著者
尾家 重治 河合 伸也
出版者
一般社団法人日本医療機器学会
雑誌
医療機器学 (ISSN:18824978)
巻号頁・発行日
vol.92, no.1, pp.14-18, 2022 (Released:2022-04-05)
参考文献数
16

The fabric structures of re-usable (cotton, polyurethane, polyester 95% with polyurethane 5%, polyester 95% with spandex 5%) face masks compared to disposable non-woven masks were observed under scanning electron microscopy. We found re-usable face masks in general have homogeneous pore sizes of approximately 0.1 - 0.5 mm. In comparison, non-woven masks have two fiber layers separated by one densely non-woven labyrinthine layer with disordered three dimensional microfibers. We found most (7 out of 8) non-woven masks shared this similar dense second layer composition. Our observation for masks under the electron microscopy provides structural evidence underlying infection-preventing superiority of non-woven over re-usable (cotton, polyurethane, polyester 95% with polyurethane 5%, polyester 95% with spandex 5%) face masks. Furthermore, we found that non-woven masks do not always have the disordered dense middle layer, which suggests that some products of non-woven masks may not provide equal protection for infection.
著者
東條 圭一 藤井 正実 木下 春奈 武田 章数 宮地 鑑
出版者
一般社団法人日本医療機器学会
雑誌
医療機器学 (ISSN:18824978)
巻号頁・発行日
vol.88, no.5, pp.549-557, 2018 (Released:2018-11-19)
参考文献数
15

The utility rate medical equipment is an essential parameter for deciding the number of clinical units required for central control. But some articles in the past have defined optimum utility rates as 70%, give or take, obviously lower than actual figures from the clinical sites. Therefore, those figures failed to represent the reality of clinical fields well known for shortages of medical equipment. The discrepancies are caused by an underestimated influence of low utility rates of medical equipment in off-season.This time, the authors have discovered that it is possible to quantify the shortages of equipment correctly by calculating hourly utility rates. In addition, the authors have succeeded in establishing the hourly utility rate as a parameter for deciding the optimum number of units with an observation of the way the hourly utility rates may shift over the passage of time.The authors hope that a new kind of medical equipment control software will become available sometime in the future so that the utility rate is displayed on an hourly basis in the form of a graph.
著者
玉澤 かほる 玉澤 佳純 島内 英俊
出版者
一般社団法人日本医療機器学会
雑誌
医療機器学 (ISSN:18824978)
巻号頁・発行日
vol.84, no.5, pp.537-542, 2014 (Released:2015-01-23)
参考文献数
19
被引用文献数
3

The purpose of this study is to assess airborne contamination of the dental operating room (DOR) in order to evaluate the risk of infection for the patients and dental staff. To examine DOR, a total of 744 air samples (0.01 Cubic Feet) collected in the particle counter hourly in 24 times a day for 31 days was used. Further, we investigated the change in the particle during tooth preparation (TP) with a highspeed hand-piece when using or not suction device. The results were as follows: 1) In almost all time from 9:00 to 17:00, the number of 1.0μm, 2.0μm and 5.0μm particles in the treatment days (20 days), were significantly (Welch’s t-test, p<0.05) greater than the closing office day (11 days). 2) The particle of 0.3μm, 0.5μm, 1.0μm, 2.0μm and 5.0μm during TP as compared to before TP, increased by 7.5 times, 50.0 times, 158.9 times, 144.6 times and 47.7 times, respectively. When using the intra-oral suction(IOS), these particles were remarkably reduced. When using the IOS and the extra-oral suction (EOS), 2.0μm and 5.0μm particles were further reduced to the level before TP, and were significantly (paired t-test, p<0.05) reduced compared to IOS alone.
著者
秋元 郁美 中野 順子 鴨志田 麻実子
出版者
一般社団法人日本医療機器学会
雑誌
医療機器学 (ISSN:18824978)
巻号頁・発行日
vol.84, no.3, pp.349-353, 2014 (Released:2014-07-24)
参考文献数
10

Heat and moisture exchanger filters (HMEFs) are commonly used in mechanical ventilation practices. We described the performances of HMEF in extreme conditions which may decrease expected moisture returns from HMEF. The experiments with dry gases were performed on the model lung-ventilator system. The test lung with soaked cotton inside was placed in the incubator where temperature was maintained at 37 °C. Relative (RH) and absolute humidity and temperature of the circuit was measured electronically (Maphy+, S.K.I. Net, Inc.). The results showed, firstly, RH went down below 90% when minute volume exceeded 12L/min. Secondary, air leak of 20% of the inspiration volume decreased RH below 90% when inspired minute volume exceeded 8L/min. Thirdly, addition of unheated cascade humidifier kept RH of the circuit at 100% in both of the above conditions throughout the minute volume of up to 20L/min by providing additional humidity of between 6 and 12 mg/L. We also reported additional effects of the atmospheric humidity as turbine ventilator inspired room air instead of dry gasses. Water content of HMEF increased approximately 8grams in seasons of high humidity whereas, that with dry gases was constantly 1.5±0.3grams(n=39). HMEF with water content of 8grams increased the inspiratory airway resistance by 33%.
著者
笹嶋 一大
出版者
一般社団法人日本医療機器学会
雑誌
医療機器学 (ISSN:18824978)
巻号頁・発行日
vol.88, no.5, pp.560-567, 2018 (Released:2018-11-19)
参考文献数
1
著者
山元 恵子 佐藤 博信
出版者
一般社団法人日本医療機器学会
雑誌
医療機器学 (ISSN:18824978)
巻号頁・発行日
vol.86, no.5, pp.459-466, 2016 (Released:2016-11-11)
参考文献数
21

It is recommended to verify the dwelling position of nasal feeding tube in the stomach by sampling gastric fluids, however, it is practically difficult to apply. We inserted a nasal feeding tube in 15 subjects, and then attempted to sample gastric fluids and confirmed the position of the tip by a X-ray examination. Measuring lengths of the tube segmented by body-landmarks (e.g., nose, gastric cardia), we verified the correlations between the body-height and the appropriate tube length to be inserted. The average ratio of the tube length from the nose to the gastric cardia against the body-height of the subjects was 0.29±0.01. The average tube length in the stomach was 103.5±9.9 mm, which was not correlated to the subjects′ body-heights. As the results, a simplified formula “Body-height (cm) × 0.3 + 10 cm” can be suggested to estimate the adequate insertion length of the tube which can sample gastric fluids. Further, to easily visualize the dwelling length of the tube in the stomach by a x-ray examination, our results might recommend non-opaque marks with 1-cm increments between the tip and 10 cm-length.
著者
石田 開 鈴木 啓太 花田 英輔 廣瀬 稔
出版者
一般社団法人日本医療機器学会
雑誌
医療機器学 (ISSN:18824978)
巻号頁・発行日
vol.87, no.3, pp.324-331, 2017 (Released:2017-08-02)
参考文献数
14

Light Emitting Diode (LED) lamps have become widespread in the clinical settings. However, electromagnetic noise from LED lamps could be problematic. In hospitals, the reception level of signals from medical telemeters might decrease after replacing traditional lighting with LED lamps. To investigate the effects of noise radiated from LED lamps on medical telemeters, we measured the electric field intensity of 34 types of LED lamps. Many of them emit 400 MHz band noise, and some types of LED lamps had increased floor level noise of 30 dB. We also observed artifact noises on electrocardiogram and respiratory waveforms when an LED lamp was placed next to the patient monitor. This effect was observed only when a medical telemeterʼs transmitter and a LED lamp were placed quite close. When approximately 50 cm apart, patient monitorsʼ signals were received normally. In hospitals, AC power supply cables and lamps are often placed near transmission cables, including leaky coaxial cables (LCX), as antenna of the patient monitors. To prevent interference with medical telemeters, selecting low noise LED lamps and maintaining sufficient separation between LED lamps and receiving antennas or LCX is necessary.