The residual amounts of detergent that remains on medical instruments after insufficient rinsing not only causes discoloration and corrosion, but it can also have some adverse effects on the human body. In this study, we measured amounts of chemical elements included in the detergent with inductivity coupled plasma (ICP) optical emission spectrometry in addition to the commonly used washer-disinfector (WD) rinsing evaluation method. We also attempted to identify the factors that could influence rinsing. Furthermore, cytotoxicity tests were performed to determine the concentration on how much the detergent was toxic to cells.

As a result of the tests, the method of elemental analysis could detect the detergent component with the highest sensitivity. The number of cleaning devices and the concentration of detergent had the most significant effect on the amount of detergent remaining. The cytotoxicity tests showed that the effluent was no longer toxic to cells after three or more wash cycles.

These findings were implied that the factors that influence the amount of residual detergent in the wastewater were the number of cleaning devices and the concentration of detergent used. Therefore, to perform three or more rinse cycles would be preferable when using a WD.

In this study, we determined the most appropriate method to evaluate the amount of pyrogens, including bacterial endotoxins, remaining on reusable medical devices after washing and sterilization, and investigated an improved sterilization method to reduce the contamination level of pyrogens. Scissors used for surgery were provided from six hospitals after cleaning with a washer disinfector, and then sterilized with an autoclave or low-temperature ozone/hydrogen peroxide (O₃/H₂O₂) mixed gas exposure. The amount of pyrogens remaining on the scissors was evaluated through direct human cell-based pyrogen tests (HCPTs) and Limulus amebocyte lysate (LAL) coagulation assays. A direct HCPT revealed that an average of 0.977-20.7 EU/device of pyrogens remained on the autoclaved scissors, and this amount decreased to 0.177-5.16 EU/device after the sterilization with O₃/H₂O₂ mixed gas. Conversely, with the LAL assay, no endotoxins were detected in two samples and only 0.0107-0.894 EU/device of endotoxins were detected on other sample sets, regardless of the type of sterilization method used. These results suggest that O₃/H₂O₂ mixed gas sterilization is very effective in reducing the contamination level of pyrogens remaining on reusable medical devices and that the HCPT is more accurate than the LAL assay by which false negative or low quantitative results were obtained in the evaluation of residual endotoxins.

The purpose of this study was to investigate important points of improvement in venipuncture support devices, which are used during blood collection, by surveying healthcare workers (HCWs). We investigated the recognition and usefulness of venipuncture support devices such as vein visualization devices and electronic tourniquets in survey responses provided by 300 HCWs registered with a net research company (R Company). Logistic regression analysis was performed to analyze the relationship between device improvement points and the attributes of the HCWs, including gender, the frequency of blood collection, and the number of blood samples collected per day. As a result, of the total HCWs, 74% were familiar with vein visualization devices, and 25% considered them potentially necessary. About 31% of HCWs knew about electronic tourniquets, and 8.3% considered them useful. Logistic regression analysis showed that participants wanted improvements in both usefulness and price, and price was reported as a higher priority than performance. For both devices, the more frequently the HCW performed blood collection as part of their job, the higher was their demand for performance improvement. Additionally, men were more likely to desire improvement in the price and performance of the electronic tourniquet.

The purpose of this study was to construct a data model that can contain data related to ventilator operation, maintenance, and inspection required by clinical engineers by utilizing a reference information model (RIM) that integrates multiple domains.

The ventilator data model in this study abstracted the structure of the database and supplemented the dynamic viewpoint by RIM.

In order to construct a data model for a ventilator in an intensive care unit, based on the entity-role-act model, the positioning of medical equipment in the hospital and the range of ventilators performed by clinical engineers were defined. This data model consisted of a ventilator ledger as the main ledger and a database that could collect data related to the operation, maintenance, and inspection of a ventilator by a related medical device management ledger, patient ledger, and usage ledger.

This study shows that the structure of RIM, an information model in the medical field, can be expressed by the entity-role-act model for a data model that can collect the safety data of ventilators in the intensive care unit.