, 86±2mmHg at 2,000m, and 75±5mmHg at 3,000m on average for three respirators. 3) P_ACO_2 decreased with increasing altitude in respirators with correction while that in those with no correction remained constant. In three respirators with the highest correcting function, P_ACO_2 was 34±3mmHg at 610m, decreased to 25±2mmHg at 2,000m, and 22±2mmHg at 3,000m, on averages for three respirators. These results suggest that since correction for increasing altitude was achieved by increasing tidal volume, which results in respiratory alkalosis due to increased expiration rate of CO_2. This is the reason that respirators are used below the altitude of 2,000m. It is necessary to develop a new respirator to maintain P_AO_2 at increased altitude without reduction in P_ACO_2.

View full abstract

The purpose of this paper is to propose setting guidance levels on entrance surface dose for radiographic examinations on children in Japan. This proposal is based on the results of surveys conducted broadly on Japanese institutes. Each value of the entrance doses (the 1st quartile, median, the 3rd quartile, and mean) was calculated with the Numerical Dose Determination method (NDD). The difference between the values of the 1st quartile and the 3rd quartile for each part of all 7 subject parts of examination ranges from 2.7 times to 3.7 times among institutions. In some institutions, the values of the 3rd quartile appeared over ten times as many as the 1st quartile. We propose the guidance levels on entrance surface doses for the children's radiographic examinations to be the value of the 3rd quartile, which was calculated from the result of the surveys.

View full abstract

Semiconductor membrane which was contained textile goods was studied for efficacy of pain control clinically and basically. Twenty chronic low back pain patients were enrolled the study to evaluate the degree of relief of pain in pain clinic. Characteristic of materials of semiconductor membrane was studied by X-ray analysis method, electron spin spectrum method and electron spectrum oxidized-deoxidized potential measuring method. Clinical result was effective for twenty chronic low back pain patients. Basic result was that we recognized a contact electric potential difference and signal reverted to superoxide by respective method. We concluded that effect of relief of pain due to semiconductor membrane might be resulted in improved blood flow by suitable stimulation to living person.

View full abstract

The pressure in endotracheal tube cuff increases during general anesthesia with nitrous oxide. High cuff pressures can be responsible for local ischemia of the tracheal mucosa, which may induce mucosal injury. In this study, we developed a prototype device to adjust cuff pressure, which can release the excessive gas mixture from the cuff through the bundled hollow silicone fibers into either atmosphere or a connected reservoir. When the device with or without the reservoir was used, diffusion rate of the gas through cuff membrane increased from 0.285 to 0.357 and 0.322ml/cmH 20/h, resulting in achievement of minimal increase in cuff pressure at incremental rate of 30% for 13 hours and 20% for 4 hours, respectively, as compared with 150% after 5 hours with the endotracheal tube alone. This novel device, with or without connection to the reservoir, would be useful in attaining the optimal cuff pressure for required hours for general anesthesia with nitrous oxide to avoid tracheal mucosal injury.

View full abstract

We have demonstrated in previous paper that waterjet flow enabled mucosal incision of the stomach and esophagus and submucosal saline injection and it could be used for endoscopic treatment. We developed the catheter with special nozzle and injection syringe for endoscopic use. The caliber of the nozzle decreases so gradually that any whirl of the flow is hardly produced. Therefore pressure loss can be regarded to yield by mainly fluid frictional resistance. The pressure loss of nozzle was 4.9×10^5 Pa and that of catheter with the full length of two meter was 7.5×10^5 Pa. We developed a polyethersulfon syringe with much lower compliance than polypropirene for Auto injector 120 R (Nemoto Kyorindo Co., Ltd.) which was used was waterjet generator. We measured actual jet pressure at the nozzle tip, and we found it was over 3 Mpa and enough to cut the muscularis mucosae. We think that these devices make it possible to apply weterjet technology to endoscopic therapy.

View full abstract