For the safe use of wireless medical telemeter, it is important to manage electromagnetic wave such as appropriate channel management and antenna placement. However, many hospitals have reported reception problems caused by inappropriate electromagnetic wave management. In our hospital, the cause of the reception failure of wireless medical telemeter that occurred May 2020 was presumed to be a mistake in the leaky coaxial cable. In this study, we measured the electromagnetic waves before and after the re-laying of the leaky coaxial cable to quantitatively evaluate and examine the electromagnetic wave conditions of the wireless medical telemeter. Before re-laying of the leaky coaxial cable, as a result of measuring the electromagnetic wave strength around the booster where the reception failure occurred, the carrier to noise ratio (CNR) was lower than 30 dB recommended by the manufacturer. Therefore, it was found that the electromagnetic wave received by the antenna was not sufficiently amplified by the booster. After re-laying of the leaky coaxial cable and changing the position of the booster, the CNR exceeded 30 dB at all measurement points and the reception problem disappeared.

There is no standard cleanliness evaluation procedure for reusable medical devices, only recommended guidelines. Our aim was to develop an efficient and reproducible method to recover proteins in greater amounts than conventional procedures. In addition to the solvents indicated in the guidelines, sample buffers (SB1 and SB2) containing the detergent sodium dodecyl sulfate (SDS) were tested. Protein recovery was compared using pseudo-blood-contaminated samples heat-treated under dry and wet conditions. Protein recovery from dry-heated samples did not change significantly regardless of extraction conditions, whereas the recovery rate from wet-heated samples using Milli-Q water or 1% SDS decreased proportionately to the increase in temperature. SB1 and SB2 extraction showed excellent protein recovery up to 95°C. In quantifying the protein using bicinchoninic acid (BCA), the interference of tris (2-carboxyethyl) phosphine in SB2, but not dithiothreitol in SB1, was quenched by pretreatment with iodoacetamide (IAM). After cleaning samples wet-heated at 95°C for 10 min with a washer-disinfector, the protein recovery rate per sample was 8.67 ± 3.0 µg using SB2 vs. 6.37 ± 2.5 µg using 1% SDS. These results indicate that residual proteins binding strongly to the surface of medical devices by thermal coagulation can be almost completely recovered and quantified by combining SB2 extraction, pretreatment with IAM, and BCA quantification.